Furnace Installation & Replacement in Derby

Derby's ranch houses usually keep the furnace in a basement or utility room, and many are on their second or third. Returns in these homes are often small, and furniture or remodeling has blocked some of them. We measure static pressure and size the furnace and blower to what the ducts can move, adding return capacity where it is clearly needed. A furnace that fits the house runs quieter and lasts longer than one that is fighting the ductwork.

At about 5,125 feet, a gas furnace loses roughly a fifth of its sea-level input once it is set up for altitude with the right orifices and manifold pressure. We size from a Manual J load calculation, not from the old furnace's label. Small ranches that have picked up new windows or insulation over the years frequently need a smaller furnace than the one coming out.

Colorado's NOx rule took effect January 1, 2026: new gas furnaces must meet 14 ng/J NOx or the current ENERGY STAR version. In a ranch with a sound metal flue, an ultra-low NOx 80% furnace keeps the existing vent. A 97% condensing furnace uses PVC and a condensate drain and is often the better buy in a basement near an outside wall. If the water heater is left alone on the old flue, we check that it still drafts. Our NOx guide has the details.

Some Derby residents near the refinery and I-76 ask about better filtration. A furnace replacement is the easiest time to get it right: we can fit a media cabinet for a 4- or 5-inch filter and choose a blower that can push air through a MERV 11 or 13 filter without starving the system. A filter will not remove outdoor odors, but it does cut the dust the system recirculates.

Unincorporated Derby addresses are permitted by Adams County's Community and Economic Development Department, which lists furnace replacement as permit-required. Addresses inside Commerce City go through the city's Building Safety Division. We check the parcel, file with the right office and schedule the inspection.