What is soffit lighting, and does it affect attic ventilation?
Short answer. Soffit lighting is outdoor lighting installed in the underside of the roof overhang, usually small recessed cans, LED wafer lights or puck lights that wash light down the walls or onto walkways. It is wired through the attic, so it needs fixtures rated for wet or damp locations, and it should be placed so it does not block soffit vents or the air channel behind them.
How it is installed
The installer cuts holes in the soffit, runs cable from a switch or lighting transformer through the attic and down into the eave, and mounts the fixtures. Thin LED wafer lights need little depth, which suits the shallow space at the eaves. Each fixture should be rated for outdoor wet or damp locations, and junction boxes have to stay accessible. Many jurisdictions require an electrical permit for a new circuit.
Protecting the attic ventilation
- Do not mount lights in place of vented panels or over continuous strip vents without adding the lost intake somewhere else.
- Keep wiring and fixtures from crushing the baffles that hold the air channel open above the insulation.
- Make sure insulation is not stuffed back into the eave after the work.
- Seal around housings that open into the attic so humid outside air does not short-circuit in around the light.
Practical tips
- Space lights evenly and line them up with windows or columns for the best look.
- Choose warm color temperatures; bright cool light under the eaves draws insects and wasps.
- On wood soffits, check for rot before cutting, since the eave is where gutter overflow does its damage.
- If a roof or gutter replacement is coming soon, do the lighting afterward so crews are not working around new fixtures.
See roof ventilation basics for why the eave air path matters and roof anatomy explained for how the overhang is built.