Smart home projects fail for boring, physical reasons far more often than software ones. Here are the three that account for most of them.
1. The missing neutral
Traditional switches only need the hot and the switch leg. Smart switches need constant power for their radio, which means a neutral in the box. Millions of homes wired before the mid-2010s do not have one at the switch.
Two ways out. Run a neutral to the box — usually easier than people fear, especially where the switch is on an exterior-adjacent wall or below an accessible attic. Or fit a no-neutral smart switch, which trickles current through the load. Those work, but can flicker with some LEDs and sometimes need a bypass capacitor at the fixture. If you are doing more than one or two, running neutrals is the better long-term answer. See smart home wiring.
2. The doorbell transformer
Video doorbells are small computers with a camera and a radio. Many houses still have a 10VA chime transformer from 1974 feeding it. Symptoms: the doorbell drops off Wi-Fi when it records, the chime buzzes, the night vision browns out. The fix is a properly sized transformer and, sometimes, a heavier gauge run — not another reboot.
3. Systems that stop working when the internet does
The test of a well-specified smart home is what happens when the router dies. If the lights will not turn on from the wall, the system was designed badly. Insist on:
- Physical wall control that always works, independent of cloud or hub.
- Local control paths — a hub on your own network, not a round trip to a data centre.
- A protocol with a mesh, so devices are not all leaning on one Wi-Fi access point.
Wire it while the walls are open
If you are already doing a remodel or a rewire, that is the moment to add what is painful to retrofit: Cat6 to every TV and access point location, conduit between the network closet and the attic, power at camera positions and at the top corner of the garage, a C-wire to every thermostat, and neutrals in every switch box whether or not you are going smart today.
What not to bother with
Smart bulbs behind a dumb switch. Somebody will flip the switch and the bulb will be unreachable forever after. Put the intelligence in the switch, and leave the bulbs simple.
See smart home wiring for a walkthrough, or outlet & switch installation if you mostly need power where there currently is none.