An all-electric home needs a generator plan built around its largest simultaneous demands, especially winter heating. A system that runs summer air conditioning may still be inadequate when electric auxiliary heat, water heating, cooking, and other loads overlap.
Find the heat-strip rating before choosing the generator
A heat pump moves heat with a compressor. An installed electric resistance heat kit supplies heat by drawing electrical power through heating elements. These are different loads. Depending on the system and conditions, auxiliary heat can operate alongside the compressor.
The U.S. Department of Energy describes the role of electric resistance backup heat in residential heat-pump systems. Ask the HVAC contractor for the installed heat-kit rating and staging behavior, not just the outdoor-unit model.
Consider an invented winter scenario: the compressor, blower, and other essential equipment together require 5 kW. If a 10 kW resistance-heat stage then operates in addition, total running demand becomes 15 kW. Those values are illustrative, but the arithmetic shows why overlooking the heat kit can materially understate the load.
Decide how the home will stay warm in a long outage
Discuss the outdoor temperatures the design needs to cover and the rooms that must remain heated. If the proposal limits auxiliary heat, have the HVAC professional confirm whether the remaining heating capacity is adequate and whether the controls support that operation.
Do not simply switch off heat-strip breakers to make a smaller generator appear adequate. The plan needs to address system operation, defrost-related behavior where applicable, indoor temperature, and freeze protection. If required heat cannot safely be deferred, provide enough capacity or develop another approved heating plan.
Give hot water its own line in the load plan
Record the water heater’s electrical input and operating modes. A resistance tank, electric tankless unit, and hybrid heat-pump water heater can place very different demands on backup power.
DOE’s heat-pump water-heater guidance notes that many hybrid models include backup resistance elements. Do not size the generator around compressor-only operation if another mode can bring those elements on. For a tankless heater, check its actual input rating rather than borrowing a tank-water-heater estimate.
Assign a clear job to each large appliance
| Load | Decision to make |
|---|---|
| Space heating | Which heating modes and zones must remain available in winter? |
| Refrigeration and required pumps | Which automatic loads must be allowed to operate with heating? |
| Water heating | Can recovery pause briefly, and what control will enforce that? |
| Cooking and laundry | Which functions are included, and which combinations can be avoided? |
| EV charging | Must the vehicle charge during the outage, at what rate, and under what controls? |
This is a discussion framework, not a universal priority order. A household depending on a vehicle for essential transportation may make a different EV decision than one with adequate stored charge.
Compare capacity and controls together
Ask for two concrete proposals if useful: one supporting broader simultaneous use, and one using defined load-management priorities. Include the installed control costs and explain the interruptions each option creates.
Do not assume an all-electric home automatically needs a particular air-cooled or liquid-cooled generator. The supported loads, starting events, fuel supply, and operating expectations should determine the equipment. Generac’s professional sizing tool includes managed-load inputs because control choices can affect the result.
Bring Brite Generators the heat-kit label, water-heater model, HVAC information, and desired EV charging plan. The HVAC sizing guide covers compressor considerations; the winter review adds the heating loads that cooling-only calculations can miss.
Connected guidance
Decisions Related to Sizing a Generator for an All-Electric Home
Continue exploring this Topic with Running Watts vs. Starting Watts for Generator Sizing. Then connect this decision to Manual vs. Automatic Generator Transfer Switches and Gasoline vs. Dual-Fuel vs. Tri-Fuel Portable Generators; those adjacent choices can change equipment, installation scope, operating readiness, and total ownership cost.