12 Best Furnace Repair and Plumbing in Longmont, CO (2026) — Vetted
Why Longmont, Colorado Winters Make Furnace Repair and Plumbing Urgent
Longmont’s high plains location and Front Range winters bring prolonged subfreezing nights that put heating systems under continuous load. When furnaces fail during these cold snaps, homeowners search for the best furnace repair companies in longmont co to restore heat quickly.
Quick Picks
Awards based on the same publicly available signals as the Vouched Score, including provider-stated certifications and dealer status. Not independently verified.
Compare top Furnace Repair providers in Longmont
| # | Provider | Score | Years | Best for | |
|---|---|---|---|---|---|
| 1 | MM and M Heating, Cooling, Plumbing and Electrical | 91 | 4.9 (3,520+) | ★ Highest Vouched ScoreHeat-Exchanger ReplacementGas Valve & Combustion Repair | |
Editorial: M and M leads with specialist furnace repair work and diagnostics in Longmont. The company states it employs NATE-certified technicians. Emergency Response is advertised as 24/7 with same-day availability. The loyalty membership lists scheduled maintenance reminders and tune-ups. Front Range winters make prompt no-heat response important for Longmont homeowners. Strengths:
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| 2 | WWelzig Heating, Air, Plumbing & Electric | 90 | 4.9 (1,445+) | 32+ | NATE-Certified Shop |
Editorial: Heat pump installations for ducted air-source systems are listed on Welzig's service pages. NATE-certified technicians are listed among their credentials. Welzig reports 30+ years serving Boulder County homeowners since 1994. Longmont's seasonal cold winters and warm summers make correct heat pump sizing important. Online mentions note same-day and emergency response availability. Strengths:
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| 3 | MMountain Valley Plumbing and Heating | 84 | 4.9 (875+) | 19+ | Combustion-Safety DiagnosisMost Transparent Pricing |
Editorial: Mountain Valley advertises furnace repair with upfront, flat-rate pricing quoted before work. The company reports same-day emergency response from its Longmont dispatch hub. Mountain Valley notes background-checked, drug-screened technicians deployed in shoe covers. The business dates to 2007, equating to 15+ years serving Northern Colorado winters. Review excerpts mention technicians by name in customer stories. Strengths:
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| 4 | BBlue Valley Heating & Cooling | 84 | 4.8 (1,280+) | Commercial Furnace Repair | |
Editorial: Blue Valley focuses on AC repair and installs, including ductless mini-split systems. Blue Valley states 30+ years in the field. Longmont's high-altitude cooling loads influence their equipment choices and sizing. The company advertises emergency service (24/7) for no-heat or no-cool calls. Local reviewers describe clear diagnostics and multiple plan options. Strengths:
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| 5 | GGroulx Mechanical Heating & Cooling Inc. | 82 | 5.0 (265+) | ||
Editorial: Groulx Mechanical lists focused furnace repair and diagnostic work as a core service. The company notes Lennox and Mitsubishi preferred-dealer relationships on its site. Same-day emergency response is advertised for no-heat situations. Groulx Mechanical states financing is available for larger repairs. Longmont winters increase combustion-safety demand, and the company highlights local furnace maintenance offerings. Strengths:
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| 6 | TTNT Home Services - Longmont | 81 | 4.8 (860+) | 10+ | |
Editorial: Cold-climate heat pump installation is listed as a specialty on their site. GoodFellas notes a company history stretching back 10+ years. Longmont winters and Front Range temperature swings make right-sized heat pumps important locally. Customer reviews highlight punctuality and clear pricing during service visits. Strengths:
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| 7 | MMy Guy Heating and Air (Firestone) | 81 | 4.9 (1,110+) | ||
Editorial: My Guy advertises same-day emergency furnace response for no-heat calls. The company notes over a decade of service in Northern Colorado. Their website highlights financing options for larger heating repairs. Local winters in Longmont demand reliable quick-response service during sudden cold snaps. Strengths:
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| 8 | CColorado's Finest Heating and Air Conditioning | 78 | 4.9 (235+) | ||
Editorial: Furnace repair work leads their website, with diagnostic services advertised for all furnace brands. Jordan's team states NATE-certified technicians handle gas and combustion issues. The company notes 24/7 emergency response and same-day service availability. Local winters in Longmont make quick no-heat response essential during freezes. Review excerpts show same-day fixes and clear explanations of needed repairs. Strengths:
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| 9 | KKJ Thomas Mechanical | 75 | 4.9 (275+) | ||
Editorial: Diagnosis-first repair approach is central to KJ Thomas Mechanical's service model. The company states 40+ years of tradesman experience. The team serves Boulder County homes through Longmont's winter cold and alpine temperature swings. Same-day emergency response is advertised for urgent heating issues. Reviews mention tidy installs and clear scheduling updates. Strengths:
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| 10 | FFlatirons Heating and Air | 71 | 5.0 (130+) | ||
Editorial: Flatirons Heating and Air is based in Longmont, Colorado. The company lists a public website for customer reference. Their business location is 1136 Kimbark St Unit a in Longmont. Longmont's high-altitude, cold winters often increase indoor dryness and filtration needs. Local reviewers have contributed a substantial number of Google opinions. Strengths:
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| 11 | JJim Needham Heating Cooling Plumbing and Drain | 71 | 4.9 (105+) | ||
Editorial: Jim Needham lists central AC installation and condenser swaps on its service pages. The company notes over 100+ years of combined experience. Jim Needham advertises financing and instant online estimates. Denver's high-altitude summers and dry winters affect cooling loads in Thornton. Strengths:
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| 12 | TThermaCare HVAC Repair | 64 | 4.8 (75+) | ||
Editorial: ThermaCare lists central AC replacement and repair among core services. The company operates from a Main Street Longmont location. Longmont's seasonal cold and hail often impact system lifespan and parts. Their Google profile shows 76 reviews at 4.8 stars. Strengths:
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Typical Furnace Repair costs in Longmont, CO (2026)
Last updated
Estimated ranges for Longmont, CO. Actual cost varies with home size, equipment, and scope — always request a written quote for your job.
| Service | Typical range |
|---|---|
| Furnace service call / diagnostic fee | $80–$210 |
| Flame sensor cleaning / replacement | $85–$260 |
| Hot surface igniter replacement (installed) | $155–$470 |
| Furnace gas valve replacement (installed) | $310–$780 |
| Draft inducer motor replacement (installed) | $310–$830 |
| Furnace control board replacement (installed) | $415–$935 |
| Heat exchanger replacement (repair-vs-replace inflection) | $1,050–$3,650 |
| Emergency / after-hours no-heat service premium | $155–$520 |
Nearby Colorado furnace repair pricing: Arvada · Aurora · Boulder
See broader context: Furnace Repair pricing in Colorado · Furnace Repair pricing nationwide
How were these Longmont furnace repair picks evaluated and what should you prioritize?
This guide evaluated 12 Longmont furnace repair providers on review scores, emergency response, certifications, pricing models, and years in business. The most weighted signals were Google review totals and verified emergency availability, with certification and pricing used as tiebreakers.
- M and M Heating, Cooling, Plumbing and Electrical has a 4.9/5.0 rating with 3,520+ reviews, according to Google Maps data.
- Welzig Heating, Air, Plumbing & Electric lists 24/7 emergency response and free estimates on its website.
- Mountain Valley Plumbing and Heating notes flat-rate pricing and same-day emergency service on its public profile.
- Groulx Mechanical and KJ Thomas Mechanical report same-day emergency response availability in their service descriptions.
- Multiple providers, including M and M and Colorado's Finest, state NATE certification or similar technician credentials on their sites.
Data sources include Google Maps and provider websites for advertised services and credentials.
How do I choose a Furnace Repair and Plumbing Company in Longmont?
- Verify company Google rating and review count.
- Compare advertised emergency response windows.
- Confirm technician certifications and years in business.
- Request written pricing and ask about flat-rate options.
- Check for financing, maintenance plans, or free estimates.
4 furnace problems Longmont homeowners report during cold snaps — and what they usually indicate
Common furnace problems in Longmont during cold snaps stem from the city’s high-plains winters and prolonged subfreezing nights. Homeowners seeking furnace repair services in Longmont often see repeated cycling, ignition failures, and vent blockages after heavy overnight freezes. These issues typically require professional diagnosis.
- Frequent short cycling. Prolonged subfreezing nights in Longmont push furnaces to run continuously and then shut off on safety limits, which causes repeated short cycles that stress components.
- Ignition or pilot failures. High-elevation combustion conditions around Longmont can make ignition more sensitive, so furnaces that worked in milder weather may struggle to light reliably.
- Cracked or stressed heat exchanger. Continuous heavy run-time during Longmont cold snaps increases thermal stress, which can accelerate cracking or warping of the heat exchanger and lower system safety margins.
- Vent and flue blockages from ice or drifting snow. Overnight freezes and local wind-driven snow can obstruct exhaust outlets in Longmont, causing backpressure warnings and reduced combustion efficiency.
- Dirty burners and reduced airflow. Longmont’s dry, dusty high-plains conditions load filters and burners faster when furnaces run more often, which lowers heat output and raises fuel use.
What Longmont’s population and seasonal patterns mean for furnace repair availability
Longmont’s prolonged subfreezing nights and dry high-plains air increase furnace run-time, which raises demand for furnace repair Longmont Colorado services. Evaluated providers often advertise emergency service and NATE certification, helping homeowners get faster diagnostics and safer combustion checks during extended cold snaps.
Longmont's prolonged subfreezing nights are the dominant local condition.
They increase continuous furnace run-time and thermal stress on heat exchangers.
Dry, dusty high-plains air loads filters and burners faster during heavy run-time.
Because Colorado has no statewide HVAC license, local jurisdiction checks matter for technician eligibility.
Look for evaluated providers that offer emergency service, NATE-certified technicians, and documented furnace-type experience.
To compare availability and scheduling, request a free quote from evaluated providers listed earlier on the page.
How long will a typical Longmont, Colorado furnace repair call take — and when is it an emergency?
- How do I get a quote from these furnace repair companies?
- Submit one request on this page and we send it to the vetted furnace repair pros in Longmont, CO listed here. They send quotes back — no obligation.
- How much does furnace repair service cost in Longmont, CO?
- Furnace service call / diagnostic fee typically runs $80–$210, and hot surface igniter replacement runs $155–$470 in Longmont, Colorado. See the Furnace Repair pricing table on this page for the full per-service breakdown.
- Do Longmont furnace technicians need a city license to replace a heat exchanger?
- Answer: Licensing for furnace work is determined by the local jurisdiction, not the state. Colorado has no statewide HVAC license, so Longmont or Boulder County rules apply. Confirm the technician's local registration and any city permits before scheduling a major combustion‑system repair.
- Is a permit required in Longmont for a furnace heat-exchanger replacement?
- Answer: Permitting depends on Longmont building code and the scope of the replacement. Many combustion-related replacements trigger a mechanical permit and inspection. Ask the contractor which Longmont permit they will obtain and verify with the city permit office.
- When is a furnace problem in Longmont considered an emergency?
- Answer: A furnace is an emergency when the home loses heat during prolonged subfreezing nights or when there is a suspected gas leak or carbon-monoxide risk. During prolonged cold snaps, arrange emergency service and avoid using unvented combustion devices.
- What immediate checks should a technician perform when a Longmont furnace won't light?
- Answer: A competent technician checks the igniter or flame sensor, gas supply and pressure, and safety switches first. They also inspect combustion air paths and venting. These quick diagnostics usually determine if a repair or part replacement is required.
- How long does a typical blower motor or inducer motor repair take in Longmont?
- Answer: Many blower or inducer motor diagnoses and simple part swaps complete in a single visit. Complex motor replacements or systems needing matched aftermarket controls can require additional parts or a return visit. Ask if parts are stocked locally.
- When is the busiest season for Longmont furnace repair companies?
- Answer: The busiest season aligns with extended subfreezing nights and the early-winter cold snap. Demand spikes when consecutive nights fall below freezing. Schedule maintenance before cold periods to avoid longer repair wait times.
- How should Longmont homeowners prepare their furnace before winter to reduce emergency calls?
- Answer: Start with a filter change, clear vents, and schedule a professional tune-up before the first prolonged freeze. Regular maintenance reduces mid-winter failures and can expose worn components before they cause an outage.
- How do I find a gas-furnace combustion specialist in Longmont?
- Answer: Look for contractors who document combustion testing, list NATE certification, or show manufacturer training for gas furnaces. Verify local permit experience, recent customer feedback on combustion work, and written safety checks in estimates.