★★★★★
“Furnace quit the coldest night in January. Dan was at our place by 8 the next morning with the part already on the truck. Heat back on before lunch, and the bill matched the quote to the dollar.”Margaret H. Old Town Longmont · Furnace repair
Family owned & operated · Longmont since 1974
The heating & air family your neighbors already call.
Furnace out in January? AC dead in an August heat wave? Call the shop and a Loos picks up — then a Loos shows up. Three generations of fixing Longmont's furnaces, ACs, and water heaters.
Call (303) 536-8922Same-day service most days. A real person answers.
Serviced by Loos & Sons HVAC
Longmont, Colorado · (303) 536-8922
| Date | Work done | Tech |
|---|---|---|
| 10 / 12 / 79 | furnace tune-up | R.L. |
| 6 / 3 / 94 | new AC install | R.L. |
| 11 / 20 / 08 | blower motor | D.L. |
| 7 / 29 / 26 | tune-up — all good | J.L. |
You'll find one of these on half the furnaces in town.
What we fix and install
One call covers the whole mechanical room.
AC Repair
Warm air, weird noises, or nothing at all — we diagnose it and give you the price before we touch a wrench.
AC repair details →AC Installation
Right-sized systems for Front Range summers, installed clean and explained in plain English.
AC installation details →Furnace Repair
No heat is an emergency in January. We carry the common parts on the truck so most fixes happen in one visit.
Furnace repair details →Furnace Installation
Honest advice on repair vs. replace, and installs sized for how Longmont homes are actually built.
Furnace installation details →Water Heaters
Repair and replacement for tank and tankless — usually swapped out the same day you call.
Water heater details →Seasonal Tune-Ups
A fall furnace check and a spring AC check, so the breakdown never happens in the first place.
Tune-up details → Why folks call us first
Three generations. Same phone number. Same handshake.
- A person answers the phone. During shop hours you get a Loos, not a call center. After hours, the emergency line rings the truck on duty.
- The price comes before the work. You approve a written price first. No surprise line items, no "while we're in here" upsells.
- We know Longmont houses. 1970s ranches off Mountain View, new builds out east — odds are we've serviced your floor plan before.
- Licensed, insured, and family. Every tech in your home is a Loos or has sat at our dinner table. Boots off at the door, work area left clean.
Family photo
goes here
goes here
Roy, Dan, and Jake Loos — and the van you've seen around town.
Where we drive
Based in Longmont. At your door across the St. Vrain Valley.
The shop sits just off Main Street, and everything we serve is a short drive from it. If you're in one of these towns, you're in our neighborhood.
- Longmont
- Niwot
- Gunbarrel
- Lyons
- Berthoud
- Mead
- Firestone
- Frederick
- Dacono
- Erie
Not on the list but close? Call anyway — if we can get there in half an hour, we'll come.
From the neighbors
The reviews sound like the town talking.
★★★★★
“Their sticker was on the furnace when we bought the house, with dates going back to the nineties. Called the number on it and Jake showed up. Now they do our tune-ups every year, same as the last owners.”Marcus & Elena T. Prospect · Seasonal tune-ups
★★★★★
“AC died at 98 degrees with a newborn in the house. Roy talked me through what to do on the phone before the truck even left the shop. These folks treat you like a neighbor, because you are one.”Priya S. Firestone · AC repair
No heat? No cool? No hot water?
Call the shop. A Loos will pick up.
Tell us what the system is doing — or not doing — and we'll tell you the next step, even if it's one you can do yourself for free.
Call (303) 536-8922Mon–Sat 7am–6pm · Emergency line after hours