Dear customer. We’re happy to give you the estimate to install new smoke detector: — Extend power from existing wall outlet in (1) bedroom, run wires through the wall to power the first smoke detector — Run interconnected 14/3 wires through the wall and use wire-mold to run wire from one bedroom to the other because there is concrete ceiling. Approximately 50ft — Supply and install (4) smoke and CO2 combination detector — Permit fee is $750 extra if customer requested — Rough patch and clean area, painting by others Thank you for choosing us and feel free to reach out for more details **********Jason - Kings Electric & AC**********