Storm Risk · Power planning
Generator Size for a Fridge and Window AC During Outages
If the power goes out, most homeowners just want to keep food cold and one room comfortable. Here is the plain math on generator size for a refrigerator and a window AC unit, so shopping can be based on real numbers instead of guessing.
The short answer
A typical refrigerator and a single window air conditioner can usually run together on a generator in the 2,000 to 3,000 watt range, depending on the exact models. That covers the electricity both appliances draw while running, plus the short power surge each one needs to start up.
This is a starting point, not a fixed number. Appliance wattage varies by size, age, and efficiency, so the only reliable way to confirm a number is to check the labels on the specific units involved or run them through the honest Generator Sizing tool.
Running watts vs. starting watts
Every motor-driven appliance, including refrigerators and window AC units, pulls extra power for a second or two when it first switches on. This is called starting watts or surge watts. Once it is running steadily, it settles down to a lower number called running watts.
A generator has to handle both numbers. It needs enough surge capacity to get the compressor started, and enough steady capacity to keep everything running afterward. This is why generator listings usually show two wattage figures: rated (running) watts and surge (starting) watts.
A sample wattage illustration
Here is a labeled arithmetic example, not a guarantee of what any specific appliance draws. A mid-size refrigerator might run around 150 to 400 running watts, with a brief surge near 800 to 1,200 watts when the compressor kicks on. A window AC unit, depending on its cooling capacity, might run around 900 to 1,500 running watts, with a surge that can briefly climb 2 to 3 times higher.
Stacking a refrigerator's running watts on top of a window AC's running watts, then checking that the generator's surge rating covers whichever appliance starts last (since that is when demand spikes highest), gives a reasonable target range. That is where the 2,000 to 3,000 watt range comes from for many households.
Because every model is different, the yellow EnergyGuide label or the nameplate on the back of each appliance shows its actual wattage or amperage. The Department of Energy has guidance on reading appliance energy labels for anyone who wants to understand the numbers before shopping.
Other things that affect the real number
A generator rarely powers just two appliances in isolation. Lights, a phone charger, a fan, or a sump pump on the same circuit all add to the running wattage total. Making a full list of what needs power during an outage, not just the two big items, is a useful step before choosing a generator size.
Portable generators are sized in running watts and peak watts, while whole-house standby generators are sized in kilowatts and are typically installed by an electrician with a transfer switch. Either way, adding up a real appliance list tends to be more reliable than a single rule of thumb. Thinking through everything a household wants powered during a multi-day outage, not just the refrigerator and AC, can help clarify the right size.
Fuel supply matters too. A generator sized correctly on paper still needs enough fuel on hand for the length of an expected outage, and safe, ventilated storage for that fuel.
Safety comes before sizing
Portable generators produce carbon monoxide, which is invisible and has no smell. The CDC and the National Fire Protection Association both note that generators should run outdoors only, well away from windows, doors, and vents, and never inside a garage even with the door open.
Ready.gov also notes the value of letting a generator cool down before refueling, keeping it dry, and using heavy-duty, outdoor-rated extension cords sized for the load. For anyone considering a permanent standby unit instead of a portable one, a licensed electrician can speak to transfer switch options, which help prevent backfeed that could endanger utility crews working to restore power.
This article is general information, not insurance or safety advice. A walk-through with a professional can help close gaps in an outage plan, and the 48-Hour Checklist covers generator setup steps ahead of time, so they are not being worked out for the first time during an actual storm.
Insurance and paperwork, briefly
A generator is a purchase worth documenting for insurance purposes, and it can also factor into claims if a storm damages appliances it was powering. The Insurance Information Institute has general guidance on documenting home equipment and storm losses. Keeping receipts, model numbers, and photos in one place ahead of a storm can make a later claim easier to support. The Insurance Checklist is a simple way to keep that paperwork organized without needing to become an expert in policy language.
Questions people ask
Can a 2,000 watt generator run a refrigerator and window AC together?
It depends on the exact models. Many smaller refrigerators and window AC units fit within a 2,000 watt generator's running and surge capacity, but larger units may need more. Comparing the wattage labels on both appliances to the generator's rated and surge watts is the way to confirm.
Do I need to add up starting watts or running watts?
Both matter. Adding up the running watts of everything running at once, then checking that the generator's surge rating covers whichever single appliance has the highest starting watts, accounts for the spike that happens on top of everything already running.
Is it safer to run a generator in the garage with the door open?
No. The CDC and NFPA both note that portable generators should run outdoors only, away from windows and vents, because carbon monoxide can build up quickly even in a garage with the door open.
Should I get a portable generator or a standby generator?
Portable generators cost less upfront and work for short-term needs like a refrigerator and window AC, while standby generators are installed by an electrician and can power more of the house automatically. The right choice depends on budget, how often outages happen in a given area, and what a licensed electrician recommends for the home's electrical panel.
Sources
- Ready.gov: Generator Safety
- CDC: About Carbon Monoxide Poisoning
- NFPA: Home Fire Safety Education
- Department of Energy: Appliance and Equipment Standards
This article is educational and is not professional contractor, insurance, or engineering advice. Some links in our articles may earn us a commission at no cost to you, and never change what we recommend.
