I live in Quebec, where the cost of electricity is low (10 cents/kwh = 7.7 US cents/kwh). I consume around 17400 kWh/year for my entire house. My consumption splits into 3 parts:
- around 5000 kwh/year for my heating and air conditioning (geothermal unit), average temperature required (winter): 22C (71 F)
- 4000 kwh/year for my electric car,
- 8000 kwh/year for the rest, including water heating (around 1600 kwh/year) and everything else. My fridge consumes 365 kwh/year.
In winter, my geothermal consumption is around 800 kwh/month (25 kwh/day).
I can do without heating throughout the season, except in winter. My fridge has to run all the time. I can wash elsewhere.
I can lower my heating temperature to 15C (60F) in case of the grid failure. Estimated consumption at this temperature: 18 kwh/day
To sum up, I estimate that my minimum consumption in winter should be 20 kwh/day.
The geothermal unit operates on 220V single-phase
Installing solar panels doesn't seem a good choice to me (cost of electricity, depreciation of equipment, aesthetic constraints on the part of the city, etc.).
So I'd like your opinion on whether I should build a powerwall to last me 3 days or more (estimated maximum duration of power cuts), i.e. 60+ kwh actually usable.
If necessary, I could add a gasoline generator (noisy), if the outage time gets longer.
What do you recommend, as a first approach? One or more commercial LiFePO4 packs (with BMS, etc.), a home-made battery kit?
And the inverter must generate 220V, I remind you.
Thanks for your comments.

- around 5000 kwh/year for my heating and air conditioning (geothermal unit), average temperature required (winter): 22C (71 F)
- 4000 kwh/year for my electric car,
- 8000 kwh/year for the rest, including water heating (around 1600 kwh/year) and everything else. My fridge consumes 365 kwh/year.
In winter, my geothermal consumption is around 800 kwh/month (25 kwh/day).
I can do without heating throughout the season, except in winter. My fridge has to run all the time. I can wash elsewhere.
I can lower my heating temperature to 15C (60F) in case of the grid failure. Estimated consumption at this temperature: 18 kwh/day
To sum up, I estimate that my minimum consumption in winter should be 20 kwh/day.
The geothermal unit operates on 220V single-phase
Installing solar panels doesn't seem a good choice to me (cost of electricity, depreciation of equipment, aesthetic constraints on the part of the city, etc.).
So I'd like your opinion on whether I should build a powerwall to last me 3 days or more (estimated maximum duration of power cuts), i.e. 60+ kwh actually usable.
If necessary, I could add a gasoline generator (noisy), if the outage time gets longer.
What do you recommend, as a first approach? One or more commercial LiFePO4 packs (with BMS, etc.), a home-made battery kit?
And the inverter must generate 220V, I remind you.
Thanks for your comments.
