Help me spec out a replacement home network using Ubiquiti bits

Build-Troys-Network

That's it - I've finally lost it with Linksys and both my WRT 1900ACs that are only a year old are getting chucked. Don't get me started on all the reasons why, but it's primarily down to continued degradation of wifi signal and the constant need for reboots. Going by the responses to this tweet, that's just what they do: https://twitter.com/troyhunt/status/778867707655487488

I’m going all out with Ubiquiti instead. No, I'm not interested in [insert the other thing you think rocks here], there's a really vocal majority in favour of Ubiquiti so that's that. Now I need help speccing out what I need for my house as it’s not quite as straight forward as just chucking in a couple of (dodgy) routers.

Here’s what I’m working with:
- Large multi-level house about 500m2 (needs at least 2 APs, probably more)
- Wired ethernet to every room (I believe Cat 5e, was here when I got here)
- Patch board in the garage and a 100Mbps hub (running patch cables out to a Linksys 8 port gigabit switch instead)
- 4 wired connections used in the lounge (presently has 1 Linksys WRT 1900AC + ISP cable modem which needs to be the because that’s where the cable enters)
- 6 wired connections used in office (presently had 1 Linksys WRT 1900AC + a Linksys 8 port gigabit switch)
- Internet connectivity: Cable modem -> Linksys WRT 1900AC (lounge) -> patch board -> Linksys WRT 1900AC (office)

Here’s the Ubiquiti bits I think I need:
- UniFi Security Gateway (sits between switch and cable modem): https://www.ubnt.com/unifi-routing/usg/
- 3 x UniFi US‑8‑150W 8 port UniFi switches, 1 for the lounge, 1 for patch board and 1 for office, both with PoE: https://www.ubnt.com/unifi-switching/unifi-switch-8-150w/
- 2 x UAP-AC-PRO access points for lounge and office (or go all out and get a 5 pack of them): https://www.ubnt.com/unifi/unifi-ap-ac-pro/
- UniFy Cloud Key to manage it all: https://www.ubnt.com/unifi/unifi-cloud-key/

Network topology wise, it then does this:

           Cable modem in bridge mode (lounge)
                            |
                            |
             UniFi Security Gateway (lounge)
                            |
                            |               Wired lounge devices
                            |             /
              US‑8‑150W switch (lounge)
                            |             \
       UAP-AC-PRO           |               UAP-AC-PRO for lounge wifi
    (somewhere else)        |
                     \      |
                       US‑8‑150W switch
                     /   (garage)
       UAP-AC-PRO           |
    (somewhere else)        |       Wired office devices
                            |     /
                       US‑8‑150W switch
                        (office)  \
                                    UAP-AC-PRO for office wifi

Questions:
- What would you do differently / better?

Thank you!

I suggest you to analyse the UBNT firmware before deciding to go all UBNT. You can get their firmware online from the support / firmware updates page and just take a look at how they do stuff. At least years back when I had to deal with support for bunch of ubnt hardware, the general rule of thumb was that their hardware is great, but products get released before software is even 50% ready for release - especially regarding locking down the system and doing basic attack surface reduction. Might be better now.
Suggestion: get one device, have some fun breaking it, and then decide for or against it 😄

regarding the wifi side: rule of thumb is to favor 5GHz over 2.4 GHz if all devices support it. Much more stable data transfer. Also, make sure to lower down the transmission power setting to only cover te area that you need. More transmission power on just one side will only raise noise level, but not improve connectivity because your laptop/smartphone/tablet will only send with the usual low dBm values and are optimized for low power consumption.
Do not use more then 3 SSIDs on one 40MHz wide channel and do not place nearby wifi APs on same or overlapping channels.
Also yes, always use proper CAT 6 or CAT 7 cable or you will have to redo some cabling in a few years. Don't be too greedy on the network cable. Replacing anything else is done quick and easily, but redoing network cable which might even be hidden inside some walls is lots of work.

I have 2 x UAP-AC-PRO covering my house using POE from an edge switch, works really well love that I can use schedules to turn off the kids ssid to make sure they are not staying online all night! Only issue I have had is the 24 port edge switch runs pretty hot. Mine is in a wall mounted mini rack cabinet (in my attached garage) along with my adsl router, qnap nas , 2x hd homerun tv tuners and a cloudkey and I had to put a fan in the cabinet to stop the switch overheating (everything else runs cool enough, even in a 42 deg C Canberra summer).

The cloudkey lost it settings last time I did a firmware upgrade but has been rock solid since then, I have not touched it in 6 months. Roaming didn't work too well so I ended up turning it off, the ap's are on different channels and do overlap slightly, in practice the range is good on both aps over most of the house.

The ap's are fussy about the cabling, one ap (furtherest from switch) will only connect at 10Mb even with Cat6, have recrimped the connectors on both ends twice, and it checks out just fine with cable testers or even my macbook... so not sure what's up there, if I take the ap and plug into short cable into the switch it connects at 100Mb.. haven't had time to look into it further and with my 5Mbit adsl1 connection it's not really an issue!

I've been looking at Ubiquiti too for a similar reason but I keep encountering posts about quality like this
https://lukas.im/2016/01/25/replace-broken-usb-stick-in-ubiquiti-edgemax-routers/index.html

So they use USB sticks for storage, power it off by pulling power and youre likely to corrupt things.

one ap (furtherest from switch) will only connect at 10Mb even with Cat6, have recrimped the connectors on both ends twice, and it checks out just fine with cable testers or even my macbook...

@vincentparrett not unusual for Ubiquiti to have some deaf units. Check if you get 100Mb/s on a very short cable and reset he device. If you don't get it to connect at 100Mb/s, send it back to your seller and request a replacement.

@basisbit - I decided to update the firmware tonight (1st time in 6 months) and now both AP's are now connecting at 1Gbps. Go figure!