I should know bc I have a whole house battery and solar system (almost 30 kWh battery and 24kW solar). It keeps the lights on, but not heating. I live in a mild climate.
The reality is that battery/solar requires major quality of life and activity time shifting trade-offs.
Spend 50k on insulation that will last the life of the building instead of 50k on heating and cooling devices which will need constant maintenance and replacement + fuel and end up costing 10x more over the life of the building.
A modern house with modern insulation in a mild climate shouldn't even need a central heating system. You can get by with 500w toaster heaters in each room for the coldest time of the year
There are electric floor heating graphene foils that put out 20w per sqm, they're more than enough, no moving part, no maintenance, no bs, not even 20% of the price of a hydro floor heating, you can even install them yourself
The end result is you're going to make big lifestyle changes to accommodate the energy. For example everyone sleeping in 1 bedroom and only cooking with an electric pressure cooker or low and slow with an induction range.
There are passive houses built at 2000m altitude in the Alps, some are made of wood and have literal strawbales for insulation, there are no excuses left in 2026 not to build good houses, it's more economical, more practical, more comfortable, more ecological
Any means to keep energy cheap and abundant must be by force because it is not a natural order.
There's probably a few lower cost things that I am overlooking, to the tune of netting out a few hundred dollars of savings after however many years they took to pay back.
In the UK, houses have energy ratings, which are largely not that useful, but they do allow estimated annual running charge.
The house that I live in we moved in and were spending ~1.7k on gas a year.
We needed to re-render the place, because it has a few missing pieces. we spent the extra £4 to put in 90mm of external wall insulation. We also had to replace the glazing. It was cheaper to get triple glazing (for some reason), however the results of that was that it was 6degrees warmer in winter, and 10 degrees (celcius) cooler in summer. Even with gas prices doubling, we spend about £70 on hotwater and heating.
How do you draw this conclusion? Like any other expensive, long-lasting part of the house, this should be seen as an asset which is “priced-in“ to the value of the building.
Not everyone has the capital (even with gov subsidies) to make those investments, and it's generally the people who need to save a few bucks on bills the most that DONT have the money.
People still spend literal millions on poorly built and poorly insulated mcmansions today btw, it's not a money issue.
However, it's not that far off for retrofitting, if you do it when your siding already needs to be replaced. Add 3-5" XPS foam to the exterior of any standard house; if a basement you bring insulation several feet down and out below the ground. If cathedral ceiling, when replacing the roof you put 6-8" polyiso down over the sheathing before the new roofing material. If vented roof, get 1.5x code minimum blown in the attic. Air seal first, of course (1-hour of air sealing is the best ROI of anything you can do in an old house).
But nobody wants to put that money up.
Where I am your house would flood when 80mph+ winds blow the rain up your walls.
Same goes with the cinder block foundation. If insulated, it moves the freeze/thaw interface inside the block and then you end up with a failing foundation.
https://planthardiness.ars.usda.gov/pages/map-downloads
https://commons.wikimedia.org/wiki/File:USDA_hardiness_zones...
A "properly insulated" house still requires something around 0,5 W/m2/K. Modeling a moderate 120 m2 house in the coldest months when the temperatures hit 15-20 negative you still need 2,5 kW of heat with domestic hot water on top. Put in the efficiency of a heat pump and you are still easily looking at half a mega watt-hour per month. ~1MWh for a whole house is very reasonable number during winter months, sans electric mobility.
That's entirely unrealistic to cover with batteries with current battery technologies alone, electricity generation is absolutely REQUIRED. Windmills can help soften the blow and storage needs substantially, but the TFA is about solar, which is effectively absent during the winter.
That was a good number in 1980 lmao (or in the US maybe), passive houses are often 1/5th of that. I'm talking 25cm+ of rockwool in the walls, 40cm on the roof and triple pane windows, mostly facing south, reasonably shaped house that conserve heat by design, etc.
0.5 W/m²/K is a good value.... for a window, certainly not for the overall house, for a wall it wouldn't even pass code in most of Europe
> That's entirely unrealistic to cover with batteries with current battery technologies alone
It already is a reality for many people.
There's a mix of miscommunication and wat. I'm using approximate floor area values here, not perimeter walls. 0.1 W/m2/K for a WALL is definitely not a "passive" house, that's barely A++.
> I'm talking 25cm+ of rockwool in the walls, 40cm on the roof and triple pane windows,
Yep, this gets you something like 0.5 realistic, maaaaybe up to 0.3 in the models.
> It already is a reality for many people.
Megawatt-hour level home-battery installs? Show us a picture. That's literally a room full of batteries. The actual reality is having ten or so kilowatt-hours to balance rooftop solar.
Regarding heating - I live in cold climate. We had average daily temperature of -10c this january, with multiple lows at -25c, and most nights at -15c. The house is 116sqm. Our heatpump COP for that month was above 2, and we used 787kWh total to heat the house, which is not a lot, actually. At 15 cents per kWh it is 118 euros for heating, for the coldest month in a decade! Considering also that we do not pay for electricity since april until october (solar panels).
We also paid less than those houses which use natural gas, wood pellets, etc. We also do not need to do anything to keep house warm. Also, during summer months we could "drive for free" in EV due to free solar electricity.
All that just to counter your take on "major quality of life and activity time shifting trade-offs".
Proper insulation and good windows go a very long way. For instance, I set my heat to 66F during the day and 60F at night. When I wake up in the morning, the register is usually still above 60F.
I genuinely do not understand why people are so afraid of solar. It's baffling.
But to be clear, it's less about night vs day and more about summer vs winter.
I had a 20kWh array and 18kWh of batteries in Texas and it was GREAT in the summer. It'd start charging by 6am and be charged by 9am, even with simultaneous usage. Then we'd live off solar for the day (even with HVAC), go back on batteries around 9pm and they'd be out around 4am. No problem.
But during an overcast winter day, the stack wouldn't get power until 8/9, not make it to 50%, start discharging by 4/5pm, and be out by 10/11pm. It would easily be 8-10 hours where we were wholly dependent on the grid.
Not a problem, just a constraint to acknowledge and plan for.
Yes surely some days are cloudy
So some days you get 5% capacity factor, and need some other energy source as well
So it harms the economics of the venture
Look at the profitability of companies building utility scale solar farms, they cost 100 million and the company hopes to get a 10% return and pay a 3% dividend.
They still have to contend with moving parts for tracking the angle of the sun, fans on inverters, contactors, clearing snow, mowing grass, site drainage, tornadoes etc, so sometimes it is not as easy as it sounds
All for a 7%? Why shouldn’t they just buy the s&p 500 and call it a day
The problem with global ecological regulations is they never differentiate between countries on the equator or 30th parallel with countries around 60. They expect everyone to only run on sun and wind. It isn't possible. There has to be at least nuclear which is ridiculously expensive.
It's generally not an easy problem to solve otherwise it wouldn't be a problem anymore.
First sensible thing to do is to relax the expectations for countries like Poland that have no good way to compete with other countries energy wise because of geographical location that noone chooses.
It is extremely unfair to treat everyone the same even though every country has different energy resources.
If no one needs it during the day, they can't sell it. That's not how markets work. Energy that is generated, needs to be consumed or else the grid breaks down. These two facts together mean, that the energy they sell is needed and used. Albeit they could generate and sell even more energy, if the energy could be stored or if the load could be shaped accordingly. The latter is a great way to lower energy costs.
Energy consumption during the night is low. So low, that night time electricity prices, which are lower than the daytime prices, are still a thing.
Heat pumps are an opportunity for load shaping. Buildings can be heated, when electricity is abundant and heated a few degree over the target temperature, if needed. The heat is stored inside the building and needs less heating during the night. That works quite well, especially here in Europe were buildings generally have good insulation and are made of brick, which can store a lot of heat.
I have a modern cold climate air source heat pump which essentially needs to run 24 hours a day to maintain a stable 20C when the outdoor temperatures reach -15C. Below that, the heat pump shuts off and the furnace kicks in to provide emergency heating. My thermostat is a modern one with full time-of-day and day-of-week scheduling for heating and cooling, but it doesn't matter because the heat pump by itself is not able to swing the temperature up (by even half a degree) on its own, so this causes the furnace to kick in every time the schedule calls for a higher temperature, defeating the entire purpose of time-of-day scheduling.
I will also add that where I live (Southern Ontario) the sky is overcast 90% of the time during the winter. Solar panels, even somehow free of snow and ice, are going to produce almost nothing on those dark days. Add in the need to keep the panels free of snow and ice (presumably with heating, since nobody is going to be climbing around on their roof in the winter), and you'd likely reach energy net-negative trying to make use of them.
Yeah, I understand I'm probably an outlier at 66F. I was using the numbers more to point out how little a house temperature will drop with good windows and insulation.
My house was built in the late 1980s. It has decent insulation but not amazing. It still needs a lot of heating when temperatures plunge below -15C. I do not have a whole-house humidifier. I had one with my previous furnace but it had issues with mold in the filter and clogging of the condensate pump.
At 66 degrees F? That sounds like put a sweater on if you’re chilly, not some near death extreme.
Any evidence that such an ‘extreme’ would cause issues?
I know people who live in the Mediterranean and get by with no heating during the winter with indoor and outdoor tempuratures this low or lower, so it seems that one can be conditioned into doing so.
Perhaps it's the presence of more sunlight on average rather than the temperature that makes the difference.
I've lived in extremely cold and extremely hot/humid places.
I cannot imagine setting the temp in the house that high.
I also agree that 66F (about 19 degrees Celsius) is not comfortable during day time. It is fine for sleeping temperature. During winter homes in heating dominated climates typically have higher indoor temperatures. One advantage of lower inside temperature is that relative humidity stays slightly higher when it is very cold outside.
Thermal curtains are more effective than good windows. Good windows are minimally helpful.
In my last house, I replaced single pane windows with properly installed, sealed, and insulated double-hungs and it practically cut my heat bill in half. I agree that modern window to modern window replacement probably won't get you much, though.
The cost of materials going into modern batteries easily leaves room for another 10x reduction in price, IMO where this all is heading is obvious. Zero marginal cost will win every day of the week.
FWIW we run our cabin on 15kWh battery today year around, though we do run a small wood stove to supplant the heat pump on cold winter days.
Also, living in SFH isn't avoiding all problems. I'd rather live in a properly-built apartment than my old house when my neighbor left her dogs outside to bark for the entire work day, every single day, and all the city would do is fine her a hundred bucks every few months. (or if you want to say "rural", that's 1 a small fraction of the population and 2 I like hospitals).
I just live far enough from the center of it all that I have a vacant quarter acre and thicker windows that happened when the last owner's mistakes caught up with me the current owner. For medical, I have UCSF, and for major medical, I have medical tourism, something I fully endorse from experience. And yes, not everyone can do that. And well, I can't touch my toes and they probably can. Life's funny that way.
For solar powered homes specifically though, multi-story buildings are much harder to run solar powered from the simple ratios - even if you reduce energy use 75%, at 4 stories you are break-even in roof-ratio-to-energy-need. I’ve worked in this space a while, and it’s now pretty straight forward to run single-family homes 24/7/367 on solar in most of the world, but multi story buildings are much harder.
Nothing is ever simple or one-dimensional :)
You don't need to colocate solar at the point it's used. Utility solar is cheaper than rooftop, by multiple.
The last part isn't true. There's no way you're running a home, including heat, entirely of solar in the winter in the Upper Peninsula of Michigan.
As for the last part not being true, can you clarify? The majority of the earths population lives between the 20th and 40th latitude, the band around the earth approximately between Madrid and the Sahara desert. Sure you can’t run a poorly insulated home in northern Michigan on solar year around without considerable expense, but that’s nowhere near where the majority of humanity lives.
From the Bay area or so and down across the country is ideal for solar, passing through a lot of red states that ought to know better. Fun fact though: Texas has the most windmills of any state by a huge margin.
This is not really a qualification to speak on how the grid works, at all.
Actually having panels on your roof doesn't give you unique insight into how solar panels operate - there is extensive data out there, any PV installation can become a data source trivially.
> The reality is that battery/solar requires major quality of life and activity time shifting trade-offs.
One residence powering itself is not representative of how the grid works, and is not a good way to evaluate any power generation technology whether its PV, coal, nuclear, etc.
But there are a lot of extra things you can do as an intermediate steps to dramatically close the gap. The main ones are:
1. Homes can be renovated to improve insulation 2. Cold weather heat pumps can handle most mild winter conditions efficiently 3. Electricity doesn't all have to be locally generated - it can be transmitted from other parts of the country. 4. You can keep using fossil fuel peaker plants, and still have incredible reduced overall emissions
A well built home with more insulation will, according to physics, lose less heat in any given scenario. So policies that push for things that improve buildings can reduce energy use.
Do you think we have reached peak building efficiency or something?
Most local electric and gas companies will do free energy audits. Many will offer rebates if you install tankless water heaters, heat pumps, and insulation. Installers get kickbacks from manufacturers and tax credits if you buy higher efficiency equipment. Lenders will give you 0% loans to fund it all. The Feds and many States offer tax credits for all of the above.
I've done every single thing on this list in the last 5 years, some in Texas, some in Indiana.
The average of installed units is closer to 2.0 COP average, unfortunately. Multi-head units really drive down efficiency. A single-head Gree Sapphire can do 4-5 COP on average and that's the best you can get, so still nowhere near your guess.
Under what circumstances? I've seen higher-end units that do maybe 1:5 in ideal conditions (heating to 68F when the ambient temp is 55F), but never seen units that do 1:10 or 1:15. This was about 2-3 years ago I did this research. Have things improved that drastically in the last few years?
Too many folks here do not understand or care to appreciate the constraints of the real world. Heat pumps are excellent and relatively cheap but have limitations. One of the biggest limitations is that a heat pump's efficiency drops as ambient temperature drops. This is the worst possible situation for heating as the conditions when the risks of losing heat are the highest, are precisely the conditions when these devices are least efficient.
What i remain opposed to is this persistent idea that heat pumps work in all situations, for all people and for all time. They do not, and heat pumps create a unique set of problems that we might not be fully prepared for.
And Canada is not exactly the warmest country on the planet.
Keep in mind we WFH and homeschool so our house is used 24/7 and I think it's a good approximation for OP's goal.
This. You have enough generation to keep a mansion toasty, but you don’t have enough storage to last a long winter night.
Which is why a lot of poorly insulated houses still exist - people have mostly done what can be done for a reasonable price, but anything that will make a difference is also very expensive with very long paybacks.
So for a mild climate your installer seems to have done you a disservice and probably overcharged you. You can heat an average house with solar for under $14K if properly installed.
Because where I live around 55th this winter we had five straight weeks below -15c / 5f daily average plus enough snowfall that it was infeasible to clean anything but the most major roads.
Solar is out of question in these conditions and when thermal pump fails you have to evacuate. When just grid electricity fails you have to either have some sort of stored fuel backup or evacuate.
The article is typical handwavy crap which is popular among people living in what amounts to subtropics who can't even imagine how crazy they sound to most everyone else.
To be fair, 90% of the population lives within 45 degrees of the equator. If we're talking about global energy solutions for CO2 reduction, we can go a long way just by focusing on what works in these areas of the globe.
The article does also point out that hydro/wind are going to be important at higher latitudes in winter, but they also acknowledge that they don't account for seasonal variation in demand. That's the biggest flaw I can find in the analysis.
FWIW: I'm down in a mild arid climate at 35N, and yeah, 90% of our winter days are nearly sunny, even when the lows are in the teens. It's a different world for sure.
Make energy so expensive that people have to move away or burn their old house.
handwavy argument. Yes, in the (sub)tropics the argument is even stronger pro-PV, not the least because it'll give you the opposite of heating - aircon - for free right when you need it. And considering summer heatwaves as have been seen the last few years "way north", that benefit will extend that way even if you wouldn't bother considering letting it "assist", if not fully replace, your heating. That said though, for 50° polewards and above, if you wanted to use PV in winter orient the panels vertically. If you can clad your too floor with shiplap larch so you can with PV panels. Given the price of timber ... there's a plan.
(only saying handwaving goes both ways)
Most everyone else? Only about two percent of the Earths population live above the 55th parallel. There’s a big gulf between that and the ‘subtropics’.
I don’t disagree that solar/battery isn’t the answer for 100% of power needs, let alone 100% of heating needs, but if we got to even 50% we’d be in a lot better situation than we are now.
I don’t know where all that energy was going. I expected some improvement but not anywhere near that much.
He even has a map that covers this and multiple paragraphs of discussion about high latitudes and wind in winter.
Cooling, on the other hand, is brutally expensive without living in basically an air tight Styrofoam box (or underground).
People just really underestimate how much energy it takes to produce heat, and how little energy a solar system produces in the winter. Double whammy!
Of course actual data like this is downvote heresy! Go for it! Also, bite me.
I had 219 days with under 24 kWh use, i.e., drawing an average under 1 kW. I got an EV in mid April that year which I charged with the included level 1 charger until getting a 12 kW EVSE installation in I think May. (2024, the last year with no EV charging, had 240 days under 24 kWh).
Almost every day that was over 30 kWh after that was a day when I charged the car which was typically on a Saturday which is also typically when I do laundry which includes about 5 kWh for the clothes dryer.
I was puzzled by the large number of days near or above 50 kWh in February. The end of 2025 doesn't look like it is setting up 2026 for that high a usage. I just checked the weather records and it doesn't look like that was a particularly cold time.
I just made another graph just showing February 2024, 2025, and 2026, and a third showing January of those 3 years, and both show that in 2026 I'm using quite a lot less power (except for the EV charging) than in the prior years.
I've not changed any habits...but in November 2025 I had my house weatherized. They added a lot more insulation under the house (I already had sufficient attic insulation) and did blower tests and sealed everything that was leaking, and it appears this cut energy use by somewhere in the 10-20% range.
It seems then early 2025 appears so high because the end of 2025 is showing the effects of weatherizing.