How long do furnaces last?

Many last 15 to 20 years or more with maintenance.

Why does my furnace smell dusty at first?

Dust burning off the heat exchanger at the start of the season is normal and should fade. Other smells aren't.

Furnace Repair & Heating in Modesto, CA

Quick checks

Make sure the thermostat is on Heat and set above room temperature. Check the furnace switch, which looks like a light switch, and the breaker. Look at the filter; a clogged one can shut a furnace down.

Furnaces that won't light

Modern furnaces use an igniter and a flame sensor. A dirty sensor or cracked igniter is a common cause of a furnace that starts, then shuts off, or never lights.

Short cycling

A furnace that turns on and off every few minutes may be overheating from poor airflow, or have a thermostat or sensor problem.

Heat pumps

A heat pump heats efficiently in the valley's mild winters. On foggy mornings it may run a defrost cycle and give off steam, which is normal.

Carbon monoxide

Gas furnaces need working carbon monoxide alarms on every level. If an alarm sounds, get everyone outside and phone 911 from there.

Gas smells

If you smell gas, leave the house, then contact your gas utility from outside. Don't flip switches or use the phone indoors.

Repair or replace

Older furnaces, especially paired with an old AC, may be worth replacing together, possibly with a heat pump. See AC installation.

Get help

Tell the technician what the furnace is doing and its age. Send a request and an HVAC technician will get in touch.

Fall check

A furnace check before the first cold, foggy mornings catches dirty flame sensors, worn igniters and blocked vents, which are the common causes of no-heat calls in December.