All Netgear dual-band home routers, including the Nighthawk AC1900, can accommodate a maximum of 32 devices on each of their two bands, giving you a total of 64 wireless devices.
- 2.4 GHz = 32 wireless devices
- 5 GHz = 32 wireless devices
I wouldn't be concerned about running out of bandwidth or saturating your network in this case. You stated that most of your wireless devices are smart devices, such as light switches, which would require extremely small amounts of bandwidth. The challenge here is working around the hard 32-device limit imposed on each band by the router.
You already have around 50 wireless devices, so you are rapidly approaching the 64-maximum number of wireless devices this router could theoretically support. There isn't much room for expanding this network right now and, if you ever have a group of visitors who want to use your WiFi, they may have a poor experience as the router would probably struggle to provide additional connections (particularly on the 2.4 GHz band).
Your 30x 2.4 GHz devices already occupy almost all of the 32 connections the router can support on the 2.4 GHz band, so you definitely want to put the 20x dual-band devices only on the 5 GHz network, to alleviate congestion on the 2.4 GHz band as much as possible.
That would leave you with:
- 2x remaining 2.4 GHz connections
- 12x remaining 5 GHz connections
I think you should consider expanding your network. This could be done either by introducing an additional access point or by replacing your dual-band router with a tri-band model. For example, the NETGEAR Nighthawk X6 AC3200 Tri-Band WiFi Router would increase the total number of potential WiFi connections from 64 to 96 devices.
It does this by simply adding a second 5 GHz radio:
- 2.4 GHz = 32 wireless devices
- 5 GHz = 32 wireless devices
- 5 GHz = 32 wireless devices
Personally, I would consider adding another dual-band router, instead of replacing your existing one with a tri-band. The reason for this is that you have an extremely high demand for 2.4 GHz connections. This is the bottleneck! Your smart devices are single-band and can't use 5 GHz, so adding another 5 GHz radio wouldn't take any pressure off the congested 2.4 GHz band.
Adding another dual-band router would give you an additional 32x 2.4 GHz + 32x 5 GHz potential wireless connections, which should eliminate all of your current connectivity problems.
Nighthawk AC1900 #1:
- 2.4 GHz = 32 wireless devices
- 5 GHz = 32 wireless devices
Nighthawk AC1900 #2:
- 2.4 GHz = 32 wireless devices
- 5 GHz = 32 wireless devices
This would give you a total of:
- 2.4 GHz = 64 wireless devices
- 5 GHz = 64 wireless devices
Summary:
- Short term: all of the 2.4 GHz devices have no option but to connect to the 2.4 GHz network but those that have the option of 5 GHz should all be on 5 GHz. This should resolve your immediate problems with what appears to be an excessive demand for 2.4 GHz connections
- Long term: you should consider expanding your wireless network to allow for more devices to connect. I would do this by buying an additional AC1900 and configuring it as an additional AP, doubling the maximum number of potential connections on each band from 32 -> 64 devices.
This whole question basically revolves around the WiFi connection limits imposed by your AC1900 router. It would be interesting to know exactly how many of your dual-band devices are currently using (or trying to use) the 2.4 GHz network and how many are on the 5 GHz network. – Mr Ethernet – 2019-08-19T05:31:05.660