How long do electric blankets last?

What the makers themselves will commit to

Warranty terms are the most honest proxy available for expected life, because they are the period a manufacturer is willing to be financially responsible for.

The pattern is worth noticing. Several of the brands that publish no wattage do publish a five-year warranty, and the brand that publishes wattage most consistently publishes no warranty term at all. Different companies choose to be transparent about different things, and no brand in this category is transparent about everything.

What actually wears out

Not the fabric. Not the controller, usually. The element insulation.

A heating element is a thin wire in an insulating jacket, sewn through fabric that flexes every time somebody turns over. Over a season that is thousands of flex cycles, concentrated at the same creases: where the blanket folds over the edge of the mattress, where it is tucked, where it is folded for storage.

Insulation embrittles and eventually cracks. There is no external sign. The blanket heats normally, the controller behaves normally, and nothing about its operation tells you the state of the wire inside it. That is why age is a better predictor here than performance, and why a blanket that still works fine is not thereby a blanket that is fine.

The three things that accelerate it

1. 1Washing. Every wash flexes and twists the element. Washing a bed blanket two or three times a season is reasonable; washing it monthly measurably shortens its life for no benefit, since a blanket above a top sheet is not against your skin.
2. 2Hard folding for storage. A crease is a stress point, and a blanket folded the same way for eight summers has eight permanent stress lines. Roll it instead. See storing a heated blanket.
3. 3Bunching and tucking in use. Tucking a blanket tightly at the sides folds the element back under itself every night, which is both a wear problem and the trapped-heat condition described on fire risk.

How to tell it is time

Two triggers, and either one on its own is enough.

Trigger one: age

Around a decade, regardless of how well it appears to work. If you cannot remember when you bought it, that is itself an answer. Older blankets also predate features that are now standard: several products in our set have auto shut-off ranges and overheat protection that a blanket from the 2000s simply does not have.

Trigger two: anything the inspection finds

Once a season, laid flat in good light: scorch marks or discoloration, a kink or hard lump in the wire, exposed conductor, damage to the cord or the connector, or a controller that is cracked or running hot.

Getting the most out of one

• Wash it two or three times a season, not monthly.
• Roll it for storage rather than folding, and store it somewhere dry and uncompressed.
• Lay it flat in use and resist tucking it in tightly.
• Preheat and switch off where you can. Fewer running hours is less thermal cycling, and it is also the cheapest way to use one, per our cost arithmetic.
• Keep animals off it or put a layer over the top. Claws puncture element insulation invisibly. See heated blankets and pets.