Smart Home Wiring: What to Run Before Drywall Goes Up

The neutral wire problem

A standard mechanical light switch only ever needed two wires — line and switched line — so in a huge number of homes, especially anything built before the last couple of decades, that's all that was ever run to the switch box. No neutral wire, because a simple switch never needed one.

A Wi-Fi or Zigbee smart switch is different: it has a small radio inside that has to stay powered even while the light is off, so it can keep listening for commands. That standby power typically has to come from a neutral connection. Industry estimates put roughly 40-50% of existing homes without a neutral wire at the switch box — which is exactly why a smart switch that worked fine in a showroom sometimes won't install in a specific room without extra work.

What to run while the walls are open

If you're framing a new build or have walls open for a renovation, this is the cheap window — running an extra wire during rough-in costs a fraction of what it costs to open a finished wall later.

• A neutral wire at every switch location, even ones you don't plan to make smart immediately — this is the single highest-value thing on this list
• Structured low-voltage wiring to key locations: Cat6 ethernet (more reliable than Wi-Fi for anything stationary — a TV, a desk, a security hub) and coax where you might want it
• A dedicated network cabinet or panel location, even a small closet, to consolidate a router, switch, and any hub hardware instead of leaving it exposed on a shelf
• Conduit or a pull-string in walls you're closing up, even where you don't have a specific plan yet — it turns a future wiring job into a pull-through instead of a wall opening
• Extra outlets near where a hub, camera, or smart display is likely to live — most smart home hardware still needs power, not just Wi-Fi

What actually drives the cost

• Timing is the single biggest factor — the same wiring run during open-wall rough-in costs a fraction of the same run after drywall, paint, and trim are done
• Scope — a couple of smart switches and a network cabinet is a modest add; wiring an entire home for structured audio, multiple camera locations, and a full home theater is a much larger project
• Whether you're retrofitting into finished walls versus running wire in an open one — fishing wire through existing finished walls typically requires an electrician and sometimes limited drywall repair
• Get quotes specific to your scope rather than assuming a flat number — a network cabinet and a dozen extra neutral wires is a very different job from wiring a whole-home audio and camera system

If you're not renovating

Not everyone has the walls open, and that's fine — it doesn't mean smart switches are off the table. No-neutral smart switch models exist specifically for this situation, designed to draw the small standby power they need without a dedicated neutral connection. They're a legitimate option, though check compatibility carefully — not every smart switch brand offers a no-neutral version, and some no-neutral models have more limited features (dimming range, compatible bulb types) than their standard counterparts.

A simple way to check before you buy: turn off the breaker, remove the existing switch plate, and look in the box. If you see a bundle of bare copper or green wires capped together with no separate white wire, that's very likely a no-neutral box.