Ductless Mini-Split Installation & Service
Ductless Mini-Split Installation & Service in Suffolk County, NY.
Ductless mini-split installation, replacement, repair and service for homes across the Hartworx service area. Residential only.
Call (631) 873-5844What a ductless mini-split is
An outdoor unit, one or more indoor units mounted in the rooms being conditioned, and a small refrigerant line set running between them through a hole roughly three inches across. No ducts. Each indoor head has its own control, so rooms can be set differently. It heats and it cools from the same equipment.
For the full explanation of how heat pumps behave in winter — cold-weather performance, backup heat, defrost and sizing — see the heat pump installation and service page. This page is about where a ductless system actually fits in a Long Island house.
Where mini-splits make sense in a Long Island house
The addition
A room added onto a house years after the original system was sized and installed. The existing furnace, boiler or air handler was sized for the old house, the ductwork was laid out for the old house, and extending a trunk line into an addition often means robbing capacity from rooms that already had it. A ductless head serves the addition on its own without touching the rest of the system.
The converted garage
Detached or attached, turned into an office, a gym, a playroom or a bedroom. Usually little or no insulation in the original build, usually a slab floor, and usually nowhere sensible to run duct. Space heaters and window units are what most people try first, and a ductless head is the actual answer — it heats and cools, it is on the thermostat rather than on a plug, and it does not put a load on a system that was never designed for that space.
The finished attic
Extremely common in this housing stock. Heat rises, the attic is under the roof, and the room is the hottest place in the house in August and often the coldest in January. Extending the existing system up there usually disappoints — long duct runs, the last room on the line, and a blower that was never sized for it. A dedicated head with its own control solves the room instead of fighting the house.
The finished basement
The opposite problem: cool, and damp. A mini-split dehumidifies while it cools, which matters more in a Long Island basement than raw cooling capacity does. Basements often have low ceilings and exposed joists where duct is unwelcome, and a head can be mounted high on a wall or, in some layouts, in a floor-standing or ceiling-cassette configuration.
The older house with no ductwork at all
This is the big one on Long Island. A house on hot water baseboard, cast iron radiators or steam has heat and no air conditioning, and there is no duct system to add central air to. The two options a homeowner really has are window units every summer, or retrofitting duct through closets and soffits, which is invasive and expensive in a finished house. Ductless sits between them. A mini-split can be added to a house with a boiler without touching the boiler — the hydronic heat stays exactly as it is and the mini-split handles the cooling, and the shoulder-season heating if the homeowner wants it. See the boiler service and repair page for the heating side of that arrangement.
The room the existing system never reached
Every house has one. The room over the garage, the far bedroom at the end of the duct run, the sunroom with three exterior walls and a wall of glass, the addition off the back that has always been ten degrees off. The usual causes are duct runs that are too long, undersized or leaking, or a room whose heat gain and loss the original design never accounted for. Sometimes the right fix is the ductwork rather than a mini-split, and Hartworx will say so if that is the case. Where the duct genuinely cannot get there, a head in that one room ends a problem the homeowner has had for years.
Single-zone and multi-zone
One outdoor unit serving one indoor head is a single-zone system. One outdoor unit serving several heads in several rooms is a multi-zone system. A multi-zone keeps one outdoor unit for several rooms and is often the tidier answer for a whole floor, while separate single-zone systems keep each room fully independent of the others. The choice depends on the house and how many rooms are in scope, and it is a conversation to have on site.
Installation — what it actually involves
Homeowners want to know what happens to their walls. The outdoor unit goes on a pad or bracket outside, and placement matters — it needs clearance to breathe, a level surface, and a route for the line set that does not put the unit where it will sit in a low, wet spot. The line set runs between the outdoor unit and the indoor head through a roughly three-inch penetration through the wall.
The condensate drain and where the water goes is the detail most often botched on a ductless install — the drain has to have a continuous downhill route or it backs up and the head drips inside. A dedicated electrical circuit and a disconnect are required at the outdoor unit. Line-hide covering is fitted on the exterior for a tidy finish. The indoor head's placement in the room affects how well it works, so it is decided deliberately rather than wherever is easiest to drill.
Someone picks up seven days a week, 7 AM to 10 PM — 9 AM on Thursdays. Most heating and cooling companies on Long Island close at 5. Call and we'll tell you honestly when we can be there.
Mini-split service and repair
This page is not installation-only. Ductless heads need their filters cleaned regularly, and when they are not, the indoor coil and blower wheel foul and produce a stale, musty smell when the unit runs — the single most common mini-split complaint. A head that drips water inside is almost always a condensate drain problem rather than a refrigerant leak. A system that heats but will not cool, or cools but will not heat, is reporting something specific, and the error codes on the head tell you what. A system short on refrigerant indicates a leak at the line set or the flares.
Hartworx is EPA Section 608 Universal certified, certification number 303313. Routine cleaning and service is covered on the seasonal tune-ups and inspections page.
Where we work
We install and service ductless mini-splits across Suffolk County — from Ronkonkoma, Holbrook and Bohemia out to Patchogue, Coram and Medford, and west to Deer Park. The full town list and coverage map are on the service areas page.
Related services
- Heat pump installation and service — how ducted and ductless heat pumps behave in cold weather, backup heat and sizing.
- AC installation and replacement — right-sized central air and condenser change-outs for houses with ductwork.
- Air conditioning repair — no-cool calls on central air systems across Suffolk County.
- Boiler service and repair — the heating side of a house that keeps its boiler and adds ductless for cooling.
- Ductwork — when the real fix for an unreached room is the duct, not a mini-split.
- Thermostats and controls — controls setup for ductless heads and whole-house systems.
Questions about ductless mini-splits
Can I put a mini-split in my house if I have baseboard heat and no ducts?
Yes. A ductless mini-split can be added to a house with a boiler without touching the boiler — the hydronic heat stays exactly as it is and the mini-split handles the cooling, and the shoulder-season heating if you want it. This is one of the most common uses for ductless on Long Island, where a lot of houses have baseboard or radiator heat and no ductwork to add central air to.
Will one outdoor unit run more than one room?
It can. A multi-zone system uses one outdoor unit to serve several indoor heads in several rooms, which is often the tidier answer for a whole floor. Separate single-zone systems keep each room fully independent of the others. The choice depends on the house and how many rooms are in scope, and it is a conversation to have on site.
How big is the hole in my wall?
Roughly three inches across. The line set — the refrigerant lines and the condensate drain — runs between the outdoor unit and the indoor head through that one penetration. Line-hide covering is fitted on the exterior for a tidy finish, and the indoor head's placement in the room is decided deliberately, because where it sits affects how well it works.
My mini-split smells musty when it starts up. What is that?
It is almost always a fouled indoor coil and blower wheel. The filters on a ductless head need regular cleaning, and when they are not, dust and moisture build up on the coil and the blower wheel and produce a stale, musty smell when the unit runs. It is the single most common mini-split complaint, and it is a cleaning and service job rather than a reason to replace the head.
Water is dripping out of the indoor unit. Is that a refrigerant leak?
Usually not. A head that drips water inside is almost always a condensate drain problem — the drain is clogged or the route is wrong and the water has nowhere to go but out of the head. It is the detail most often botched on an install. A system short on refrigerant is a different problem, and what that indicates is a leak at the line set or the flares, not water on the floor.
Can a mini-split heat a converted garage through the winter?
It depends on the insulation and the size of the space, and that is what gets looked at on site. A converted garage usually has a slab floor and little or no insulation in the original build, and a ductless head heats and cools the space on its own thermostat without putting a load on a system that was never designed for it. Whether it carries the room through January is a question for the actual building, not a web page.
Do mini-splits need maintenance, or do you just leave them alone?
They need maintenance. The filters need regular cleaning, the indoor coil and blower wheel foul over time and produce a musty smell when they do, and the condensate drain needs to stay clear or the head drips. A system short on refrigerant indicates a leak at the line set or the flares. We service and repair ductless systems as well as installing them.
Call and describe the room.
Tell us which room is the problem and what the house has now. We will come look and lay out the honest options for that space.
(631) 873-5844Thart@hartworxhvac.com
Fri–Wed 7 AM – 10 PM · Thu 9 AM – 10 PM
Ductless mini-split installed in a Suffolk County home
Real photo to be supplied
Rather send a message?
If you are ready to talk installation now, call — that is faster. Otherwise tell us about the room.