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HVAC Services · Heating

Furnace Repair, Tune-Ups & High-Efficiency Installation

Gas furnace repair, replacement, and maintenance. We service every major brand and install 95%+ AFUE high-efficiency furnaces sized for your home.

Schedule Service (435) 674-1275
Family-owned since 1992 Licensed & insured All makes and models Free estimates

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Same-day service available across the St. George metro area. Free estimates on installs.

Call (435) 674-1275 Request a Quote Online
  • › 24/7 emergency dispatch
  • › 30+ years of local experience
  • › Honest diagnostics

Heating, done safely

A no-heat call in January is a real problem. We treat it that way.

Southern Utah winter nights drop into the 20s, and a furnace that won't fire is more than an inconvenience. Our technicians arrive in fully stocked trucks and finish most repairs the same visit. When a system has reached the end of its life, we'll show you the math on repair-vs-replace before you decide.

Southern Utah doesn't have Wisconsin winters, but Washington County overnight lows hit the low 20s most years and we get the occasional single-digit cold snap. A furnace that won't fire on those nights freezes pipes, cracks fixtures, and turns a small problem into an expensive one. Our service trucks carry ignitors, flame sensors, gas valves, pressure switches, and inducer motor assemblies for every common brand, so most no-heat calls are wrapped up the same visit.

Beyond repair, we replace furnaces with high-efficiency 95%+ AFUE condensing units that genuinely cut gas bills, and we coordinate the venting, condensate drainage, and combustion-air requirements that come with that upgrade. If you're weighing a replacement against a heat pump, read our writeup on heat pumps vs. furnaces in Southern Utah. The math has shifted in the last few years, and a heat pump is often the better long-term call.

Schedule heating service Compare to a heat pump

Why M&M Mechanical Inc.

Three decades of furnace work, in one shop.

We've worked on every era of furnace from atmospheric 70% units in '70s ranchers to two-stage modulating condensing systems in custom builds.

Family-owned since 1992

Same shop, same family, same phone number for over thirty years.

Licensed & insured

Utah-licensed gas-line and HVAC contractor. Permits pulled, inspections passed.

All makes & models

Carrier, Lennox, Trane, Goodman, Rheem, Bryant, York, Amana. We service them all.

Carbon monoxide tested

Every service includes CO testing. We won't leave an unsafe appliance running.

Service area

Heating service across Southern Utah

From historic St. George bungalows with original ductwork to high-elevation builds in Toquerville, we work on every kind of heating system in the region.

Washington

0 minutes. Our shop is in Washington

St. George

8–15 minutes from our Washington shop

Hurricane

20–25 minutes from our Washington shop

Ivins

20 minutes from our Washington shop

Santa Clara

15 minutes from our Washington shop

La Verkin

25 minutes from our Washington shop

Toquerville

25 minutes from our Washington shop

Springdale

45 minutes from our Washington shop

What working with us looks like

Four steps from cold house to comfortable.

Whether it's a quick repair or a full furnace replacement, the process is the same.

  1. 01

    Call the shop

    We dispatch from Washington, so most homes see a tech same-day in winter.

  2. 02

    Diagnose & test

    Combustion analysis, gas pressures, CO levels, electrical, ignition.

  3. 03

    Honest quote

    Repair vs. replace, written numbers, no commission salespeople.

  4. 04

    Safe install

    Permits pulled, vents sized correctly, system commissioned to spec.

Heating & furnace FAQ

My furnace won't turn on. What's the most common cause?
In Southern Utah, the most frequent winter no-heat call is a failed hot-surface ignitor or a dirty flame sensor. Both are inexpensive parts we keep stocked on every truck. After that: thermostat issues, tripped pressure switches (often from a clogged condensate line on high-efficiency units), and bad capacitors on the inducer motor. If you're hearing the unit try to fire and shut off after a few seconds, it's almost always a flame-sensing issue.
Should I get my furnace tuned up every year?
Yes, and the best time is September or early October before the rush. A pre-season tune-up catches cracked heat exchangers, weak ignitors, and dirty burners before they leave you cold on a 25° January morning. It's also when we test for carbon monoxide leaks, which is a non-negotiable safety check on any gas appliance.
How long does a furnace typically last in Southern Utah?
Gas furnaces in our climate routinely last 18–25 years because they don't run nearly as many hours as the AC does. The exception is poorly-installed or undersized units that short-cycle, or units that were neglected for so long the heat exchanger cracked. We'll always show you why a furnace is at the end of its life: pictures, readings, and the math behind the recommendation.
What's the difference between 80% and 95% AFUE furnaces?
AFUE (Annual Fuel Utilization Efficiency) is the percent of gas that becomes useful heat. An 80% furnace wastes 20% up the flue. A 95%+ condensing furnace recovers heat from combustion gases and only loses 5%. The downside: condensing furnaces produce acidic condensate that needs proper drainage, and they require a different vent setup. For most Southern Utah retrofits, the higher upfront cost pays back in 5–8 years.
Do you check for carbon monoxide on every service?
Yes. Every furnace tune-up and repair includes a CO test in the supply air stream and around the unit. Cracked heat exchangers, blocked flues, and improperly vented appliances can leak CO into living spaces, and you can't smell it. We won't leave a system running that's producing dangerous CO, period.
Can you replace a furnace in winter?
Yes. We stock furnaces in common sizes year-round, and most replacements are wrapped up in a single day. If you're without heat, we can usually have a temporary plan in place same-day and the new system installed within 24–48 hours.

No heat? Call the shop.

Same-day furnace repair available across Southern Utah, even in the middle of a January cold snap.

(435) 674-1275 Schedule Online