Generator Covers: Protection from Weather and Dust

What a generator cover does

A generator weatherproof cover is a fabric or vinyl shell that fits over a portable generator when it is not running. Its purpose is to keep rain, snow, dust, leaves, and direct sunlight off the unit while it sits in a shed, on a porch, in a garage, or in the back of a truck. A cover is not a running enclosure. It is meant for storage only, and the maker's manual will describe how to store the unit between uses.

When you shop for a cover, you will see listings that name the material, the dimensions, and the fit. The material is usually a coated fabric such as polyester with a waterproof backing, or a vinyl that resists water and UV rays. The dimensions are the length, width, and height of the generator, and the cover is sized to those measurements. Some covers have a drawstring, an elastic hem, or straps to hold them in place on a windy day.

A cover does not change how you run the generator. The CPSC, CDC, and EPA all state that portable generators must be operated outdoors, far from windows, doors, and vents, and never inside a home, garage, basement, crawlspace, or shed. A cover is for the unit when it is off and cool, not for the unit while it is producing power. Follow the maker's manual and the safety guidance from the CPSC, CDC, and EPA for all operation and storage questions.

Choosing the right size

The most important step in buying a cover is matching its dimensions to your generator. A cover that is too small will not fit over the frame, the handles, or the wheels. A cover that is too large will flap in the wind and may let water pool on top. Measure the generator from the ground to the highest point, usually the handle or the control panel, and then measure the length and width of the frame. Compare those numbers to the cover's stated dimensions.

Listings for covers often give a range, such as fitting generators from a certain length to a certain length. If the listing does not state the dimensions, the seller has not given you the information you need. In that case, move on to a cover that lists its measurements. The same principle applies to the generator itself: the listing for the generator will state its dimensions, and you can use those to find a cover that fits.

Some covers are described as fitting a class of generator, such as a 3,000 to 5,000 watt set or a 5,001 to 9,000 watt set. Those groupings are a starting point, but the actual fit depends on the frame size, not the wattage. Two generators with the same wattage can have different heights and widths. Always check the cover's stated dimensions against the generator's stated dimensions before you buy. For a portable generator, see the best portable generators guide.

Material and construction

The material of a cover determines how well it sheds water and how long it lasts in sunlight. Common materials are polyester with a waterproof coating, vinyl, and canvas. Polyester covers are lightweight and fold small for storage. Vinyl covers are heavier and resist water and UV rays well. Canvas covers are breathable but may need a waterproof treatment. The listing will name the material, and you can compare that to your storage conditions.

Look for a cover with vents. Vents allow air to move under the cover, which reduces condensation when the generator cools down after a run. A cover without vents can trap moisture against the metal frame and the control panel. The listing will state whether the cover has vents, and the maker's page for the cover will describe how the vents work.

The construction details matter too. A cover with a drawstring or an elastic hem fits more snugly than a flat sheet. Straps or buckles at the bottom keep the cover from blowing off. Reinforced seams and a double-stitched hem resist tearing at the corners. The listing will state these features, and you can read them the same way you read the features on a generator listing. For inverter models, the best inverter generator guide compares stated details.

What a cover does not do

A cover does not make a generator safe to run indoors or in a partially enclosed space. The CPSC warns that carbon monoxide from a generator is deadly and can kill in minutes, and that generators should never be used indoors, in garages, basements, or sheds. The CDC and EPA give the same guidance: operate the generator outdoors, more than 20 feet from windows, doors, and vents. A cover is not a substitute for that distance.

A cover also does not protect the generator from fuel or oil issues. The maker's manual will describe how to store the unit between seasons, including whether to drain the fuel or add a stabilizer. That is a question for the maker, not for the cover. The cover only keeps weather and dust off the outside of the unit.

Finally, a cover is not a repair. If the generator has a damaged frame, a cracked panel, or a worn cord, a cover will not fix it. Those are questions for the maker or a qualified service person. The cover is a storage accessory, and its only job is to keep the unit clean and dry when it is not running. For a generator with a CO sensor, see the best generator with CO sensor guide.

Shopping for a cover

When you shop for a cover, read the listing the same way you read a generator listing. The title will name the material and the size range. The bullet list will state the dimensions, the vents, and the closure type. The image set will show the cover on a generator and may show the straps or the drawstring. If the listing does not state the dimensions or the material, the seller has not given you the information you need.

A cover is a separate purchase, so it will not come with the generator. Some generator listings include a cover as a bundle, but most do not. If you want a cover, plan to buy it at the same time as the generator or shortly after. The cover's dimensions must match the generator's dimensions, so you need the generator's measurements first.

The price of a cover depends on the material, the size, and the brand. Covers for small inverter generators are less expensive than covers for large open-frame sets. The price tier is a shopping question, not a quality claim. A cover that fits well and sheds water is the goal, and the listing will tell you whether it does that. For a camping generator, the best camping generators guide lists inverter picks.

What to pick for your situation

The right cover depends on where you store the generator and how often you use it. If you keep the generator in a shed or a garage, a lightweight polyester cover that keeps dust off may be enough. If you store it outside under a tarp or on a porch, a vinyl cover with UV resistance and a drawstring will hold up better in sun and wind. If you take the generator camping or to a job site, a cover that folds small and has straps for the ride is practical.

For a small inverter generator used for camping, look for a cover sized to the unit's dimensions and one that fits in the storage compartment of an RV or a truck. For a large open-frame generator used for home backup, a cover with vents and a snug hem will handle the weather in a shed or a carport. The cover is a storage item, so match it to the storage space, not to the wattage.

The guides on this site compare generators by their stated details, and the same method applies to covers. Read the dimensions, the material, and the closure type on the listing, and compare those to your generator's measurements and your storage conditions. Then choose the cover that fits. For a home backup unit, see the best generator guide.

What to pick for your situation

Questions

Can I run a generator under a weatherproof cover?

No. A cover is for storage only. The CPSC, CDC, and EPA state that portable generators must be operated outdoors, far from windows, doors, and vents, and never inside a home, garage, basement, crawlspace, or shed. Running a generator under a cover traps heat and exhaust and is not safe.

How do I know what size cover to buy?

Measure the generator's length, width, and height from the ground to the highest point, usually the handle or control panel. Compare those numbers to the cover's stated dimensions. If the cover listing does not state dimensions, the seller has not given you the information you need.

What material is best for a generator cover?

The best material depends on your storage conditions. Polyester with a waterproof coating is lightweight and good for indoor storage. Vinyl resists water and UV rays and suits outdoor storage. Canvas is breathable but may need a waterproof treatment. The listing will name the material.

Do I need a cover with vents?

Vents reduce condensation when the generator cools down after a run. If you store the generator in a damp shed or outside, a cover with vents helps keep moisture from building up under the fabric. The listing will state whether the cover has vents.

Will a cover protect my generator from dust?

Yes, a cover keeps dust and debris off the outside of the unit while it is stored. It does not protect the fuel system or the engine internals. The maker's manual will describe how to prepare the generator for storage, including fuel and oil questions.

Can I use a tarp instead of a cover?

A tarp may keep rain off, but it does not fit snugly and can trap moisture against the generator. A cover designed for a generator has vents, straps, and a hem that fit the frame. For the best fit, use a cover made for the generator's dimensions.