Count the obstacles rather than the rooms: one unit per floor is a reasonable starting point, plus one for any area cut off by dense masonry or metal. Where each one can be cabled matters more than how many there are.
The right number falls out of the building, and there is no square-metre figure that will produce it for you.
Start by counting obstacles, not rooms
Walk the house and note where the signal has to cross something serious: a thick internal wall, a chimney breast, a floor, a metal-framed partition, an extension with coated glazing, a detached garage or outbuilding.
Each of those is a candidate boundary. A room on the other side of one is a room that a further unit serves properly and a stronger single unit does not.
A reasonable starting shape
One unit per floor, positioned centrally and not directly above one another, so the coverage overlaps at the edges rather than at the middle.
Plus one for any area cut off by masonry or metal — a garden room, a converted loft with an insulated floor, a basement.
Minus any the plan does not need. A small flat needs one radio, and the second unit people buy for it makes things marginally worse rather than better.
Cabling is the constraint that shapes the answer
Every unit needs to get its traffic back to the router. A cabled unit relays nothing; a wireless one spends airtime doing so.
So the practical question becomes: how many of these positions can be reached with a cable? Where the answer is all of them, wired access points are the arrangement, and they will be quieter, more predictable and easier to specify — PoE type required, uplink port speed, mounting plate, management method, all published.
Where the answer is none of them, a tri-band mesh pack with a dedicated radio for the link between nodes is the arrangement, and the node count is what you are choosing.
Where the answer is some of them, mesh packs accept a wired backhaul per node, and mixing is normal and sensible.
Too many is a real failure mode
Units placed close together on overlapping channels contend with one another, and every unit is also a device the others have to be polite to. Symptoms are a network that feels busy at quiet times and devices that cling to a distant unit.
Two things prevent it. A channel plan — neighbouring units on non-overlapping channels, which in the 2.4 GHz band means the three that do not overlap and nothing else. And restraint: adding a unit because a corner reads slightly low is how a house ends up with five radios and a worse network than it had with three.
Where the units should go
Ceiling-mounted in the middle of the area each serves, if the mounting allows it, because that is where the fewest obstacles stand between them and the devices. High on a wall is the next best thing.
Not in a cupboard, not beside the boiler, and not stacked in the same room as the router.
And the wired side underneath it all
Each unit’s uplink port sets the ceiling on everything it serves, and the switch it plugs into is where all of them meet. A house with three busy access points on gigabit uplinks is a house where the uplink is worth reading about before another radio is bought.
The questions that come up before an order
Can I have too many access points?
Yes. Units close together on overlapping channels interfere with one another, and devices may hold on to a distant unit rather than moving to a nearer one. More radios in a small space is not more coverage; it is more contention, and the channel plan is what keeps it from being a problem.
Do the units have to be from the same maker?
To behave as one system with coordinated handover, generally yes, or at least certified under a common programme such as the Wi-Fi Alliance’s EasyMesh. Units from different makers can still be used together as independent access points sharing a network name — it works, and the handover is left to the client devices.
Last reviewed 10 September 2026