Ductless Mini-Split Installation in Centennial

Willow Creek and Southglenn are established suburban neighborhoods, and Piney Creek has larger two-story houses. In both, the common ductless projects are a basement turned into an office, a bonus room or a sunroom added after the original system was sized. A single-zone unit is ideal for one space.

About 15% of the housing dates from 1940 to 1969, before Centennial incorporated in 2001. Those ranches may have heating-only ducts too small for cooling. Two or three ductless heads can provide air conditioning without enlarging them. Our guide to mini-splits in older homes explains how.

A room that's always 6 degrees off usually has a specific cause: a big west window, a ceiling under an unconditioned attic, a floor over the garage or a long duct run. We measure the room, account for those loads, and size the head to them rather than to square footage. An oversized head cools fast, shuts off and leaves the room clammy; a right-sized one runs longer at low speed and holds the temperature steady.

For a lower-level family room the load is often small, since the ground moderates it, and a compact head is plenty.

Centennial sits around 5,722 feet, and Arapahoe County's heating design temperature is 4°F. Thinner air slightly reduces how much heat a coil moves, so we use manufacturer data rather than nameplate numbers and choose cold-climate models with published output at 5°F.

Outdoor units sit on stands above drifts; indoor condensate goes to an interior drain or pump.

In split-levels the line set can often run through the garage or a closet to reach the head with little exterior exposure. Outside, we cover the line set in a channel painted to match the siding. Single-room jobs usually take a day; a two-zone system takes one to two. We pressure-test and vacuum every system before releasing refrigerant, then show you the remote and filter.

The City of Centennial Building Division treats like-for-like AC and furnace replacements as One-Stop permits. A mini-split added where none existed is new equipment, so expect a regular mechanical and electrical permit rather than One-Stop. We file it and handle the inspection. Each outdoor unit needs a dedicated 240-volt circuit and disconnect.

The city lists both Xcel Energy and CORE Electric Cooperative as providers depending on address. If Xcel serves you, its heat pump rebates may apply; amounts changed October 1, 2026, so verify. CORE's efficiency page showed no heat pump rebate in November 2026.

Either way, Centennial is a DRCOG member, so Power Ahead Colorado's $1,500 rebate can help on a cold-climate system in an existing home when we apply before starting. The state's 2026 credit is $1,000, of which at least $333 must appear as an invoice discount. The federal 25C credit ended after 2025.