Smart-home pre-wire checklist for a gut renovation

The checklist

Eight items cover what a locally controlled smart home needs from the electrical and low-voltage rough-in. They apply to gut renovations and to any room where walls or ceilings will be opened.

• A neutral (white) conductor in every switch box, including 3-way and 4-way locations.
• Deeper single and multi-gang switch boxes sized for smart dimmers, with box fill calculated under NEC 314.16.
• Thermostat cable with spare conductors at each thermostat location, even where today's system uses two wires.
• Low-voltage cable to each main entry door for a door station, contact sensors and an electric strike or powered lock.
• Network cable to each planned camera location.
• A controller location in the network closet with a dedicated circuit and a UPS, plus a central, high, non-metal location for the radios.
• Low-voltage runs to shade pockets, the garage door opener, the boiler or water heater room for leak sensors and a shutoff valve, the electrical panel for an energy monitor, and the EV charger location.
• Conduit or a pull string to each floor for future cabling.

Neutrals and box depth

Most Wi-Fi, Zigbee, Z-Wave and Matter switches need a neutral conductor to stay powered while the light is off. Many older NYC switch loops carry only the hot and the switched hot, with no neutral in the box, and that is the most common obstacle when owners add smart switches to pre-war apartments and row houses.

When walls are open, our licensed partner electrician runs a neutral to every switch location. Borrowing a neutral from a different circuit is a code violation and a hazard, never an acceptable shortcut. Where a neutral cannot be added, there are two practical alternatives:

• Smart bulbs on a circuit whose switch stays on, controlled from a wireless wall remote so the wall still works as a switch.
• A smart relay installed at the fixture, where power and neutral are already present.

Smart dimmers are deeper than standard switches and give off heat. Shallow boxes in plaster walls are a frequent problem: a dimmer forced into a tight box can crack the faceplate or strain and overheat the splices. Deeper boxes give the conductors and the device room, and the electrician calculates box fill under NEC 314.16 for the conductors and devices in each box. When two or more dimmers share a box, manufacturers often require derating, which lowers the load each dimmer may carry, so we check the instructions for the selected dimmers before the boxes are set.

Thermostat cable and door hardware

Many smart thermostats need a common wire (C-wire) for continuous power, and a later change to a heat pump can add control stages. Door preparation follows the same logic: simple during framing, awkward afterward.

• Run thermostat cable with more conductors than today's system uses, such as 18/8, so that a C-wire and future stages can be connected without opening the wall.
• Place each thermostat on an interior wall, away from radiators, supply registers and direct sunlight. For local control, choose a Z-Wave thermostat or one that pairs with Home Assistant through HomeKit, as described in our guide to smart-home devices that work without the cloud.
• In New York City, connecting thermostat and control wiring to a boiler or heat pump is work for a licensed master or special electrician under section 28-105.4.7 of the Administrative Code, and we coordinate that connection through our licensed electrical partner; on Long Island the HVAC contractor completes it. Automation adjusts setpoints only and is never wired into boiler or heat pump safety circuits.
• Use a standard door bore and backset so that Z-Wave or Matter deadbolts fit without modification.
• Run Cat6 or 22/4 cable to the main entry for a door station, and low-voltage cable into the frame for an electric strike or powered lock.
• Pre-wire contact sensors at entry doors and accessible windows. Intrusion alarm work is performed by a New York State licensed alarm installer.
• Keep a keyed override on every lock so the door opens without power or a network.

In small multifamily buildings, NYC's Tenant Data Privacy Law (opens an external site) prohibits requiring a smart access system for entry to a tenant's own unit, so unit doors keep a key option. Door hardware that releases on a fire alarm signal is coordinated with licensed electrical and fire alarm trades.

Controller, radios and network separation

The controller, whether Home Assistant Green or a mini PC, sits in the network closet with the router and switch. The radios have different needs. Zigbee, Thread and Z-Wave signals carry poorly out of a metal cabinet or a basement, so the adapters usually belong in a central, elevated location on the main living floor.

• Connect each adapter with a shielded USB 2.0 extension cable to a central shelf, or use a network-attached coordinator wired back to the closet.
• Keep the Zigbee adapter away from Wi-Fi access points and USB 3 ports, and use Zigbee channel 15, 20 or 25 (opens an external site).
• Stand the Connect ZWA-2 Z-Wave adapter (opens an external site) upright, clear of obstructions.
• A single Connect ZBT-2 runs Zigbee or Thread, not both, so plan two adapter positions if the home will use both.
• Keep Thread border routers (opens an external site) and Wi-Fi Matter devices on the same network segment (VLAN) as Home Assistant. A strict segmentation design can break Matter, HomeKit and camera discovery (opens an external site), which rely on multicast, so the segments are planned before the network is configured.
• Plan three segments: a home automation network for Home Assistant, Matter, Thread and other locally controlled equipment; a separate network for cloud-only gadgets and guests; and a camera network without internet access, reachable from Home Assistant and the recorder.
• Put the fiber terminal, router, switch and controller on a UPS. Home Assistant monitors the UPS through its NUT integration and can shut down cleanly. If the home has a battery, Tesla Powershare or a generator, the closet circuit goes on the backed-up panel.

Remote access uses Home Assistant Cloud or a VPN (opens an external site) rather than an open router port. In March 2026, the FCC added foreign-produced consumer routers to its Covered List. The action concerns new equipment authorizations, not the continued use of routers already installed, though it may affect which models are sold and how long they receive updates. Keeping the controller independent of any one router brand avoids relying on a single product line.

Cost, permits and handover

Neutrals, deeper boxes and spare cable add modest material and labor while walls are open. The cost depends on the number of switch and device locations, plaster versus drywall, the distance to the network closet, and building approvals in co-ops and condominiums. Adding the same work after finishes means opening and repairing walls. Replacing or adding switches is electrical work: our licensed partner electrician performs it and files for the permit and inspection when the scope requires one. At handover you receive:

• A panel schedule showing smart switch locations.
• A device list with the Home Assistant IoT class of each device.
• Backups of the Z-Wave, Zigbee and Thread networks.
• Administrator credentials held in the owner's name.
• Home Assistant backups stored off the controller.

We mark neutrals, box sizes, thermostat and door runs, and the controller and radio locations on your plans, and we price the electrical and low-voltage work together.