How Do Murphy Beds Work?

The three mechanisms

Pistons are the easiest to live with and the only one you cannot adjust. They are matched to a weight range at the factory, which is exactly why the mattress spec is stated so tightly. A piston that has lost pressure over years shows up as a bed that is heavy to lift, and it is a replaceable part.

Springs are adjustable to your actual mattress, do not lose pressure, and require you to do the tensioning — which is the step people skip, and then the bed slams.

Manual fold has no assist, which sounds worse than it is: you are lifting a frame and mattress that has been balanced by geometry rather than by a cylinder. It also has nothing to service, ever.

A cabinet bed is not really this mechanism at all. The mattress tri-folds onto a platform that slides out at floor level, so nothing is ever overhead.

Why the mattress has a minimum weight

This is the part that catches everyone, and it follows directly from the bed being balanced.

If the mattress is too heavy, the counterbalance is insufficient and the bed wants to fall rather than descend. If it is too light, the counterbalance is excessive and the bed wants to rise — which means it does not sit closed properly and can push back when you close it.

Hence Bestar’s 60-to-90-pound window on the Key West, its 35-to-70-pound window on the horizontal Claremont 80W, and the universal instruction against box springs. Bedding counts towards the weight, so a heavy comforter on a mattress near the top of the range puts you over it.

Depth is a separate limit and a simpler one: 12 inches is the cabinet cavity. There is no workaround for a 14-inch pillow-top. Full detail in Murphy bed mattresses.

Why the ceiling and the extension are what they are

The cabinet has to be tall enough to contain a vertical mattress plus the frame plus the mechanism, which is why a queen vertical wall bed needs about 86 inches of cabinet and therefore a ceiling clear of a cabinet 85 to 91.3 inches tall depending on the model.

The extension is simply the mattress length plus the cabinet depth: a Bestar Key West extends 69.43 inches from the wall on Bestar's horizontal Claremont 80W, out of a 19.53-inch cabinet. No vertical queen here publishes the figure.

Rotate the whole thing ninety degrees and both numbers change: a horizontal queen is 64 inches tall closed and 84 inches wide, and it projects roughly the mattress width rather than its length. That is the workaround for a low ceiling — horizontal wall beds.

What using one is actually like

You pull a handle at the top of the cabinet, and the bed swings down on its pivot. With a piston or spring system the last third of the travel is controlled rather than free-fall. Legs at the foot of the frame drop or fold into place and take the weight at the far end.

Bedding stays on the mattress, held by straps, which is the single most useful practical feature of the format: nothing is stripped or remade. It is also why a bunched duvet is the usual reason a bed is hard to close.

Clear the landing zone first. We allow 30 to 36 inches of clear movement space around the open bed, and a coffee table in the way is the realistic accident in this category. More on that in are Murphy beds safe.

Knowing how one works is not the same as deciding to buy one. The benefit is quantifiable — a Bestar Key West hands back about 31 square feet of floor every morning — and so are the three things that rule it out, which is the whole of is a Murphy bed worth it. If the real alternative on your shortlist is a futon rather than a sofa bed, the straight comparison is Murphy bed vs futon.

Three ownership questions follow from the mechanism rather than from the purchase. When a bed starts creeping down or will not latch, the cause is usually the mattress weight rather than the hardware — how to fix a Murphy bed runs the checks in order and says where to stop. If lifting is the concern, the best Murphy beds for seniors ranks the field on effort and open bed height. And if the closed cabinet has to disappear into a living room, that is how to hide a Murphy bed.

Between understanding the mechanism and owning one sits the job nobody describes in order: the install itself. How to install a Murphy bed sets out the eight steps every wall bed install requires and the two that are never optional — anchoring into real structure, and keeping the mattress inside the maker’s published window.