Whole-home generators

Essential circuits or the whole house

There are two common ways to set up a standby generator. An essential-circuit system powers a selected set of circuits through a smaller transfer switch: heat, well pump, sump pump, fridge, some lights and outlets. A whole-home system uses a service-rated transfer switch, often 200 amps, so the generator can feed the entire panel.

In larger Armonk houses, the whole-home option is popular because outages can stretch into days and families want air conditioning in summer storms and full heat in winter ones. The tradeoff is cost and generator size.

Load management

Running a whole house does not always require the biggest generator. Many installers use load management modules that briefly hold back large appliances, like a central air compressor or an electric dryer, until the generator has room for them. That lets a mid-size unit cover the whole house without overloading. Ask whether your quote includes load management and which appliances it will control.

What drives the size

The biggest loads in a typical house are central air conditioning, electric cooking, electric water heating, a well pump, pool equipment and, more and more, an EV charger. Each one needs to be counted. Starting loads matter too: motors draw far more power for a moment when they start than when they run. A careful load calculation accounts for this. Fuel affects output as well, since manufacturers usually rate the same generator lower on natural gas than on propane.

• List every large appliance, including any you plan to add
• Tell the installer about a well, sump or pool
• Ask how an EV charger will be handled during an outage
• Ask for the calculation in writing

Fuel for a larger unit

A whole-home generator burns more fuel than a small unit, especially under heavy load. On natural gas, the utility has to confirm that your meter and service can supply the generator and everything else at once, and a meter upgrade is sometimes needed. On propane, tank size sets how long you can run before a refill, so ask the installer and your propane company to size the tank for a multi-day outage. All gas and propane connections should be made by licensed professionals.

Panels and older wiring

A whole-home transfer switch connects at the service entrance, so the condition of your panel matters. An older or undersized panel may need replacing first. See electrical panel upgrades for what that involves and what it typically costs.

Questions homeowners ask