Furnace Replacement & Installation in Longmont, CO
When repairs stop making sense, we size and install a new furnace properly, back it with our One Year Test Drive and offer financing to make it manageable.
Furnace Replacement Done Right the First Time
A new furnace is one of the larger purchases you will make for your home, and it will be there for the next 15 to 20 winters. The difference between a good installation and a mediocre one shows up every month on your gas bill and every time the temperature drops below zero. M&M Heating, Cooling, Plumbing & Electrical has handled furnace replacement in Longmont and across the Front Range since 1996, and we treat every installation like it is going into our own home.
That starts with honesty about whether you need a new furnace at all. If a repair will give you several more reliable years, we will say so. If the heat exchanger is cracked or the repair history is adding up, we will show you both numbers and let you decide.
When replacement is the right call, our NATE-certified installers perform a proper load calculation rather than copying the size of the old unit. Homes here sit at elevation, where gas furnaces must be adjusted to burn correctly, and the dry climate and wide daily temperature swings reward a system that is sized and set up for the house, not a guess. We walk you through standard and high-efficiency furnace options, explain what each means for your bills, and offer financing on new equipment. Ask about available utility rebates as well.
Every new furnace installation is backed by our One Year Test Drive: if you are not 100% happy within the first year, we make it right. Once it is in, our furnace maintenance plan keeps it running like new.
Signs Your Furnace Is Ready for Replacement
One of these alone is not a verdict. Two or three together usually mean a new furnace is the smarter spend.
It Is 15 Years Old or Older
Most gas furnaces last 15 to 20 years. Past that point, parts get harder to find, efficiency has slipped and the odds of a mid-winter failure climb every season.
Gas Bills Keep Climbing
If your usage is up but your habits are not, the furnace is burning more fuel to deliver the same heat. Worn burners, a tired blower and an old low-efficiency design all add up on the bill.
Repeat Repairs
A good rule of thumb: if a repair costs more than a third of a new furnace, or you have paid for repairs two winters in a row, you are financing an old system one breakdown at a time.
Cracked Heat Exchanger
This is the one that ends the conversation. A cracked heat exchanger can leak carbon monoxide into the home, and on an older furnace the replacement part rarely makes financial sense compared to a new unit.
Uneven Heat and Constant Running
Some rooms roast while others stay cold, and the furnace never seems to shut off. That often means the old unit was sized wrong for the house or has simply lost capacity.
Yellow Flame, Soot or Rust
Burner flames should be steady and blue. A yellow, flickering flame, soot streaks around the cabinet or rust on the exchanger point to incomplete combustion and a furnace near the end of its life.
How We Help You Decide
There is no wrong answer, only the right one for your furnace, your budget and how long you plan to stay in the home.
Repair Your Furnace
The right choice when the furnace is younger, the problem is isolated and the fix is reasonable relative to the unit's remaining life.
- Furnace under 10 to 12 years old
- First major repair, or minor part
- Heat exchanger intact and safe
- Upfront price, approved before work
- Lower cost today
Replace Your Furnace
The better investment when age, repair history or safety make continued repairs a losing bet. New equipment is properly sized, more efficient and fully guaranteed.
- Furnace 15 years or older
- Repeat repairs or cracked heat exchanger
- Lower gas bills with high-efficiency models
- Load calculation and altitude setup included
- Financing available on new equipment
The M&M Difference
A new furnace is only as good as the people who size it, install it and stand behind it.
The One Year Test Drive
Within the first year of a new installation, if you are not 100% happy for any reason, we make it right, from exchanging the equipment to removing it and refunding your money in full. Conditions may apply, and we explain them upfront.
Sized for Your Home, Not Guessed
We run a load calculation on every replacement, accounting for square footage, insulation, windows and Longmont's elevation. An oversized furnace short cycles and an undersized one never catches up. We get it right.
NATE-Certified Installers
Our installation crews are NATE-certified, licensed and insured, and trained on every major furnace brand. Proper venting, gas pressure, altitude adjustment and airflow setup are not optional on our jobs.
Financing and Upfront Pricing
You get a written, all-in price before we schedule the install, with no surprises on the day. Financing is available on new equipment, and we will help you ask about available utility rebates.
Our 4-Step Process
From the first conversation to the first warm night, here is how a furnace installation goes with M&M.
Free In-Home Assessment
A comfort advisor inspects your current furnace, ductwork and venting, listens to what has bothered you about the old system and performs a load calculation to size the replacement.
Clear Options, Clear Prices
We present standard and high-efficiency furnace options with upfront pricing for each, explain the differences in plain terms and go over financing. You choose, with no pressure.
Professional Installation
Our crew removes the old unit, sets the new furnace with proper venting, gas and electrical connections, adjusts it for altitude and verifies airflow and combustion before startup.
Walkthrough and Test Drive
We show you how the new system and thermostat work, haul away the old equipment and leave the space clean. Your One Year Test Drive begins the day it is installed.
Furnace Replacement Questions
How long does a furnace replacement take?
A straightforward furnace swap is typically completed in a single day. If the job also involves ductwork modifications, a new venting route for a high-efficiency model or an added air conditioner or heat pump, it can run longer. We give you a realistic timeline at the estimate, and if you are without heat, we work to get the new system in as quickly as possible.
What does a load calculation do, and why does it matter?
A load calculation measures how much heat your home actually loses on a cold day, based on square footage, insulation, window area, orientation and local climate. It tells us the correct furnace size. Many furnaces are installed by matching the old unit's size, which was often wrong to begin with. An oversized furnace short cycles, wears out faster and heats unevenly. A properly sized one runs longer, quieter cycles and costs less to operate.
Is a high-efficiency furnace worth it in Longmont?
Usually, yes. Front Range heating seasons are long, so a furnace that converts more of its gas into usable heat pays back faster here than in a milder climate. High-efficiency condensing furnaces also run quieter and modulate their output for steadier comfort. We lay out the cost difference and expected savings side by side so you can decide what makes sense for your budget and how long you plan to stay.
Does altitude affect which furnace I should buy?
Yes. At Longmont's elevation the air is thinner, and gas furnaces must be adjusted so they burn correctly and deliver their rated output. That can involve manufacturer high-altitude kits, gas pressure adjustments and pressure switch changes depending on the model. Our installers handle this on every job. It is one of the most commonly skipped steps we see on furnaces installed by others.
Do you offer financing on a new furnace?
We do. Financing is available on new equipment, and we will go over the options with you at the estimate so you know your monthly cost before deciding. We also encourage you to ask about available utility rebates for qualifying high-efficiency equipment, which can lower the upfront cost.
What exactly does the One Year Test Drive cover?
It covers new equipment installations. If you are not 100% happy with the operation of your new furnace for any reason within the first year, we will do what it takes to make it right, up to exchanging it for different equipment or removing it and refunding your money in full. Conditions may apply, and we go over them with you before installation so there are no surprises.
Get an Honest Furnace Replacement Estimate
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Call (720) 608-3973Furnace Replacement 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
