Furnace & Heating Repair in Longmont, CO
Furnace quit on the coldest night of the year? Our NATE-certified technicians diagnose furnaces, heat pumps and boilers around the clock, and nights and weekends cost no extra.
Fast, Honest Furnace Repair for Longmont Homes
When the heat goes out in January, you do not want a technician who guesses. You want one who finds the real problem, explains it in plain language and gives you a firm price before touching a tool. That is how M&M Heating, Cooling, Plumbing & Electrical has handled furnace repair in Longmont since 1996.
Our NATE-certified, licensed and insured technicians carry the diagnostic equipment and common parts to repair most gas furnaces, heat pumps and boilers in a single visit, regardless of brand or age. Dry Front Range air is hard on igniters and flame sensors, hard water scales up boilers, and the swing from a 60-degree afternoon to a single-digit night makes systems short cycle. We see these failures every winter and know where to look.
You will never pay more for a night, weekend or holiday call, and every repair is backed by our 100% satisfaction guarantee. If the system is older and the repair bill is climbing, we will tell you so and lay out your replacement options without pressure. If a repair is the smart call, that is what we will recommend. And once the heat is back on, a furnace tune-up is the best way to keep it from happening again.
Common Furnace Problems We Fix
If your heating system is doing any of the following, call before a small fault becomes a no-heat emergency.
Furnace Runs but Blows Cool Air
Usually a failed igniter, a dirty flame sensor, a stuck gas valve or a limit switch tripping on overheating. In a heat pump it can mean low refrigerant or a stuck reversing valve. All are quick to diagnose with the right tools.
Short Cycling On and Off
A furnace that fires for a minute and shuts down is overheating, starved for airflow or being told the wrong thing by its thermostat. Left alone, short cycling burns out blower motors and heat exchangers.
Banging, Squealing or Rattling
A boom at startup points to delayed ignition from dirty burners. Squealing means a blower belt or bearing. Rattling is often a loose panel or a cracked heat exchanger, which is a safety issue, not a nuisance.
Gas Smell or Carbon Monoxide Alarm
Leave the house, then call us from outside. Gas odors and CO alarms are emergencies we respond to 24/7. We test for leaks, inspect the heat exchanger and venting, and will not relight the system until it is safe.
Thermostat Not Responding
Sometimes it really is the thermostat: dead batteries, a bad wire or a settings glitch. Other times the control board or a safety switch is refusing to call for heat. We trace the signal end to end.
Water Around the Furnace or Boiler
High-efficiency furnaces drain condensate and a clogged line will shut the unit down. On a boiler, a puddle can mean a failed relief valve, expansion tank or a leaking pipe joint. Both need attention before they damage the floor.
The M&M Difference
Repair done right the first time, by people who live where you live.
24/7 Without the Overtime Bill
Furnaces fail on the worst nights, not the convenient ones. We answer the phone around the clock, and the price is the same at midnight on a Saturday as it is on a weekday morning.
NATE-Certified Diagnostics
Our technicians are NATE-certified, licensed and insured, and trained across all furnace, heat pump and boiler brands. They diagnose with instruments, not guesswork, so you only pay for the part that actually failed.
Upfront Pricing, Every Time
After diagnosis you get a written price for the repair. You approve it before we start, and it does not change. If replacement makes more sense, we show you both numbers side by side.
100% Satisfaction Guarantee
Family-owned since 1996, we have built our name in Longmont on standing behind our work. If a repair does not hold up or you are not happy with how it went, we come back and make it right.
Our 4-Step Process
From your first call to warm air, here is how a furnace repair visit works.
Call Any Time, Day or Night
Describe what the system is doing. For no-heat, gas odor or CO alarm calls we dispatch immediately. For everything else we schedule a window that works for you.
Thorough Diagnosis
Your technician checks the ignition system, safeties, airflow, venting, heat exchanger and controls to find the root cause, not just the symptom that tripped the system.
Written Price, Your Approval
We explain what failed, why, and what it costs to fix. You approve the upfront price before any work begins. No surprises when the invoice arrives.
Repair, Test and Verify
Most repairs are completed on the same visit from parts on the truck. We run the system through full cycles, confirm safe operation and clean up before we leave.
Furnace Repair Questions
My furnace stopped working at night. Should I wait until morning to call?
Call now. We are open 24/7 and there is no extra charge for nights, weekends or holidays, so waiting only means a colder house and, in a hard freeze, a real risk of frozen pipes. If the problem is something simple like a tripped breaker or a dead thermostat battery, we will tell you over the phone and save you the visit.
How much does furnace repair cost?
It depends entirely on what failed. A flame sensor cleaning is a small job, while a blower motor or control board is a larger one. What we can promise is that you will know the exact price before we begin. Your technician diagnoses the problem, writes up the repair and gets your approval first. The diagnostic visit is the only thing you commit to by calling.
Do you repair heat pumps and boilers too, or just furnaces?
All three, and all brands. Our technicians handle gas furnaces, cold-climate and standard heat pumps, dual-fuel systems and hydronic boilers, for both homes and commercial buildings across Longmont and the Front Range. Heat pump and boiler repairs require different tools and training than furnace work, and our team carries both.
Why does my furnace keep shutting off after a few minutes?
That is short cycling, and the most common causes are a clogged filter restricting airflow, a dirty flame sensor dropping the flame signal, an overheating limit switch, or a furnace that is oversized for the house. Our dry climate also makes static and dust buildup on sensors more common. It is worth fixing quickly because repeated restarts wear out igniters and heat exchangers.
Should I repair my furnace or replace it?
As a rule, if the furnace is under 10 to 12 years old and this is its first significant repair, fix it. If it is 15 years or older, has needed repairs more than once in recent winters, or has a cracked heat exchanger, replacement is usually the better investment. We give you both prices honestly and never push a new system when a repair will serve you well.
Can you work on my furnace if another company installed it?
Yes. We repair all makes and models no matter who installed them, and we offer a free second opinion if you have a diagnosis from another contractor that does not sit right. Bring us their write-up and we will review it with you honestly, with no obligation.
No Heat? Call M&M, Any Hour, Any Day
Open 24/7 | Emergency Service Available
Call (720) 608-3973Furnace Repair Across the Front Range
Proudly serving Longmont, CO and surrounding communities.
Primary Service Area
- Longmont, CO
- Erie, CO
- Frederick, CO
- Firestone, CO
- Dacono, CO
Extended Area
- Mead, CO
- Johnstown, CO
- Berthoud, CO
- Niwot, CO
- Gunbarrel, CO
Also Serving
- Lafayette, CO
- Louisville, CO
- Superior, CO
