Mini-Splits & Retrofits
10 Phoenix-specific guides. Garages, casitas, historic homes, additions, swamp-cooler conversions, hot upstairs. Each guide answers five real homeowner questions, direct answer first, with every figure sourced.
The Phoenix Mini-Split Guide
- Are mini-splits a good option in the Phoenix climate?
- Where do mini-splits make more sense than central AC in an Arizona home?
- How efficient are mini-splits in extreme heat?
- How long do mini-splits last in the desert compared to central systems?
- What maintenance does a mini-split need in a dusty climate?
Cooling a Phoenix Garage
- What is the best way to cool a garage in Phoenix?
- What size mini-split does a 2-car garage need in Arizona?
- Should I insulate my garage door before adding cooling?
- What does garage cooling cost to install and to run each month?
- Can I use a portable or window AC in a garage instead — and why do they struggle?
Cooling a Casita or Arizona Room
- How do I add cooling to a casita or guest house?
- Why is my Arizona room so much hotter than the rest of the house?
- Can I extend my existing ductwork to an addition, or is a mini-split smarter?
- What does it cost to cool a casita properly?
- What do Phoenix-area permits require when adding cooling to a converted space?
Cooling Historic Phoenix Homes Without Ductwork
- How do I add modern AC to a historic Phoenix home with no ductwork?
- What are the cooling options for homes in districts like Willo, Coronado, and Encanto-Palmcroft?
- Do historic district rules limit where condensers and line sets can go?
- What does high-velocity mini-duct AC cost versus mini-splits in an older home?
- How do I cool a 1930s–1950s masonry home without ruining its character?
Converting a Swamp Cooler to Refrigerated AC
- What does it cost to convert from a swamp cooler to refrigerated AC in Phoenix?
- What does a swamp-cooler-to-AC conversion actually involve (roof, ducts, electrical)?
- Can my existing swamp cooler ductwork be reused for AC?
- Will my electric bill jump after converting to refrigerated air?
- Should I keep the swamp cooler as a dual system or remove it entirely?
Swamp Cooler vs AC in the Monsoon
- Why does my swamp cooler stop working when the monsoon arrives?
- At what humidity level does evaporative cooling become ineffective?
- Is a swamp cooler still worth it anywhere in the Phoenix metro?
- How do swamp cooler running costs compare to AC across a full summer?
- What maintenance and water costs does a swamp cooler add?
Adding Cooling to a Home Addition
- How should I cool a new room addition in Phoenix?
- Can my existing AC handle an addition, or will it be undersized afterward?
- Extend ducts, add a mini-split, or upsize the whole system — how do I decide?
- What does each addition-cooling option cost?
- Why do additions so often end up as the hottest room in the house?
Fixing a Hot Upstairs in a Two-Story Home
- Why is my upstairs so much hotter than downstairs in my Phoenix home?
- Is a 5–10 degree difference between floors normal in summer?
- What is HVAC zoning and what does it cost to add?
- Would a second unit or a mini-split for upstairs bedrooms solve it?
- Which cheap fixes (dampers, fans, filters, attic insulation) should I try before spending big?
DIY Mini-Split Kits: Honest Assessment
- Are DIY mini-split kits like MRCOOL worth it in Arizona?
- What can legally be self-installed versus what requires a licensed contractor in Arizona?
- What voids the warranty on a DIY mini-split?
- What do DIY installs commonly get wrong in extreme-heat conditions?
- What would a professional charge to install a unit I bought online — and will they?
Window & Portable AC: Stopgap Guide
- Can a window or portable AC keep up with Phoenix summer heat?
- Why do portable ACs perform so poorly in the desert?
- Can my HOA or landlord prohibit window AC units in Arizona?
- What are a renter's options when the landlord's AC is inadequate or broken?
- What is the safest way to bridge the gap while waiting for an AC repair or replacement?
Other Phoenix cooling topics
Cost & Pricing Repair or Replace Buying a New System The Refrigerant Transition Heat Pumps in the Desert Troubleshooting & Symptoms Maintenance & Lifespan Utility Bills, Rates & Rebates Desert Homes & Seasonal Realities