We’re Ponderosa Heating & Air Conditioning, based on South Golden Road in Golden — the next town down the hill. Evergreen isn’t a side market for us. It’s the kind of place our work is built around: homes sitting between 7,000 and 7,800 feet, on propane or gas, heated by everything from a 1970s forced-air furnace to a boiler and radiant loop, on roads the county plows last.
Heating a home in Evergreen is genuinely different from heating one in Arvada, and not in a marketing way. The equipment is rated differently, the county calculates the load differently, and the failure modes are different. Here’s what that actually means.
Ponderosa Heating & Air Conditioning services furnaces, boilers, water heaters and gas fireplaces in Evergreen, Colorado (ZIP 80439), from its Conifer office. Equipment is sized for 7,200 ft and Jefferson County code. Evergreen at a glance:
7,162–7,798 ftelevation, Kittredge to Bergen Park
−11 °FJeffco winter design temp above 7,400 ft
1977median year built
107–133″snow per season
Jefferson Countypermitting authority (Upper Bear Creek: Clear Creek)
80 °Faverage July high — most homes skip central AC
Gas or propaneboth common; we confirm before quoting
HVAC & gas onlyour mountain crew — no electrical or plumbing up here
Gas furnaces are rated at sea level. Air gets thinner as you climb, so there’s less oxygen to burn the gas with, and manufacturers publish a derate to account for it. Trane’s own product data is typical: input ratings hold up to 2,000 feet, then derate 4% for every 1,000 feet above that.
Run that for Evergreen. A furnace with 100,000 BTU on the nameplate delivers roughly:
| Location | Elevation | What a 100,000 BTU furnace actually delivers |
|---|---|---|
| Golden | ~5,700 ft | ~85,300 BTU |
| Downtown Evergreen | 7,220 ft | ~79,000 BTU |
| Bergen Park | 7,798 ft | ~76,800 BTU |
That’s most of a ton of heating capacity gone between the bottom of the hill and the top. Size a furnace off the nameplate in Evergreen and the homeowner spends every January wondering why the new system can’t keep up.
Every home in Evergreen sits above 7,000 ft, so a gas furnace needs the manufacturer’s documented high-altitude conversion before it is installed here. Derating is arithmetic. This part is compliance. Manufacturers set an elevation ceiling for equipment as shipped, and above it the furnace needs a documented high-altitude conversion — different orifices, sometimes a different pressure switch.
Goodman and Amana publish three bands: 0–7,000 feet is “standard altitude.” From 7,001 to 9,000 feet, a natural gas furnace requires orifice kit HANG11 and pressure switch HAPS27. Above 9,000 feet it changes again.
Downtown Evergreen is 7,220 feet. Upper Bear Creek is around 7,530. Bergen Park is 7,798. All of Evergreen sits in that second band. A furnace pulled off the same truck that serves Wheat Ridge and installed here without the conversion kit is outside the manufacturer’s instructions — which is what the mechanical code requires an installer to follow.
Other brands draw the line in different places. Rheem calls for a kit between 5,000 and 8,000 feet, and some of its high-efficiency models derate at 2% per 1,000 feet instead of 4%. Lennox typically starts modifications around 5,000 feet and adds a second pressure switch above 9,000. Part of quoting a furnace in Evergreen is knowing which brand’s threshold you’re crossing.
Jefferson County uses a colder winter design temperature above 7,400 ft — −11 °F instead of −7 °F — and that line runs through the middle of Evergreen. It is the detail almost nobody outside the foothills knows about, and it’s in the county’s own adopted code.
Jefferson County publishes two sets of Manual J design criteria depending on elevation:
| Design criterion | Below 7,400 ft | Above 7,400 ft |
|---|---|---|
| Winter outdoor design temperature | −7°F | −11°F |
| Summer outdoor design temperature | 95°F | 90°F |
| Winter design temperature difference | 79°F | 83°F |
| Daily range | 20°F | 15°F |
That 7,400-foot line runs straight through Evergreen. A house in Bergen Park and a house down in Kittredge are in the same town, share a post office, and get different load calculations under the same county code. Four degrees of design temperature and four degrees of delta-T is not a rounding error. It’s the difference between a system that holds on the coldest night of the year and one that doesn’t.
When we quote a replacement in Evergreen, we check which side of 7,400 feet the address falls on before we size anything.
Evergreen is inside Xcel Energy’s natural gas territory. It’s also a town where a national propane company keeps a staffed office on Bryant Drive, which tells you plenty about how many homes here are on a tank.
The two aren’t interchangeable. Propane burns hotter per cubic foot and needs different orifices and different manifold pressure. A furnace set up for natural gas will not run correctly on propane, and a conversion kit is not optional. Add the altitude conversion on top and an Evergreen propane furnace may need two separate sets of changes before it’s correctly commissioned.
We do this work, and we’ll confirm which fuel you’re on before we quote rather than after we arrive. Propane conversions and high-altitude setups are quoted individually — there’s no flat rate, because the answer depends on your equipment, your elevation and what’s already been done to the system.
Most Evergreen homes do not need central air conditioning. The average July high is 80 °F and Jefferson County’s summer design temperature above 7,400 ft is 90 °F, so there is very little cooling load to design for. We’d rather tell you this than sell you a condenser.
Evergreen’s average July high is 80°F. Denver’s is 88°F. Jefferson County’s own code assigns a summer design temperature of 90°F above 7,400 feet versus 95°F below it. There is very little cooling load up here, and central air is a large expense against a handful of genuinely warm afternoons.
What usually works better in an Evergreen home:
If you want central air, we’ll install it properly. But we won’t pretend Evergreen is Littleton.
The median Evergreen home was built in 1977, and 55% of the housing stock went up between 1970 and 1999. Nearly 90% is detached single-family.
That matters because it tells you what’s failing. A furnace installed during a 1990s remodel is past 30 years old. Original 1970s equipment has usually been replaced once and is now on its second unit’s end of life. And the systems in these homes are more varied than in a tract subdivision — Evergreen homes run on forced air, boilers with baseboard or in-floor radiant, electric baseboard, and gas fireplaces used as real heat rather than decoration.
We service all of it. Boiler work in particular is something a lot of metro companies quietly don’t do well, and in a town with this many hydronic systems that’s a problem. Because no two hydronic setups in Evergreen are laid out the same way, boiler and radiant work is quoted per system after we’ve looked at it — call us and we’ll come out.
Colorado’s HB23-1161 took effect on January 1, 2026. New furnaces and water heaters sold in the state now have to meet NOx emissions limits set by CDPHE. In practice it narrows which models can legally be sold and installed here, and some older model numbers are simply off the table now. If you’re comparing a quote against one you got in 2024, that’s part of why the equipment list looks different.
Evergreen Fire Rescue puts it plainly: if you reside in Evergreen, you are living in the WUI. Jefferson County’s own risk assessment goes further. More than two-thirds of the county is wildland-urban interface, and the Evergreen/Conifer area ranks first in Colorado for wildfire property loss risk. The Elephant Butte fire in July 2020 evacuated over 1,000 homes here.
Two consequences for your mechanical systems.
Smoke season is an indoor air quality problem. On smoke days the fix is a properly sized filter and knowing when to close the outside air. MERV 13 is the target where the equipment can handle the static pressure. Not every older furnace can. Upgrading filtration on a system that wasn’t designed for it can starve the blower. That makes it worth a conversation rather than a filter swap at the hardware store.
The code around vents has changed. Colorado’s Wildfire Resiliency Code took effect July 1, 2025. Jefferson County adopted updated wildfire regulations effective July 1, 2026, and expanded the county’s WUI boundary at the same time. Ember-resistant venting is part of the structure-hardening requirements. If you’re replacing equipment and re-terminating a vent, check whether your address moved inside the expanded boundary.
Xcel Energy’s Public Safety Power Shutoffs can cut power to Evergreen for hours or days on high-wind fire-danger days, and no furnace or boiler runs without electricity. It is a foothills problem more than a Denver one, and it changes what “backup heat” means.
Xcel now runs Public Safety Power Shutoffs on high-wind, high-fire-danger days. On December 17, 2025, about 52,000 customers in Boulder, Clear Creek, Jefferson, Larimer and Weld counties lost power at 10 a.m. Xcel’s own estimate for restoration was “a couple hours, or it could be a day or two.” In April 2024, more than 150,000 customers lost power in a wind event. Some 55,000 of those were shut off on purpose.
That’s a different problem from a storm outage. It’s planned, it’s regional, and it can last long enough for pipes to freeze. Every furnace and boiler in Evergreen needs electricity to run: the blower, the circulator pump, the ignition. On a shutoff day the house cools no matter what fuel it burns. The one heat source that keeps going is a gas fireplace on a standing pilot; newer units with electronic ignition need a battery backup to light without power. If your fireplace is your plan for shutoff days, find out which kind you have before December. We don’t install standby generators in the Evergreen area — our mountain crew is heating, cooling and gas only. But we can tell you whether your fireplace will carry the house, and set it up so it does.
Evergreen has no municipal government — it’s an unincorporated community, so Jefferson County’s Division of Building Safety is your permitting authority. A few things worth knowing:
The exception worth knowing: Upper Bear Creek uses an Evergreen address and the 80439 ZIP, but it’s in Clear Creek County, not Jefferson. Different authority, different adopted code, different energy code climate zone. If you’re up there, the permit goes somewhere else.
Jefferson County plows unincorporated roads in four priority tiers, and cul-de-sacs and dead-ends are tier four. In mountain areas the county stops plowing entirely between 9 p.m. and 3 a.m. Driveway approaches are the property owner’s responsibility, and a north-facing drive holds snow all winter while the south-facing one across the road is dry by ten.
Evergreen gets roughly 107 to 133 inches of snow a season depending on where you sit — against a Denver normal of about 49 inches. We schedule around it and we show up in trucks that can get up your road. If you’re at the end of a long private drive, tell us when you call and we’ll plan for it.
Sized for your elevation, with the altitude conversion kit your brand calls for.
Baseboard, in-floor radiant, and the mechanical-room repipes that go with them.
Repair and replacement, tank and tankless, gas or propane.
Cleaning, inspection and repair — including the standing-pilot check for shutoff days.
Whole-house fans, ductless mini-splits, and central air only if your house actually needs it.
Fuel conversions and high-altitude commissioning, quoted per system after we look at it.
Boiler and radiant work, propane conversions and high-altitude equipment setup are all quoted individually. Ask us for a custom quote and we’ll come look at what you’ve actually got.
Usually yes. Between the 4%-per-1,000-feet derate and Jefferson County’s colder design temperature above 7,400 feet, an Evergreen home typically needs a larger nameplate furnace than the same house in the metro. The right number comes from a Manual J calculation at your actual address, not from a rule of thumb.
Not as shipped. Golden is below most manufacturers’ altitude thresholds; Evergreen is above them. The same model will generally need a high-altitude conversion kit here, and installing it without one puts it outside the manufacturer’s instructions.
Both exist here. If you have a tank on the property you’re on propane; if you get a gas bill from Xcel you’re on the main. We’ll confirm before quoting, because the equipment setup differs.
For most Evergreen homes, no. The July average high is 80°F and there’s very little cooling load. A whole-house fan or a single ductless mini-split in the room that actually overheats usually solves the problem for a fraction of the cost.
Mechanical work in unincorporated Jefferson County is permitted through the county’s Division of Building Safety, and fees start at $45 for work valued up to $2,000. Ask us when you call and we’ll tell you what your job needs.
Filtration is the lever, but it has to match your equipment. A MERV 13 filter in a system that can’t handle the added static pressure will hurt more than it helps. We’ll tell you what your blower can actually take.
All of it: downtown Evergreen, Bergen Park, Kittredge, Upper Bear Creek, Hiwan, Evergreen Meadows and the roads off Highway 73 and Evergreen Parkway. Upper Bear Creek is in Clear Creek County rather than Jefferson, which changes the permit but not whether we come out.
Evergreen is served from our Conifer office at 26267 Conifer Rd, the mountain side of the business. That crew works heating, cooling, water heaters and gas fireplaces only. Electrical, plumbing and standby generators are Golden-office services and are not offered in the Evergreen area.
We’re up the hill from Golden and we work in Evergreen, Bergen Park, Kittredge, Upper Bear Creek and the surrounding foothills every week. Call 720-470-1133 or request a quote and tell us your address — the elevation is the first thing we’ll want to know.
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