1800 kWh is very little. We use around 12000 kWh and our neighbours' new house uses around 8000 kWh annually and most of that is heating. I'm not sure how many houses can hit 1800.
A modern house in Finland needs around 15-24kWh a year of heat energy if it's well insulated. On the higher end for big + northern houses, and less if you're smaller and further south.
Some get this energy by burning wood, others with heat pumps, and some with direct electricity.
That can’t possibly heat any home for an entire year.
The ground beneath the footprint of the house was insulated around the sides to a depth of about 2m, effectively extending the thermal mass of the house into the ground. After construction, it took about 2 years (IIRC) to warm to a stable level, but thereafter required little to no energy to stay at a comfortable temperature year round.
I'd like to see the stats on temperature levels over a lifetime.
Ground source heat pumps are expensive because of the buried piping, I imagine this would be even more costly.
Because building houses is already expensive, and that would add significant amount, pushing it into "can't afford it in the first place". And zero ability to realistically service it means anything going wrong might make whole investment moot.
On top of that, any investment like that competes with "why not just put the money into low risk fund"
> 1800kWh per year
now factor in losses for months now factor the fact the energy you're using for heating is one you're not using for... energy or selling
also is that heat or energy ? Because if that's "what power heat pump used", multiply that by 3-4
It's just... expensive to do it like this. Expensive enough that most people that could did the math and it wasn't mathing
- You're talking about what heat pumps use in electricity. However, the system would store heat. If a heat pump uses 1 kWh to get 3 kWh of heat into the house, a heat based storage system needs to store the 3 kWh.
- You're confusing gas & electricity. 1800 m3 in gas would be about correct. However, that's about 9,5 kwh per m3 in heat.
There are interesting heat storage methods though, there is a long term basalt heat storage system in 'Ecodorp Boekel' in The Netherlands. It uses solar to heat during the summer and heats the homes with that in winter.
Due to size though, it only really works in 'collective' communities. The bigger the size, the more heat it can store per size.
Nowadays, solar thermal collectors are completely obsolete except in very niche applications. Solar PV is so cheap that it’s literally cheaper (not to mention much less maintenance) to wire a bunch of PV panels to a resistance hot water heater than it is to directly heat the water with thermal collectors!
Skip the tank completely. Use the ground directly. This is what geothermal heating does.
Drill a deep hole and drop tubes into it. Use a heat pump to pump heat into or out of the ground. There is so much easily accessible thermal mass in a borehole that you don’t need to deal with a giant underground water tank
Thorstein Chlupp, of Rienna LLC, built several net-zero homes in the Fairbanks, AK, area. He hasn't been active for a number of years now, but released several videos in the mid-2010s detailing his design, construction, thought, and results.
He's apparently been with NREL since 2023: <https://research-hub.nrel.gov/en/persons/thorsten-chlupp/>.
There's a nearly-decade-later review of one of Chlupp's Alaskan homes, the Sunrise House, written in 2020 (the house was constructed in 2011): <https://www.greenbuildingadvisor.com/article/the-sunrise-hou...> (paywall).
And the original video series and channel:
<https://www.youtube.com/watch?v=AtHkvpRI6fc>
<https://www.youtube.com/@REINALLC/videos>
At the core of Chlupp's homes was a thermally-stratified 5,000 gallon storage tank. This was ideally aligned vertically (to improve thermal stratification), though at least one home had a horizontal alignment. The tank was inside the core of the home, which means it occupies significant internal space. I don't know if there have been any mechanical / technical issues with the design over time, though at least initial results were strongly positive.
If you assume a modern house with a heat load of 1800kWh per year (fairly standard for a new build medium sized home where I live, in Northern Europe) that means you'd need a tank roughly 50m3, or 10,000 gallons for Americans. In terms of insulation you'd need around 50cm of XPS foam, and it would be buried a meter below ground.
It's nothing terribly complicated in terms of construction or engineering. Of course you'd pay more upfront, but then your heating bills would be practically zero. In warmer climates it would be much simpler, you could probably get away without burying it.