Heating and cooling checks to try first
Filters, furnaces and air conditioners. A big share of no-heat and no-cool calls turn out to be a dirty filter, a tripped breaker or a thermostat setting. Check those first, then call for service with a clearer idea of what's wrong.
Where to start: The single most useful habit is changing the air filter on schedule. If the heat won't come on, run through the five furnace checks. If the AC runs but the air isn't cold, work through the AC checklist before you book a visit.
What are you dealing with?
Change your HVAC air filter
AC not cooling? Check these first
Furnace not turning on? Check these first
Common questions
How often should I change my furnace filter?
Every 1 to 3 months for standard 1-inch filters. Check it monthly if you have pets, allergies or construction dust.
When should I call an HVAC technician?
If you smell gas, the unit trips the breaker again after a reset, or the free checks don't help. Refrigerant, gas valves and electrical parts inside the unit are jobs for a pro.
Looking for something else? Browse all guides or see emergency steps.