Identify the heating technology
Electric resistance furnaces, baseboards, heat pumps, gas furnaces with electric blowers, and portable heaters have very different electrical profiles. Begin with what equipment is actually serving the home.
Watch for auxiliary resistance heat
A heat pump may energize electric resistance strips during cold conditions, defrost, large thermostat recoveries, or equipment faults. Those strips can draw several times the compressor power.
- Avoid large setbacks that trigger recovery heat.
- Check whether the thermostat shows auxiliary or emergency heat.
- Have unexplained continuous backup heat diagnosed.
Water heating works harder
Colder inlet water and longer hot showers can raise water-heating energy even when the tank setpoint stays the same.
Normalize the comparison
Compare kWh per day, similar outdoor temperatures, occupancy, and billing-period length. A 35-day winter bill should not be compared directly with a 28-day bill.
Sources and further reading
DOE Energy Saver: Heat pump systemsCalculations are estimates. Utility bills, appliance measurements, and manufacturer documentation take priority over generic examples.