Quick answer
Run a portable generator outdoors only, on a level spot well away from your home, with the exhaust pointed away from every door, window, vent, and air intake. Many manufacturers and public-safety agencies cite 20 feet or more as a starting point. Your owner’s manual and local guidance set the actual distance, and more is better when wind blows toward the house. Never run one in a garage, basement, crawlspace, shed, or enclosed porch, even with the door open. A standby generator’s location is set at install by the manufacturer’s clearances and your local code. Whatever you have, put battery-backed carbon monoxide (CO) alarms on every level of the home and near sleeping areas.
Why placement matters more than the generator
A generator engine makes carbon monoxide every minute it runs. You can’t see or smell CO, and it can drift back toward the house through an open window, a dryer vent, a gap under a door, or an attached garage. Most generator CO incidents come from where the unit was put, not a fault in the machine. Picking the spot ahead of time, in daylight and good weather, is the single most useful thing you can do before an outage.
This page is about choosing and planning that spot. For running a generator in snow and cold, see the Winter Generator Guide. For the broader outage plan, see the Home Power Outage Checklist.
Places a generator should never run
- Inside the house, including a basement or crawlspace
- In an attached or detached garage, even with the big door open
- In a shed, barn, or workshop
- On an enclosed or screened porch, or under a deck that sits against the house
- In a carport or breezeway that’s tucked against the house
- Under a window, next to a door, or near a dryer, furnace, or bathroom vent
- Inside an RV, camper, tent, or vehicle
Open doors and fans don’t make these places safe. CO can build up faster than air moves it out.
How to choose the spot: five checks
1. Distance from every opening
Walk the outside of your house and note every door, window, vent, and air intake, including the furnace and water heater intakes, the dryer vent, bathroom fans, attic vents, and a crawlspace vent. Your spot needs to be well away from all of them, not just the nearest door. Use the distance your manual gives as a minimum, and choose more if you can. Remember the neighbor’s openings too if the houses are close.
2. Which way the exhaust points
Turn the generator so its exhaust faces away from the house and from any neighbor’s home. Most portables have the muffler on one side. Check yours before an outage, so you aren’t working it out in the dark.
3. Wind and terrain
Exhaust follows the air. Think about which way the wind usually blows where you live, and in storms. A spot that’s downwind of the house is better than one upwind. Low spots, walled-in side yards, and areas between two houses can let exhaust pool rather than disperse. Open ground is better.
4. A firm, level, dry base
Pick a level surface that won’t turn to mud or flood, such as a patio edge, gravel pad, or paver base away from the wall. A generator on a slope can leak fuel or tip. Keep it out of standing water and away from downspouts.
5. A practical route for cords and fuel
The spot needs a safe way to connect to the house and a clear path for refueling. Plan the cord run so it isn’t pinched in a door or window, which would also leave an opening for exhaust. Plan where you’ll stand to refuel, after the engine has cooled. If you’re connecting to your home’s wiring, it must go through a transfer switch or interlock, never a back-fed outlet. See Transfer Switch vs Interlock.
Reading your own house: common layouts
Attached garage. Treat the garage as part of the house. Keep the generator away from the garage door as well as the house doors, because exhaust that gets into the garage can reach living space through the connecting door.
Basement windows and window wells. Low windows and wells sit at the same height as the exhaust and are easy to miss. Include them in your walk-around.
Decks and raised porches. Exhaust can collect under a deck and rise through gaps toward doors. Keep the generator out from under and away from decks attached to the house.
Homes with side-wall furnace or water heater vents. High-efficiency appliances often vent and draw air through pipes on a side wall. Keep the generator well away from both the exhaust and the intake pipes, because the intake can pull generator exhaust into the appliance.
Corner and wind-tunnel yards. Narrow side yards between houses act like channels. Wind there can carry exhaust along the wall instead of away from it.
Portable vs standby placement
Portables: you choose the spot every time
A portable gets carried out during an outage, often at night and in bad weather. That’s when people cut corners and set it close to the house. The fix is to decide the spot now:
- Mark it with a paver, stake, or painted line so anyone in the household can find it.
- Measure the cord run from that spot to the inlet or to where cords enter, and use outdoor-rated cords long enough to reach without moving the generator closer.
- If an inlet and interlock are installed, locate the inlet so the generator can sit far enough away and still connect. Your electrician can advise.
- If rain or snow is likely, use only a cover made or approved for your model that leaves the sides open. Never wrap or enclose a running generator.
Standbys: placement is decided at install
A standby is installed on a pad by a licensed installer. The manufacturer sets minimum clearances from the house, windows, doors, and vents, and local codes add their own rules. Your installer and the inspector check them. What you can do:
- Ask during quotes where they plan to put it and why. The Generator Installer Quote Checklist includes placement questions.
- Don’t add things later that break the clearances, such as a new window, a deck, a fence close to the enclosure, shrubs, or stored items.
- Keep the area around the enclosure clear of leaves, snow, and debris.
- Placement also affects install cost, through the length of the gas line and wiring runs. See Standby Generator Installed Cost.
Neighbors, noise, and rules
In close neighborhoods, the safest spot for you may push exhaust toward someone else’s window. Look at their side of the fence too. Some towns and homeowner associations have rules about where generators can sit and when they can run. Check those before an outage rather than during one. A quick conversation with a close neighbor about where each of you will put a generator can head off problems.
Carbon monoxide alarms: your backup if placement goes wrong
Placement is the first line of defense. CO alarms are the second.
- Install CO alarms on every level of the home and near sleeping areas, following the alarm maker’s instructions.
- Choose battery-powered or battery-backup models, because the power will be out when you need them.
- Test them at the start of outage season and replace batteries on the maker’s schedule.
- Know the signs of CO exposure: headache, dizziness, weakness, nausea, confusion, and sleepiness. They can feel like the flu.
If an alarm sounds or anyone has those symptoms, get everyone outside to fresh air right away and call 911. Don’t go back in until responders say it’s safe.
Special situations
Townhouses, condos, and duplexes
Shared walls and small yards make safe placement harder. You may not have a spot far enough from your own openings and your neighbor’s. Check your association’s rules first, since many restrict or ban portable generators. If you can’t find a safe spot, don’t compromise on distance. Look at a battery backup or power station for essentials instead, and see Portable Power Stations vs Gas Generators.
Several generators on one street
During a long outage, several neighbors may run generators at once. Exhaust from theirs can reach your home even if yours is well placed. This is one more reason to keep CO alarms working on every level, and to keep windows on the generator side of the house closed while units are running nearby.
Camping and RV use
The same rules apply away from home. Keep the generator well away from the RV, camper, or tent, with the exhaust pointed away from doors, windows, and roof vents, and never run it inside a vehicle or under an awning. RVs need their own working CO alarm.
Kids, pets, and the hot unit
A running generator is hot, noisy, and attractive to curious kids and pets. Choose a spot where you can see it from the house, keep children and animals away from it, and keep fuel cans away from the generator and out of reach.
Rehearse before the outage
A plan you’ve never tried tends to fall apart in the dark. Once a season, in daylight:
- Carry the generator to its marked spot and check that it sits level.
- Run the cords to the inlet or pass-through and confirm they reach without moving the generator closer.
- Start it, run a light load, and walk around the house to check that the exhaust is going away from openings.
- Practice the shutdown, cool-down, and refueling routine.
- Test the CO alarms and remind everyone what the alarm sounds like and what to do.
Write any changes on your placement plan so the next person to set it up does the same thing.
Common placement mistakes
| Mistake | Why it’s a problem | Better approach |
|---|---|---|
| Running it in the garage "just for a minute" with the door up | CO builds up in the garage and gets into the house | Outdoors only, at your planned spot |
| Setting it right outside a door to keep cords short | Exhaust drifts in when the door opens | Use longer outdoor-rated cords and keep the unit at distance |
| Feeding a cord through a cracked window | The gap lets exhaust in | Use an inlet, or a door sweep or cord pass-through that seals |
| Placing it near a dryer, furnace, or bathroom vent | Vents can pull air inward | Check every vent on your walk-around |
| Putting it between two close houses | Exhaust pools and can reach both homes | Open ground, exhaust pointed away from both |
| Covering it with a tarp | Traps heat and exhaust | Model-approved open-sided cover only |
| Skipping CO alarms because it’s "far enough" | Wind and terrain change | Alarms on every level regardless |
Planning scenarios (outlines)
These are structures to adapt to your home, not prescriptions.
Scenario 1: Small suburban lot, portable with cords
- Walk-around. Note doors on two sides, a dryer vent on the side yard, and a neighbor’s bedroom window across the fence.
- Spot chosen. The back corner of the yard on open ground, exhaust pointed toward the rear fence line and away from both houses.
- Cords. Outdoor-rated cords sized for the run, entering through a sealed pass-through, not a window.
- Household plan. The spot is marked with a paver, everyone knows it, and CO alarms are tested.
Scenario 2: Rural home, portable on an inlet and interlock
- Walk-around. Prevailing winds come from one direction, and the inlet is on the wall the wind blows toward.
- Spot chosen. Downwind of the house on a gravel pad, at a distance the electrician confirmed the inlet cord can reach.
- Path. A clear route for refueling, with the fuel stored away from the generator spot.
- Household plan. A printed placement plan by the inlet, CO alarms on both floors.
Scenario 3: Standby going in
- Quote stage. Each installer proposes a location and explains the clearances. Compare them.
- After install. The clearance zone stays clear: no new deck, fence, or shrubs crowding it.
- Ongoing. Seasonal clearing around the enclosure, and CO alarms on every level.
Printable placement plan
Fill this in now and keep it with your generator.
| Item | Done? | Date | Notes |
|---|---|---|---|
| Walked the house and listed every door, window, vent, and intake | ☐ | ||
| Chose a spot well away from all of them, at or beyond the manual’s distance | ☐ | ||
| Exhaust direction checked and pointed away from my home and neighbors | ☐ | ||
| Prevailing wind considered; spot is not in a low or walled-in pocket | ☐ | ||
| Firm, level, dry base that won’t flood | ☐ | ||
| Spot marked so anyone in the household can find it | ☐ | ||
| Cords measured and long enough; no window or door left open for them | ☐ | ||
| Transfer switch or interlock in place if connecting to home wiring | ☐ | ||
| Refueling route planned; fuel stored away from the spot | ☐ | ||
| Local or HOA rules checked | ☐ | ||
| CO alarms on every level and near bedrooms, battery-backed, tested | ☐ | ||
| Everyone knows CO symptoms and to get outside and call 911 | ☐ |
FAQ
How far from the house should a portable generator be?
Follow your owner’s manual and local guidance. Many sources cite 20 feet or more as a starting point, with the exhaust pointed away from the house. Farther is better, especially when the wind blows toward your home.
Is the garage OK if the door is fully open?
No. CO can build up in the garage and get into the house even with the door open.
Can I run it under a covered patio or carport?
Not if the cover is attached to or tucked against the house. Exhaust can collect under the roof and reach openings. Use open ground away from the house.
Do I need CO alarms if the generator is far away?
Yes. Wind, terrain, and a neighbor’s generator can all bring CO toward your home. Alarms are your backup.
Who decides where a standby generator goes?
Your installer, based on the manufacturer’s clearances and local code, and the inspector checks it. Ask about placement when you collect quotes.
What if my yard is too small for a safe spot?
Talk to an electrician about inlet location, consider other backup options such as a battery system, and see Battery Backup vs Generator.