How much should you spend on a spare room mattress?
The spare room mattress is usually the oldest one in the house. It came from the main bedroom when that was replaced, or it came with the sofa bed, or it is the one a child slept on for fifteen years before they left. Guests sleep on it, say it was fine, and stay one night instead of two. This is a guide to what a spare room actually needs, and where to stop spending.
What a spare room mattress has to do
It has a harder job than the one in your own bedroom, in one way: it has to suit everyone. Your mattress only has to suit you. The spare one gets your mother-in-law, your student nephew, a friend with a bad back and two children top-to-tail, and none of them get to choose.
That points to a medium-firm mattress. Softer suits fewer people. Firmer feels like a hotel that cut corners. Medium-firm with a real comfort layer is what suits the widest range of bodies, which is also why hotels buy it.
It also has to be cool enough, because spare rooms are often the warmest or the coldest room in the house and the guest cannot adjust anything. A knitted cover over a spring unit, not a solid foam block.
And it needs a firm edge, because guests sit on the bed to unpack.
Sofa beds and guest beds
Check two things before buying anything.
Depth. Pull-out sofa beds with a folding metal action take a thin mattress, typically 8 to 12 cm, and a standard mattress will not fold into them; they need a replacement sofa-bed mattress. Day beds, guest beds, trundles and ottoman guest beds take a standard mattress, usually up to about 25 cm. Measure the current mattress and check the manufacturer's limit before buying anything.
Size. "Double" sofa beds are very often a 4ft small double (120 × 190 cm), not a 4ft 6 double. Some are shorter than 190 cm. Measure the frame, not the label.
For a day bed, guest bed or ottoman guest bed, a 20 to 22 cm pocket-sprung mattress with a knitted cover is the sweet spot: deep enough to have a proper spring unit and a comfort layer, shallow enough for the frame. For a metal-action pull-out, buy a purpose-made sofa-bed mattress and accept that it is a compromise; see the best mattress for a sofa bed.
The price bands
| Spend (double) | What you get | Who it is for |
|---|---|---|
| Under £200 | Open coil or basic foam, thin comfort layer, a couple of years | The room nobody uses |
| £200 to £350 | Rolled pocket sprung, 40 kg foams, a decent cover | Occasional guests, two or three nights a year |
| £350 to £500 | Pocket sprung with specified foams (50 kg memory, 35 kg CMHR), firm edge, ten-year guarantee | Regular guests, family staying a week, anyone over fifty |
| £500 and up | The same builds you would buy for yourself | Airbnb, a room that is really a second bedroom |
Above about £500 the extra money is buying features a guest will not use: tension choice, natural fillings, a pillow-top. Below about £350 you are buying a mattress that will need replacing before the guests stop coming. The band in between is where a spare room should be.
Airbnb and rental rooms
The maths changes. A mattress in a room that is let is slept on 100 to 200 nights a year, by people who write reviews. Two rules from hosts who have learned the hard way:
- Buy the same mattress you would sleep on yourself, in medium-firm, with a firm edge and a washable or protected cover. The reviews are about the bed more than the wallpaper.
- Buy three of the same thing at once if you have three rooms. Makers who build to order will usually do a better price on a multiple of one size, and guests moving between rooms get the same bed.
Landlords letting furnished rooms should do the same, with the addition of a properly waterproof protector.
Downsizing and the empty room
If the spare room used to be a child's room, the mattress is probably a single that has done fifteen years. Nobody is going to enjoy it. A double or a small double in a medium-firm pocket sprung is the difference between the room being "the spare room" and being somewhere people want to stay. It is also the purchase that lets the family come for a weekend rather than a night.
How we built ours
The Empty Nester is our entry build: 22 cm, medium-firm, 1,000 pocket springs with a foam-encapsulated edge, 50 kg/m³ memory foam over 35 kg CMHR, a knitted breathable cover. It fits most sofa beds, suits the widest range of guests, and it is the same mattress we sell to students as The Uni Student, so it is built to cope. Ask us about three or more of a size.
The short version
- Medium-firm, breathable, firm edge: it has to suit everyone.
- Measure the sofa bed: depth limit and real size.
- £350 to £500 is the band. Below it you rebuy; above it you are paying for features guests will not use.
- Rentals: buy what you would sleep on, in multiples.
What mattress should an Airbnb host buy? The bed is the review
A rental mattress is slept on by a hundred strangers a year who write reviews. What to buy, how to protect it, when to replace it, and the two rules experienced hosts follow.
The best mattress for a sofa bed: depth and size first, then everything else
Sofa bed" covers four different things, and only one of them takes a normal mattress. How to tell which you have, the depth each can take, what to buy for a metal-action pull-out, and when to replace the whole bed instead.
Guest bed: single, small double or double? Choosing the size for a spare room
The spare room is usually the smallest bedroom, and the bed size decides who can stay. The sizes, what each allows, room dimensions that make the decision for you, and why small double is the underrated answer.