Given 6 MWh of exports with only 3.2 MWh of total solar production, they are cycling their powerwall to get paid for the fact that their off-peak rate is half the price of their peak export tariff rate which is inflating the number you're looking at.
In my house I only run LED lighting and an occasional oven, some phones and laptops, a cycling fridge and two weekly wash cycles, in other words, virtually no electricity. I'm at like 2 kWh per day.
The ~45 kWh a day for this family is gigantic compared to mine, like >20 of my homes in one.
But I don't have an electric car, nor electric heating or cooling, nor an electric stove.
If you have say a standard electric car like a Peugeot 208 which uses 15 kWh per 100km, and you both drive one hour (say 60km) to work and back, five days a week, that's already 25 kWh per day.
My heating bill (gas, europe) is an order of magnitude of my electric bill. Even if I'd electrify it (cheaper), it'd likely be an additional 10 kWh per day.
If you have slightly more fancy lifestyle (they run home-servers and a hottub for example), you can easily get to 45 kWh.
I think the fair comparison is to look at a household total energy expenditure (energy & $). My household has a low electrical share, theirs has an almost exclusive electrical share.
- Base electricity: 17 kWh/day (10 in months without AC)
- Heating (currently gas): 33 kWh/day
- Heating (if I switched to heat pump with COP 3): 10 kWh/day
- EV charging at 10k miles/yr: 9 kWh/day
Total if I was fully electrified: 36 kWh/day, or 13 MWh/yr
I have 2 EVs (Tesla and BMW), an electric oven, and a homelab rack (but no HVAC), and my usage was 34.4 MWh last year — with 100% from Solar and Powerwall.
I’m waiting on a quote for an hvac that uses its waste heat for the home hot water. Im irritated that I’m cooling the house, pushing out hot air, and heating water at the same time.
All in one systems with water heating are way too complex and _will_ fail relatively quickly, mini heat pumps won't last 10 years, and by the time it dies you won't be able to find a replacement for your specific model
Yay for New Zealand housing.
Can you offer some evidence of this? I don't see how adding a refrigerant to water heat exchanger after the compressor, before the reversing valve, could possibly hurt the longevity of a system.
> ... mini heat pumps won't last 10 years, and by the time it dies you won't be able to find a replacement for your specific model
Thing with mini-splits is you replace the entire unit so it doesn't matter.
The nearly infinite amount of forum posts about heat pumps dying prematurely and costing thousands and thousands to fix. You don't see how adding complexity on top of complexity in a complex system add points of failures ?
> Thing with mini-splits is you replace the entire unit so it doesn't matter.
I forgot this is an american centric forum and things are just made cheap/disposable because "it's cheaper'
I don't see see a heat pump as complex. It's a compressor, valves and coils. The complexity are the stupid computers foisted onto us.
> I forgot this is an american centric forum and things are just made cheap/disposable because "it's cheaper'
We don't have a choice. Do you? We're all at the mercy of the manufactures.
Some of this extra is certainly my 6kw homelab + HVAC for that. ;)
I was stoked at the power saving from turning off an espresso machine a bit sooner, a swapping out a nuc to a Mac mini.
Maybe there is a bit coin mining operation in his basement?
If you have a heat pump water heater and heat pump based floor heating you'll use 1/4th of the energy as the same house with resistive water/floor heating.
A house which barely passed regulation from 2010 will consume 5-10x the energy of a certified passive house.
etc.
That being said I think you have to draw the line somewhere. I'd much rather have inefficient appliances (resistive boiler/heaters) and be fully solar powered than spend 50k in heatpumps and other gimmicks that are rated for 10 years and cost a kidney in maintenance and the eventual replacement.
That's my reasoning my new build house with plenty of land. In other scenarios it might be more beneficial to go for them.
Of course the average american living in a mcmansion which wouldn't pass regulations in 1992 Poland cannot use such solutions, but really it isn't a problem of climate, you'll find passive houses from africa to norway and everywhere in between, most of them without heat pumps
They're also technically simpler and have fewer components that can wear out. And they're a single system that works both for cooling and heating, rather than needing multiple system investments.
The majority of experts believe that its the future technology stack to manage heat, not a gimmick at all.
That having been said, always start with good insulation first.
I do think more people should consider mini-split reversible AC in the UK, but the subsidy system specifically excludes it.
https://www.gov.uk/government/news/discounts-for-families-to...
Anecdotally, two of the smartest people I know love heat pumps—doesn’t Technology Connections too?
Was probably this:
Heat Pumps: the Future of Home HeatingNo one is heating their place with air/air heat pumps besides americans who haven't figured out that heating spaces via air is shit tier in term of comfort and efficiency
At least here in Finland a lot of people do. Very popular choice when replacing old oil furnaces (and as a "replacement" for direct electric heating offcourse)
Geothermal heatpump is something people mostly think about when building new.
Air heatpumps with the inside unit start from around 1000€ and 300€ to 500€ for the install. The price is mainly based on the size of the house (and in big houses you will need multiple or one with multiple inside units)
A fireplace for the couple really cold weeks to cut down the electricity bills are popular but people had those even before the air heatpumps so nothing new really.
You can already do most of that with a passive heat recovery ventilation system coupled to a ground/water exchanger. All systems are independent and the most high tech equipments you need are fans and a water pump
Only using ductwork for heat recovery ventilation without also using it for heating and cooling means more complexity, instillation costs, and maintenance issues etc. Further moving air allows you to use dramatically less material for heat exchangers.
Net result higher efficiency, fewer things that can break, fewer locations something can break, and lower risks of water damage to your home etc.
I am, and I am not an american, lol.
How many sq/ft is the house?
Is it filled with windows facing south?
Are they firing a continuous laser beam at the moon?
2-3x usage is actually pretty typical when looking at a single house when comparing to average. It's when you start getting close to an order of mag difference that you're an outlier.
I live in the Bay Area, CA in a 1,500 square foot house and consumed 7.8MWh in 2025 and 7.6 MWh in 2024.
Digging a bit more into our solar system data: We produced a bit over 9MWh in solar each year and it looks like our Enphase batteries discharged 2MWh each year.
thus perhaps leading to more global warming
We still have an ICE car and gas central heating but our combined electricity and gas bill is around £140 / month
Plan to go to EV and heat pump in our next house though
That probably explains it.
An average EV gets what, ~3.5mi/kWH? An average US car does ~12,000mi/yr. That theoretical average EV would then use ~3.5MWh. Two would be ~7. But this author is in the UK, where the average car only does ~7,500mi/yr or so or a little over 2MWh/yr. So for their two UK cars, assuming they drove an average mileage in an average EV efficiency, they would likely have used something like 4.3MWh/yr for their cars. About 20% of their total electricity usage. This drops a good bit if they're really getting closer to 4mi/kWh in efficiency, which is likely if they're not driving on many highways like one does in the US.
We have one car and charge it quite often.
I just checked last month: 184kwh went into the Leaf. We used 557kwh in total (excluding the car charging).
We generated 1170kwh.
The key thing for me is the wild energy usage from the house. It’s a lot.
Edit: Your car energy usage calculation works out awfully close to what we use.
In 2025 I produced 6.5MWh (solar) and consumed 12.7MWh (excluding solar production); this is a family of 4 in a 4 season climate with electric heating and a single electric car.
That was my highest year over the past 5 years.
An additional EV can really add up, especially if both people have long commutes.
Still, even with our lower usage, solar still makes sense (especially with a South-facing roof) because electricity is so damned expensive in the UK :(