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What You Need to Know About Mattresses

By Ben Slater

From firmness to spring density, we highlight the mattress features you need to know about if you want to find the mattress that’s right for you.

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Mattresses may seem simple enough, but when you're at the shops you're likely to come across various features that you need to know about if you want to sleep soundly. Read our expert advice to find out more.

We've talked to our mattress experts so we can give you the answers you need before buying. Are 'orthopedic' mattresses really better for you? Does a greater spring density offer more support? Find out below.

Once you're up to speed on mattress features, don't forget to check out our review of the best mattress brands.

Washable mattress covers

Some mattresses come with a removable cover, which is handy if you're expecting to have to wash the mattress. 

If the mattress you want to buy doesn't come with a cover, you can buy a cover separately.

Mattress firmness

Contrary to popular belief, a mattress doesn’t have to be hard to be good for you. How firm it is comes down to personal preference, as long as it does a good job of supporting your body. 

We measure the shape of a person's body at 36 different points both when standing up and lying down on the mattress - this way we can tell how well the mattress keeps your spine in the same shape as when you're standing up.

For each mattress, check our body-support scores for both lying on your back and lying on your side, and read our full mattress reviews to find the one that's right for you.

'Orthopedic' mattresses

Medical-sounding terms, such as ‘orthopedic’ and ‘posturepedic’, don't necessarily mean a mattress is better for you. There are no restrictions on the term 'orthopedic mattress', so any mattress can use that description.

The body-support rating we give in our mattress reviews shows how well each mattress keeps your spine in its natural position. This is your best guide to finding one that's good for your back.

Mattress toppers

A mattress topper is an easy way to make your mattress more comfortable. It sits on top of a mattress, offering a layer of memory foam or extra padding. You can buy a mattress topper for as little as £10 – although most cost more than that.

When we surveyed 924 owners of mattress toppers in January 2014, almost a third said that their topper made their mattress much more comfortable. A further half said it made their mattress a little more comfortable.

But we've found that the quality of mattress toppers can vary, with some offering more comfort than others. Read our review of the best mattress topper brands to find out which you should go for.

Mattress padding

Mattresses with spring systems are usually padded with man-made polymers, but some contain natural fibres such as horsehair or wool. These layers can affect firmness and breathability, both of which we test in every mattress. But more layers aren’t always better – the support from the springs is more important.

Mattress spring density

When it comes to springs, it's quality rather than quantity that's important. The number of springs in your mattress is less important than how they’re constructed. Which? has tested mattresses with densities ranging from 440 to 1,085 springs and found wide variation in the level of support offered.

Mattress handles

Handles help with flipping, turning and positioning the mattress. Many new bed mattresses don’t need to be flipped over, but they may still benefit from being rotated from head to foot a few times a year. 

Memory-foam mattresses are a good example of this - most manufacturers don't advise flipping, but you should use the handles to rotate the mattress from time to time.

Rolled-up mattresses

Some mattresses come vacuum-packed in a handy cotton bag, so you can take these rolled-up mattresses home with you instead of waiting for delivery.

Now that you know about mattress features, you're well-placed to pick the perfect mattress for you using our exclusive mattress reviews.


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