Furnace Repair in Cambridge, MA
Furnaces here run from October through May. If yours quits, tell us what it's doing and a licensed contractor who covers Middlesex County will get in touch.
Tell us about the job
It takes about a minute.
Eight months of heat, nights near 19 degrees
Your furnace works from October to May here, and on the coldest nights it is holding the house against a low near 19°F. That means long stretches where the burner cycles on and off for hours at a time, night after night. Every start puts load on the igniter and the flame sensor, and those are the parts most likely to fail first. You will notice it as a furnace that tries to start and can't, or one that shuts off partway through a cycle.
The region has logged 89 winter storms and 467 damaging wind events over the past ten years, and weather like that brings power loss with it. In Massachusetts, 10% of households went at least 24 hours without power in 2024. A furnace with no power will not run no matter how sound the rest of it is, so when the lights come back on and the house is still cold, the problem may be in the furnace itself, not just the outage.
- 8 months
- October through May, your furnace is on duty
- 19°F
- the average winter night it heats against
- 59%
- of homes here heat with gas, so most furnaces here burn gas
- 89 winter storms
- in ten years, the nights a failure hurts most
NOAA nClimDiv, 1991–2020 normals
A new furnace would cut about $200 a year off heating for a typical Middlesex County home.
Estimates for a typical Middlesex County home, compared with an older unit built to the previous federal minimum, from EIA household energy data, Massachusetts fuel prices and NOAA climate normals. Your home will differ.
Repair makes sense when one part has failed and the heat exchanger is sound.
Replacement makes sense when the heat exchanger is cracked or the furnace keeps needing parts.
- Why won't my furnace turn on?
- Start with the thermostat. Check that it's set to heat and the temperature is above room temperature, and check the batteries if it uses them. If the thermostat looks fine, check the furnace's power switch, usually a light switch by the unit, and the breaker for it in your panel. A dirty air filter can also make a furnace shut itself off before it starts, so check that next. If none of this brings it back on, the igniter, the flame sensor, or the control board may have failed, and a contractor will need to test each one to find out which.
- Why is my furnace blowing cold air?
- Most often the furnace is still warming up. Cold air blows for a short time when a cycle starts, before the heat exchanger gets hot enough to warm the air passing over it. If cold air keeps coming the whole time it runs, the igniter may not be lighting the burners at all, so the blower is just moving unheated air through your ducts. A clogged filter can also cause this by starving the burners of the airflow they need to work properly. If your winters here run cold nights near 19°F, a furnace that isn't actually heating will show itself fast, and it's worth having a contractor look at it right away rather than waiting.
- Why won't my furnace pilot light stay lit?
- This usually points to the thermocouple, the small sensor that tells the gas valve the pilot is burning. When it wears out or sits out of position, the valve shuts the gas off as a safety measure, even though the pilot was lit a moment before. A draft blowing across the pilot can cause the same thing, so check whether air is reaching it from a vent or a door nearby. If the flame is lit but looks weak or yellow instead of steady blue, that's a different problem, likely dirt in the pilot assembly, and it's worth having a contractor clean or replace the part rather than relighting it repeatedly.