Ductless mini-split heat pumps
No ducts? No problem. Mini-splits heat and cool room by room — here's how they work, what they cost per zone, and how to size them.
How ductless mini-splits work
A ductless mini-split — also called a ductless heat pump — pairs an outdoor compressor with one or more indoor "heads" mounted on walls or ceilings, connected by a small refrigerant line through a 3-inch hole. Each head can be controlled independently, so you condition only the rooms you use. There are no ducts, which eliminates the 20–30% energy loss ducts can cause.
Cost per zone
Mini-splits are priced per zone (indoor head). A single-zone system runs roughly $3,500–$5,000 installed; each additional zone adds a few thousand. A whole-home multi-zone system can reach $10,000–$20,000+ before rebates. State and utility rebates may apply to qualifying systems (the federal credit expired at the end of 2025) — see our cost calculator.
How many zones do I need?
One head per open area or per room you want independently controlled. A typical guide:
| Home | Typical heads |
|---|---|
| Single room / addition | 1 |
| Small home / condo | 2–3 |
| Average house | 3–5 |
Each head is sized in BTU (commonly 9,000 or 12,000). Use our size calculator for the total load, then split it across zones.
When to choose a mini-split
- Homes without ductwork (older homes, radiant or baseboard heat).
- Additions, garages, or finished basements where extending ducts is costly.
- When you want room-by-room control and zoning.
Pros and cons
Pros: no duct losses, precise zoning, easy retrofit, very efficient. Cons: indoor heads are visible, higher per-zone cost for whole-home coverage, and more units to maintain.
Frequently asked questions
How much does a ductless mini-split cost?
About $3,500–$5,000 per zone installed; whole-home multi-zone systems run $10,000–$20,000+ before any state or utility rebates.
How many mini-split zones do I need?
One head per room or open area you want to control independently — typically 3–5 for an average house.
Are mini-splits more efficient than ducted systems?
Often, because they avoid the 20–30% energy loss from ductwork and allow you to heat only occupied rooms.
Do mini-splits work in cold weather?
Cold-climate mini-splits maintain output well below freezing; pair with backup heat below the balance point.
Related
Sources & further reading
Educational guide, reviewed against US DOE & ENERGY STAR guidance and updated June 2026. Estimates only — not a substitute for a professional assessment or Manual J load calculation.