HVAC
Cooling and heating equipment can drive the plan because the equipment’s demand and starting requirements must be considered with other selected loads.
Standby Generator Sizing: What Actually Needs to Run
Start with the loads you need during an outage—not the size of the electrical panel.
Backup-power planning
A generator is sized for what the home must carry at the same time.
Request a generator assessment →Backup power works when the load plan, transfer equipment, fuel supply, installation details, and test procedure all agree. The first decision is whether you need the whole house or a carefully selected critical-load plan.
Start with a real load plan
- Identify the equipment you want to operate together
- Account for motors and other equipment with higher starting demand
- Define which loads are essential during an outage
- Coordinate transfer equipment, fuel supply, and installation requirements
What decides the size01 02 03 04
Panel capacity is not the same as outage demand.
Pumps
Well pumps, sump pumps, and other motor-driven equipment may have demand that needs to be planned for rather than assumed from the panel alone.
Appliances
Electric ranges, dryers, water heaters, refrigeration, communications, and selected outlets shape a practical plan for how the home will operate.
Transfer
The transfer equipment and panel arrangement define how the generator connects, operates during an outage, and returns to utility power.
Whole home or critical loads
Decide what matters before choosing equipment.
Critical-load backup can focus capacity on lighting, refrigeration, communications, selected outlets, and equipment you define. Whole-home backup requires a larger coordinated plan based on the loads that may operate together.
Fuel and testing matter too
Plan the complete system.
Natural gas and propane supply need to support the chosen load and expected run time. Fuel routing, clearances, service capacity, transfer operation, output under demand, and return to utility power should be coordinated and tested as one system.
A clear sizing assessment considers
Loads, transfer, fuel, installation, and testing.
- Loads that must operate during an outage
- Starting demand for pumps and HVAC equipment
- Whole-home or critical-circuit backup goals
- Fuel type, supply, routing, and expected run time
- Transfer equipment, clearances, commissioning, and load testing
Common questions
Avoid assumptions before the generator is installed.
Can a small generator run my entire house?
Only if the actual connected load and starting demands fit the generator and transfer plan. A load evaluation makes those decisions explicit.
Why is a load test important after installation?
Testing confirms transfer operation, output under demand, and return to utility power rather than leaving the system unverified.
Does the fuel supply change the plan?
Yes. Natural gas and propane supply need to support the chosen load and run time. Confirm service capacity and routing before installation.
Free · No obligation
Request a generator assessment.
The existing Sentinel HighLevel form records your request for follow-up.
Plan backup power
around real loads.
Request a generator assessment and define what the home needs during an outage.