Open coil is cheap because the springs are joined into one unit
Open coil is the cheapest way to build a sprung mattress because there are fewer components, assembly is faster and the comfort layer is usually thinner. I like a straightforward explanation for a low price. It's considerably more useful than a photograph of someone looking delighted in white pyjamas.
Inside, hourglass-shaped springs are joined by helical wires, which are wires wound into a spiral. A thicker rod runs around the perimeter to hold the edge of the unit together. The springs move as one connected unit, with a comfort layer between you and the metal.
You will also see open coil sold as Bonnell, traditional sprung or open spring. Continuous coil is a related version made from one length of wire formed into rows. More names to remember, lucky you. The important thing is that the springs are connected, so pressure in one place affects the surrounding surface.
Pocket springs sit in separate fabric pockets and compress individually. Weight on one part of the bed therefore doesn't pull the rest down in the same way. That's the construction difference I care about when you compare the two. Check how the springs are arranged before you compare cover fabric: a pretty top changes none of this.
Open coil gives you bounce, airflow and an easier mattress to turn
Open coil does its best work when you want a low-cost bed with a firm, springy feel that is easy to move. There's a proper bounce when you change position. If you enjoy a little trampoline feeling, you might genuinely prefer it to sinking into foam; buying cheaply doesn't mean you're obliged to dislike the result.
The open space through the spring unit lets air move, so this construction sleeps cooler than foam. That makes it a sensible option for an occasional bed where you want a simple, airy build. Keep the bedding in mind too: piling a heavy duvet over yourself is a fairly committed way to undo your cool-bed shopping.
Open coil mattresses are also relatively light, which matters when you're changing sheets or turning a mattress without help. I think ease of maintenance deserves more attention than it gets. A mattress you can actually lift has an advantage over one you need to arrange a small gathering to move.
A two-sided mattress can be slept on from either side. You can flip it as well as rotate it head to foot, which spreads the wear over both sleeping surfaces. Most pocket-sprung and foam mattresses are one-sided and can only be rotated. Check the care instructions before flipping anything: a finished-looking underside isn't enough to tell you it's a sleeping surface.
Connected springs are a poor fit for sharing every night
Open coil's biggest weakness is that you feel movement across the whole bed, which is why I rule it out for two adults sharing every night. When one person turns over, the connected springs move beyond the spot they're lying on. You might be very fond of your partner, but receiving a mattress-based update on every change of position is a bit much.
With repeated use, two people also produce a dip towards the middle. That's the trench: you start with your own space and gradually find yourselves lying in the same hollow. Romantic in a bedding advert, bloody irritating when you're trying to stay on your side. The shared spring unit wears sooner than a pocket-sprung build.
The thinner comfort layer is another weak point. As it wears, you feel more of the springs beneath you, particularly if you're heavier and compress the padding further. A firm feel on the first lie-down doesn't tell you how well that thin top will cushion you after regular use. Look at how much comfort material sits over the unit before you accept firmness as a sign of quality.
For a child's bed, my buying preference is firm: find the money for pocket springs. A growing back is where I refuse to trim the mattress budget. For an adult's occasional spare bed, I accept open coil's limitations because the mattress gets much less use. A child's bed gets used every night, and I want a better construction for that job.
I also pass over open coil for a heavier sleeper or someone buying with a bad back. Pocket springs are my starting point in both cases. However tempting the saving, a thin comfort layer over a connected unit is too much of a compromise for those purchases.
Choose a flippable build and put your money beneath the cover
Buy a two-sided open coil mattress with thicker spring wire and a deeper comfort layer, then give it an even, undamaged base. Those are the details that make this construction a better buy. The embroidered cover can wait; you won't be admiring the stitching through a fitted sheet at midnight.
Start by confirming that both sides are intended for sleeping. Being able to flip the mattress is one of open coil's most useful advantages, and I wouldn't give that up casually. Then look for the wire gauge. A lower gauge number means thicker wire, which makes a firmer, longer-lasting spring unit. Within open coil, a firmer tension holds its shape longer than a soft one.
Choose enough padding over those springs to cushion you properly. If the description gives you paragraphs about the cover but barely mentions what's underneath, ask for the comfort-layer details before buying. I have very little patience for the word "luxury" when you can feel the metal through the top. A plain cover over better springs and more padding is the purchase I favour.
Give the mattress a fair chance by checking the base before it arrives. A dipped or broken base shows through an open coil unit especially quickly. Remove the old mattress and inspect the support underneath; replacing the mattress while leaving a dip below it wastes money.
Set reminders to rotate it and, if it's two-sided, flip it according to its care instructions. Spreading the wear is the point, so doing it once when you remember the receipt isn't much of a maintenance plan. Regular turning is particularly useful with a construction that wears sooner.
For a couple's everyday bed, a heavier sleeper or a bad back, step up to pocket springs instead. If your budget is tight, look for an ex-display pocket-sprung mattress and check its condition and returns terms. For an adult, I would also take a well-kept, better-made second-hand mattress from someone whose history I trust over a poor new one, provided I'm comfortable with the hygiene. My preference for children remains a proper new pocket-sprung mattress.
Avoid these open coil purchases
Skip open coil when the daily use will expose its weaknesses, and skip versions that remove its practical advantages. I can forgive a basic spare bed. I can't see the appeal of paying extra for decorative fabric wrapped around the same compromise.
- Two adults sharing every night. Movement travels between you, and repeated use produces the trench in the middle.
- A child's everyday mattress. I prioritise a new pocket-sprung build for a growing child's bed.
- A one-sided open coil mattress. You lose the option to flip it and spread wear across both sleeping surfaces.
- A thin quilted top for a heavier sleeper. The padding compresses further, and you feel the springs as it wears.
- Open coil priced alongside pocket springs because the label says "luxury". Compare the spring construction and comfort layer before paying for the cover.
A grand name is cheap to print; I prefer spending the money on what's beneath it. Before you order, confirm the build, read the returns conditions and check whether the mattress can be slept on from both sides.
