Heated Mattress Pads: Sizes, Dual Controls and Safe Use

A heated mattress pad lies flat on the mattress under the fitted sheet and warms the bed from below, so your usual duvet stays on top. Buy it in your mattress size, with a skirt deep enough for the mattress. For a queen or king, dual controls let each sleeper pick their own heat or leave their side off.

Pad or electric blanket: which one suits your bed

Both are electrically heated bedding, and in the U.S. both fall under UL 964, the safety standard whose scope covers blankets, throws and mattress pads. The difference is where the heat sits.

If your quilt is one you love, or you dislike a blanket’s weight, a pad lets you keep it. Our best heated blankets guide covers the over-the-top kind, and our heated bedding guide compares every option.

Which size heated mattress pad to buy

Match the pad to the mattress, not the bed frame. The Better Sleep Council lists these standard U.S. mattress sizes:

A pad sized for a king will not sit flat on a California king, and a pad that is too big bunches up, which every manual warns against. Sharper Image, for example, sells its dual pad in Full, Queen and King only, so check the size list before you set your heart on a model.

Dual controls for two sleepers

On queen and king pads, two controllers are common. Biddeford’s manual explains how this works on its pads: each controller runs one side of the bed, and both have to be plugged in for the whole bed to heat. One sleeper can run warm while the other leaves their side off.

Settings vary by brand. Sharper Image lists 10 heat settings on its dual pad, and Sunbeam’s manual says each of its dual controls works on its own and turns off 10 hours after it is switched on. Some pads have a preheat setting: Biddeford says some of its models drop back to your chosen setting after an hour and a half of preheat.

How to fit a heated mattress pad

The fitting steps in the maker manuals are short, and each one is there for safety:

1. Connectors at the foot. Biddeford says to lay the pad flat with the connectors at the foot of the bed.
2. Cord through the skirt. Run the connector through the slot in the skirt so it sits between the pad and the mattress, with the cord hanging free.
3. Secure the skirt or straps to the mattress so the pad cannot slide. Electrical Safety First notes that under-blankets are usually held in place with elastic straps.
4. Keep the cords clear. Biddeford warns not to run cords between the mattress and box spring, or anywhere they can be pinched or trapped.
5. Leave the controller uncovered, and plug it into a standard wall outlet.

Once it is on the bed, do not tuck in the wired area, fold the pad or bunch it up, and never use pins to hold it in place. Electrical Safety First adds that you should not use a hot water bottle with heated bedding, since water and electricity do not mix.

Where a heated pad should not go

Some beds are off limits. Sunbeam’s manual says not to use its heated products on a waterbed, bunk bed, mechanically adjustable bed, or a child’s crib or bed, and Electrical Safety First also advises against under-blankets on adjustable beds. Biddeford says not to use its pads on a child under 12, or on anyone who is diabetic, sedated, unable to feel heat well or has poor circulation. Our guide to whether heated throws and electric blankets are safe covers who should skip heated bedding altogether.

Sheets to go over a heated pad

The fitted sheet has to cover the pad as well as the mattress, so a pad adds a little depth to the bed. Flannel sheets are the cozy choice for winter, and our flannel sheets guide explains how they are rated and what to look for.

Washing, storing and replacing a pad

Unplug and remove the controller first. Biddeford says to wash its pads by hand or in a machine on slow agitation, then dry on low heat for five minutes or line dry, and never to switch the pad on while it is damp. Sunbeam’s manual says wash cold on a gentle cycle, tumble dry low and keep heated bedding out of commercial dryers.

Out of season, Electrical Safety First, a UK safety charity, suggests leaving the pad on the bed unplugged, or folding it loosely and storing it somewhere cool and dry with nothing heavy on top. Check it over before the first cold night. The charity says to replace electric blankets every ten years, or sooner if you see worn fabric, scorch marks or visible wires, or if the cord is damaged or the control buzzes or smells. It also says an old one should be recycled as electrical waste rather than thrown out. Rules for small electrical items vary across the U.S., so ask your local trash or recycling service, or a nearby electronics recycler, where to take a worn-out pad.