GeneratorWatts

What size generator for a 1,500 sq ft home?

Short answer

To keep the essentials running in a 1,500 sq ft home during an outage you need a generator rated for at least 4,180 starting watts — about 2,630 running watts for a fridge, heating/cooling, pumps and lights, plus the furnace blower fan's startup surge. A 5,000W (midsize portable) unit gives comfortable headroom. Size it by the appliances you actually need, not by square footage.

Running watts

2,630W

Peak (surge)

4,180W

Minimum generator

4,180W

Recommended

5,000W

Sizing a generator for a 1,500 sq ft home

Square footage on its own doesn't tell you a generator size — a 1,500 sq ft home with gas heat and city water draws far less than the same area with an electric furnace and a well pump. What actually sets the size is the outage load: the blower fan, any pump, a window AC, the fridge and your lights. This page sizes a realistic essentials set for a home this size.

These essentials draw about 2,630 running wattstogether. You don't add every appliance's starting watts, though — only one motor surges at a time, so the generator only has to cover that running total plus the single largest startup surge (the furnace blower fan's), which brings the peak to 4,180 watts.

To power the whole set, choose a generator rated for at least 4,180 starting watts. A 5,000W unit leaves comfortable headroom to add more — the calculator below does that math for your exact list.

Essentials wattage breakdown

ApplianceRunning wattsStarting watts
Refrigerator / Freezer700W2,200W
Furnace Blower Fan (1/2 HP)800W2,350W
Sump Pump (1/3 HP)800W1,300W
LED Light Bulb (each) ×8120W120W
WiFi Router / Modem20W20W
Phone / Device Charger ×240W40W
LED TV (up to 55")150W150W

Size your own list

This page sizes a typical essentials set for a 1,500 sq ft home. Open the calculator with them pre-selected, then add or remove anything to match your home exactly.

Size a generator for a 1,500 sq ft home

Related

Recommended midsize portable generators

Real, widely available units in the 3,500 – 8,500W class. Independent picks — we're not affiliated with any manufacturer or retailer and earn nothing from these links.

Best overall

Westinghouse iGen4500

4,500W start · 3,700W run

Gasoline · Inverter · 52 dBA · remote start · RV-ready TT-30R

Quiet enough for a campground and strong enough to start a 30-amp RV air conditioner.

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Best value

Westinghouse WGen7500

9,500W start · 7,500W run

Gasoline · Remote start · transfer-switch ready (L14-30R)

Serious home-backup wattage — enough for essentials circuits via a transfer switch — at a midsize price.

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Quietest

Champion 6250W Open Frame Inverter (100519)

6,250W start · 5,000W run

Gasoline · Open-frame inverter · 69 dBA · <3% THD

50% quieter and 20% lighter than a conventional 5,000W unit, with inverter-clean output.

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Frequently asked questions

What size generator do I need for a 1,500 sq ft home?

There's no single answer from square footage alone — it depends on what you run during an outage. For the essentials in a 1,500 sq ft home (fridge, heating/cooling, pumps, lights and device charging) you need a generator rated for at least 4,180 starting watts. We recommend a 5,000W (midsize portable) unit so you have headroom without running it at its limit.

Can a portable generator power a 1,500 sq ft home?

Yes, for the essentials — not for running every circuit at once. A 5,000W portable covers the outage basics this page sizes (about 2,630 running watts, peaking at 4,180W). Powering central AC, an electric range and an electric dryer simultaneously would instead call for a home standby unit spec'd by an electrician.

Why size a generator by appliances instead of square footage?

Because two homes of the same size can have completely different electrical loads — gas vs. electric heat, well pump vs. city water, central vs. window AC. Square footage is only a rough proxy; the honest number comes from adding up the specific appliances you need, which is exactly what this page and the calculator do.