How to size a standby generator for a Florida home

Published 2026-04-30 · 7 min read

Start with the list, not the number

Write down what genuinely has to work in an outage. For most Florida households that is: the air conditioning or at least one zone of it, the refrigerator and freezer, the well pump if you have one, lighting, internet, and enough outlets to charge things and run a medical device if anyone needs one.

The list drives the size. Working the other way, picking a unit and then discovering it will not start the AC compressor, is how people end up disappointed with an expensive machine.

Air conditioning is the deciding load

A compressor draws far more starting than running, and that inrush is what sets the minimum generator size. Soft starters can reduce it substantially and sometimes let a smaller generator carry the same house, which is worth pricing before you buy up a size.

Be honest about how many tons you are trying to run. A house with two systems trying to run both at once is a different machine from a house running one zone.

Whole house or essentials

Whole house means the generator carries everything and you notice nothing. Essentials means a subset of circuits move to a dedicated panel and the rest stay dark.

Load management sits between the two: the system sheds lower-priority loads automatically when demand climbs, letting a smaller generator behave like a bigger one. For many Florida homes this is the best value point in the whole decision.

Natural gas or propane

Natural gas is simpler where a main is available, because there is no tank and nothing to refill during a multi-day outage. Propane covers everywhere else, but you need to size the tank for the run time you want, not just for the appliance.

Do the arithmetic on tank size honestly. A generator running a house through a five-day outage consumes considerably more than most people assume.

The transfer switch is not an accessory

An automatic transfer switch is what makes a standby generator standby. It senses the loss of utility power, starts the unit, transfers the load, and reverses all of it when the grid returns, whether or not you are home.

It also isolates your house from the utility line, which is the safety function that makes backfeeding a portable generator through an outlet so dangerous by comparison.

Florida installation specifics

Mount above your flood elevation, not just above grade. Anchor for wind: the pad and tie-down detail is not paperwork, it is what keeps the unit where you left it.

Respect the clearance requirements around the enclosure, including from windows and openings, and expect the exercise cycle to be audible to a neighbour. Siting it thoughtfully once avoids a long conversation later.