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How to add central air to an older Spokane house
A lot of Spokane houses were built before anyone expected air conditioning. Whether yours can take central air depends on three things: the furnace, the ducts and the electrical panel.
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NBy Nell Bradshaw, HVAC Guides Editor · Updated September 2026
Quick answerAdding central air to an older Spokane house works when there is a forced-air furnace with ducts, a blower strong enough for cooling airflow, room for an indoor coil and panel capacity for a new circuit. Homes without ducts, or with small ducts built for gravity heat, are usually better served by a ductless heat pump.
Why so many older homes lack AC
Inside the city the median Spokane home was built in 1961, about a quarter predate 1940, and in West Central most homes were built before 1940. Many were heated by gravity furnaces, boilers or baseboard, and summers used to be mild enough to get by with fans. Hotter recent summers have changed that.
Check 1: is there a forced-air furnace?
If the house has a furnace with supply registers and at least one return, central AC can usually be added on top. The indoor coil sits on the furnace, the outdoor condenser sits outside, and a line set connects them. If the house has radiators or baseboard, there are no ducts to carry cold air, and the choice becomes new ductwork or ductless.
Check 2: can the ducts carry cooling airflow?
Cooling needs more airflow than heating. Older duct systems often have small returns and supply runs designed for a gravity or early forced-air furnace. The usual fix is an added or enlarged return, sometimes an upstairs return, which our ductwork installation crews do as part of the AC job when it is needed. Skipping it leaves a noisy, weak system.
Want to know if your house can take central air?
Call (509) 404-0016Check 3: the blower and the panel
An old furnace blower may not move enough air for cooling. If the furnace is also past 15 years, replacing both together often makes sense. The electrical panel needs space and capacity for a new 240-volt circuit and a disconnect at the outdoor unit. Older panels sometimes need an upgrade first.
When ductless is the better answer
In homes with radiators, baseboard or ducts that would need rebuilding, a ductless heat pump often costs less and disrupts less. Each room gets its own head, the line sets need only small openings, and the system also heats, which cuts electric bills in baseboard homes.
Where the outdoor unit should go
Placement matters more than most people expect. The condenser needs clear airflow on all sides and a couple of feet of clearance for service, away from dryer vents that blow lint into the coil. It should sit where roof runoff and sliding snow will not land on it, on a level pad or bracket above the ground.
Bedroom windows are worth avoiding where you can, since even quiet units make some noise at night. Shorter line-set runs are better for performance, so the ideal spot is usually close to the furnace, on a side of the house that does not bake in afternoon sun.
What it costs and how long it takes
Published 2026 figures put central AC alone at roughly $3,500 to $12,500 installed, depending on size and efficiency tier. Adding AC to a furnace-only house usually takes one to two days, and Washington requires a mechanical permit. Our AC installation service starts with a load calculation so the system is sized for the house, not guessed. For a comparison with heat pumps, read heat pump or gas furnace.
More Spokane heating and cooling guides
Central AC questions
Can I add AC if I have radiators?
Not with the radiators themselves. You would need new ductwork or a ductless system.
Will adding AC make my furnace work harder?
The blower runs more hours, so an older blower may need attention, but the burners are unaffected.
Do I need a bigger electrical panel?
Sometimes. It depends on available space and capacity.
Should I choose a heat pump instead of AC?
It costs a bit more and adds efficient heating. Many Spokane homes do well with dual fuel.
How long does installation take?
One to two days for most furnace homes.
Find out what your house can take.
Call for an AC sizing visit in Spokane, WA.
