Generator sizing Updated June 2026
What Size Generator Do I Need for a 2,000 Sq Ft House?
By Yann Buf, HVAC tech 5 min read Standards-reviewed
For a 2,000 sq ft house, you need at least a 7,500-watt generator to run essentials (fridge, lights, well pump, furnace fan). For whole-house backup including central AC, you need 14,000-22,000 watts with a standby generator.
What a 2,000 Sq Ft Home Needs During an Outage
A 2,000 sq ft home typically has 3-4 bedrooms, central HVAC, a well pump or municipal water, and the usual array of appliances. During a power outage, you don't need to power everything at once — but you do need to prioritize.
The essential circuits — refrigerator, furnace fan, well pump, lights, and a few outlets — typically draw about 3,500-5,000 running watts. Adding a window AC unit or microwave brings you to 5,000-6,000W. For the whole house including central AC (3.5 ton), you're looking at 10,000-14,000W running, requiring a 14kW+ standby generator.
A 7,500W portable generator is the sweet spot for most 2,000 sq ft homes — enough for all essentials plus space for a window AC, but affordable at around $800-1,000.
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7,500W vs 14,000W: Which to Choose?
- Choose 7,500W portable if: you only need essentials (fridge, furnace, well pump, lights), you're willing to manually connect via transfer switch, budget under $1,000
- Choose 14,000W standby if: you want automatic backup, need to run central AC, have medical equipment, want whole-house coverage
- Choose 22,000W standby if: you have electric heat, electric water heater, large central AC, or a home business
Frequently asked questions
Will a 7,500W generator run my whole house?
A 7,500W generator can run most essentials in a 2,000 sq ft home but not everything at once. You'll need to prioritize — run the fridge, furnace fan, well pump, and lights, but not the central AC, electric dryer, or oven simultaneously.
How do I connect a portable generator to my house?
The safest way is a manual transfer switch installed by an electrician ($500-800 installed). Never plug a generator into a wall outlet — this can backfeed power and electrocute utility workers.
What's the fuel consumption of a 7,500W generator?
A 7,500W generator running at 50% load burns about 0.6-0.8 gallons of gasoline per hour. A full tank (6-8 gallons) gives you 8-10 hours of runtime. Consider a dual-fuel model that runs on propane for longer storage life.