No AC in your older Prescott home? Here's how to add it.

Why so many Prescott homes have no AC

At around 5,300 feet, Prescott stays much milder than the desert below it, and for a long time open windows were enough. Older homes near downtown and in the historic neighborhoods, cabins in the pines and plenty of mid-century houses were built with a furnace, a floor furnace or a wall heater, and no cooling.

Summer afternoons in the 90s still happen, though, and wildfire smoke can mean days when opening the windows isn't an option. That's usually when people start asking what it takes to add AC.

Option 1: add central air to the furnace you have

If your home already has a forced-air furnace and ductwork, adding central air is the most direct route. The job adds three things: a cooling coil on top of the furnace, an outdoor unit, and the refrigerant lines between them. Instead of a straight AC, the outdoor unit can be a heat pump, which cools in summer and takes over much of the heating in mild weather, with the furnace as backup.

Before we quote it, we check a few things that decide whether the existing ducts will work:

• Duct size. Cooling needs more airflow than heating. Ducts that were sized only for a furnace are often too small or have too few returns.
• The furnace blower. It has to be able to move enough air for the new coil. An old furnace near the end of its life may be worth replacing at the same time.
• Attic ducts. Uninsulated or leaky ducts in a hot attic waste a lot of the cooling you're paying for.
• Electrical. The outdoor unit needs its own circuit. Some older panels don't have room, which means an electrician's visit first.

Option 2: a ductless mini split

If the house has a floor furnace, wall heaters, a boiler or no ducts at all, a ductless mini split is usually the better fit. An outdoor unit connects to one or more indoor heads through a small line set that passes through the wall. There's no ductwork to build.

• Each head is its own zone, so you cool the rooms you use.
• Mini splits are heat pumps, so they heat too. On many days in fall and spring they can carry the house without the old heater.
• The tradeoffs: the indoor heads are visible on the wall, cost rises with each room you add, and the head filters need regular cleaning.

There's also a middle option for some homes: a ducted mini split, a compact air handler tucked in an attic or closet with short duct runs to a few rooms.

What elevation changes

Air at Prescott's elevation is roughly 15 percent thinner than at sea level. Thinner air carries less heat per cubic foot, which affects how outdoor coils and fans perform. Prescott also has big swings between day and night temperatures, and older homes vary a lot in insulation and window quality. All of that is why we size with a load calculation for your actual house, not a square-foot rule of thumb built for Phoenix.

Older and historic homes

Plaster walls, tight attics and original trim take more planning. We route line sets where they won't show from the street, place outdoor units out of sight where we can, and use line-set covers that can be painted to match. If your home is in one of Prescott's historic districts, it's worth checking with the city whether outdoor equipment placement needs review before work starts.

Why fall and winter are a good time to plan

Adding AC isn't an emergency, and it goes better when it isn't treated like one. We run set days in Prescott, and planning it in the off-season gives time for a proper survey of the house. If you choose a heat pump or a mini split, it'll be heating for you this winter instead of sitting idle until June. New equipment is also moving to R-454B refrigerant, so a new install now is on the current standard.

If smoke is part of why you want the windows closed, ask about air purification at the same time.

What our quote looks like

We're a Trane dealer, and we quote every install in three tiers side by side so you can compare options. 0% APR financing is available on approved credit. Air-Exx is veteran owned, licensed, bonded and insured (AZ ROC 350424). Learn more on our Prescott service page and our installation page, or call (928) 565-6440 to set up a visit.