HVAC Repair in Cambridge, MA
Homes here need heat from October through May and cooling from July through August. If your system 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.
Ten months of work a year, most of it in the cold
Your furnace in Cambridge runs from October through May. Winter nights here average 19°F, and every time the burner fires to keep the house warm, it puts a load on the igniter. A system running that many months a year wears those parts down, and a worn igniter can leave you without heat on a cold morning.
Summer is short here, just July and August, with afternoons averaging 81°F. That doesn't give a strained air conditioner much time to show a problem before the season ends, but a low refrigerant charge or a failing capacitor will still leave you without cooling on the hottest days. The region sees its share of winter storms and high wind, and outdoor units and the power lines that feed your system take the brunt of that. Statewide, 10% of households went at least 24 hours without power in 2024. Most furnaces restart on their own once power returns, but a long outage during a hard freeze can still leave pipes and a furnace's electronics at risk.
- 8 months
- October through May, your system heats
- 2 months
- July through August, it cools
- 19°F
- the average winter night it heats against
- 81°F
- the average summer afternoon it cools against
NOAA nClimDiv, 1991–2020 normals
A new furnace and air conditioner would cut about $230 a year off heating and cooling 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.
Replacement makes sense when the furnace's heat exchanger is cracked, the air conditioner's compressor has failed, or repairs keep coming.
- Why is my heat not working?
- Check your thermostat first, then your breaker or gas valve, before you assume the worst. A furnace that won't fire is often the igniter or a flame sensor that's told it to shut off for safety. If it's blowing cold air instead of staying off, the blower may be running while the burner isn't lighting. With winter lows here averaging 19°F, a furnace that's short cycling or not heating at all needs a look soon, since a house can lose heat fast on a night that cold.
- Why is my system running but not cooling the house?
- The system is running but the air coming out isn't cold, or the air is cold but the house never catches up. A dirty filter or blocked return can starve the system of airflow, and a frozen or dirty coil will do the same from the other side. Low refrigerant is another cause, but that points to a leak, not something to just top off. On an 81°F afternoon here, a system that's losing this fight usually needs a technician to check airflow and refrigerant charge rather than time to work through it.
- What can I check before calling for HVAC repair?
- Check the thermostat is set to heat or cool, not just on, and that the batteries aren't dead. Check the breaker for the system and, for a furnace, the gas valve is open. Pull the filter and hold it up to a light. If it's gray and you can't see through it, replace it, since a clogged filter can cause both weak heat and weak cooling. If the outdoor unit is covered in ice or the vent hood outside is blocked, clear it before calling. After a storm, check that the outdoor unit wasn't hit by wind debris, since this area sees dozens of damaging wind events most years.