How to determine numbers and location(s) of hardwired Wifi access points?

Question

I hope this question is "Home Improvement" enough. I would like to hardwire/install 1-3 Wifi access points in my home. From my understanding, ceiling mount is best and I got TP-Link EAP610 (which I will power via PoE).

In a single story, square home this task is somewhat trivial: Just take one and place it in the center and call it the day. But reality is more complex. In my case:

1. I have two stories
2. Not the entire lower floor is covered by the upper floor, only the backside of the house
3. Everything else equal, I would like to prefer some spots over others. For example, placing an AP next to the entrance is preferable than on the nice living room ceiling
4. As much as possible of the exterior (patio etc) should be covered as well without requiring a dedicated outdoor AP (exterior distances are on the same order as the structure)
5. The number of APs for good coverage should be minimized

Here is a plan of the house (annotated rooms, sizes, exterior distances and the red part on the lower level indicated that the upper level is above):

I was planning to place two access points where indicated with the red dots (one on the lower floor, one on the upper), but this is just a random guess.

I can't imagine that there is no structured approach to do this, something that's based on quantitive data/calculations/measurements rather than wild guesses.

1. How do I decide how many APs I need?
2. How do I decide where to place them?

Answer 1

Welcome to (part of) my day job. Practically speaking, the correct way to determine what coverage/placement works is to test it.

Various outfits make various software tools to attempt to model coverage - all suffer from making broad and often incorrect assumptions about how radio waves will interact with building materials, and what those building materials are. If you had a tool that could accurately model the interactions, discovering and inputing the details of the building (at the level of detail and accuracy needed for accurate modeling) would be considerably harder than temporarily hanging some access points (some sort of pole or tripod arrangement is normal so you don't have to poke holes and can easily move them to test) and running a coverage survey.

If (as seems likely/implied from the drawing) your walls are masonry, expect poor penetration, especially on the 5GHz band. So AP1 will have very poor odds of working well in the living room, per that drawing.

Old windows are fairly radio-transparent. Both masonry walls and newer, coated high-efficiency windows are rather radio-opaque, which will impact your exterior coverage. An AP in line with a plain glass window will give some coverage.

Since Mesh wifi has been mentioned, I'm going to point out that having mesh instantly cuts your actual available speed at least in half (usually worse) .vs. Access Points connected to cables. All the traffic between you and a mesh AP has to be transmitted to the next AP, and that uses up the available bandwidth. It's a crutch if you can't manage to run cables, but not something you should default to if you can run cables.

Answer 2

There is too much variability between homes and other buildings to be able to say how many nodes you would need. Walls and what they're made of (sheet rock vs plaster, for instance) makes a difference in signal strength and coverage. So does how many other devices you have that may be using the WiFi band. That's why area-of-coverage (for example, 2,500 sq ft) numbers in ads are probable best case, like in a gymnasium.

I would start with two and see what your coverage and performance is. Put one on the first floor and one on the second floor. You should be able to add the third one after the fact if your need better coverage.

FWIW, I went with the Tp-Link Deco XE75 mesh WiFi system for our church. I bought two nodes knowing I could easily add more nodes if I needed better coverage. Also, with a mesh system, there is only one (unless you deliberately set up a guest network) WiFi network that shows up on your computer or other device.

Answer 3

As @Stevesh says, this really depends on the building, your needs, and the equipment you choose.

Friends who have a 1400-square-foot ranch with a centrally located chimney started with the router/access point at one end of the building, and found that at the far end the combination of distance and the "radio shadow" of the chimney weakened the signal too much. They used a WiFi repeater for a while as a temporary fix, but eventually replaced that with a second router/AP.

I could get adequate (not ideal, but quite usable) coverage from a single WiFi access point in the basement of my 1400-square-foot 2-storey wood-frame house, if I placed it so the chimney shadow didn't cover any of the rooms. Moving the AP up to a shelf on the ground floor improved reception in the back yard at the cost of weaker but usable reception in the living room. I eventually went with multiple APs for firewalling reasons, still using those two locations rather than worrying about trying to optimize placement, plus running cat6 cable to a few places where speed actually mattered.

If you want to jump straight to a mesh system and trying to optimize placement and so on, go for it. We haven't felt a need to do so. Good enough is good enough, and where it isn't WiFi may not be the right answer anyway.