Ductless mini splits for houses with no ductwork
Vermont pays $475 per indoor head. New Hampshire pays per ton. For a farmhouse with no ducts and one bedroom that never gets warm, this is usually the answer.
Why mini splits fit Upper Valley houses
Most houses in this valley have no ductwork and never did. A 1840s farmhouse in Strafford heated by a boiler and cast-iron radiators, a Hanover colonial on hot water baseboard, a Lebanon cape with a wood stove and electric backup — none of them has a duct system worth extending, and retrofitting one into a plaster-and-lath house is expensive and destructive.
A ductless mini split sidesteps the problem entirely. An outdoor compressor connects to one to five indoor heads through a three-inch penetration carrying refrigerant lines. Each head is independently controlled, which means the cold north bedroom finally gets heat without cooking the south-facing living room.
What Vermont and New Hampshire pay
| Vermont | New Hampshire | |
|---|---|---|
| Rebate structure | $475 per indoor head | Per ton of system capacity |
| Standard amount | $475 × number of heads | $250/ton, max $1,250 (from fossil fuel) |
| Replacing electric resistance | Same, plus income bonus | $1,250/ton, max $6,250 — pre-verification required |
| Income bonus | $200–$2,200; GMP ≤80% AMI adds $2,000 | 100% Home Energy Assistance for qualifying households |
| Equipment requirement | ENERGY STAR Cold Climate certified | ENERGY STAR Cold Climate + R-32 or R-454B refrigerant |
A four-head system in Thetford earns $1,900 from Efficiency Vermont — four separate $475 rebates — where a single-head system earns $475. If your house genuinely needs multiple zones, Vermont’s structure rewards you for it. Do not let that push you into buying heads you do not need, but do not under-scope a rambling floor plan either.
How many heads, and where
The common Upper Valley configurations:
- One head, main living space. $4,500–$7,500 installed. Works when the floor plan is open and you are supplementing an existing system rather than replacing it.
- Two to three heads. $8,000–$17,000. Living space plus the bedrooms that are always cold. The most common retrofit here.
- Four to five heads. $16,000–$26,000. Whole-house on a farmhouse with an ell, or a house being converted off oil entirely.
Heads do not push heat around corners or up stairs well. A single head in a hallway serving four closed bedrooms is the classic disappointment. If the doors are usually shut, that room needs its own head or it will not be comfortable.
Cooling, which matters more than it used to
Every mini split is an air conditioner running in reverse. Upper Valley summers have gotten warmer and more humid, and the second story of an uninsulated 1900 farmhouse in late July is genuinely difficult to sleep in. A system bought for heating delivers cooling as a free consequence — no separate equipment, no window units, no condensation on the sills.
The things people complain about
Worth knowing before you commit rather than after:
- They are visible. A wall cassette is a white plastic box near the ceiling. Floor-mounted and low-wall units read better in an old house; ducted mini-split cassettes hidden in a closet or knee wall are an option at higher cost.
- The outdoor unit needs clearance and elevation. In this snow belt it should be on a wall bracket or a stand well above expected snowpack, with a clear defrost drain path.
- Filters need cleaning. Every month or two in a wood-heated house. Neglected filters are the leading cause of “my mini split stopped working well.”
- Defrost cycles happen. The unit periodically reverses to melt ice off the outdoor coil. It is normal and brief, and it is not the system failing.
Insulate first, then size
The same rule as any heat pump, only more so with ductless: heads are sized per zone, and a leaky uninsulated room needs a bigger head. Air sealing and insulating first can drop a four-head plan to three, which saves more money than the rebate on the fourth head would have. Insulation and air sealing →
Figures checked July 2026. Rebate programs change their amounts, caps and equipment requirements during the year, and several are capped by available funding. Confirm the current offer with the program or your contractor before you sign anything.
Ductless mini splits: common questions
How much is the Vermont mini split rebate?
$475 per indoor head from Efficiency Vermont, on ENERGY STAR Cold Climate certified equipment. A three-head system earns $1,425; a four-head system earns $1,900. Income-eligible households add $200–$2,200 depending on utility, with Green Mountain Power customers at or below 80% AMI adding $2,000.
And in New Hampshire?
New Hampshire pays by system capacity rather than by head: $250 per ton to a maximum of $1,250 if you are displacing oil, propane or gas, or $1,250 per ton to a maximum of $6,250 if you are displacing electric resistance heat. The enhanced tier requires pre-verification before the install.
Can one head heat my whole house?
Rarely, in an Upper Valley house. Open-plan spaces do reasonably well; closed bedrooms off a hallway do not, because heat does not move through doorways on its own. A single head is a good supplement to an existing system and a poor whole-house solution in a compartmentalised old floor plan.
Do they work when it is well below zero?
Cold Climate certified units produce heat at those temperatures at reduced capacity. Most designs here keep a backup for the coldest nights. The colder your house is running relative to its design load, the more likely the answer is that the house needs air sealing rather than that the equipment is inadequate.
How disruptive is the installation?
Modest. A three-inch hole per head for the line set, a mount on the wall or floor, a pad or bracket for the outdoor unit, and an electrical circuit. A single-head job is often one day; a three-head job typically two. No walls opened, no ducts run.
What maintenance do they need?
Clean the indoor filters every one to two months, more often with wood heat or pets. Keep the outdoor unit clear of snow and leaves. Have a technician check refrigerant charge and coils annually — that visit also keeps efficiency in the range the rebate assumed. More on tune-ups.
How many zones does your house actually need?
Tell us the layout and we’ll tell you what a right-sized system earns in rebates on your side of the river.