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TRUSTED BY LONGMONT, CO HOMEOWNERS

  • Average homeowner rating star icon4.6
    Average homeowner rating
  • Verified reviews icon541
    Verified heating and air conditioning services reviews

Verified Reviews for Heating And Air Conditioning Service pros in Longmont, CO

*The Angi rating for Heating And Air Conditioning Service companies in Longmont, CO is a rating based on verified reviews from our community of homeowners who have used these pros to meet their Heating And Air Conditioning Service needs.

*The HomeAdvisor rating for Heating And Air Conditioning Service companies in Longmont, CO is a rating based on verified reviews from our community of homeowners who have used these pros to meet their Heating And Air Conditioning Service needs.

Last update on July 16, 2026

Find Heating and air conditioning pros in Longmont

Avatar for M & H Air, LLC
M & H Air, LLC
5.0(
18
)
Central A/C - Service or RepairGas Furnace / Forced Air Heating System - InstallCentral A/C - Install+14 more

Serving Longmont, CO and surrounding areas

Approved

In business since 2001

Free estimates

Credit card accepted

"M&H saved our bacon. We had so many problems with a prior hvac sizing and install and they came out, *told* us the problems (which hadn't even been explained to us before) and gave us real options to fix the whole system. The house has never been more equally conditioned. Since then, we've had M&H as our regular checkup and inspector and they continue to deliver fixes that keep us running as needed. Thanks!"
M & H Air, LLC
Victory Outreach Church
2 neighbors recently requested a quote
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Avatar for Absolute 1st Choice Heating & Air Conditioning Inc.
Absolute 1st Choice Heating & Air Conditioning Inc.
4.5(
122
)
Central A/C - Service or RepairCentral Air Cleaner - Repair or ServiceElectric Boiler or Radiator Heating System - Repair+10 more

Serving Longmont, CO and surrounding areas

Approved

In business since 2009

Free estimates

Emergency services offered

"Very satisfied. He worked through each step it took to install my Google Nest thermostat, insuring all was working well before he left."
Response time8 hrs
4 neighbors recently requested a quote
Recommended by97%of homeowners
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Avatar for Behold Heating & Cooling Services
Behold Heating & Cooling Services
4.9(
47
)
Central A/C - Service or RepairGas Furnace / Forced Air Heating System - RepairGas Boiler or Radiator Heating System - Repair+4 more

Serving Longmont, CO and surrounding areas

Approved

In business since 2023

Free estimates

Emergency services offered

"Top tier heating and cooling hvac contractor! If youâ re in the Denver area you definitely want to utilize their services."
Boiler Repair/Replacement
Boiler Replacement and Repipe
Boiler Replacement and Repipe
Furnace, AC, Water Heater Replacement
Furnace Tune-up

+35

Response time6 hrs
Response rate100%
85 neighbors recently requested a quote
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Avatar for One Hour Heating & Air Conditioning - Loveland
One Hour Heating & Air Conditioning - Loveland
4.7(
207
)
Air Ducts & Vents - Clean

Serving Longmont, CO and surrounding areas

Approved (Corporate)

Super Service Award Winner

In business since 1978

Free estimates

Emergency services offered

"Brian, the HVAC technician was professional, friendly and extremely knowledgeable, he provided a full estimate before starting the work and then performed the repair immediately. We were back up and running in minutes. Well Done 1 hr team."
4 neighbors recently requested a quote
Recommended by93%of homeowners
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Avatar for 1st Action Plumbing Heating and Air, Inc.
1st Action Plumbing Heating and Air, Inc.
4.6(
152
)
Ductless Mini-split Heating System - Install or ReplaceDuctless Mini-split A/C - Install or ReplaceElectric Furnace / Forced Air Heating System - Install+7 more

Serving Longmont, CO and surrounding areas

Approved

In business since 2017

Free estimates

Small jobs welcome

"I hired 1st action for a tune-up of my HVAC system. Rob did a thorough job and was very professional. I'll hire them if I need other work in the future without hesitation."
Navien Tankless
Lennox EL296V
Response time5 hrs
5 neighbors recently requested a quote
Recommended by91%of homeowners
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Avatar for Mountain Pro HVAC Services, LLC
Mountain Pro HVAC Services, LLC
5.0(
126
)
Central A/C - Service or RepairElectric Furnace / Forced Air Heating System - RepairElectric Furnace / Forced Air Heating System - Repair - For Business+4 more

Serving Longmont, CO and surrounding areas

Approved

In business since 2018

Free estimates

Emergency services offered

"Adrian was tremendous! He took on a tough project, never gave up and solved my HVAC problem. Patient, thoughtful, collaborative with pricing. Recommend him without reservation."
Maintenance Services
Maintenance Services
Maintenance Services
Maintenance Services
New AC / Furnace Install

+4

Response time11 hrs
Response rate92%
Recommended by100%of homeowners
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Avatar for HighPoint HVAC
HighPoint HVAC
5.0(
22
)
Air Ducts & Vents - Clean

Serving Longmont, CO and surrounding areas

Approved

Credit card accepted

"had such a great experience with HighPoint HVAC! The entire process was seamless and incredibly easy from start to finish. I was able to schedule an appointment right away, and the team arrived exactly on time. They were professional, friendly, and took the time to explain everything clearly. After finishing the job, they left the space spotless; you’d never know any work had been done. Their quality of service and attention to detail really stood out, and the pricing was very fair. I’d highly recommend this company to anyone looking for reliable, high-quality HVAC service"
2 neighbors recently requested a quote
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Avatar for AT Mechanical LLC
AT Mechanical LLC
5.0(
10
)
Electric Furnace / Forced Air Heating System - Install - For BusinessElectric Furnace / Forced Air Heating System - Repair - For BusinessGas Furnace / Forced Air Heating System - Install - For Business+3 more

Serving Longmont, CO and surrounding areas

Approved

In business since 2025

Emergency services offered

Warranties offered

"Highly recommended! Jason makes sure everything is right and also uses some technology for metrics. Most HVAC people I’ve dealt with, didn’t so, you had no baselines for references and just their word. My AC is fixed now and blows super cold!"
AT Mechanical LLC
AT Mechanical
AT Mechanical
AT Mechanical
AT Mechanical

+3

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A-Moonlight Heating & Air Conditioning
5.0(
52
)
Central A/C - Service or RepairGas Furnace / Forced Air Heating System - Repair

Serving Longmont, CO and surrounding areas

Approved

In business since 2014

Emergency services offered

Warranties offered

"Quickly worked out a long term problem from an incorrect furnace installation by another installer. Corrected the problem at a very fair price. They are now my preferred HVAC company."
Response time3 hrs
2 neighbors recently requested a quote
Recommended by96%of homeowners
Request Quote
Avatar for Your Comfort Heating and Cooling
Your Comfort Heating and Cooling
5.0(
19
)
Ductless Mini-split A/C - Install or ReplaceDucts & Vents - Install or ReplaceGas Boiler or Radiator Heating System - Repair+8 more

Serving Longmont, CO and surrounding areas

Approved

In business since 2008

Free estimates

Emergency services offered

"We had two AC units and a new furnace installed they were prompt, efficient, very respectful and great customer service! Dean was an absolute pleasure to work with, they have earned my business for life on any HvAC services I might need! Highly recommend"
New Amana Furnace
New Amana Heat Pump
High Efficiency
Outside Condensers
two new condensers

+3

Response time2 hrs
Response rate98%
18 neighbors recently requested a quote
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Showing 1-10 of 614
Heating and Air Conditioning questions, answered by experts

Yes, high-efficiency models reduce environmental impact with lower energy use.

Ideally, an AC system should never need more Freon (a popular refrigerant) because it circulates in a closed loop. However, refrigerant leaks are not uncommon and may occur gradually over 5 to 15 years. If your system has a leak, it will need to be topped up in a process known as an AC recharge. Signs of a refrigerant leak include weakened AC performance, increased humidity in your home, higher utility bills, and a hissing sound from the unit. The cost of an AC recharge will depend on the size and type of your AC unit, as well as the type of refrigerant it uses.

To make the most out of your AC, consider implementing the following best practices: 

  • Choose the right size AC for your home to ensure your unit runs as efficiently as possible.

  • Choose a window with shade, as direct sunlight can cause your AC unit to overheat. 

  • Clean or replace the filter at least every two months. 

  • Inspect the AC’s fan and straighten it if necessary. 

  • Discontinue use immediately if you suspect a malfunction, as running the AC while broken can lead to significant issues. 

  • Turn off (or adjust the temperature) when you leave the house.

Unfreezing an AC unit is not a DIY project unless the problem is a dirty air filter. Changing out an air filter is easy for homeowners, but otherwise, trying to repair ductwork, refill refrigerant, or replace a blower fan motor are tasks best left to the pros. Otherwise, you could cause further damage to your cooling system or even harm to yourself.

Not if you have a standard unit. Because portable AC units actually work to dehumidify the room, you’ll likely need to drain the unit from time to time—but you won’t have to put water into it. There is, however, another type of air conditioner called a swamp cooler that requires water to operate. If you have a swamp cooler, you may need to fill a reservoir with water and potentially ice. But a swamp cooler is different from a standard portable AC unit.

The Longmont, CO homeowners’ guide to heating and air conditioning services

From average costs to expert advice, get all the answers you need to get your job done.

See all articles