Your living room gets a quiet upgrade once a smart thermostat is on the wall, learning your schedule and cutting wasted heat while you sleep. The physical swap takes about thirty minutes of wiring, and booking it during the shoulder season of spring or fall usually means quicker appointments and better utility promotions.
Before you commit to a single price, get more than one quote from local electricians or HVAC techs so you know what the labor should actually cost. Pair those estimates with whatever instant rebates your local power utility is currently running on their website to lower your upfront material costs.
Remember that the 0% intro window is a strict deadline, not free money, and any remaining balance left over when those 18 months end will start getting hit with regular interest charges.