Smart home devices can slow down your WiFi, and the usual cause is the number of devices. Most smart plugs, bulbs and sensors send tiny amounts of data, but each one is another device your router has to keep track of and another device taking turns on the same airwaves. Security cameras and video streaming use the most bandwidth. Once a home passes a few dozen connected devices, a single consumer router often starts to struggle.
Here is how much different devices use, why the device count matters, and what fixes the problem.
How smart home devices connect to WiFi
Your router (or your access points) is the meeting place for every wireless device in the house. Devices on the same WiFi band take turns sending data, so a busy device or a slow, distant one can hold up everything else. Many smart devices only use the 2.4 GHz band, which travels farther through walls but is more crowded and slower than 5 GHz or 6 GHz.
Some smart devices don’t use your WiFi at all. Lutron Caséta and RadioRA 3 use Lutron’s own Clear Connect radio, and many locks and sensors use Z-Wave, Zigbee or Thread. Those devices talk to a hub or processor, and only the hub sits on your network. That is one reason professionally installed lighting and sensors put much less strain on WiFi than a house full of WiFi bulbs and plugs.
How much bandwidth do smart devices use?
These are typical figures. Actual use depends on the model, settings and how often the device is active.
| Device | Typical bandwidth |
|---|---|
| Smart plugs, bulbs, switches, sensors, locks, thermostats | A tiny fraction of 1 Mbps, in short bursts |
| Smart speaker answering a voice request | Well under 1 Mbps |
| Music streaming at CD quality | About 1.4 Mbps per stream |
| 1080p security camera uploading to the cloud | About 2 Mbps upload per camera |
| 4K security camera uploading to the cloud | Up to about 15 Mbps upload per camera |
| 4K movie or TV stream | About 15 to 25 Mbps per stream, depending on the service |
A few cloud cameras can use more upload bandwidth than many internet plans provide, because cable internet plans often have much slower upload than download speeds. The small devices barely register in bandwidth, so if your network slows down as you add them, the bottleneck is the router’s capacity and the crowded 2.4 GHz band.
Signs your smart devices are slowing your network
- Devices show offline in their apps and come back on their own.
- Voice commands lag or the speaker says it is having trouble connecting.
- Camera clips are choppy or missing, or live view takes a long time to load.
- Video calls freeze when the cameras are busy, such as when someone walks up the driveway.
- Restarting the router fixes things for a few days.
A typical example: a family starts with a mesh kit, a few smart speakers and some WiFi plugs, and everything works. Over a couple of years they add six cloud cameras, a video doorbell, TVs in every room and two people working from home. The internet plan hasn’t changed and neither has the router, and now video calls drop every afternoon. The fix is usually a combination of the steps below.
How to keep your WiFi fast with lots of smart devices
Quick fixes
- Move the router to a central, open spot, off the floor and out of cabinets.
- Update the router’s firmware and restart it.
- Connect phones, laptops and TVs to 5 GHz or 6 GHz so they leave 2.4 GHz to the smart devices that need it.
- Turn on Quality of Service (QoS) if your router has it, and give priority to video calls and streaming.
- Check your internet plan’s upload speed if you use cloud cameras.
Bigger fixes
- Plug stationary devices into Ethernet. TVs, streaming boxes, game consoles, audio streamers and desktop computers all work better wired, and every device you take off WiFi frees up airtime for the rest.
- Wire your cameras. Power over Ethernet cameras recording to a recorder in the house keep camera video off your WiFi and off your internet connection.
- Replace extenders with wired access points. Access points connected by Ethernet cable give full speed in every part of the house. Mesh systems work well too, especially when the nodes are wired together.
- Put smart devices on their own network. A separate network (VLAN) for smart home gear keeps it from competing with your computers and makes the network more secure.
- Use non-WiFi lighting and sensors. A Lutron system or Z-Wave, Zigbee and Thread devices take dozens of devices off WiFi entirely.
Choosing a router or WiFi system for a smart home
Look for WiFi 6 or newer. WiFi 6 handles many devices at once far better than older standards. WiFi 6E adds the 6 GHz band, which is less crowded, and WiFi 7 adds more speed and lower delay for newer phones, laptops and TVs. Features like MU-MIMO and OFDMA let the router talk to several devices at the same time, which helps most in homes with lots of smart devices.
For larger homes, a business-grade system from a brand such as Araknis, Access Networks, Ubiquiti or Ruckus, with a separate router, network switch and ceiling-mounted access points, handles a large number of devices and can be managed remotely. A consumer mesh kit is fine for a smaller house with a moderate number of devices. Our guide to smart home servers and switches explains how those pieces fit together.
Planning for more devices
Most homes add smart devices every year, so build in room to grow. Run Ethernet to every TV location and to the ceiling where access points will go, especially during a renovation. Choose a network switch with spare ports and enough Power over Ethernet budget for future cameras and access points. Keep your network secure as it grows, too, since every device is another way in. Our guide to securing your home WiFi covers the steps.
When a professionally designed network makes sense
If you have a few dozen devices in a modest house, the quick fixes above and a good mesh system may be all you need. A designed network makes sense when the house is large or has plaster walls, stone or several floors, when you have more than a handful of cameras, when people work from home and can’t afford dropped calls, or when you are renovating and can run cable. A good installer will survey the house, place access points where the coverage is needed, separate smart devices onto their own network and keep an eye on it after the install.
Questions we hear often
How many smart devices can home WiFi handle?
It depends on the equipment. Many consumer routers start to struggle once you pass a few dozen active devices. A WiFi 6 or newer system with several wired access points can handle many more, because the load is spread across the access points.
Will a faster internet plan fix slow WiFi?
Only if the internet connection is the bottleneck. If your speed test is fast next to the router and slow across the house, the problem is coverage or the router, and a faster plan won’t help.
Do smart devices use data when I’m not using them?
A little. They check in with their servers and download updates. Cameras are the exception, since they upload video every time they detect motion.
Planning a home WiFi project?
We design and install whole-home WiFi and wired networks for houses across Greater Boston, the South Shore and Rhode Island. Book a free consultation or read more about our smart home WiFi and networking.
