What size generator for a 1,000 sq ft house?
Essentials for a 1,000 sq ft house (fridge, furnace fan, lights, TV, phones) run about 1,900 watts and fit a 3,500W portable. Add the typical 2 ton central AC and you need a 6,500W portable; full standby sizing is 10 kW with gas appliances, past air-cooled sizes all-electric. The tiers below are the whole decision.
Portable tiers at 1,000 sq ft
| What you power | Running | Peak | Buy |
|---|---|---|---|
| Essentials: fridge, furnace fan, lights, TV, phones | 1,900 W | 3,450 W | 3,500W portable |
| Comfort: essentials + sump pump + window AC | 4,150 W | 5,700 W | 6,500W portable |
| Essentials + 2 ton central AC | 4,300 W | 5,980 W | 6,500W portable |
Standby classes at 1,000 sq ft
Rule-of-thumb demand from the whole-house calculator: NEC-style 3W per square foot with demand factors, plus the appliances named.
| House configuration | Estimated demand | Standby class |
|---|---|---|
| Gas heat and water heater, 2 ton AC | 7 kW | 10 kW |
| All-electric (resistance heat, water heater, range, dryer) | 32.1 kW | 30 kW+ liquid-cooled |
Which tier is right at this size
At 1,000 square feet, portable is the natural answer. The essentials list runs 1,900 watts, small enough that a 3,500W portable carries the house's actual needs, and even the comfort list with a sump pump and a window AC stays inside a 6,500W portable. A standby install costs more than some houses this size spend on electricity in six years; buy it for the automatic start if nobody is home to pull a cord, not for capacity.
The one load that breaks the pattern is central air: even the modest 2 ton unit typical at this footprint triples the running load and drags the answer to a 6,500W portable. In a short outage, shade and a window unit cool one room for a quarter of the watts.
Questions people ask
What size generator do I need for a 1,000 sq ft house?
For essentials (fridge, furnace fan, lights, electronics) a 3,500W portable covers the 1,900W load. To include the typical 2 ton central AC you need a 6,500W portable, and whole-house standby sizing lands at 10 kW with gas appliances or past 26 kW all-electric.
Can a portable generator run a 1,000 sq ft house?
The parts that matter, yes: the essentials list is 1,900 running watts, well inside portable range on an interlock or transfer switch. What a portable can't carry at this size is everything at once (central AC pushes the list to a 6,500W portable), so the play is picking circuits, not powering the panel like the utility does.
Does square footage even determine generator size?
Loosely. Square footage sets the lighting and plug load (3W per square foot in the NEC convention, demand-factored) and predicts the AC tonnage, but the 240V appliance list determines more: one electric water heater outweighs a thousand square feet of lights. That is why the tables here show gas and all-electric versions of the same house.