Home / The guide / Heating and cooling

Build a thermal energy budget and hand it to the power design

Every electric heater, heat pump, fan, pump, fridge and cooktop adds to your daily kWh and peak watts. Agree the thermal loads with the power design before buying either system.

How

1. List each thermal appliance with its expected daily kWh by season (winter heating, summer cooling, hot water, cooking, refrigeration, fans and pumps).
2. For heat pumps, use the heat pump electricity calculator in this module to turn the heat loss into daily kWh.
3. Note controls that need power even for fuel appliances: most pellet stoves need electricity (about 100 kWh a month in DOE guidance) and give no heat in a power cut without backup.
4. Separate loads that can run in sunny hours (water heating, pre-cooling) from loads that must run at night.
5. Send the seasonal list and peak loads to the power module so the array, battery and inverter are sized for your worst month, not the average.
6. Plan a non-electric fallback heat source in cold climates.

Do these first

• power-1

Sources

1. Wood and Pellet Heating. U.S. Department of Energy, Energy Saver, accessed 2026-11
2. Decarbonization Tech Snapshot: Heat Pump Water Heaters. U.S. Department of Energy, accessed 2026-11

Open in the interactive guide