Casita & Guest House Cooling: The Right Way to Add Comfort

Detached casitas and pool houses are a Coachella Valley signature. They're also almost always cooled the wrong way.

What we usually find

• A window shaker unit installed by the previous owner (loud, inefficient, unreliable)
• A long buried duct run from the main house AC (expensive, leaky, and steals capacity from the primary residence)
• Nothing — guests just suffer

The right solution

A dedicated single-zone ductless mini-split heat pump, sized to the casita's specific load:

• Wall-mounted indoor head (or ceiling cassette if you want it invisible)
• Outdoor condenser mounted on a discrete side wall or on the roof
• Short refrigerant line set — the shorter the run, the more efficient
• Own thermostat/remote/app — guest controls, no interaction with the main house

Sizing

Most Valley casitas are 300–800 sq ft. Typical sizing:

• 300–450 sq ft → 12,000 BTU (1 ton) single-zone mini-split
• 450–650 sq ft → 18,000 BTU (1.5 ton)
• 650–800 sq ft → 24,000 BTU (2 ton)

Oversizing a casita is even worse than oversizing a main house — short cycles all summer.

Installed cost

2026 pricing for a properly installed single-zone mini-split in the Valley:

• 12k BTU: $4,500–$5,800+
• 18k BTU: $5,000–$6,500+
• 24k BTU: $6,000–$7,800+

Common mistakes we replace

• Undersized "portable" AC units. These are the same as window ACs but dumber. They exhaust hot air through a hose to the outside via an open window (which lets more hot air in).
• Stretched central-duct runs. 60+ feet of undersized flex duct buried in landscaping. Delivers maybe 40% of nominal capacity.
• Single ceiling cassette on a shared multi-zone. Fine in theory, but if the main house is on 3 heads and the casita is head #4, the casita rarely gets what it needs when everyone's home in summer.

Every casita is different — pool house, guest suite, home office, ADU. Have us look at the space and we'll size the right system and give you a real quote.