Project book · an afternoon

Fit a smart thermostat

Low-voltage wiring, one screwdriver, and the bill drops every month afterwards.

How many thermostats?

thermostats

This fits in a car

About 5 lb of materials. Comfortably inside what a car carries (200 lb), so any shopper can take it.

Before you start

Thermostat wiring is low voltage, but the system it controls is not — turn the furnace or air handler off at the breaker first. If you find mains voltage at the thermostat, or the system is a heat pump you cannot identify, stop and get an HVAC technician.

What to buy — untick anything you have

Climate

1 Smart thermostatPhotograph the wires behind the old one before you buy, and check the model works with what you have. A system with no C wire needs the adapter that some kits include and some do not.
1 Thermostat trim plate

Hardware

1 pack of drywall anchors and screws
1 pack of wire labels

Tools — already ticked off, since most people have them

Tools

1 Small screwdriver set· most people have this
1 Small level· most people have this
1 Drill driver· most people have this
1 Phone, for the photograph· most people have this

It lands in the shopping form, where you can edit anything and say what you think each thing costs. Nothing is ordered until you send it.

How it goes · about an afternoon · beginner

Switch the heating and cooling off at the breaker, not just at the thermostat.
Take the old face off and photograph the wiring before you disconnect anything, then label each wire with the letter on the terminal it came out of.
Fit the new base plate level, feeding the wires through, and connect each labelled wire to the matching letter.
Clip the thermostat on, restore the breaker, and run it through the setup on the app.
Test heating and cooling both actually come on before you call it done.

Something else

Build a raised garden bed Mulch a flower bed Paint a room Put up garage shelving Fix a patchy lawn Build a fire pit Mount a TV on the wall Cookout for a crowd

Feeding people instead? The recipe book works the same way — pick a meal, say how many, every ingredient lands on the list.