Ductless systems
Ductless mini-split installation and repair
The practical answer for a space the central system cannot serve. Converted garages, additions, sunrooms, workshops and the room over the garage that has never been usable in July.
When it is the right tool
The spaces central systems handle badly
A central system is sized and ducted for the house as it was built. Spaces added or repurposed afterwards are usually served either badly or not at all, and forcing the central system to cover them tends to disappoint everybody.
A ductless system puts capacity exactly where it is needed, with an outdoor unit, a refrigerant line set through the wall and one or more indoor heads. There is no duct, so there is no duct loss, and the space gets its own thermostat and its own control.
The cases that come up most often around Stafford, Sugar Land and Missouri City:
- Garage conversions. A converted garage typically has no ductwork, poor insulation and a large uninsulated door assembly. Tapping into the house system almost never works well.
- Room additions. Adding square footage to a house whose system was sized for the original footprint. Either the existing system gets stretched past its capacity or the new space gets its own.
- Rooms over garages. Attic above, unconditioned space below, and usually the longest duct run in the house. A perennial complaint.
- Sunrooms and enclosed patios. Large glass area and a load that changes dramatically through the day.
- Home offices and workshops. Spaces used at different times from the rest of the house, where cooling one room is far cheaper than cooling all of it.
- Primary bedrooms that run warm. Sometimes a supplementary head is a more sensible spend than rebuilding the whole distribution system.
Worth knowing before you call
- What the space is and roughly its dimensions
- Whether it is insulated, and what is above and below it
- How much glass it has and which way it faces
- Whether there is an exterior wall available for the line set
- Whether the space has its own electrical circuit
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What a good installation involves
Ductless is simpler, not effortless
Mini-splits have a reputation for being easy to install, which has produced a lot of poor installations. The equipment is forgiving of many things but not of these.
Sizing
Ductless systems are more often oversized than ducted ones, because it is tempting to pick a capacity from square footage alone. An oversized head in a humid climate short cycles and leaves the room cold and damp, the same failure mode as an oversized central system but concentrated in one space. A converted garage with a west-facing door needs a different answer from a north-facing office of the same size.
Line set and penetration
The refrigerant lines have to be properly sized, correctly evacuated before charging, and routed so the penetration through the wall is sealed and finished. In this climate an unsealed penetration is an invitation for humid air and insects.
Condensate
The indoor head produces condensate that has to go somewhere by gravity or by pump. Getting this wrong on a wall-mounted head means water tracking down an interior wall, and it is one of the commonest defects on hurried installations.
Electrical
Most installations need a dedicated circuit and a disconnect. On a garage conversion or an addition, that frequently means panel work as well, which is one of the places the electrical side of this business is useful rather than an extra contractor to schedule.
Related pages
HVAC for remodels and additions
Where most mini-split conversations actually start.
Zoning and airflow
The alternative approach when the central system has capacity to share.
Upstairs not cooling
Sometimes a supplementary head beats rebuilding the duct system.
Electrical work
Circuits and panel capacity for new equipment in converted spaces.
AC replacement
When the answer is the central system rather than a ductless addition.
Cost calculator
Repair and replacement ranges for central systems.
Mini-split questions
What does a mini-split cost to install?
Is a mini-split cheaper than extending my ductwork?
Do mini-splits heat as well as cool?
How much maintenance do they need?
Describe the space and what it is used for. That determines whether ductless is genuinely the right call.
Call (866) 427-9264Got a room the house system was never built to cool?
Worth a conversation about whether ductless, zoning or duct work is the sensible spend for that particular space.