How to Use a Gas Generator Safely in Your Home
What a gas generator does and why you might need one
A gas generator is a machine that burns gasoline to create electrical power. It produces electricity when your home loses power from the grid — during a storm, outage, or planned maintenance. The generator runs on its own fuel supply and can power lights, refrigerators, medical equipment, or other devices you plug into it.
Generators are useful during extended outages because they keep your food from spoiling and your home functioning. However, they require careful handling because they produce carbon monoxide, a colorless, odorless gas that is deadly in enclosed spaces. Understanding how to operate one safely is the difference between having backup power and creating a serious hazard.
Key Takeaways
- Gas generators must always run outdoors, at least 20 feet away from windows, doors, and vents that lead into your home.
- Never refuel a generator while it is running or hot — wait at least two hours after shutdown, and always do this outdoors.
- A generator produces carbon monoxide within minutes, which can kill a person in an enclosed space in under an hour.
- Store gasoline in approved metal cans in a shed or garage, never indoors, and use fuel stabilizer if the generator will sit unused for more than a month.
- Test your generator monthly during calm weather so you know it works before you need it in an emergency.
Where to place your generator and why distance matters
The single most important safety rule is that your generator must run outdoors only, and it must be at least 20 feet away from any opening into your home. This includes windows, doors, crawl space vents, and air conditioning units. Carbon monoxide seeps into homes through these openings, and even a small generator can produce enough to poison everyone inside within minutes.
Place the generator on level, dry ground. If rain is falling, build a simple shelter over it using plywood and a frame — never use a tent or enclosed structure, because that traps the exhaust. Point the exhaust away from your home and any neighbor's home. If you live in an apartment or close quarters, talk to your neighbors about placement before you run it, because the exhaust travels farther than you might expect.
Keep the area around the generator clear of leaves, grass clippings, and other debris. These materials can catch fire if they touch the hot engine. Do not run the generator in wet conditions unless it is sheltered from rain — water on the engine or fuel cap can cause electrical hazards or fuel contamination.
Fueling safely and storing gasoline correctly
Always turn off the generator and let it cool for at least two hours before you refuel it. Gasoline vapors are extremely flammable, and a hot engine can ignite them. Refuel outdoors, away from your home, and never smoke or use an open flame near the fuel area.
Store gasoline in approved metal fuel cans only — never in plastic jugs or glass bottles. Keep these cans in a shed, garage, or outdoor storage area, never inside your home or basement. Gasoline fumes can accumulate indoors and create a fire or explosion hazard. Store cans away from heat sources, direct sunlight, and any ignition source.
If you plan to store fuel for more than a month, add a fuel stabilizer to the gasoline. Gasoline degrades over time and can gum up the generator's carburetor, making it hard to start when you need it. Follow the stabilizer instructions on the bottle for the correct amount. If you store fuel for the winter, drain the tank completely before long-term storage, or run the generator until the tank is empty.
Operating the generator during an outage
Before you start the generator, plug in only the devices you truly need — your refrigerator, freezer, a light or two, and any medical equipment. Do not try to power your whole house. Overloading a generator can damage it and create a fire hazard. Check the generator's manual for its wattage capacity and add up the wattage of each device you want to run.
Start the generator outdoors in daylight if possible, so you can see what you are doing and spot any problems. Turn the fuel valve to the "on" position, set the choke (if your model has one) to "start," and pull the recoil cord or press the electric start button. Once it is running, move the choke to "run." Let it warm up for a minute before you plug in devices.
Check the generator every few hours. Listen for any unusual sounds, look for leaks under the engine, and make sure the exhaust is still pointing away from your home. Keep a fire extinguisher rated for gasoline fires nearby. Never leave a running generator unattended for long periods, and turn it off at night if possible to reduce noise and fuel use.
Preventing carbon monoxide poisoning in your home
Carbon monoxide is produced by any gasoline engine, including your generator. It has no smell or color, so you cannot detect it without a monitor. Symptoms of poisoning include headache, dizziness, weakness, nausea, and confusion — and they can appear within minutes of exposure. If anyone in your home feels these symptoms during an outage, get outside immediately and call 911.
Install a battery-powered carbon monoxide detector in your home before you need the generator. Place it on a wall or shelf in a central location, away from windows and doors. Test it monthly to make sure the battery works. If the alarm sounds, leave your home right away, call 911 from outside, and do not go back in until emergency responders say it is safe.
The best prevention is distance and outdoor operation. Never run a generator in a garage, basement, attic, or shed that is attached to your home, even if the door is open. Never run it in a tent or enclosed shelter. The only safe place is outside, at least 20 feet away, with the exhaust pointing away from all buildings.
Testing and maintaining your generator before you need it
Test your generator at least once a month during calm, dry weather. This tells you whether it starts, runs smoothly, and produces power. Do not wait for an emergency to find out it does not work. Run it for 10 to 15 minutes under light load — plug in a lamp or small device — and listen for any unusual sounds or vibrations.
Check the oil level before each use. Most generators have a dipstick or sight glass on the side of the engine. If the oil is low, add the type specified in your manual — usually SAE 10W-30. Low oil can damage the engine and cause it to shut down during an outage. Change the oil after the first 20 hours of use, then every 50 to 100 hours depending on your manual.
Keep your generator in a dry place when it is not in use. Cover it loosely with a tarp to keep dust and debris off, but do not seal it in plastic, because moisture can accumulate. Store it away from your home, in a shed or garage, and keep the fuel cans separate. If you live in a cold climate, drain the fuel or add stabilizer before winter storage.
What to do if your generator fails or runs out of fuel
If your generator will not start, check the fuel level first. If the tank is empty, refuel it outdoors and try again. If it has fuel but will not start, check the oil level — a low-oil shutoff switch will prevent the engine from running. If the oil is low, add the correct type and try starting again.
If the generator starts but shuts down after a few minutes, it may be overloaded. Unplug some devices and try again. If it still shuts down, the generator may have a mechanical problem. Do not attempt to repair it yourself — contact a small-engine repair shop or the manufacturer.
If you run out of fuel during an outage, turn off the generator and let it cool completely before refueling. Do not try to refuel a warm or running generator. Once it has cooled for at least two hours, refuel outdoors and restart it. If you cannot refuel safely, turn off the generator and wait until daylight or until conditions improve.
Frequently Asked Questions
Can I run a generator in my garage if the door is open?
No. Even with the door open, a garage is still partially enclosed and carbon monoxide can seep into your home through walls, vents, and gaps. The generator must run completely outdoors, at least 20 feet away from any opening into your home. This is the only safe setup.
How long can I run a generator continuously?
Most residential generators can run 8 to 12 hours on a full tank, depending on the model and load. Check your manual for the exact runtime. You can run it continuously as long as you have fuel and the engine has oil, but turn it off periodically to let it cool and to reduce noise and fuel use.
What size generator do I need for my home?
This depends on which devices you want to power. A refrigerator uses about 600 watts running, a freezer about 800 watts, and a light about 60 watts. Add up the wattage of the devices you need most, then choose a generator with at least that capacity. Most home generators range from 3,000 to 7,500 watts. Your manual or the device labels will list wattage requirements.
Is it safe to use a generator if I have a gas furnace or water heater?
Yes, but keep the generator outdoors and away from your furnace or water heater vents. These appliances also produce carbon monoxide, so proper outdoor placement of the generator is even more important. Never run a generator in a basement or enclosed space near these appliances.
What should I do with old gasoline that has been stored for years?
Old gasoline can gum up your generator's carburetor and prevent it from starting. If you have fuel that has been stored for more than a year without stabilizer, dispose of it at a hazardous waste facility in your area. Do not pour it down the drain or into the ground. Contact your local waste management office for the nearest drop-off location.