Can You Run a Generator in a Shed or Garage?

Can you run a generator in a shed? You should always avoid running a generator indoors. There is a high risk of toxic exhaust fumes causing harm to the residents.

Can you run a generator in a shed or a garage? It is not recommended to run a generator inside a confined space. However, there are certain occasions when you can run a generator inside a shed if you follow the necessary safety precautions. Let’s find out more about the ventilation requirements of a generator and the risks of running a generator indoors. 

How Much Ventilation Does a Generator Need?

A generator needs a space of around 2 – 3 feet around it as ‘breathing’ room. However, this does not mean that you can run your generator in an enclosed space with that space around it. A generator needs this space to allow air circulation necessary for the combustion. This is around 3 CFM per kW or 300 CFM for a 100 kW generator. It should also have room for the airflow needed in cooling down the components that heat up as the engine runs. This is approximately around 65 CFM per kW, which would be 6500 CFM for a 100 kW generator.

Dangers of Running a Generator Indoors

You should avoid running a generator indoors at all costs as it could lead to severe hazards. The following are some of the major situations that could lead to harmful effects.

Poor Airflow

Garages or detached sheds may have a window or two at the maximum. Most of them have no windows which creates poor airflow. This causes uncomfortable work conditions even when you are not running any appliance. It will keep more dust and smoke inside leading to poor air quality. 

Toxic Fumes

Generators burn different fuels namely gasoline, diesel, and propane which are all forms of hydrocarbons. Theoretically, this should emit by-products such as Carbon dioxide (CO2), water (H2O), and Nitrogen (N2). However, due to less efficient combustion, there are many more by-products caused in the practical scenario. This includes Carbon monoxide (CO), Nitrogen oxides (NOx), unburned fuel, soot, and other debris. All these harmful gases filling the confined space inside your garage could easily pass you out which can even be fatal.

Carbon Monoxide Poisoning

Generators emit carbon monoxide during fuel combustion. This is a colorless and odorless gas that cannot be detected easily. Since this is a poisonous gas, it can be fatal if anyone inhales a large amount without realizing it. Having 50% of carbon monoxide in blood for several hours can even kill a person. The best way to avoid this is allocating proper ventilation around the generator so that any poisonous gas exhausted will flow away with the wind, reducing its concentration which will reduce any negative impact on the people.

High Risks of Fire

Lack of air circulation causes the engine to heat up. This overheating can cause the engine to stall or even go ahead to cause further damage. If you select a location such as a garage, there will be so many things stored in it. There could even be some things that can easily catch fire. If there are any chemicals, paint cans, and gas, there is a higher chance of a fire starting in your garage. The heat from the generator can easily ignite combustible material including wood. 

Dirty engines can easily backfire where flames can shoot out of the engine’s air intake. Frayed generator wires can even cause sparking if it comes to contact with other conductive surfaces. These possibilities increase the risks of fire if you place your generator indoors. 

Even if a fire doesn’t occur, there is a higher chance of you bumping against some frayed generator wire and receiving an electric shock. You may even get severe burning injuries if you accidentally touch a heated surface. Therefore, it is very important to keep the generator away from your working space at least about 20 feet away.

Noise Pollution

This is another major issue you will face if you run a generator indoors. The walls surrounding it will cause the sound to echo and disturb you especially if the garage is attached to your home. It will even annoy your neighbors when the background noise levels are low. Avoid working near a generator as high levels of noise for a long time can damage your hearing. The rule of thumb is that if you have to raise your voice to speak to someone near you, then the generator is too loud for your ear. In this case, you should definitely wear hearing protectors. 

Can You Run a Generator in the Garage?

You can only run a generator safely if the garage is ventilated well. The garage should have large doors and windows that can be opened widely. Assuming that your garage is ventilated properly like a shed, you can run a generator in it. However, the garage should be detached and away from your house and neighbors. 

How to Vent a Generator in a Garage        

Ventilation is the most important aspect when placing a generator in a garage. Venting a generator is quite similar to installing a fireplace. As you position the generator on the base, you can figure out where the hole should be. It should be close enough so that the exhaust will not be too long. Here’s how to fix a generator exhaust through wall.

  1. Create a hole in the side of your garage, through the wall.
  2. Get a vent cap and stuff it through the hole of your detached garage. The size of the vent cap and the hole depends on the size of the exhaust extension and the hose that you use. Do not use plastic or cheap aluminum hoses as they could melt and cause fire hazards.
  3. Use a coupler to fix the hose directly to the generator exhaust or muffler with bolts or screws. Then attach a flexible metal exhaust tube with muffler clamps. These exhaust tubes are sold at auto parts supply stores.
  4. If the generator has a nipple on the muffler, you can attach the tubing to that by clamping. Make sure not to restrict the exhaust by making it too long.
  5. Since this is not completely safe, you should not work in the garage while the generator is running. 

How to Safely Run a Generator in a Garage

You are warned of the risks and dangers of running a generator indoors or inside a garage. So, it is highly not recommended to run your generator in a garage. But there are certain ways in which you can reduce the risks involved. 

Install a CO Detector in Every Room

Installing a carbon monoxide detector in every room including the garage will ensure your safety. It contains a loud alarm that goes off once it detects high CO concentration in the air.  You can even purchase a smart CO detector that can send notifications to your phone.

Maximize the Ventilation of the Garage

You should make sure that all harmful gases generated by the engine are sent outdoors. It will prevent poisoning the garage’s air and safe for anyone to walk in. So, open all the windows widely including the garage door to maximize the airflow. Place the generator close to the garage door as much as possible to make sure that it is ventilated well. If you can, use a fan to blow the gas outside so that fumes don’t get concentrated inside. 

Don’t Come Near the Generator When It’s Running

Always avoid staying in the garage for long when the generator is running. Since CO is both colorless and odorless, you cannot tell when the concentration levels are high. So it is always better to keep away from the garage as much as possible.

Don’t Start the Generator Before You Plug Everything

Make sure that you have plugged everything into the generator before you turn it on to prevent electrocution. If not, you may get electric shocks caused by any short circuits in trying to connect cables.

Don’t Store Fuel in the Garage

Do not store any fuel inside the garage, especially gasoline which is highly flammable. Storing them in closed spaces such as the generator can cause them to fill up the room easily. There is a higher possibility that the room can explode with any spark from the generator. Always store your excess fuel in a separate location away from the generator.

Never Overload the Generator

Overloading the generator will cause it to overheat. This increases the risk of possible fire hazards in your garage. So go through the user manual properly and stick to the wattage recommended by the manufacturer.

Use Proper Power Cords

Generator extension cords have risks related to tripping hazards and short-circuits. Always check the manual to decide which extension cord to use with your generator. Low-quality power cords have higher risks of damage, causing electric shocks.

Never Refill When the Generator Is Running

Do not refill the generator while it is running. If something goes wrong, it can even blow up everything. Turn off the generator and leave it to cool down completely before you refuel it.

Install an Exhaust Venting System 

Having a proper venting system in your garage will remove the exhaust fumes safely from the garage. It increases the quality of air inside the garage, further reducing the risks of harmful gases. You can find generator exhaust venting systems at affordable prices online. If you cannot do it on your own, get the support of a technician to fix the generator exhaust through wall.

Use Solar-powered Generators (Optional)

The best solution for running a generator safely in a garage is to get a solar or battery-powered generator. It does not emit any fumes as no fuel combustion takes place. Instead, the battery is charged from electricity or solar energy and releases power when needed. 

Avoid Attached Garages 

It is always a good decision to avoid running a generator in a garage attached to your house. There are too many risks involved as it can easily poison the residents. So make sure to run your generator in a detached garage or a separate shed for portable generator        

Place the Generator Outside With a Shield Cover (Optional)

If it is impossible to run your generator in a garage while following the above-mentioned safety precautions, then you can place the generator outside. However, you need to shield it properly with an appropriate cover to protect your generator from rain and snow.

Frequently Asked Questions

Can I Run a Generator in a Shed With Door Open?

If you are running a generator inside a garage or shed, you should always make sure that it is properly ventilated. Open all the doors and windows completely and allow maximum air circulation. However, since this is not safe enough, you should also install carbon monoxide detectors inside the garage to detect any harmful levels of CO and notify you immediately.

Can You Run a Generator on a Porch?

You should not run a generator on your porch as it is too enclosed. Especially since it is too close to the doors and windows of your home, you will not be able to control the exhaust fumes from going inside. This is very dangerous for your family and pets. Despite the minor inconvenience, you should move the generator outside to a suitable location away from home. If you are concerned about the length of the wires running from your generator to the house, you can run them underground with proper advice from a professional. You will have to use a sturdy pipe or PVC tubing for this.

Can You Run a Portable Generator Continuously?

You can run a generator continuously as long as there is enough fuel in the tank. However, you need to check this in the specifications of your user manual. You can even have two generators to use alternatively to power up your needs during a power outage. However, it is important to give regular breaks to a generator. You need to allow the generator to cool down properly and carry out the necessary maintenance to enhance the useful life of your generator.

Can You Enclose a Portable Generator?

You can enclose a portable generator as long as it contains enough room around the generator. Measure the dimensions of your generator, and create a frame or shed for portable generator with at least 2 – 3 feet distance from each side. This will allow air circulation to cool down the engine as it runs. However, you should provide even more room for the generator so that any harmful fumes can get blown away by the wind and reduce the concentration around it. You will need to take care of it in case your generator gets wet.


We hope you found the answer to your question; can you run a generator in a shed? Since this is an important discussion related to the health and safety of the users, you are encouraged to avoid using generators indoors as much as possible. If you have any doubts related to this or generator connections, you can contact your professional technician for advice.

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