I have to agree, although wood does require more manual labour than everything else where you just flip a switch. That said, I have to admit I was quite surprised to discover that wood pellet stoves also need electricity to work. The worst combination, I thought.
A wood stove does require physical work and frequent tending, but these characteristics provide a salient understanding of energy. When all one must do is turn a dial on the wall or poke a smartphone screen, it is easy to forget how precious and meaningful energy is. Chopping kindling in the frosty morning air or hauling logs from the woodshed teaches a person the value of energy. It's weight. How it must be protected so it is usable when needed. How long-term planning is key to a cozy winter. A wood stove doesn't just provide heat -- it is a teacher whose lessons are about the value of energy.
I quite like this perspective and I agree with it. Also, it provides a good daily exercise opportunity for people with otherwise sedentary lifestyles, not to mention the ashes that can be used as soil fertiliser.
Fireplace. Heat pumps make a lot of noise. My neighborhood installed one at the end of the garden last year and in winter it rumbles like a jet engine.
This type of question does not have a yes or no answer... instead the answer is "it depends."
The heat pump is an excellent technology in its own right. And incidentally the air conditioner and refrigerator are a type of heat pump. Clearly if reliable electricity is not available then you are forced to burn something to keep warm. But to burn wood pellets or trees at scale is absolutely insane and criminal. Keep in mind that it was coal that allowed mankind to move away from burning trees in the first place.
You're absolutely right, heat pumps are impressive, especially with regard to efficiency. But they are not a cheap thing to buy and this is a problem for a lot of people. I didn't mean one or the other as a large-scale heating choice, rather as a personal choice.
When people moved from wood to coal, modern woodstoves did not exist. The newer types of airtight stoves which do a secondary burn of the smoke achieve about 75% efficiency with some hitting the low 80% range. You couldn't tell such a stove was burning by looking at the chimney -- there's zero smoke.
Here is an EPA list of wood stoves sorted by efficiency (I used a link shortener because the link is about a paragraph long otherwise): https://linkshortner.net/HabuU
Dec 16, 2022·edited Dec 16, 2022Liked by Irina Slav
The heat pump needs already electricity to work, the fireplace is independed of it.
The heat pump do not need fuel storage, the fireplace do - and as far as I know, you'll better cut and store the wood two years before using it. And it must be stored in a safe place, in case of emergency and your wood becoming precious in the preying eyes of others.
But of course for Germans the question is purely academical, because in some houses fireplaces will be forbidden 'cause of the bad dust ("Feinstaub") coming out of them and killing so much people.
At least one dies here of winter cold, and not of dust particles, especially if you are old and poor.
Facts: following the Bundesimmisionsschutzgesetz (BImSchV), after 2024 emissions from a fireplace have to follow these norms:
max. 1,25 g of carbon monoxide per m3 of exhaustion
max 0.04 g of fine particles per m3 of exhaustion
min. efficiency factor of 73%
If your house has a fireplace of older type, and you're technically or economically not able to insert the necessary filters or the e.factor is to low, you have to decommission it.
One must say, however, that in the last 20 years a lot of older fireplaces have already been updated (or outlawed and decommissioned). - But this is another example how the German government adds each year new a layer of new rules to make life more difficult and more expensive.
UPDATE: I'm just reading that the Umweltbundesamt (Federal Environment Agency) however asks for a complete stop of fireplaces in new buildings. Because of the fine particles. Also pellet ovens are not longer seen as a good thing.
There is no type of heating that is perfect. Germany will regret this decision to ban fireplaces. I do not know if anyone likes to sit and stare at a heat pump like you can with a fire !
We used a heat pump in the city. Here, in the country, it's wood + a radiator for the bedrooms. I can safely say the fireplace is a lot more reliable than our air-air heat pump. It doesn't care how cold it is outside. As long as I feed it wood, it will heat us.
Heat pumps are great especially when temperature differences are not to large. For my location I am a bit skeptical of them given next Tuesday's high is -26C. They are not common in Alberta, I don't know now a Single person with one.
A fireplace would be great insurance if other forms of heating fail.
Both. Use the heat pump for heating and cooling and the fireplace/wood stove as a backup when there is no electricity. Heat pump technology has improved, new models can maintain heat output down to 0 deg F/ -17 deg C (or lower??). Older heat pumps would not provide much heat output when ambient temperatures were near 32 deg F/ 0 deg C.
A heat pump is much less efficient than an open flame of any kind since it’s compressing refrigerant and using it for heat exchange. Your power consumption is the same as if the unit were running in cool mode, although a lot of systems have a series of resistors in line with the pump. Anytime electricity is being used to generator heat via a resistor, very large amounts of power are used. A resistor is essentially a dead short that generates heat.
So to answer your question, flames are better than electricity for making heat.
Actually no, a heat pump moves heat it does not generate heat. They can actually be 400% or more efficient than resistance heating because of this, at least under good conditions where the temperature gradient is not too great. The problem comes when you are close to the cold limits (usually -15-20C or so) then the efficiency drops like a stone and you need to use resistive heating to supplement the heat pump.
Of course there is the caveat that you have to generate electricity first and that is somewhere between 30 and 55% thermodynamically efficient depending on the system. But even with that, heat pumps are more efficient under most circumstances.
The issue is the lack of backup for the electricity...
It works because the system is not generating the heat, it is only moving it. It is very different than say a resistive heater which is generating the heat directly.
So basically you can move 4kWh of heat “upstream” with 1kWh of thermodynamic work, hence “400% efficiency.” I promise no laws of physics need to be broken 😉
Got it. Thank you. Sounds like something a marketing exec who never heard of the 2nd law dreamed up. I wonder how many people thought "baloney" (or something less polite) and ignored the technology from that point on. Maybe something like "4x times the heat for the same cost of electricity" would have been better marketing.
The use of the term efficiency with regard to heat pumps is not quite correct. The proper metric is called coefficient of performance COP which can be one or greater.
I wasn’t necessarily arguing whether resistance heating or heat pumps are more efficient. I was stating that neither of them are more efficient than using a flame (natty gas, propane, heating oil, etc.) to heat. And yes a heat pump does not generate heat - I mentioned they move heat via refrigerant.
But overall, agree with your comments. Thanks for the feedback!
Both, although our household has a third option, in the guise of a NG-fired forced-air furnace for the downstairs, with electric heat pump upstairs.
We also have a fireplace insert with an electric blower, which can heat our downstairs into the 80 degree F-range on the coldest day our 37.5 degree N latitude brings us.
As Simon said before me, it's good to have a lights-out backup.
Duel-fuel heating unit. The dual fuel system uses the heat pump in hot or mild temperatures (about 40°F and higher) and the furnace in colder temperatures (about 39°F and below). It switches between the two depending on which is more efficient for the circumstances, which saves time and energy in getting your home to the desired temperature. Dual fuel systems are great for any type of climate and function year-round. Plus, because each piece only works when it’s optimal, dual fuel systems have a life expectancy between 20 and 25 years!
Plus, if they use coal to generate the electricity as in Europe, the natgas furnace emits a lot fewer emissions!
If you live in a place with high electricity rates, a heat pump is just brutal., especially if you live somewhere with cold winters. They are simply not efficient.. a great concept though. On the other hand, the cost of fire wood has gone up dramatically due to the woke politicians focus on renewables (the world is going to end) and everyone scrambling for alternatives.. Here in Canada, I will rely on natural gas for my highly efficient (94 %)German boiler(I have radiators) and my nat gas powered Generac standby generator that power the whole house and eliminates any concerns. I do have a wood burning fireplace and a nat gas fireplace, they are essential options, but seriously they cannot heat the house.
I did some research on heat pumps recently, and one producer claimed that for 1 kWh consumed the pump yields 4 kWh of energy, which impressed me. A friend installed one at his house because he claims it's the cheapest option. But you're not the only one saying they are not very efficient and now I'm confused. I've no plans to buy one, I'm just theoretically confused.
Dec 17, 2022·edited Dec 17, 2022Liked by Irina Slav
The performance of a heat pump is a function of the ∆T, in other words the temperature difference between outdoors and indoors. The 4:1 ratio that the manufacturers always quote is the maximum performance you can expect under a specific test condition. In practice as the ∆T increases that ratio degrades until it reaches 1:1 which is no better than electric resistance heating. Therefore air-sourced heat pumps are quite sensitive to very low outside temperatures... Geothermal installations less so. But as many readers commented if you live in chronically frigid parts of the world or where the cost of electricity is exorbitantly high then the heat pump is probably not a good choice. Interestingly the northeast of the United States is full of heat pumps... And this is the last place I would have thought to see the proliferation of this technology. It turns out that natural gas is extremely expensive in this part of the US and not readily available to many residences. Therefore many builders instead of installing the usual oil-fired burners will simply install an air source heat pump.
In a region with high electricity costs such as Ontario, they are expensive to run. As well, the cost to retrofit a home is also very high.
The third issue is that once the outside air temperature drops below 5C, the efficiency starts to decline and when it’s -20c, hopeless. So high cost electricity in region that has winter is not a good recipe for a heat pump. When I google heat pumps, there seems to be a lot of very biased articles from government agencies, manufacturers and installers(lower your heating costs and help save the planet from man-made Climate change). Got it.
Sandro is bang-on.
Have a look at Windy.com and see the arctic air outbreak next week in Western Canada and Central US states. They are looking at -20c to -30C next week. Even the temps in Texas are forecast to be low single digits. I will stay with my Viessmann German-engineered natural gas boiler that has a 94% efficiency rating. When I bought my house 20 years ago, the boiler in-place had a 60% efficiency ratio. So I am doing my part.
This is why I post these threads -- I learn a lot from people with actual knowledge of the topic and no reason to advertise anything. Incidentally, could you send some Arctic wind this way because global warming seems to have localised in my part of the world and I'm not enjoying it.
Heat pumps don't work in cold climates, the air is too cold for an air-source heat pump and a ground source will freeze the soil and stop working. In cold climates the ideal heating source is a CHP generator. Supplying power, heat and hot water. They are far more practical now with the advent of cheaper & better batteries. For a solar off-grid typical home you need about 30kwh of batteries. For a CHP you only need a 1.8kwe generator and 5kwh of batteries. The ideal fuel is Methanol which can be burned in a high efficiency ICE generator or a DMFC fuel cell. In the summer a small solar array will augment the CHP generator, since heating needs are lower.
As another commenter said, it depends. If it is easier to get firewood, gas, pellets, or other fuel than electricity, then fire may be best. If electricity is reliable and cheap, and if the minimum temperature is within the range of operation for the heat pump, then heat pump would be preferable. There are other options in extreme conditions: resistance heaters, kerosene/diesel heaters, etc.
I recently purchased two mini-split heat pumps to run off my solar installation. One is a 38 SEER 9,000 BTU unit that will work down to -22F, and the other is a 12,000 BTU unit that will run off DC or AC voltage. It can run entirely on DC from just 3-4 large solar panels during the day, and switch to AC when solar is unavailable (which will also be supplied by solar via batteries and inverters).
I am also looking at installing a geothermal loop, first in an air-to-air system using a radiator, pump, and fan to maintain near constant temperatures, and eventually an air-to-water heat pump/hydronic system. This is another option for very low temp heat pump installations - if you have the room to install the geothermal ground loop.
Unless you have an insert, fireplaces are grossly inefficient…10% of energy is recovered. I have a fireplace, two heat pumps and a gas pack for three story house. The gas pack (ground floor) is a 16 seer air conditioner with a high efficiency gas furnace. You can’t beat a gas furnace for comfort and gas is cheap in the US..$1.5/therm. For 350 m2 living space my all in energy cost for water heating, cooking, space heating is $1000/y.
Yes. We considered getting one but it turned out we have no good place to put it so it heats the whole house. A neighbour has one and maintains tropical temps at his house during winter. But we are currently using an ancient, I mean, vintage, Russian heater for our bedroom because it heats up quite well and does not consume a lot of electricity. Cold is certainly one thing Russians know a lot about and how to deal with it.
My decision is based on reliability. We experience power cuts which can last several hours up to 2-3 days, so a fireplace (or stove) is the priority for space heating and bottled gas for cooking. The same storms that cur the power also knock down trees so wood is widely available for burning.
A fireplace is barely useful but modern airtight stoves are extremely efficient, especially if you have an outside air connection (the fire burns oxygen and if you draw it from room air you have to let cold air into the house to replace that combustion oxygen -- the better way to feed air to the stove stove is to run some of that aluminum dryer hose under the floor to an inlet vent on the side of the house). Most modern stoves have the ability to accept outside air.
The EPA lists wood stoves and efficiency ratings: https://linkshortner.net/HabuU -- This link sorts by efficiency but you can also sort by any of the data columns (BTUs, particulates, and a bunch of others).
I'm in Western Oregon where the summer and winter temperatures are not extreme, so my primary source of heating and cooling is a heat pump. I have a standby propane-powered generator. We also have a propane fireplace and wood stove. We live on rural property, so there is plenty of wood with which to heat the entire house if needed. Most of Oregon's electric power is hydroelectric, so rates are low.
Wood because we can also cook food in the oven stove and warm water for my kid bath on it, saving A LOT of power and cost while warming the house with said heat.
Also, I can store 2 years of heat in my back yard
When the eurocrats are unable to guarantee enough power in the Baltic States and with war with Russia a risk, the least you want is unreliable heat supply in the North (we just had a period of high wind, snow and -15 celcius)
Also, heat pump stop being efficient when it get really cold. At -10 there is not enough heat in the air to pump, so it conversion rate turn closer to a 1 to 1 instead of the advertised 1 to 4
I have a fireplace and a high efficiency split system HVAC unit. What you are not told is heat pumps are not really efficient in winter when the temps hit freezing. Heat pumps are great when the temps are above freezing. Heat pumps will never put out the heated air like a fireplace or my hvac system. At HUD they installed 150 heat pumps and all they did was freeze up defrost and use their emergency heating strips. But many of you may not have a choice to use natural gas to heat your home.
I saved over 4400.00 a month using high efficiency HVAC units the first month after I had them installed.
It seems opinions on just when heat pumps stop working properly vary greatly -- from -25 to, as you say, zero, which I've heard from others, too. And with heat pumps a rather sizeable investment, experimentation is hardly the best choice. What's more interesting is whether the authorities somewhere will make them obligatory (I think it's being discussed in the UK) and how many people will suffer the consequences if efficiency is indeed so easily compromisable by low temperatures.
Heat pumps are great for climates that do not have long cold winters. I managed HUD projects for 19 years in Arkansas. The government is the first to jump in headfirst into new supposedly cost and energy saving equipment, only to replace it when it is feasible. The most efficient way to heat your home is natural gas. Some will scoff at me but running the numbers it always won. Heat pumps are also limited as to how hot or warm the air is at the vents. Usually, 75 degrees is the most you will get for air, 80 for heat. Many elderly residents complained all the time to the point we had to replace some of the units because of this. When the units froze, they make loud noises while in defrost mode again pissing off my elderly residents. My maintenance guys carried hard rubber mallet to tap the reversing valve in spring to get some of them back in the A/C mode. This is actually minor compared to installing the low flow water heads on faucets and the showers LOL another story.
Great thread. Heat pumps are great and have their place. In my homes I have a separate propane heater that can work with no electricity, generators, and fireplaces. Being in the middle of nowhere we have to plan on outages. In the City (4 hours away) we do not have all of the back up heat or power. We just keep our cars always over 1/2 to 3/4 full to get out of the city. Redundant heating and power have always been important. It has been needed through out the years. And it is wonderful to be able to help people in disasters. Tornadoes are frightening and have been hit 3 times. Plan for the worst so you don't have to worry.
Dear Irina, there's no need to imply an either/or relationship. In fact, HPs and wood-burning stoves are a beautiful combination to heat a house. The thing is, a stove comes much cheaper and provides a wonderful atmosphere, as well as grid-independent heat.
Not used a heat pump but I can't imagine they would be very effective when the ambient temp gets down below 40°F. Wood burners throw out a lot of heat compared to open fires but burn wood quickly at very high temps. Neither options are great compared to natural gas if you worry about CO2 and heating more than just one room. Can't we just go back 20yrs in time?
You can heat a whole house with a fireplace if it has one of those water+heating attachments. Ours warms two rooms, the one it's in and the one above because of the chimney. With wood the biggest problem is waste of heat but still enough remains in the room to warm it so I've made my peace with that waste.
As for going back in time, even five years back would be appreciated.
I heat my entire house with one wood stove -- 2000 sq ft, two floors. It's currently 17.4F outside and 72.8F in the kitchen which is rather far from the stove. I'll stoke it again around 11pm and tomorrow around 8am, it'll still be ~65F in the kitchen and there will be enough burning coals left in the stove to easily get the fire going without using kindling -- just put in new logs. Modern airtight stoves give a minimum 8 hr burn -- some will do a 12 hr burn.
Anthracite (or a good bituminous) in a fireplace is the best backup. No forest is cut down. One ton is a little over a cubic meter and is rather pretty, as well. It is a glossy black, almost crystalline in appearance. It is clean burning and has three times the heat contact of an equivalent mass of wood. The Franklin stove is a reasonably efficient stove and needs no electricity, at least not in the USA.
Burning wood was replaced, except for esthetic purposes, after 1850 in Europe and North America. If wood (biomass) is burned as our energy resource, it means a return to 1850 AND a global population, after terrible freezing and starving, under one billion.
In the case of a heat pump versus an NG furnace, it is slightly more complicated. A heat pump is just a refrigerator running the other way. All that is required is an extra valve. If you have enough yard space to place sufficient in-ground heat exchangers so as not to freeze the ground, the heat pump may give a factor of 3-4 X the heat moved by the NG furnace. The ground is a rather poor heat conductor, meaning the ground surrounding your pipes gets very cold and freezes. A water tank with flowing water would be a lot better, but also more costly.
BUT, that is not the whole story. It never is!
Most electricity is made in a thermal power plant at 33% efficiency, so a factor of 3 just breaks even, compared to a 96% NG furnace. As the ground temperature descends from its usual 10C toward 0C, during cold weather, the heat pump efficiency drops off. The 4X becomes 1X. Air heat exchange heat pumps are worse since the heat exchanger freezes below 0C and no longer works at lower temperatures. Then, auxiliary resistance heaters take over from heat pumps. Some heat pumps have resistance heaters on the elements of the air exchanger to prevent icing up. Naturally, that also reduces and remaining gain of the heat pump, but it does continue to work at least.
The sad result is that heat pumps work best where and when they are least needed.
Heat pumps are in a class with Battery electric cars; they look great as long as you do not look too closely.
Very nice comment...I agree, the devil is in the details.
I live in the New England area of the US and many of the retrofit air-sourced HP installations keep the NG furnace as backup for very cold weather. In any case - the government bureaucrats have no place mandating technology. Thanx for the post.
"Why have the heat pump at all, if it is useless when I really need it?"
In an electric grid serviced by wind turbines and photovoltaics, the grid will be OFF on a weekly basis, for half a day at a time. That is already the experience of countries where wind has partly replaced base power.
It is a most inconvenient way to try to live. Try it, and you will NOT like it.
If you think long-term, a wood burner or fireplace does not scale. A heat pump does, but as has been previously noted, at present, they do not fit within most budgets.
Might I suggest that not enough copies have been made, but that or something superior will come, no doubt?
A future historian might observe, "The utilities had a great run. They were able to supply something that the general public could not afford and a business deal was struck. While it is true that monopolies were awarded far and wide, it is equally true that. as a legal construct, a "monopoly' does not mean 'forever'".
Utilities have known for a decade that their client base can harvest Distributed Energy Resources (like Solar, DER) and produce their own electricity.
Now, years later, a professional standards organization, The eMerge Alliance, whose membership includes well over one hundred companies, is creating an extensive DC standards base.
Developments are happening so rapidly that they are hard to keep up with.
I have to believe that anyone who wants to walk the energy sustainability walk must recognize that introducing new technologies, especially as we try to lift a world whose present technological fluency is low, but may be able to leapfrog our understandings.
That said, since the US kept getting drawn into world wars during the twentieth century, and ended up punctuating our skill with the Atom Bomb. We showed 'em. When it comes to blowing shit up, killing people and generally being good at waging war, we're tough and we've been to the rodeo. OK, check.
Wouldn't it / couldn't it be a helpful adjunct to our foreign and domestic policy if we were to consciously and intentionally dedicate some part of our twenty-first century to-do list to the development of lifestyles, technologies, science, etc. dedicated to help people meet the measure of their creation?
Yes, the well-dressed, well-spoken Gorilla in the Brioni suit, the one surrounded by expensive, likewise-well-dressed lawyers, accountants, actuaries, professors, PR specialists, MBA's and Schpinmeisters, represent the $1.23 Trillion US annual energy business.
Refereeing this will be very interesting but I still believe that people have what it takes to lift each other up in a global renaissance.
I have to agree, although wood does require more manual labour than everything else where you just flip a switch. That said, I have to admit I was quite surprised to discover that wood pellet stoves also need electricity to work. The worst combination, I thought.
A wood stove does require physical work and frequent tending, but these characteristics provide a salient understanding of energy. When all one must do is turn a dial on the wall or poke a smartphone screen, it is easy to forget how precious and meaningful energy is. Chopping kindling in the frosty morning air or hauling logs from the woodshed teaches a person the value of energy. It's weight. How it must be protected so it is usable when needed. How long-term planning is key to a cozy winter. A wood stove doesn't just provide heat -- it is a teacher whose lessons are about the value of energy.
I quite like this perspective and I agree with it. Also, it provides a good daily exercise opportunity for people with otherwise sedentary lifestyles, not to mention the ashes that can be used as soil fertiliser.
Wood heats you three times--when you cut it, when you split it and when you burn it.
Fireplace. Gives you immediate heat and a level of autonomy.
Is it an either/or? I would like both, please
Well, everyone would, I guess. But if you had to choose?
Then it would be heat pump, Irina. Because it heats the whole house. Fire is for backup and general feeling of wellbeing
Fireplace. Heat pumps make a lot of noise. My neighborhood installed one at the end of the garden last year and in winter it rumbles like a jet engine.
Our heat pump used to moan and groan when it got really cold, and sigh deeply while it defrosted.
This type of question does not have a yes or no answer... instead the answer is "it depends."
The heat pump is an excellent technology in its own right. And incidentally the air conditioner and refrigerator are a type of heat pump. Clearly if reliable electricity is not available then you are forced to burn something to keep warm. But to burn wood pellets or trees at scale is absolutely insane and criminal. Keep in mind that it was coal that allowed mankind to move away from burning trees in the first place.
You're absolutely right, heat pumps are impressive, especially with regard to efficiency. But they are not a cheap thing to buy and this is a problem for a lot of people. I didn't mean one or the other as a large-scale heating choice, rather as a personal choice.
When people moved from wood to coal, modern woodstoves did not exist. The newer types of airtight stoves which do a secondary burn of the smoke achieve about 75% efficiency with some hitting the low 80% range. You couldn't tell such a stove was burning by looking at the chimney -- there's zero smoke.
Here is an EPA list of wood stoves sorted by efficiency (I used a link shortener because the link is about a paragraph long otherwise): https://linkshortner.net/HabuU
The heat pump needs already electricity to work, the fireplace is independed of it.
The heat pump do not need fuel storage, the fireplace do - and as far as I know, you'll better cut and store the wood two years before using it. And it must be stored in a safe place, in case of emergency and your wood becoming precious in the preying eyes of others.
But of course for Germans the question is purely academical, because in some houses fireplaces will be forbidden 'cause of the bad dust ("Feinstaub") coming out of them and killing so much people.
At least one dies here of winter cold, and not of dust particles, especially if you are old and poor.
Facts: following the Bundesimmisionsschutzgesetz (BImSchV), after 2024 emissions from a fireplace have to follow these norms:
max. 1,25 g of carbon monoxide per m3 of exhaustion
max 0.04 g of fine particles per m3 of exhaustion
min. efficiency factor of 73%
If your house has a fireplace of older type, and you're technically or economically not able to insert the necessary filters or the e.factor is to low, you have to decommission it.
One must say, however, that in the last 20 years a lot of older fireplaces have already been updated (or outlawed and decommissioned). - But this is another example how the German government adds each year new a layer of new rules to make life more difficult and more expensive.
UPDATE: I'm just reading that the Umweltbundesamt (Federal Environment Agency) however asks for a complete stop of fireplaces in new buildings. Because of the fine particles. Also pellet ovens are not longer seen as a good thing.
https://bnn.de/nachrichten/deutschland-und-welt/trotz-guter-luftqualitaet-umweltbundesamt-will-kamine-verbieten
There is no type of heating that is perfect. Germany will regret this decision to ban fireplaces. I do not know if anyone likes to sit and stare at a heat pump like you can with a fire !
Fire is hypnotic in a wonderful way, yes.
it sounds like a squeeze on people's heating choices.
I'll vote for fireplace, as I have one already, but not a heat pump. But I like the heat pump idea.
We used a heat pump in the city. Here, in the country, it's wood + a radiator for the bedrooms. I can safely say the fireplace is a lot more reliable than our air-air heat pump. It doesn't care how cold it is outside. As long as I feed it wood, it will heat us.
I don't have either one.
Heat pumps are great especially when temperature differences are not to large. For my location I am a bit skeptical of them given next Tuesday's high is -26C. They are not common in Alberta, I don't know now a Single person with one.
A fireplace would be great insurance if other forms of heating fail.
Both. Use the heat pump for heating and cooling and the fireplace/wood stove as a backup when there is no electricity. Heat pump technology has improved, new models can maintain heat output down to 0 deg F/ -17 deg C (or lower??). Older heat pumps would not provide much heat output when ambient temperatures were near 32 deg F/ 0 deg C.
A heat pump is much less efficient than an open flame of any kind since it’s compressing refrigerant and using it for heat exchange. Your power consumption is the same as if the unit were running in cool mode, although a lot of systems have a series of resistors in line with the pump. Anytime electricity is being used to generator heat via a resistor, very large amounts of power are used. A resistor is essentially a dead short that generates heat.
So to answer your question, flames are better than electricity for making heat.
Actually no, a heat pump moves heat it does not generate heat. They can actually be 400% or more efficient than resistance heating because of this, at least under good conditions where the temperature gradient is not too great. The problem comes when you are close to the cold limits (usually -15-20C or so) then the efficiency drops like a stone and you need to use resistive heating to supplement the heat pump.
Of course there is the caveat that you have to generate electricity first and that is somewhere between 30 and 55% thermodynamically efficient depending on the system. But even with that, heat pumps are more efficient under most circumstances.
The issue is the lack of backup for the electricity...
400%? That doesn't make sense. How can anything be more than a max 100% efficient?
It works because the system is not generating the heat, it is only moving it. It is very different than say a resistive heater which is generating the heat directly.
So basically you can move 4kWh of heat “upstream” with 1kWh of thermodynamic work, hence “400% efficiency.” I promise no laws of physics need to be broken 😉
Got it. Thank you. Sounds like something a marketing exec who never heard of the 2nd law dreamed up. I wonder how many people thought "baloney" (or something less polite) and ignored the technology from that point on. Maybe something like "4x times the heat for the same cost of electricity" would have been better marketing.
The use of the term efficiency with regard to heat pumps is not quite correct. The proper metric is called coefficient of performance COP which can be one or greater.
I wasn’t necessarily arguing whether resistance heating or heat pumps are more efficient. I was stating that neither of them are more efficient than using a flame (natty gas, propane, heating oil, etc.) to heat. And yes a heat pump does not generate heat - I mentioned they move heat via refrigerant.
But overall, agree with your comments. Thanks for the feedback!
Both, although our household has a third option, in the guise of a NG-fired forced-air furnace for the downstairs, with electric heat pump upstairs.
We also have a fireplace insert with an electric blower, which can heat our downstairs into the 80 degree F-range on the coldest day our 37.5 degree N latitude brings us.
As Simon said before me, it's good to have a lights-out backup.
Duel-fuel heating unit. The dual fuel system uses the heat pump in hot or mild temperatures (about 40°F and higher) and the furnace in colder temperatures (about 39°F and below). It switches between the two depending on which is more efficient for the circumstances, which saves time and energy in getting your home to the desired temperature. Dual fuel systems are great for any type of climate and function year-round. Plus, because each piece only works when it’s optimal, dual fuel systems have a life expectancy between 20 and 25 years!
Plus, if they use coal to generate the electricity as in Europe, the natgas furnace emits a lot fewer emissions!
Technology is great!
If you have energy to run it!
Good point!
If you live in a place with high electricity rates, a heat pump is just brutal., especially if you live somewhere with cold winters. They are simply not efficient.. a great concept though. On the other hand, the cost of fire wood has gone up dramatically due to the woke politicians focus on renewables (the world is going to end) and everyone scrambling for alternatives.. Here in Canada, I will rely on natural gas for my highly efficient (94 %)German boiler(I have radiators) and my nat gas powered Generac standby generator that power the whole house and eliminates any concerns. I do have a wood burning fireplace and a nat gas fireplace, they are essential options, but seriously they cannot heat the house.
I did some research on heat pumps recently, and one producer claimed that for 1 kWh consumed the pump yields 4 kWh of energy, which impressed me. A friend installed one at his house because he claims it's the cheapest option. But you're not the only one saying they are not very efficient and now I'm confused. I've no plans to buy one, I'm just theoretically confused.
The performance of a heat pump is a function of the ∆T, in other words the temperature difference between outdoors and indoors. The 4:1 ratio that the manufacturers always quote is the maximum performance you can expect under a specific test condition. In practice as the ∆T increases that ratio degrades until it reaches 1:1 which is no better than electric resistance heating. Therefore air-sourced heat pumps are quite sensitive to very low outside temperatures... Geothermal installations less so. But as many readers commented if you live in chronically frigid parts of the world or where the cost of electricity is exorbitantly high then the heat pump is probably not a good choice. Interestingly the northeast of the United States is full of heat pumps... And this is the last place I would have thought to see the proliferation of this technology. It turns out that natural gas is extremely expensive in this part of the US and not readily available to many residences. Therefore many builders instead of installing the usual oil-fired burners will simply install an air source heat pump.
Thank you for this detailed explanation!
Irina,
In a region with high electricity costs such as Ontario, they are expensive to run. As well, the cost to retrofit a home is also very high.
The third issue is that once the outside air temperature drops below 5C, the efficiency starts to decline and when it’s -20c, hopeless. So high cost electricity in region that has winter is not a good recipe for a heat pump. When I google heat pumps, there seems to be a lot of very biased articles from government agencies, manufacturers and installers(lower your heating costs and help save the planet from man-made Climate change). Got it.
Sandro is bang-on.
Have a look at Windy.com and see the arctic air outbreak next week in Western Canada and Central US states. They are looking at -20c to -30C next week. Even the temps in Texas are forecast to be low single digits. I will stay with my Viessmann German-engineered natural gas boiler that has a 94% efficiency rating. When I bought my house 20 years ago, the boiler in-place had a 60% efficiency ratio. So I am doing my part.
This is why I post these threads -- I learn a lot from people with actual knowledge of the topic and no reason to advertise anything. Incidentally, could you send some Arctic wind this way because global warming seems to have localised in my part of the world and I'm not enjoying it.
Heat pumps don't work in cold climates, the air is too cold for an air-source heat pump and a ground source will freeze the soil and stop working. In cold climates the ideal heating source is a CHP generator. Supplying power, heat and hot water. They are far more practical now with the advent of cheaper & better batteries. For a solar off-grid typical home you need about 30kwh of batteries. For a CHP you only need a 1.8kwe generator and 5kwh of batteries. The ideal fuel is Methanol which can be burned in a high efficiency ICE generator or a DMFC fuel cell. In the summer a small solar array will augment the CHP generator, since heating needs are lower.
As another commenter said, it depends. If it is easier to get firewood, gas, pellets, or other fuel than electricity, then fire may be best. If electricity is reliable and cheap, and if the minimum temperature is within the range of operation for the heat pump, then heat pump would be preferable. There are other options in extreme conditions: resistance heaters, kerosene/diesel heaters, etc.
I recently purchased two mini-split heat pumps to run off my solar installation. One is a 38 SEER 9,000 BTU unit that will work down to -22F, and the other is a 12,000 BTU unit that will run off DC or AC voltage. It can run entirely on DC from just 3-4 large solar panels during the day, and switch to AC when solar is unavailable (which will also be supplied by solar via batteries and inverters).
I am also looking at installing a geothermal loop, first in an air-to-air system using a radiator, pump, and fan to maintain near constant temperatures, and eventually an air-to-water heat pump/hydronic system. This is another option for very low temp heat pump installations - if you have the room to install the geothermal ground loop.
Unless you have an insert, fireplaces are grossly inefficient…10% of energy is recovered. I have a fireplace, two heat pumps and a gas pack for three story house. The gas pack (ground floor) is a 16 seer air conditioner with a high efficiency gas furnace. You can’t beat a gas furnace for comfort and gas is cheap in the US..$1.5/therm. For 350 m2 living space my all in energy cost for water heating, cooking, space heating is $1000/y.
Has anyone heard of a “Russian stove”? It was a large stove that can be slept on. Google “Russian stove” and look at the images
Yes. We considered getting one but it turned out we have no good place to put it so it heats the whole house. A neighbour has one and maintains tropical temps at his house during winter. But we are currently using an ancient, I mean, vintage, Russian heater for our bedroom because it heats up quite well and does not consume a lot of electricity. Cold is certainly one thing Russians know a lot about and how to deal with it.
My decision is based on reliability. We experience power cuts which can last several hours up to 2-3 days, so a fireplace (or stove) is the priority for space heating and bottled gas for cooking. The same storms that cur the power also knock down trees so wood is widely available for burning.
Best basis for energy decision-making.
A fireplace is barely useful but modern airtight stoves are extremely efficient, especially if you have an outside air connection (the fire burns oxygen and if you draw it from room air you have to let cold air into the house to replace that combustion oxygen -- the better way to feed air to the stove stove is to run some of that aluminum dryer hose under the floor to an inlet vent on the side of the house). Most modern stoves have the ability to accept outside air.
The EPA lists wood stoves and efficiency ratings: https://linkshortner.net/HabuU -- This link sorts by efficiency but you can also sort by any of the data columns (BTUs, particulates, and a bunch of others).
I'm in Western Oregon where the summer and winter temperatures are not extreme, so my primary source of heating and cooling is a heat pump. I have a standby propane-powered generator. We also have a propane fireplace and wood stove. We live on rural property, so there is plenty of wood with which to heat the entire house if needed. Most of Oregon's electric power is hydroelectric, so rates are low.
Wood because we can also cook food in the oven stove and warm water for my kid bath on it, saving A LOT of power and cost while warming the house with said heat.
Also, I can store 2 years of heat in my back yard
When the eurocrats are unable to guarantee enough power in the Baltic States and with war with Russia a risk, the least you want is unreliable heat supply in the North (we just had a period of high wind, snow and -15 celcius)
Also, heat pump stop being efficient when it get really cold. At -10 there is not enough heat in the air to pump, so it conversion rate turn closer to a 1 to 1 instead of the advertised 1 to 4
Wood is certainly more versatile, yes, AND it can be stored, excellent point.
I have a fireplace and a high efficiency split system HVAC unit. What you are not told is heat pumps are not really efficient in winter when the temps hit freezing. Heat pumps are great when the temps are above freezing. Heat pumps will never put out the heated air like a fireplace or my hvac system. At HUD they installed 150 heat pumps and all they did was freeze up defrost and use their emergency heating strips. But many of you may not have a choice to use natural gas to heat your home.
I saved over 4400.00 a month using high efficiency HVAC units the first month after I had them installed.
It seems opinions on just when heat pumps stop working properly vary greatly -- from -25 to, as you say, zero, which I've heard from others, too. And with heat pumps a rather sizeable investment, experimentation is hardly the best choice. What's more interesting is whether the authorities somewhere will make them obligatory (I think it's being discussed in the UK) and how many people will suffer the consequences if efficiency is indeed so easily compromisable by low temperatures.
Heat pumps are great for climates that do not have long cold winters. I managed HUD projects for 19 years in Arkansas. The government is the first to jump in headfirst into new supposedly cost and energy saving equipment, only to replace it when it is feasible. The most efficient way to heat your home is natural gas. Some will scoff at me but running the numbers it always won. Heat pumps are also limited as to how hot or warm the air is at the vents. Usually, 75 degrees is the most you will get for air, 80 for heat. Many elderly residents complained all the time to the point we had to replace some of the units because of this. When the units froze, they make loud noises while in defrost mode again pissing off my elderly residents. My maintenance guys carried hard rubber mallet to tap the reversing valve in spring to get some of them back in the A/C mode. This is actually minor compared to installing the low flow water heads on faucets and the showers LOL another story.
Great thread. Heat pumps are great and have their place. In my homes I have a separate propane heater that can work with no electricity, generators, and fireplaces. Being in the middle of nowhere we have to plan on outages. In the City (4 hours away) we do not have all of the back up heat or power. We just keep our cars always over 1/2 to 3/4 full to get out of the city. Redundant heating and power have always been important. It has been needed through out the years. And it is wonderful to be able to help people in disasters. Tornadoes are frightening and have been hit 3 times. Plan for the worst so you don't have to worry.
That's my motto -- planning for the worst, that is. Saves a lot of trouble, I've always thought.
Dear Irina, there's no need to imply an either/or relationship. In fact, HPs and wood-burning stoves are a beautiful combination to heat a house. The thing is, a stove comes much cheaper and provides a wonderful atmosphere, as well as grid-independent heat.
I know, but we would all choose both if we could and there would be no discussion. :)
Not used a heat pump but I can't imagine they would be very effective when the ambient temp gets down below 40°F. Wood burners throw out a lot of heat compared to open fires but burn wood quickly at very high temps. Neither options are great compared to natural gas if you worry about CO2 and heating more than just one room. Can't we just go back 20yrs in time?
You can heat a whole house with a fireplace if it has one of those water+heating attachments. Ours warms two rooms, the one it's in and the one above because of the chimney. With wood the biggest problem is waste of heat but still enough remains in the room to warm it so I've made my peace with that waste.
As for going back in time, even five years back would be appreciated.
I heat my entire house with one wood stove -- 2000 sq ft, two floors. It's currently 17.4F outside and 72.8F in the kitchen which is rather far from the stove. I'll stoke it again around 11pm and tomorrow around 8am, it'll still be ~65F in the kitchen and there will be enough burning coals left in the stove to easily get the fire going without using kindling -- just put in new logs. Modern airtight stoves give a minimum 8 hr burn -- some will do a 12 hr burn.
Anthracite (or a good bituminous) in a fireplace is the best backup. No forest is cut down. One ton is a little over a cubic meter and is rather pretty, as well. It is a glossy black, almost crystalline in appearance. It is clean burning and has three times the heat contact of an equivalent mass of wood. The Franklin stove is a reasonably efficient stove and needs no electricity, at least not in the USA.
Burning wood was replaced, except for esthetic purposes, after 1850 in Europe and North America. If wood (biomass) is burned as our energy resource, it means a return to 1850 AND a global population, after terrible freezing and starving, under one billion.
In the case of a heat pump versus an NG furnace, it is slightly more complicated. A heat pump is just a refrigerator running the other way. All that is required is an extra valve. If you have enough yard space to place sufficient in-ground heat exchangers so as not to freeze the ground, the heat pump may give a factor of 3-4 X the heat moved by the NG furnace. The ground is a rather poor heat conductor, meaning the ground surrounding your pipes gets very cold and freezes. A water tank with flowing water would be a lot better, but also more costly.
BUT, that is not the whole story. It never is!
Most electricity is made in a thermal power plant at 33% efficiency, so a factor of 3 just breaks even, compared to a 96% NG furnace. As the ground temperature descends from its usual 10C toward 0C, during cold weather, the heat pump efficiency drops off. The 4X becomes 1X. Air heat exchange heat pumps are worse since the heat exchanger freezes below 0C and no longer works at lower temperatures. Then, auxiliary resistance heaters take over from heat pumps. Some heat pumps have resistance heaters on the elements of the air exchanger to prevent icing up. Naturally, that also reduces and remaining gain of the heat pump, but it does continue to work at least.
The sad result is that heat pumps work best where and when they are least needed.
Heat pumps are in a class with Battery electric cars; they look great as long as you do not look too closely.
Very nice comment...I agree, the devil is in the details.
I live in the New England area of the US and many of the retrofit air-sourced HP installations keep the NG furnace as backup for very cold weather. In any case - the government bureaucrats have no place mandating technology. Thanx for the post.
The next step in your thought process should be
"Why have the heat pump at all, if it is useless when I really need it?"
In an electric grid serviced by wind turbines and photovoltaics, the grid will be OFF on a weekly basis, for half a day at a time. That is already the experience of countries where wind has partly replaced base power.
It is a most inconvenient way to try to live. Try it, and you will NOT like it.
If you think long-term, a wood burner or fireplace does not scale. A heat pump does, but as has been previously noted, at present, they do not fit within most budgets.
Might I suggest that not enough copies have been made, but that or something superior will come, no doubt?
A future historian might observe, "The utilities had a great run. They were able to supply something that the general public could not afford and a business deal was struck. While it is true that monopolies were awarded far and wide, it is equally true that. as a legal construct, a "monopoly' does not mean 'forever'".
Utilities have known for a decade that their client base can harvest Distributed Energy Resources (like Solar, DER) and produce their own electricity.
Now, years later, a professional standards organization, The eMerge Alliance, whose membership includes well over one hundred companies, is creating an extensive DC standards base.
Developments are happening so rapidly that they are hard to keep up with.
I have to believe that anyone who wants to walk the energy sustainability walk must recognize that introducing new technologies, especially as we try to lift a world whose present technological fluency is low, but may be able to leapfrog our understandings.
That said, since the US kept getting drawn into world wars during the twentieth century, and ended up punctuating our skill with the Atom Bomb. We showed 'em. When it comes to blowing shit up, killing people and generally being good at waging war, we're tough and we've been to the rodeo. OK, check.
Wouldn't it / couldn't it be a helpful adjunct to our foreign and domestic policy if we were to consciously and intentionally dedicate some part of our twenty-first century to-do list to the development of lifestyles, technologies, science, etc. dedicated to help people meet the measure of their creation?
Yes, the well-dressed, well-spoken Gorilla in the Brioni suit, the one surrounded by expensive, likewise-well-dressed lawyers, accountants, actuaries, professors, PR specialists, MBA's and Schpinmeisters, represent the $1.23 Trillion US annual energy business.
Refereeing this will be very interesting but I still believe that people have what it takes to lift each other up in a global renaissance.