AC Installation & Replacement in Boulder

Most of Mapleton Hill's roughly 500 homes predate 1910, and many have radiators or gravity-era layouts with no ductwork worth using for cooling. For those houses, a ducted system is often a major remodel; a ductless or small-duct heat pump can cool bedrooms and living areas without opening plaster walls. Our guide to mini-splits in older homes covers the options.

Martin Acres' 1950s ranches are simpler: a basement furnace, short duct runs, and a yard for the condenser. The common snag is the electrical service. Many of these homes have small panels already crowded with circuits, and a heat pump or AC needs its own 240-volt breaker. We check capacity first and tell you if an electrician needs to be involved.

At around 5,300 feet, coils deliver a little less than their sea-level ratings, so we run a Manual J on every installation rather than matching the old unit's tonnage. Because Boulder homes often shut tight during wildfire smoke, we also plan the return and filter rack for a higher-efficiency filter, which needs more filter area to avoid choking airflow.

Boulder's downslope windstorms have produced gusts above 100 mph, including 112 mph during the Marshall Fire. Outdoor units should sit on a secure, level pad, out of the path of blowing debris where possible, and line sets should be strapped and sealed where they enter the house.

New split systems now use R-454B or R-32, so the indoor coil is replaced with the outdoor unit. Colorado is in the DOE North region, where the minimum for a split heat pump is 14.3 SEER2 and 7.5 HSPF2 and for a split AC 13.4 SEER2.

On the money side: Boulder County's EnergySmart rebates are limited to income-qualified households in 2026, and the county has run the Switch Together heat pump group-buy. Colorado's $1,000 heat pump tax credit is claimed by the contractor with at least $333 discounted to you, and Power Ahead Colorado offers $1,500 for cold-climate units, filed before work begins. Xcel Energy is the electric utility; confirm its current rebates, which changed in October 2026.