What should you check before winter in Tucson?

Check your heat before the first cold night, not on it. Winters here are mild. Heating demand is about 1,333 degree days a year against 3,424 for cooling, and there are fewer than 12 nights a year at or below 32F (1991-2020 normals at Tucson International Airport). Because heat runs so rarely, problems sit hidden until you need it. Climate Pros Tucson matches you with a licensed local pro if the test below fails.

What goes on the checklist?

  1. Test heat early. On a mild fall day, switch the thermostat to heat and let it run a full cycle. A gas furnace should light and warm the house. A heat pump should blow warm air. If a heat pump blows cool, see heat pump reversing valve.
  2. Change the filter. Tucson dust loads a filter quickly. See HVAC filter guide for Tucson dust.
  3. Look at the outdoor unit. A heat pump needs clear space around it. Debris and plant growth reduce airflow.
  4. Check the thermostat. Replace batteries if it uses them and confirm the heat schedule.
  5. Test carbon monoxide alarms. If you have a gas furnace, gas water heater or gas range, make sure CO alarms work. Replace any that are past their stated life. Leave the house and call 911 if an alarm sounds.
  6. Listen for noise and watch for odd smells. A burning smell at the first start is common with dust on a furnace, but it should pass. A smell that stays needs a pro.
  7. Check the vents. Make sure furniture isn’t blocking registers.

Is heat pump frost or steam a problem?

A heat pump in heat mode may build frost on the outdoor coil and run a defrost cycle. You may see steam. That’s normal in short bursts. Ice that stays or a unit that stops heating is not. See heat pump frozen or steaming.

Do TEP peak hours matter in winter?

If you’re on a TEP time-of-use plan, winter on-peak runs weekdays 6 to 9 a.m. and 6 to 9 p.m., October to April. Heat running at those times costs more on that plan. Check your plan with TEP.

Is Mount Lemmon different?

Yes. Summerhaven and the upper mountain are in code climate zone 5B with a 4F winter design temperature, and about 53 nights a year at or below 32F. Backup heat there is a question for the pro. See HVAC in Mount Lemmon and Summerhaven.

When is it time for a pro?

  • The furnace won’t light, or the heat pump never warms the house.
  • A gas smell. Leave the house and call 911 or the gas utility.
  • Short cycling, banging or a persistent burning smell.

Related: do heat pumps work in Tucson winters and fall HVAC checklist. Service pages: furnace repair and HVAC maintenance. Area overview: Tucson HVAC hub.

When to call us

If the heat test fails or you smell gas, you need a licensed pro. Call (520) 353-2520 and we’ll match you with a licensed local pro.