Can You Put an Electric Blanket Under a Mattress Topper?

If you’ve ever spent a winter in the UK, you’ll know there are two types of people: those who brave the cold with pure stubbornness, and those who unapologetically layer their beds like they’re building a thermal lasagne. Electric blanket? Check. Mattress topper? Check. Heated throw, hot water bottle, thermal socks? Check, check, and absolutely check.

But one question seems to pop up every winter: can you actually put an electric blanket under a mattress topper? Or is that a one-way ticket to ruining your bedding — or worse, blowing a fuse at 2 a.m. when you’re finally warm for the first time in days?

Let’s find out.

So… can you actually put an electric blanket under a mattress topper?

The short answer is: sometimes yes, sometimes no. It ultimately depends on the type of electric blanket AND the type of topper.

The slightly longer answer is below (don’t worry, we’ll keep it simple and non-electrical-engineering-like).

Most traditional electric blankets — the kind made to lie directly under your sheet — should not be placed under a topper. They’re designed to have only a single sheet between them and you. Layering something thick on top can trap heat, stop the blanket from regulating temperature properly, and potentially damage the internal wiring.

But many modern under-blanket electric blankets or heated mattress pads are designed to sit underneath a topper. Some brands even recommend it, because the topper helps distribute heat more evenly and keeps everything comfy.

Confusing? Slightly. But here’s what it really comes down to:

• If the manufacturer says it can go under a topper, you’re good.
• If the manufacturer doesn’t mention it, leave it above the topper.

Always check your model's instructions because different brands have different safety testing and heat output.

Why would you want the electric blanket under the topper in the first place?

There are a few reasons this question keeps coming up, and to be honest, they’re all pretty relatable:

1. Comfort

Some people don’t love the texture of an electric blanket — the wires, the connectors, the odd lumps. A topper hides all of that and makes everything feel smooth again.

2. Even heat

Memory foam toppers especially do a great job of spreading warmth. Instead of feeling like you’re lying on warm lines of spaghetti, you get a more consistent warmth.

3. Protecting the blanket

A topper can shield the blanket from spills, pets, and the occasional “breakfast in bed that definitely didn’t go as planned.”

So the temptation to shove the electric blanket under the topper is strong. But — as we’ll get into — you’ve got to be sure you’re doing it safely.

What types of mattress toppers work best over an electric blanket?

If your blanket is designed to go under a topper, the type of topper you choose matters a lot more than you’d expect.

Memory foam toppers

These are the warmest option because they trap heat like nobody’s business. This is good for staying warm but not so great if your blanket is older or tends to get hot quickly. Memory foam + high heat isn’t always a great combo.

Use memory foam only with electric blankets specifically approved for use underneath.

Polyester or hollowfibre toppers

These are lighter and allow heat to pass through more easily. If you’re set on putting a topper over your blanket, this is generally the safer and more compatible choice.

Feather or down toppers

These add a lot of insulation. Lovely for cosy winters, but like memory foam, they can trap heat. That can make the blanket work harder and may shorten its lifespan.

Safety tips (because staying warm shouldn’t be risky)

Electric blankets today are much safer than the ones your nan used to use in the ’90s, but there are still some basics worth keeping in mind.

1. Always follow the manufacturer’s instructions

This is the boring but crucial one. Some blankets explicitly say “Do not use with a topper,” and if that’s the case, ignore your instincts, ignore this blog, ignore everything except that label.

2. Don’t fold, scrunch or squash the blanket

If you put your topper over the blanket and it compresses the wiring too much, you risk damaging it. You want the blanket lying flat with no creases.

3. Don’t use a heated blanket with a very thick topper

Anything thicker than 7–10 cm starts to trap heat unevenly. If your topper looks like a marshmallow, keep the electric blanket on top.

4. Test the heat after setting everything up

Turn your blanket on for a few minutes. If the topper gets too warm too fast, it might be too thick or too insulating.

5. Replace old electric blankets

If yours is older than your favourite pair of pyjama bottoms (say 8+ years), it’s time to upgrade. Technology has moved on, and so has safety.

A general rule of thumb

If you’re not sure, then assume:

→ Electric blanket under sheet → Mattress topper under blanket

This is the setup that works for the widest range of models without risking overheating.

But if your blanket explicitly says “safe under mattress topper” (many modern ones do), then flip the order to:

→ Mattress topper → Electric blanket → Fitted sheet

This is the cosy sandwich you’re probably dreaming of.

What about heated mattress toppers?

Ah, the plot twist.

If you really want heat coming from below the topper without worrying about whether it’s allowed, consider buying a heated mattress topper instead of a traditional electric blanket.

These are designed to be slept on directly, and they’re usually thicker, more durable, and more evenly heated. They don’t usually go under another topper, though — the topper is built in.

Think of them as the luxury version of an electric blanket.

So, what’s the final verdict?

Yes — you can put an electric blanket under a mattress topper, but only if the blanket is specifically designed for it, and the topper isn’t too thick or insulating.

If the label says it’s not designed for that purpose, then don’t be tempted to do it. But, if your blanket’s instructions give you the green light, then relax and enjoy your ultra-cosy, extra-toasty bed.

After all, winter is long, heating bills are high, and we all deserve to feel like a baked potato when we go to sleep if we want to.