How does the cost estimation work?

Optiwatt uses your home address to find the size of your home, its age, the outside temperature, and other relevant data points. This is used to calculate the thermal efficiency of your insulation, the daily losses that occur as a result of heat exchange, and the output of your heater(s) and/or air conditioner(s) that keep you comfortable. If you feel your costs are inaccurate, you can update them accordingly via the Home Estimations section in your thermostat's Devices page.