Best Generator Covers and Storage Sheds: How to Protect Your Investment

This post contains affiliate links. If you purchase through our links we may earn a small commission at no extra cost to you.

Why Generator Storage Matters More Than Most Owners Realize

A generator stored uncovered in a garage or shed is exposed to dust, moisture, rodents, and UV degradation that accelerate component wear and cause corrosion on electrical connections. A generator stored outdoors without a weatherproof cover takes direct sun, rain, frost, and pest exposure that can damage the fuel system, corrode the alternator, and cause premature failure of plastic components. Proper storage is one of the simplest and cheapest ways to extend a generator’s service life significantly.

This guide covers both generator covers — fabric covers for portable generators in storage or during use — and permanent generator sheds for homeowners who need weather protection during operation.

Generator Covers for Storage: What to Look For

A quality generator storage cover should:

• Be waterproof, not just water-resistant: Look for covers with a waterproof rating or waterproof coating, not just polyester weave that slows water penetration. Seam-sealed covers provide better waterproofing at stress points.
• Allow ventilation: A fully sealed cover traps moisture inside, causing condensation damage. Good covers have ventilation flaps or breathable panels that allow moisture to escape while keeping rain out.
• Fit your specific generator size: A cover that is too large bunches around the generator, creating pockets that collect water. Measure your generator (length x width x height) and compare to cover dimensions before buying.
• Include tie-down straps or elastic hem: Covers that stay in place during wind keep the generator protected. Tie-down straps or a tight elastic hem prevent the cover from blowing off during storms.
• Be UV resistant: For outdoor storage, UV resistance prevents the cover material from degrading in sunlight — which would leave the generator exposed.

Top Generator Cover Picks

GenTent Running Cover — Best for Operation in Rain

The GenTent is a purpose-built generator canopy designed specifically for protecting a running portable generator from rain, sleet, and snow. Unlike storage covers, the GenTent mounts directly to the generator frame and provides a protective canopy during operation — allowing the generator to run in wet weather while keeping electrical components dry. It is the most widely recommended running-protection solution for portable generators and is compatible with most major portable generator brands.

View GenTent Generator Covers on Amazon

Classic Accessories Generator Cover — Best Budget Storage Cover

Classic Accessories makes a well-regarded line of generator storage covers in multiple sizes to fit generators from 2,000W to 10,000W class. The StormPro series uses heavy-duty water-resistant fabric with a welded seam and adjustable straps. At $25 to $45 depending on size, it is the most practical storage cover for homeowners who garage their generator and need basic protection from dust and incidental moisture.

View Classic Accessories Generator Covers on Amazon

Generator Storage Sheds: Permanent Outdoor Protection

For homeowners who keep their generator outdoors year-round or want protection during operation without moving the generator, a dedicated generator shed or enclosure is the most comprehensive solution. A generator shed provides weather protection, noise reduction, security, and a defined permanent location for the generator — simplifying every outage response.

What a Generator Shed Must Include

Carbon monoxide safety requirements apply to generator sheds just as to any generator enclosure. A proper generator shed must have:

• Adequate ventilation on at least two sides: Louvered vents on opposing walls allow airflow for engine cooling and prevent CO accumulation. Vents should be sized generously — at least 1 square foot of open vent area per 1,000 watts of generator output.
• Exhaust routing away from the structure: The exhaust must exit the shed directly to the outside, directed away from living spaces. A simple metal exhaust extension routed through the shed wall accomplishes this.
• Easy access for starting and refueling: The shed door must allow full access to the generator’s controls, fuel cap, and oil fill. A hinged or sliding door that opens fully is practical.
• Maintained clearance from the home: The shed itself must maintain 20-foot clearance from windows, doors, and vents — the shed does not change the CO safety requirement, it just provides weather protection for the generator within that required clearance zone.

Pre-Built Generator Enclosures

Several manufacturers offer pre-built generator enclosures designed specifically for portable generator storage and operation. These steel or heavy-duty polyethylene enclosures include pre-cut ventilation, exhaust ports, and locking doors. They install in under an hour and provide a weather-resistant, semi-permanent generator housing without building from scratch.

View Generator Storage Enclosures on Amazon

DIY Generator Shed: Basic Build Guide

A simple DIY generator shed can be built from lumber and plywood for $150 to $300 in materials. Basic design parameters:

• Interior dimensions: at least 6 inches of clearance on all sides of the generator for heat dissipation and access
• Roof: sloped to shed rain, metal roofing or asphalt shingles over plywood sheathing
• Walls: 3/4-inch plywood or OSB, painted or sealed for weather resistance
• Ventilation: 4-inch x 8-inch louvered vents on two opposing walls, positioned low on one wall and high on the opposite wall for natural air circulation
• Door: hinged plywood panel with a simple latch — removable or folding door provides best access
• Foundation: treated lumber skids or concrete blocks — keep the floor off ground contact to prevent rot

Rodent Protection: An Overlooked Storage Concern

Rodents are a significant threat to stored generators — mice and squirrels nest in warm engine compartments and chew through wiring, fuel lines, and air filter housings. Protection measures:

• Place rodent repellent sachets inside the engine compartment and near the air intake during storage
• Seal all entry points in a generator shed larger than 1/4 inch — rodents can enter through surprisingly small gaps
• Inspect the engine compartment before the first use each season for signs of nesting — chewed materials, droppings, or nest debris near the carburetor or air filter

Bottom Line

A quality generator cover costs $25 to $50 and significantly extends the service life of a generator stored indoors or outdoors. For wet-weather operation, the GenTent running canopy is the most practical solution. For permanent outdoor storage or year-round readiness, a generator shed — pre-built or DIY — provides complete weather protection while maintaining the CO safety clearances required for operation. Either solution is a small investment relative to the generator it protects.