Florida generator guide

Two Generators, Same House, Very Different Fuel Bills

Picture two houses on the same street. Same square footage, same AC, same week without power after the storm. When the propane truck comes back around, one owner's tank is barely touched and the other's is half gone — and here's the part that doesn't add up. The one burning more fuel bought the bigger generator, the one everybody said was the safe choice. So how does more machine end up costing more to run the exact same house?

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About five minutes. No salesman, no all-day window.

Bigger sounds safer. Your engine disagrees.

The logic feels airtight. Buy more generator than you need, leave yourself headroom, never worry about running short. Nobody ever got fired for buying the big one.

But a generator engine isn't a light switch that's either on or off. It's an engine, and engines have a sweet spot — a load where they turn fuel into power cleanly and everywhere else where they waste a little. Run one way below what it's built for and it doesn't sip daintily because it's barely trying. It loafs. And loafing, it turns out, is its own kind of expensive.

That's the whole trick behind those two tanks. The right-sized unit spends the outage working near its sweet spot. The oversized one spends the outage barely awake — and pays for the privilege.

Why loafing burns fuel you never use

Here's the thing most people get wrong: they assume half the load means half the propane. It doesn't. Drop a unit to half its rated load and the fuel bill only comes down by a bit less than half. Cut the load to a quarter and you don't cut the fuel to a quarter — not even close.

Think of your car sitting at a long red light. You're going nowhere, but the engine's still drinking gas just to keep itself spinning. A generator has that same baseline appetite. A chunk of every gallon goes to keeping the crankshaft turning and the electronics fed before a single watt reaches your fridge. On a right-sized unit that overhead is a small slice of the pie. On an oversized one loafing at a third of what it can do, that same fixed overhead is now a huge share of a small amount of real work — so every kilowatt-hour it delivers to your house arrives more expensive.

The cleanest burn happens up near three-quarters of what the engine's rated for. Slide down toward a quarter or a third, and the fuel it takes to make each unit of power climbs — not a rounding error, but the kind of gap that shows up on the propane invoice after a five-day outage. The big generator wasn't lazy. It was overqualified, and you paid the overqualification tax by the hour.

In Florida, the AC decides the whole thing

So how do you land near that sweet spot instead of way below it? You size to what your house actually pulls — and in Florida, that conversation starts and ends with the air conditioner.

Your AC is almost always the biggest single thing your generator has to feed, and it's sneaky about it. For a fraction of a second when the compressor kicks on, it demands several times its normal draw — a hard jolt the generator has to swallow without stumbling. That inrush is the reason so many homes get talked into an oversized unit: buy enough machine to absorb the spike and you're covered, right?

Except there's a quieter fix. A soft-start on the AC shaves most of that startup jolt down to something manageable, which means a smaller, right-sized generator can handle the same house without breaking a sweat. A trimmer unit with the AC tamed can carry a home that a bigger unit was only handling by brute force — and it does it living near its efficient band instead of loafing below it. Same comfort, cooler-running engine, lighter tank. The goal was never the most generator. It was the right one, matched to the load your house really has.

The only way to know is your actual address

Every rule of thumb in this article breaks the second it meets a real house. Your AC tonnage, whether it's one system or two, the well pump, the electric range, the pool equipment, the panel you're actually working with — that's what decides which size lands in the sweet spot for you, and none of it is guessable from a blog. The homeowners who nail their fuel bill are the ones who sized to their house, not to a hunch.

That's the number worth having before you buy anything. Tell GENERasic your address and what's in the house, and you get one committed installed price for the unit that fits it — not a range, not a ballpark that grows on install day, one price for the right-sized generator for your home. Run your address through the price tool and see the size — and the number — your house actually calls for.

Common questions

During an outage, how do I even know what load my generator is running at?

You mostly don't feel it, which is why this catches people off guard. A whole-home unit quietly matches whatever your house is pulling at that moment — high when the AC and dryer both kick on, low at 3 a.m. when it's just the fridge and a couple of fans. Across a real outage most homes average somewhere in the lower-to-middle part of the generator's range, not full tilt. That's exactly why a right-sized unit matters: it keeps that everyday average closer to the engine's efficient zone instead of way down in loafing territory.

Isn't a bigger generator just a waste of fuel then?

Oversizing works against you two ways — you pay more up front for the bigger machine, and then it runs less efficiently every hour of every outage because it's rarely working hard enough to hit its sweet spot. That doesn't mean grab the smallest box on the shelf. Too small and it can't carry your house at all, or it runs pinned at full load the whole time, which is its own kind of strain. The win is the middle: the size that lets your real load sit near the efficient band. Right-sized beats both oversized and undersized.

Should I shut the generator off at night to save propane?

Plenty of homeowners do exactly that — run it through the day, cut it at night, fire it back up at breakfast — and it does stretch a tank. Just weigh what you're protecting. In a Florida summer, killing the AC overnight means a hot, humid house and a fridge slowly warming toward the danger zone. A right-sized unit running low-and-steady overnight often costs less than people fear, precisely because a light nighttime load is a light burn. If you're sizing correctly in the first place, running through the night usually isn't the budget-breaker it feels like.

How long will one propane tank actually last?

It depends far more on your load than on the sticker size of the generator. Homeowners running mid-sized units through real outages routinely report getting a couple of days of steady use out of a common tank before it's meaningfully down — because they're never running flat-out. Push everything at once and it drains faster; run a sensible load and it stretches. If you want the tank to go further, the two biggest levers are a right-sized generator and taming the AC startup — both keep the burn lower every hour.

Do I really need the load calculation, or can I just pick a size off a chart?

Charts get you a guess; your panel gets you the answer. Two houses that look identical from the street can call for different sizes once you count the AC tonnage, the well pump, the water heater, and whether there's a second system or a pool. Sizing off your actual electrical load is what puts the engine in its efficient zone instead of loafing or straining — and it's the difference between a fuel bill that surprises you and one that doesn't. Give GENERasic your address and the load calc drives the committed price you get back.

Stop reading ranges. Get your number.

GENERasic pulls the real property, flood, and elevation data for your exact address and returns one all-in installed price — sized to your home, your fuel, and your flood elevation. The vetted local installer confirms it on site.

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