Guide
What to Buy With a Generator
Five items make a generator usable: CO alarm, cord, cover, fuel storage, oil. In that order.
Top pick: Kidde Nighthawk KN-COPP-3 CO alarm
Watt & Warden
Backup Power Accessories
Nobody buys a generator for the accessories, and then discovers the machine is unusable without four of them. This is the short list, and the reasoning for each.
Start here
If you have just bought a generator, start with what to buy with it — five items, in the order they matter.
If you buy one thing, make it a carbon monoxide alarm. The alarm picks are here, and it is the cheapest item on this site.
If the machine cannot reach the house, the problem is the cord. Gauge, length and connector decide whether twenty feet of separation is even possible.
Everything in accessories
Best Carbon Monoxide Detectors
The Best Carbon Monoxide Detectors (2026)
The one non-optional item. Digital ppm readouts, battery backup, placement, and expiration dates.
Top pick: Kidde Nighthawk KN-COPP-3 CO alarm
Best Generator Extension Cords
The Best Generator Extension Cords (2026)
Gauge, length and connector type. Why 10/4 twist-lock is the standard house connection.
Top pick: GearIT 30A L14-30 generator cord, 25 ft
Best Generator Covers
The Best Generator Covers (2026)
Running covers vs storage covers - a critical distinction. Ratings, fit, and why a tarp is dangerous.
Top pick: GenTent Safety Canopy, open-frame
Best Fuel Cans and Storage
The Best Fuel Cans and Storage (2026)
How much fuel three days needs, costed at EIA prices, plus spouts that do not spill.
Top pick: No-Spill 1450 5-gallon gas can
Guide
The Generator Maintenance Kit
Three items on a shelf - oil, stabilizer, a spare filter - and an hour twice a year.
Top pick: Briggs & Stratton SAE 30 engine oil, 48 oz
Why the accessories decide whether the machine gets used
A generator on its own does almost nothing useful. It has to be twenty feet from the house for carbon monoxide reasons, which means a cord. It has to run in the rain that caused the outage, which means a cover. It has to be refueled without spilling gasoline on a hot muffler, which means a proper can. And it has to still start next winter, which means treated fuel and an oil change.
None of that is optional, and all of it costs a small fraction of the machine. The common failure is spending everything on watts and nothing on the four items that make watts reachable.
The five that actually matter
- A carbon monoxide alarm. Not a generator accessory in the marketing sense, and the only genuinely non-optional item here. The picks.
- A cord rated for the load. Undersized cord is a fire, not an inconvenience. Gauge and length.
- A running cover. Rain is the weather that causes outages. A tarp is not a cover. What a running cover is.
- Fuel cans and a stabilizer. Stale gasoline is the single most common no-start cause. Cans and storage.
- Oil, on a shelf, before you need it. The maintenance kit is three items and takes an hour twice a year.
What we deliberately do not sell you
Wheel kits for machines that already have wheels. Branded funnels. Magnetic dipstick trays. Hour meters on generators that ship with one. Every category accumulates accessories that exist because the margin is good, and this one is no exception.
The test we apply is simple: does the absence of this item stop the generator being used safely, or stop it starting next year? If not, it is not on the list.
The one for battery owners
If you own a power station rather than a generator, almost none of this applies — no fuel, no oil, no exhaust, no cover. What you may want instead is a panel and a cable long enough to put the panel in sun and the battery in shade. Portable solar panels and the connector guide cover that side.
Buy this list out of season
Cords, cans, covers and alarms all sell out within hours of a storm warning, and they are the cheapest part of the whole setup. Buying them in the spring or fall costs the same money and removes the one scenario where you own a generator you cannot use.
Questions people actually ask
What do I need to buy with a generator?
Five things: a carbon monoxide alarm, a cord rated for the load and long enough to keep the machine twenty feet away, a purpose-made running cover, fuel cans plus a stabilizer, and oil for the first change. Everything else in the category is optional.
Do I need a special cover for my generator?
Yes, if you expect to run it in rain -- and rain is what causes most outages. A running cover is designed to keep water off while leaving cooling airflow and the exhaust path clear. A tarp or a storage bag does the opposite and is genuinely dangerous.
What size extension cord do I need for a generator?
It depends on the load and the distance, and getting it wrong is a fire risk rather than a performance one. For a house connection the standard answer is a 10-gauge L14-30 cord rated for the full 30A; for individual appliances, heavy-duty 12-gauge or thicker outdoor cord.
How much does it cost to accessorize a generator?
A small fraction of the machine. The five items on this list together cost far less than the difference between two generator sizes, and without them the generator either cannot be used safely or will not start when you next need it.
Not sure which of these you need? Work out the number first — capacity falls out of how long your power is usually off, not out of a budget.