Apparently it doesn’t work in Germany. Physics work differently here. At least that’s what our corrupt politicians want us to think
I hear that too. Not just politicians, there’s loads of experts lecturing on heating technologies. It’s just too cold in Germany for heat pumps. Doesn’t stop Scandinavia from getting them, granted, but in Germany it’s just too cold. No point. Sorry.
I can’t get an electrician and contractor to come install one (as an AC mainly) inside of 6 months, and I’ve been trying to find one for 6 months.
The heat is actually killing me I can’t sleep and have other health problems. I brought a dual hose unit from the US with me I’m running on a voltage converter and it’s the only thing keeping my apartment livable.
Too cold, too cold…
Germany has corrupt politicians? Say it ain’t so!
/s (all politicians are corrupt)
Actually, there is a noticeable difference between right leaning and left leaning parties, with the former being a lot more corrupt than the latter.
Makes sense. Heat pumps are one of the few heating systems that can achieve greater than 100% efficiency. (energy in vs total heat output)
As long as you can keep the evaporator above the evaporation temperature of your compressed refrigerant, you’re golden. Burried lines are excellent for that in colder climates, but the space for it isn’t always easy to find.
It’s a little more expensive, but most places can find the space by drilling straight down. Still worth it from what I’ve seen in most places.
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The coldest temperature ever recorded in the UK is -27. That’s right around the inflection point for where heat pumps become less efficient than electric heaters. Until the gulf stream fails, the UK is pretty safe to use heat pumps everywhere.
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So yeah, going 100% air-source heat pump if you’re area regularly spends time around -30°C (-22F) might not be the best idea. Though even the last report you cited said it might be 1.5-2x as efficient as resistive heating. And that Site 1 with bad COPs was because they manually lowered the fan speed…
There are vanishingly few people who live in areas with weather consistently below -30C. I’ve been seeing that kind of concern trolling all over the place in the past year or so, and they always have the same song and dance about low efficiency in extreme cold - technically correct, but taken as part of the bigger context, so niche as to be practically irrelevant. Yeah, if you live in Yakutsk you won’t want to rely only on a heat pump. Big fuckin’ deal - the other 99.5% of people on earth can benefit greatly.
Edit: I wouldn’t be susprised if this is the exact same guy I once argued with on Mastodon, actually. He was German too.
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Get a heat pump with resistive (electric) defrosting, not one that defrosts by running like an AC.
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I’ll chime in here since I own 2 heat pumps and live in a cold climate (often below 20C). Our house is heated with 100% electricity and after installing heat pumps our power bill dropped by about 18%. That includes all electricity, not just heating, so the gain in heating efficiency was very considerable.
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The Guardian is a UK publication.
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Generally, cold climate heat pumps are an efficient source of heat down to -15 degrees Fahrenheit
“Generally” is the wrong way to approach this. What you should be looking at is the specific capabilities of the actual system that you are considering installing. Some of them can go much colder.
If the Mitsubishi FE18 isn’t efficient in your climate… then don’t buy that unit. Simple.
If it’s really cold where you are… then you could consider a ground source heat pump instead one that uses air as a heat source. The ground doesn’t get anywhere near cold to have efficiency issues no matter where you are in the world and ground source heat pumps don’t cost all that much… though they do require a bit of digging.
Also, if your heat pump is inefficient for a couple really cold weeks a year… oh well. You’re still coming out ahead because it’s very efficient the other 50 weeks a year. It’s not like they stop working at extremely cold temperatures, they just produce a bit less heat than you might like for the amount of power consumed. Maybe they’re “only” 80% efficient instead of 600% efficient… you know what else is 80% efficient? Heating with gas.
it cannot be the only source of heat in a lot of cold climates.
I live in Finland. Heat pump is the only source of heat in my house.
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Some of the stations in Antarctica use heat pumps. They have been proven to work effectively at -53°C (-64°F) and do so reliably.
Are they more efficient at more reasonable temperatures? Yes. But they still work even when it’s very cold outside.
How well a heat pump works in cold temperatures obviously depends what temperatures it was designed to operate at. Don’t waste your money on a model that is designed to operate in a different climate. In fact a lot of heat pumps aren’t even capable of heating at all - they can only output cold air (which they can do even if it’s stinking hot outside by the way).
It can go down to -30C (-22f) sometimes or even below that
Are you intimately familiar with the inner workings of your heatpump? Nearly all heatpumps in a cold climate have backup heat built in and it would automatically switch to backup when it gets too cold outside. -30C is well into the too cold category for it to function as a heatpump alone
Which makes the argument that heat pumps don’t work in the cold completely wrong from a user perspective.
Yeah I have no idea. The alternative would be electric radiators anyways so in most cases that wouldn’t make a difference anyways. Temperatures that low are quite rare - maybe just a handful of nights a year. Generally it stays around -10C
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Yeah averages are way higher than that. My point just was that saying they don’t work in cold climates isn’t quite true. Yes, there are locations with way colder climates than this but if Finland isn’t considered a “cold climate” then I don’t know what is.
Heat pumps are super common here. Many houses just have a electric resistance heating so people switch to heat pumps to save on electricity.
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What happens when the power goes out
The same thing that happens when you have electric or gas heating. It stops working, because none of those work without electricity nowadays. Hell if you have a coal/wood burner for central heating chances are it doesn’t work without electricity either.
how often do you think the power goes out in finland
How often does it got out in Germany At least Finland built a Nuclear reactor to power most of the country unlike Germany which shut all their’s down
afaik power never really goes out in western europe unless something happens to the infrastructure (e.g. lightning strike or tree falling on a power line), what instead happens when we run out of generation capacity is that prices skyrocket.
In my house? Pretty much never. We have solar as well as a grid connection and can connect a generator as well.
In fact, I even have a second stand alone portable solar system that we take camping. It’s not powerful enough to heat a house… but it is powerful enough for pretty much everything else. And I can heat my house with a fire if it came to that.
Redundancy is the name of the game if you’re worried about reliability.
Well it obviously stops working and unless you have some other means of heating your house you’re kinda fucked and can only hope it comes back on soon as it generally does.
So? It is basically always as efficient as resistive heating at its worst, and the vast majority of the time it is massively more efficient. And even then they can remain more efficient even as low as -25C and might need resistive heating backup at places that get below that. But even in places that can dip below that they are often not that cold all year round. So overall throughout the year they are way more efficient on the majority of days even if you need a less efficient backup system.
We really need to think of the whole situation rather than just focus on the but sometimes part of the problem. Yes, sometimes they dont work as well. But overall through a year for the vast majority of places a heat pump can be all you need and is a lot more efficient than other heating systems.
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And what point does that happen? According to the article and other sources say similar things:
Even at temperatures approaching -30C, heat pumps outperform oil and gas heating systems, according to the research from Oxford University and the Regulatory Assistance Project thinktank.
And the lowest recorded temperature in the UK since 1961 is -27.2 °C. So the times you need to fall back to resistive or other backup systems is 0% of the time. And what do you count as a cold climate? is 0C cold? or -10C? -20C? I know many people that would say yes at any other those and I bet there are others that live in places that go way lower. Yeah, what you said is technically true, but without these numbers is almost a meaningless statement. In the UK, and most of europe this article is basically saying that heat pumps are more effective than other sources of heat even at colder temperatures and it takes extremes before they require alternative heating methods.
The way you worded your post it makes it sounds like on a average coldish winters day heat pumps become useless and there is little point in having them. Even if that is not what you intended.
Most modern heat pump systems account for that and have electric heating/defrosting built-in for those few cold days a year.
Also it’s not like you have to remove your old heating system*; you can just plumb in the heat pump into your central heating and have cut off valves for the original system, so you can still use it as a backup.
*) unless your government is retarded and in order to get subsidies they require you to uninstall it
Quite frankly, in really really cold places (the only places where your criticism applies) you should not have a single source of heat period. You always need a backup in case one of your heat sources fails. It does not have to be able to heat your house a lot, just keep it stable above freezing, but you do need a backup.
As long as you can keep the evaporator above the evaporation temperature of your compressed refrigerant, you’re golden.
Also keeping the evaporator from getting covered in ice where it doesn’t work. Yeah you can defrost but in certain weather it’s just going to ice up immediately.
I mean, in the colder climates that have natural gas piped to homes anyway.
Why not use a pilot light worth of gas to keep the evap side a tad bit warmer on the days that it drops real cold.
Sure, your still using some gas, but you’ll be extreme sipping at it.
I’d rather go full electric and get rid of the gas infrastructure entirely tbh. Take that cost and put it towards local power generation+storage.
Heat pumps most of the time and radiant electric heat for the few times the heat pump won’t quite cut it. Geothermal if that’s an option in your location.
the upfront cost for something like geothermal is still outrageous, though. anecdotally, i bought my house with an older unit that ended up catastrophically failing after the reversing valve got stuck and destroyed the compressor. only 1 local shop in the area serviced the thing (same people who installed it when the house was built…) and the unit had long been discontinued since the company that made it (hydro delta) went bankrupt years ago. it was over $15k to put in a new updated unit… luckily my home owners insurance (with the help of a rider i added a year earlier that covered home systems) footed the bill, albeit after a long and arduous battle with the 3rd party shits that state farm outsourced it to. now this new system has a 10 year warranty on parts and labor, otherwise, i would have switched to gas in a heart beat. i can put in a new gas unit every year for 10 years at the same price… so while the geo’s monthly electric bill is nice, i wouldn’t dare install a new residential build with geo… plus add another easy $50k for the loop field if it’s a new install.
i’m afraid what’s going to happen once then 10 years are up since that always seems to be about the time major home appliances fail… probably try to move by then so it isn’t my problem, lol.
Counterpoint: electrifying homes is also a huge cost savings in general once you are at the point where you’re willing to forgo that big gas furnace in favor of an efficient heat pump system.
Cookers use very little gas. It’s really only water heaters and furnaces that use a lot of it, and heat pump units are incredibly efficient for both those tasks. Though I will admit that the noise a heat pump water heater makes is just atrocious and you’ll need to figure out if your can manage that in your life (e.g., by setting it to only run at night, when you’re out of the house, or putting it somewhere far away from where you spend time).
Keeping a gas hookup at $15+/month for a single appliance like a water heater or range is an expense a lot of people can and should trim, but instead they treat it like a sunk cost and think “well I have this one appliance, so I may as well get MORE gas appliances”. Which is intended. The whole “now you’re cooking with gas” campaign and all the nonsense ad campaigns about how gas ranges cook better than electric* was a deliberate (astroturf) marketing campaign from natural gas utilities because they knew that keeping electric cookers in the house would stop people from abandoning the appliances that ACTUALLY use gas but were hard to get people passionate about. This isn’t a conspiracy theory; we have the memos and POs.
* the difference is at best unnoticeable to the average cook and I truly believe the performance is worse, especially when factoring in time spent cleaning. Electric ovens are flatly better and modern electric cook tops work super well, even if not induction.
It’s not an argument I’ve seen in this conversation yet, but I’ll also head this off: gas ranges are not the best cooktop for ultimate temperature control either. If you cook sugar or temper chocolate a lot, a standalone induction cooktop like the Breville Control Freak will do a way better job, and you don’t need to change your permanent kitchen appliances to make that work. Combine that with an induction kettle like others have mentioned, and the broiler for peppers (I do this weekly having moved somewhere that doesn’t have gas) and there is literally no reason to choose gas in the kitchen.
Perhaps more importantly gas is just way more dangerous, heats up the space way too much when you don’t need it and wastes the heat, and overall just isn’t good for you - you need a well ventilated kitchen. Gas ranges need to die.
a standalone induction cooktop like the Breville Control Freak will do a way better job,
at $1,499.95 for a single burner it better damn well.
It’s for sure a professional tool, but nobody else really needs those features anyway.
Gas is great if you need to boil a pot of water right now. Like in a restaurant kitchen.
Any application that is not in a massive rush is just fine on electric.
Even modern radiant electric boils water faster (pretty typical for even a pretty low-end electric top to have a 3500-5000W quick boil burner). And induction or a kettle both do it a near order of magnitude faster. Not to mention none of them hugely heat up the room or require a superpower ventilator that sucks out your conditioned air. If boiling water fast is the task you care about, gas is almost certainly the worst choice. At least for home use.
Commercial kitchens are a different story that isn’t even part of the discussion. Even with three-phase power, to run an all-electric mid size-large commercial kitchen would likely require some crazy service level that wouldn’t be available in many places. It’ll be a while before that is an option.
If boiling water fast is the task you care about, gas is almost certainly the worst choice. At least for home use.
Well technically electric ranges are worse, but other than that you’re right.
Technology Connections on YT did a side-channel experiment on this very thing.
Normally I wholeheartedly recommend his stuff, but the side-channel content gets very long winded and rambling, linked video included.
I’ve found induction cooktops do just as well as gas at boiling water. The frustrating thing about them right now is the market is immature, so the good ones cost well over $1000 per burner and the cheap ones are so much worse (lousy coil sizes and poor heating precision) they aren’t worth using as anything more than a camping stove for tiny little pans where you don’t need precision. It’s like nobody in the industry wants to make these things good enough to actually replace the old technology, they just want to price gouge for all it’s worth while it’s still seen as the “expensive, hard to make, premium option”.
I have both a gas and the cheapest induction range/oven combo I could find and the induction is way better.
People saying gas is better are just wrong.
Gas should be incentivized out of residential new construction, and probably banned from new multi family dwellings
Very good induction cooktops are nowhere near $1,000 per hob and can boil water in a fraction the time as gas. Don’t buy the Frigidaire crapola and the stating price for a very good full induction convection range with 4-5 hobs is ~$1,250. Spend twice that and you’ll have a machine with no downsides.
Even then induction is faster and cooks more even, maybe restaurants need open flame, but yeah I don’t think anyone at home needs gas anymore. If you don’t care how you cook you can go electric. If you really care in many ways induction is better than gas.
Really, the only thing you can’t do on an electric range that you can do on a typical gas cooker is, for example, directly fire a pepper.
And you really don’t need to do that. You can just do it under the broiler, for example. I also don’t even insist on induction. A mid-range radiant top is STILL better than gas, in my opinion, though the induction is worth it if you can afford it.
People will bring up woks a lot, but a gas range also can’t draw out the real advantages of a wok and you’re better off with an outdoor chimney cooker or a dedicated wok burner (induction with a small torch or gas bottle) if that’s what you really care about.
Plus, I must again point out how fucking AWFUL it is to clean a gas cooktop compared to how trivially easy it is to clean a glass-top electric cooker. The time saved cleaning more than makes up for the advantages people list with gas even if we grant those advantages exist. Which I clearly don’t.
many people just have a lil’ torch for when they need flame, presumably vastly more efficient than turning on an entire burner just to scorch a chili
restaurants need open flame
They don’t; not from gas. The obscene heat it generates in the kitchen alone is horrible for everyone working there.
Induction is much, much faster.
I haven’t seen this argument listed yet, but my reason for wanting to go off natural gas is how much we lose in transmission. I don’t feel like finding sources right at this moment but most estimates I’ve seen are ~2%, and methane is a pretty potent greenhouse gas.
Methane is one of the cleanest burning fuels there is. There should be more effort put into fixing the distribution leaks rather than trying to switch everything to electric.
Fossil methane is still fossil. Ie. not part of the CO2 cycle, and thus contributing to the greenhouse effect. Methane itself is 20 times more potent, and we should do everything we can to limit methane emissions, both fossil and natural.
Agriculture is a big source of natural methane emissions, and even fairly small dietary changes can significantly reduce livestock emissions, but don’t see anyone doing that either.
Highly suspect small gas line leaks won’t be fixed either.
That is a rather big ask and maybe that effort would be better directed elsewhere.
Also, think of it this way. Isn’t it a bit crazy we send lines of pressurized, explosive gas directly to most homes in North America? If we do need to keep burning natural gas, we can do that in power plants and get about the same, if not better efficiency by using this electrical generation with heat pumps.
That’s a fair argument. Even if every used a tiny bit, there would still be a lot of loss to the atmosphere through leaks/etc of the distribution system.
So yes 100% elimination would be ideal.
But this could be a viable middle step between 100% gas heating -> Supplemental/Heat Pump -> 100% Heat Pump
You’re better off heating the inside of the house with gas that heating the outside of the house with gas and using the heat pump to transfer that heat into the house. Replacing the gas line with lines for the heat pump would be best.
It’s literally pulling heat out of thin air (or ground).
Bless you. I love that guy. So gosh darn nit-picky on the details and its the best!! Never thought hour long videos on heat pumps or refrigerators or car headlights would hold my attention or be a favorite part of my week but he makes it happen.
His Christmas light videos are a highlight of the season every year!
The study isn’t wrong, but it’s also not right, IMO.
This doesn’t seem to mention the cost of the energy, just how “efficient” it is… which, honestly, “efficient” can imply several things, and they don’t seem to clarify what (at least from my first pass of this doc).
The issue is that even if you’re getting 3-4 times as much heating/cooling as you could with something else, per jule of energy potential that is put into the system (in whatever form that is), if your energy cost for that source of power is high, it’s going to lose the financial argument every time.
Sure, a natural gas furnace will consume “more fuel” and produce less effective heat than a heat pump, but if you’re paying 10x the cost for electricity, then you’re still going to end up spending more per degree of heating than with the cheaper fuel.
Where I am, electricity is pretty cheap, but natural gas is tremendously cheaper per jule… so we can actually pay less by using the “inefficient” fuel for our home.
I don’t think the numbers are dramatically different at the end of the day, but this study seems to completely ignore the core issue that most people will be concerned with… which is: “will this save me money?” Which is arguably the more important metric.
honestly, “efficient” can imply several things, and they don’t seem to clarify what (at least from my first pass of this doc).
How would you like to define it?
How about this for an analogy - which of these two is more efficient:
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Plant some wheat in your back yard, buy fertilised eggs to hatch into chickens, plant tomatoes and basil, plant an olive to grow a tree, and eventually, years down the track, you can make yourself a bowl of pasta.
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Notice your next door neighbour already cooked some pasta and made more than they can eat. Ask politely and they’ll just give you a serving.
Obviously - the second option is more efficient, and that’s effectively what a heat pump does. They don’t heat up your home, they just take a bit of heat from the air outside and move (pump) it into your home. It’s far far more efficient than creating new heat from scratch with a gas system.
Exactly how much more efficient will depend on the outdoor and indoor air temperature, and on the brand/model of heat pump you buy, and other factors (such as the length of the pipe between the outdoor unit and the indoor unit). You really should ask for specific advice on your home - but in general, a heat pump is extremely efficient.
Where I am, electricity is pretty cheap, but natural gas is tremendously cheaper per jule… so we can actually pay less by using the “inefficient” fuel for our home.
Have you actually looked into it, or are you just making assumptions?
I can tell you that my heat pump, in my house (yours will be different), in my climate, adds about $5 per week to my electricity bill. Is your gas bill less than $5 per week?
Or at least - that’s how much it cost before I had solar panels. Now that I have solar… it uses about 20% of the power typically produced by the solar panels on my roof leaving plenty of excess power that we sell to the grid for about the same amount of money as what we spend buying power overnight. Since we installed solar our entire electricity bill is about $0 (and we use power for a bunch of other stuff, including to cook breakfast and dinner when the sun typically isn’t shining*). We don’t have a large solar system either - in fact, installing solar cost less than installing heat pumps.
(* our solar system comes with instruments and software to measure our consumption - and I can tell you that heating up a family meal with an electric cooktop uses more electricity than heating an entire house with heat pump… because the cooktop is creating heat, and the heat pump is simply moving heat)
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What’s also interesting is that you have to factor in the costs and CO2 emissions of the fuel source and it’s delivery method. A new building code for a county in my area was adopted which requires calculations for energy efficient HVAC systems and also CO2 emissions with those systems. Surprisingly, natural gas has less CO2 emissions associated with it, while electricity is 2.86 times as much. This is because grid electricity is mostly produced by fossil fuels, then needs to be delivered to the site but there are many losses along the way. So even if the all electric equipment is twice as efficient as the equivalent natural gas equipment, it still contributes more CO2 production. This is part of the issue with phasing out natural gas and moving to all electric in its current state. But with that is the push (and requirements) to produce energy on site and shift towards net zero energy for commercial sites, which is definitely better than using grid power from an emissions standpoint.
Where I am, electricity is pretty cheap, but natural gas is tremendously cheaper per jule… so we can actually pay less by using the “inefficient” fuel for our home.
Most of the push towards rapid adoption of heat pumps is happening in Europe, where geopolitical developments (to put it mildly) caused gas prices to spike last winter. The nature of the natural gas logistics means that different continents can have wildly different prices (unlike petroleum, where you can always throw it on a ship and send it from where it’s cheap to where it’s expensive), so a lot of European countries are seeing these debates play out against the backdrop of their own energy markets. Germany passed a law this year that would phase out new gas furnace installations, so that’s why a lot of the debate is happening with a focus on German markets.
Whether (or how quickly) a transition to heat pumps pays for itself in euros will depend a lot on what happens in the future to gas and electricity prices.
if your energy cost for that source of power is high, it’s going to lose the financial argument every time.
How high, is the question. How much more is electricity where you live that heat pumps “lose the financial argument every time”? Where I’m from a kWh of electricity is roughly 2.8-3x that of natural gas, so most modern heat pumps will beat that, some by quite a margin.
If globalpetrolprices.com is to be trusted and Canadian natural gas is 0.063 CAD and electricity is 0.165 CAD you’re very much in the same boat with a 2.6 ratio. Most heat pumps should be able to beat a 2.6 SCOP even in Canada.
So, sure, the study only looks at COPs and not at overall cost, but I think it’s not unreasonable to expect home owners to be able to divide electricity price by gas price and compare it to the SCOP of heat pumps on offer.
Finally someone taking sense.
Asking me to compare my own bills between natural gas and heat pump is insanity, I don’t have both systems installed just for shits and giggles… but it doesn’t seem to stop people from saying I should do that sort of insane thing to really know.
That site sure is interesting, I haven’t dived into the data enough to know how they got the figures they did, or what it represents… but assuming they’re saying that it’s saying that $0.63 worth of natural gas gives you the equivalent thermal output of 1kWh of conventional electric heating (more or less)… which I think it kind of does, since, to the best of my knowledge, electric heating systems are among the most efficient at converting 100% of the energy input to heat output (or as close as we can get to that). As we know heat pumps exceed this because they’re not generating heat, they’re just moving it around.
Also, a blanket statement like “heat pumps should be able to beat 2.6 SCOP, even in Canada” is problematic, since Canada is huge, and some of that landmass is in the Arctic circle. To be fair, 90% of Canada’s population (or something similar to that) is in the southern 10% of the landmass… still. If we’re being detailed, then such blanket statements should be avoided. A good alternative is “for the majority of the population of Canada”, which is wholly accurate.
There’s also other inefficiencies that aren’t being considered and unless we get really deep with the information, that fact is unlikely to change; however, those inefficiencies may make heat pumps even better on paper…
There’s a lot to say about this incredibly complex topic. And that’s not even touching on the nuances of the word “efficiency”… since efficiency relies on specific conditions, and usually is a comparative figure. Eg, the Ford F-350 super duty is an extremely efficient vehicle, when compared to the Ford model T… many decades of innovation will pretty much guarantee that statement is accurate. But comparing the F-350 to, say, a Toyota Prius on MPG alone, then the F-350 seems like a gas guzzling bohemouth, that’s a symbol of gluttony… Wasting so much more fuel, to travel the same distance. Both saying that the 350 is incredibly efficient and also that it’s extremely inefficient, these are both true, depending on context.
There’s too much nuance here that I’m just going to stop talking before I ramble myself into getting cancelled somehow.
but assuming they’re saying that it’s saying that $0.63 worth of natural gas gives you the equivalent thermal output of 1kWh
Correct (although $0.063), and interesting to see you seem unfamiliar with this, this is the standard way of listing energy prices in Europe, it’s not just that site. That site was just my first hit when I looked up Canadian energy prices. It’s the low heat value and it’s determined by the energy in a fuel if not allowed to condense (which is the relevant value for a traditional furnace, if you have a more modern condensing furnace you take the high heat value) and it makes it relatively easy to compare different sources of energy.
Canada is huge, and some of that landmass is in the Arctic circle.
What people never realise is that being far up in arctic climates doesn’t only impair an SCOP. Yeah the lowest temps are very cold, but that means temporarily bad COPs. An SCOP is made up of the whole heating period though, which in colder climates is longer, so in turn you have several months more of the time where heat pumps are extremely viable with temporary COPs above 5 or 6 saving loads of energy. The real problem is if your lowest temps are so low that a heat pump will stop working entirely, in which case you get a hybrid system or just leave your old furnace in as backup, which is even better for your SCOP because you omit the month(s) with the worst COP and only use the heat pump when it’s most viable. Let’s say you live in Tuktoyaktuk and heating period is basically all year, then you have your furnace on for 3-4 months but you’re saving massive amounts of energy with your heat pump in the other 8-9 months of the year.
touching on the nuances of the word “efficiency”
I actually tend to avoid using that term for heat pumps anyway, as it’s not really correct in terms of physics. What makes heat pumps so viable is a coefficient of performance, their actual electrical efficiency isn’t all that good at 50-60%, but it’s also kinda irrelevant. It’s sometimes easier to just call it efficiency, but like you say, once you go into the nitty gritty it falls apart.
I like you.
I agree, there’s a lot more to it than just the argument that was presented. I am also woefully unfamiliar with measurements of energy in common use, and sort of come at things from a more physics mindset. I’m no physics major, but it just makes sense to me that way.
Personally I’m a fan of heat pumps. There’s plenty of reasons not to go that route, but when it comes to electrically driven heating and cooling, you’ll be hard pressed to find a better alternative.
I’m in the camp of going independent with power. Getting solar, a battery system, and converting everything to electric. That’s the plan at least. If my power is free (from solar) then if I lose some efficiency in the conversation, that’s okay, it’s free power either way… though, not “free”… just, I’m not paying per watt (or kWh) I just need to buy the material to make the system go… that’s not free, but day to day operations are. If I’m making sense.
I’m not where I want to be yet, everything is a work in progress for now. I still have several natural gas systems in the house, including the furnace. I can’t afford to do everything all at once. My current plan is to buy and install a grid-tied solar system, with the option of batteries, in the near future. Maybe the next few years. We have a good South (ish) facing roof above our garage which will be ground zero for solar panels. It’s sizeable, so hopefully 20+ kW of solar will fit.
After that’s in, start working on electrification inside, make sure our grid connection is up to par, and start replacing and upgrading our furnace/water heater/whatever with electric counterparts and try to make everything as efficient as possible.
When finances allow, buy a battery system that can power the house for ~24-48h, based on usage, and add it to the solar system. Maybe start with 10-12h worth, and upgrade as we go. I’m thinking of getting the rack-mount LiFePO4 packs, and starting with around 4 (~20kWh), and go up from there. I’m an IT guy, so racks are a go to for me. As finances allow, pick up another pack to bring it to 5, and another, and another, etc, until we hit my goals. The goals are very specific and I have reasons to want 20+ kW of solar, and 2 days of battery backup. Our area supports net metering, so we should be good to start on the plan. It’s going to take decades to get it done.
This is all very off topic, but I figure were so far down this thread and so deep into the bowels of post history that nobody but you and I will be reading it. I felt like sharing my plan; for no other reason than to say it out loud… more or less.
Heat pumps are in my future. So regardless of all other factors, like “efficiency”… that’s what I’ll be doing. Hybrid is definitely an option, though, I’ll probably go with “dual source” (heat pump + electric resistive) for my system if possible. We’re pretty far south in Canada where I am (Niagara region) so I’m ok for the heat pump to provide 100% of my heating for over 99% of the year. We only occasionally get cold spikes into the -30c range for a few days at a time at most… but I’ll get crucified if the inside temp drops too far (the Mrs will see to that). In the interest of electrification, I’m hoping to get a resistive electric heating system for the alternative heat system. It’s not as “efficient” as the heat pump, but when the heat pump won’t work because of the extreme cold, it’s the next best thing IMO.
I want a battery system because I don’t want to be down if the grid goes away, and I want enough battery that we don’t have to rush onto the roof every time it snows, to clear the panels else we need to run on grid power… having some leaway in how much time we have to deal with the problems that might prevent the system from working, will be perfect.
It’s sometimes easier to just call it efficiency, but like you say, once you go into the nitty gritty it falls apart.
It depends. It’s certainly economically and CO2 efficient. Thermodynamically? That’s something for physicists and engineers to worry about, not J. Random Bloke.
leave your old furnace in as backup
I’ve seen plenty of old houses over here in Germany which did have a gas furnance that was somehow under-dimensioned – the idea is that in the real cold days you’d still have the good ole fireplace (or coal oven), as well as not so old houses which still have one because sitting in front of it.
Gets a wee bit more complicated with heat pumps and maximising the efficiency of everything as the fireplace needs to be hooked up to the heat exchanger or there won’t be any hot water and modern units are closed and look rather different, but you still get a window and plenty of infrared radiation.
Then, last but not least, there’s insulation. Especially up in the arctic you should be doing your darnedest to build passive houses. Certainly possible in Kiruna, I’ve heard that the Norwegians are trying on Svalbard.
gas furnance that was somehow under-dimensioned – the idea is that in the real cold days you’d still have the good ole fireplace
Oddly enough I’ve never encountered that in Germany, I only ever see catastrophically oversized furnaces that start cycling in March… Seems to me plumbers never really worry too much about correct dimensioning, they just put the same 20 kW furnace that they know and love to install in every apartment and single family home. For some it will be somewhat adequate, for some it’ll be oversized, who cares, customers never complain when the furnace cycles, but when it’s too cold, you’ve got a problem. Same as they’re never too worried about finding suitable supply water temps. Just set it to 80 and you’re good, it’s the customer who pays horrendous gas bills, not you lmao. That’s also why everyone thinks their Altbau has to have 80°+ supply water when they have never really tried anything lower to see if it maybe suffices. My parents had their oil-furnace on 80C supply for the past 40 years and last winter when everybody was trying to save as much energy as possible they figured out you can set it to 55 as well.
It also doesn’t add up if you’re getting twice the heating per joule of input if you can only input a quarter the number of joules as your source is limited.
No shit
A sticking point I encountered - the drop in efficiency as the weather gets colder means you need a unit sized to heat your home on the coldest days you expect to encounter. So you need to buy a heat pump that’s larger than you need for 98% of the year just so you don’t freeze that other 2%. In addition to higher cost an oversized unit is less efficient because it’s cycling more.
So this is where “heating strips” or “backup heating” come in, and then I get we’ve come full-circle.
I don’t see how this is “full circle”. In places where it does get that cold, most homes already have a form of heating for the house. Adding on a heat pump or, at least in my case in the Midwest, replacing the central AC unit with a heat pump just means that you’re only kicking that original heating system on a few days out of the year. That’s a massive reduction in use compared to being the only source of heat for half the year.
It’s a problem that new construction homes would need to fix if they don’t want an NG connection at all, but it’s not unsolvable.
You’d usually run two or more units in a cascade/multiplex when requiring large amounts of power rather than having one giant unit. Means you can turn off one or more units entirely for low heating demand.
Also choosing a unit (or units) that use a speed controlled compressor will limit cycling as they can ramp for the actual load.
I think modern inverter units are not less efficient when oversized. They are able to run at varying levels rather than cycling.
Those “heating strips” are only used a few weeks every year in my case.
The optimal solution is to add a small heatpump in addition to a gas heating
The only downside (in comparison to fuel burners) is complexity. Heat pump systems are extremely complex with a lot of parts that could get fucked up over time.
A gas furnace is as simple as it gets with almost no moving parts. Coal/wood furnaces are a bit more complicated if you don’t want to blow 100% of the emissions into the air… you need good well maintained filter systems. But it’s still far less complex than a heat pump.
So I understand the appeal of furnaces. Simpler systems are easier to understand, are harder to break and easier to repair/maintain.
I think that problem is tackled too rarely in these articles. If you can’t take away the fear that people will have a higher upfront invest and higher maintenance costs and higher failure risk, that makes it too convenient to cling to what they know and understand.
Edit: oven --> furnace
Eh, I think you might think heat pumps are more complicated than they are. I think they’re about as complicated as a furnace. At the end of the day, in both your just pumping a gas from one place to another, changing the state of the gas, and then running that past air to heat or cool it.
It depends. The most basic implementation of a heat pump is basically an AC system with a reversal valve.
To be fair to the previous commenter, the air conditioning system of an air handler (aka furnace), is usually one of the more complicated parts of the system.
The issue is that even air conditioning systems are getting rather complex, with multi-speed or continuously variable speed systems… which add significant complexity… meanwhile adding a reversal valve to a continuously variable system easily makes it far more complex than any other system that’s integrated into the air handler.
I’ll also note that heat pumps come in many different shapes and sizes, some are mini split systems, others are geothermal bohemouths, and some are air-exchange systems to be integrated into an air handler (aka furnace). The most efficient heat pumps are usually the geothermal kind, which are pretty easily the most complex; air exchange heat pumps are basically just AC systems with a reversal valve… they all have their challenges though…
It’s just, a much deeper topic than saying that it’s strictly more, less, or the same level of complexity as something else, since from the start, the term “heat pump” represents an entire class of diverse devices… the same can be said about a furnace or just about any heating system… some are extremely simple while others make my HVAC guy cry out for someone to make it make sense. YMMV.
Heat pumps dont replace gas ovens. They replace central heating systems. They are not that much more complex then a central heating system and come with a lot fewer safety concerns. And heat pumps are not new technology - they are just AC units that can run in reverse to heat instead of cool. We already know how well they work and how often they fail and a lot of the world is already reliant on them just as much as others are reliant on gas central heating.
Non-native speaker; sorry. I meant furnace, not oven.
To be fair, they kinda do similar things. One heats up a tiny room, the other heats up the whole house… it’s sort of the same idea in concept.
Now if electricity was just less than 3x the price of gas, we’d be winning.
Unfortunately gas costs a lot less for the same amount of energy. So it’s only going to save you money if you use simple electric heating.
For those of us on gas boilers, the prospect of a system paying for itself (maybe) in 50 years time isn’t overly enticing.
In this context is a “heat pump” the same thing as an inverter air conditioner?
A split system.
That’s what most of Australia uses and looks like the pic but Ive never heard them called a heat pump.
A split system AC is a heat pump in any context. So is a refrigerator. They’re all the same technology that move energy via a refrigerant’s latent heat by compressing it into a warm part and letting it expand into a cold part.
Cool, thanks. In that case it’s about one month until I can’t live without my heat pumps. They stop my balls from sticking to my leg.
Yeah, for some reason we renamed them to heat pump.
I suppose they can also be used to slowly heat water as well as the air, which is the main difference.
I like “heat pump”. It’s a very nice ELI5 name. It’s a pump for heat. A water pump takes water and forces it to where it wouldn’t go naturally. A heat pump does the same.
For larger homes with central heating and radiators inverter air conditioners aren’t really a great solution - they are expensive (especially when you don’t have/need an air conditioner in the first place), unsightly and work for more or less just one room. A heat pump is a generic term for a multitude of things, but as a replacement for central heating you’d most likely have just one outdoor unit that spews cold air and inside you’d have a large heat exchanger where you warm up the water for your central heating (and possibly warm water in general for showering and the like).
It’s pretty amazing.
Has not been updated for a while, but relevant link…
https://www.energy.gov/eere/buildings/residential-cold-climate-heat-pump-challenge
would be a neat story in 1920
It’s still news today because every time heat pumps are mentioned someone will say that ‘they are nice but it’s too cold to use them where I live’.
That’s like the stupidest take, especially for most of Germany. In the worst case you’d supplement the heat pump with electric heat so in the coldest days when it doesn’t work at all (which will be a few days a year at most) you’d get to … checks notes … 1x efficiency, which is only as bad as having regular electric heating which many people have anyway.
In Germany this will likely still be a controversial take in 2026. Our political right managed to shift this debate into ideology territory and a good chunk of people believe heat pumps are environmentalists’ fever dreams that don’t really work in cold Germany.
Follow the Money for who funds these studies
they do https://www.raponline.org/# feel free to investigate on them.
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Sadly, makes bugger all difference here in Australia - our electricity is mostly coal-generated.
At this time, we’re up to over 36% renewable… So we are getting better. In 2017, it was only 17%. If we got rid of the libs earlier (who made the carbon tax debate toxic), we’d be so much better. Even with coal generation though, Heat pumps are still more efficient, as they’re measured well over 100% efficient (200%+), whereas gas is less than 100%
It’s still usually more efficient and better for emissions when the coal is burned at a power plant with high efficiency and filtering systems.
Yeah, you’re probably right. Just grumpy that we still burn fucking coal for our power here, and we have so much wide open space we could be using for solar generation.
