• Portable fuel-based generators must operate outside, even during storms, because they emit dangerous exhaust fumes, including carbon monoxide (CO).
• It’s essential to protect your generator from severe weather while it’s running, using a cover or partial enclosure.
• There must be adequate space between the generator and cover for ventilation and heat dissipation—figure at least three to four feet.

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A portable generator can be a godsend when the power goes out during a severe storm to keep essential appliances and home systems running. However, because fuel-based generators emit exhaust (and thus, carbon monoxide) it’s dangerous to run them in a garage—even with the garage door opened—or on a porch or inside a shed. In fact, generators must be set up at least 20 feet from your home’s windows, doors, or vents.

But exposing generators to heavy rain or snow also creates an unsafe scenario with the potential for electrocution, never mind that it can cause damage to the unit. As such, keeping it under cover is essential. That said, you can’t simply throw a tarp over it and call it a day because heat and exhaust can create hazards like fire or the buildup of deadly fumes. Whatever is set on top or over a running generator must be fire-retardant and allow for proper ventilation.

There are several ways to solve for this, from framed covers to customized boxes to partial enclosures you can build yourself. Ahead, we dive into the pros and cons of each option.

Running Covers

The storage covers that typically come with generators aren’t suitable for use during operation because they don’t allow for proper ventilation and heat dissipation, and typically aren’t durable enough to hold up in heavy winds and precipitation.

That’s where specialized “running covers” come in, which are the most widely available and affordable solution for most people, often costing between $100 and $200. They’re also pretty simple to install with the use of basic tools. Running covers generally come in two styles: flat-top and dome.

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One of the most important considerations is to find one that’s sized correctly and is compatible with your type and size generator—open-frame generators require different configurations compared to closed-framed models, which are common for inverter generators. As you might expect, generator brands sometimes also make their own running covers.

The downside of running covers is that they may not be suitable for extremely disruptive weather events, such as flash flooding or hurricane-level winds. Most act as canopies to deflect water coming from above, not rushing in from below.

Always look for brands that comply with safety guidance from organizations like UL Solutions (UL), the National Fire and Protection Association (NFPA), and the Portable Generator Manufacturers’ Association (PGMA).

Customized Boxes

As large portable generators become more popular, the market for custom solutions for generator enclosures has grown in interest. One of the most talked about in enthusiast circles is ZombieBox, a company that sells built-to-order enclosures that offer automated ventilation, heat dissipation, and noise reduction, which is a key selling feature for owners who live in neighborhoods where noise ordinances might preclude the use of generators that can be quite loud. Boxes like these also offer more weather protection than a running cover; they keep the generator protected from top to bottom.

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You’ll want to consider how badly you need an option like this one. These boxes, even the pre-made ones, can be costly, often exceeding $1,000 (sometimes more than the generator itself). Additionally, while they’re designed to withstand the heat of a generator, if accidental overheating does occur and causes damage, some manufacturers’ warranties might regard placement in a non-approved enclosure as “improper installation” and could void any claims.

Build a Simple Lean-To

You’ll find no shortage of DIY-minded generator owners who’ve constructed their own weatherproof enclosures. We’ve seen simple lean-to constructions of four wooden posts and a slanted roof or more complicated projects, like a converted shed with built-in fan ventilation, heat vents, and noise insulation. We’ve also seen some pretty scary stuff, such as a PVC frame draped tightly with a blue poly tarp and very little ventilation. If you do decide to construct your own enclosure, don’t follow projects you find online blindly; there’s a lot of bad advice out there.

The biggest mistakes DIYers can make are underestimating the amount of heat their generators create and not providing enough ventilation for exhaust fumes. So, if you’re looking to create your own enclosure in the simplest way possible, we recommend a lean-to built onto a level surface, made of 4-by-4-inch posts with an angled roof.

Leave a foot or more from the edges of your generator to each post and the lowest point of the roof for adequate ventilation and heat resistance. To resist strong winds, the posts should go into the ground about 1/3 of their total length, set on a layer of gravel and concrete filling the hole. Weatherproofing sealant will also help the structure to resist the elements.

Generator Placement Safety Tips

Trevor Raab

In addition to providing adequate weather protection for your generator, there are other things you should do if you plan to use your generator for backup power during emergencies.

• Place it on level ground. This is true anytime you use a generator, because it ensures the proper circulation of the engine oil. Generators are also quite heavy and have wheels, so you don’t want them to tip or roll away. When it comes to the weather, uneven ground may expose one end of your generator to the wind and rain or place it in the way of running water. Some homeowners have created level concrete or gravel pads that their generators can sit on, which can also protect them from muddy ground conditions.
• Clear snow and debris. During or after a snowstorm, don’t allow snow banks to form around your generator. Keep it clear by 3 to 4 feet around the generator to avoid blocking any vents or the exhaust port. If you have it protected with a running cover or other enclosure, clear snow from the top, as well. This goes for other types of debris from other weather events, such as leaves and brush.
• **Keep it at least five feet away from flammable materials. **Generators get hot, so sitting one directly next to a wood pile, trash cans, or other mechanical equipment can be a fire hazard. The same goes for vinyl siding on a house—the heat could actually melt the siding. If your generator is not a least 5 feet from the outside walls of your home, you’re inviting potential damage or fire.
• Point the exhaust away from the house. Even if you’ve set your generator 20 feet from windows and doors, it’s a good idea to keep the exhaust port away from the house. This helps to keep deadly CO fumes from floating into the home. For an extra piece of mind, installing a CO alarm is a simple way to stay safe.

David is a Reviews Editor for Hearst’s Enthusiast Group, contributing to Popular Mechanics, Runner’s World, Bicycling, Best Products, and Biography. He has over 25 years of experience writing about and reviewing consumer electronics, kitchen appliances, DIY products, outdoor gear, and more. He also spent years covering the ever-changing world of online retail. To relax, he loves experimenting with new recipes, tweaking his smart home setup, and spending time outdoors on his bike or camping.