Licensed Maryland HVACR contractor · 41 years in Montgomery County 24/7 emergency service
Poteete HVAC · since 1985

Maryland · Cooling

Ductless Air Conditioning System Installation in Maryland

Mini-split systems for additions, converted attics, sunrooms and older homes where running ductwork would cost more than the equipment.

Ductless mini-splits solve a specific Maryland problem elegantly: the room that the existing system was never designed to serve. A converted attic in a Takoma Park bungalow, a three-season porch in Olney closed in for year-round use, a finished basement in Germantown, a garage workshop in Glen Hills, or an entire 1915 house with plaster walls and no place to run a duct. Each indoor head is its own zone with its own thermostat, so you condition the room you are in rather than the whole house.

Modern inverter-driven mini-splits are also genuinely good heaters. Cold-climate models hold rated capacity down into the single digits, which comfortably covers a Maryland winter, so a single system can replace both a window unit and a space heater in a room the main system never reached. We size per head, because an oversized mini-split in a small bedroom short-cycles and leaves the room humid — the same failure mode as an oversized central system, in miniature.

Where we work
Multi-zone ductless system A single outdoor condenser connected by individual line sets to three indoor wall heads on separate floors, each with its own thermostat setpoint. 68° 72° 70° Zone 01 Zone 02 Zone 03 One outdoor unit Line sets
Each head is its own zone with its own setpoint, so you condition the room you are in rather than the whole house. Sizing is still per room — an oversized head in a small bedroom short-cycles and leaves it humid, which is the same failure as an oversized central system in miniature.

Scope

What the job actually includes

  • Per-zone load calculation so each head is sized to its own room, not to a catalog default
  • Single-zone or multi-zone outdoor unit selection with correct line-set lengths and lift limits
  • Wall, ceiling-cassette, floor-console or slim ducted indoor units depending on the room
  • Line-set routing planned for the shortest visible run, with paintable line-hide covers outdoors
  • Condensate handling by gravity where possible, condensate pump where it is not
  • Dedicated electrical circuit, disconnect and surge protection for the outdoor unit
  • Vacuum to 500 microns and torque-wrenched flare connections — the leading cause of mini-split leaks

Maryland specifics

Code, permits and rebates

Ductless heat pumps are among the best-supported equipment types for incentives in Maryland: qualifying cold-climate heat pumps can be eligible for the federal 25C tax credit and for EmPOWER Maryland utility rebates through Pepco. Because a mini-split condenser is a visible exterior addition, Takoma Park and other locally designated historic districts may require historic preservation review of its placement, and several Montgomery County HOAs — Avenel in Potomac among them — have their own screening requirements. Montgomery County DPS requires a mechanical permit and the electrical work requires its own permit and inspection.

Licensing

MD HVACR Contractor License #01-XXXXX. All refrigerant handling is performed by EPA Section 608 certified technicians, and equipment replacement is permitted and inspected through the county.

Process

How we run a mini-split installation job

  1. Room-by-room load and head placement

    We calculate each zone independently and place heads for throw and return path, avoiding the common mistake of aiming a head directly at a seating area or mounting it where a door swing blocks the airflow pattern.

  2. Line-set routing walkthrough

    We walk the exterior with you and agree on exactly where the line-hide will run and where the outdoor unit sits before we drill anything. In a historic district, that route is also what gets submitted for review.

  3. Installation

    Wall brackets lag-bolted into structure, three-inch core drilled with a downward slope, flares cut and torqued to the manufacturer's spec, and the entire circuit pulled to a 500-micron vacuum and held before the service valves are opened.

  4. Commissioning and handover

    We verify operation in both heating and cooling, register the warranty, and spend fifteen minutes teaching the remote and app — mini-splits are frequently run badly simply because nobody explained the fan and mode settings.

Pricing

What moves the price

We do not publish a single number, because a number without your house attached to it is marketing rather than information. These are the variables that actually decide what a job costs, and we itemise all of them in writing before any work begins.

Number of zones

A single-zone system for one room is the entry point. Multi-zone systems with three, four or five heads on one condenser cost more per zone in equipment but far less in exterior units, and only need one outdoor location — which matters on small lots.

Line-set length and routing difficulty

A head on the wall directly behind the condenser is a short, clean run. A third-floor attic head with the condenser at grade means significant vertical lift, longer line sets and sometimes an oil trap.

Indoor unit style

Standard high-wall heads are the most economical. Ceiling cassettes, floor consoles and slim concealed-duct units cost more and are chosen when the room or the homeowner will not accept a wall head.

Questions

Ductless Air Conditioning System Installation questions

Do mini-splits heat well enough for a Maryland winter?
Cold-climate inverter models do. They are rated to deliver full or near-full capacity down to around 5°F, and Maryland design temperatures in the Washington suburbs sit near 15°F. For most rooms a properly sized cold-climate head is the only heat source needed, though we often keep existing heat as backup in whole-house conversions.
How loud are they?
Indoor heads typically run in the 19 to 40 decibel range depending on fan speed — quieter than a refrigerator at low speed. Outdoor units are noticeably quieter than conventional condensers, which is a real advantage on the narrow side yards in Bethesda and Takoma Park where the neighbor's bedroom window is fifteen feet away.
Can one outdoor unit run several rooms?
Yes. Multi-zone condensers commonly support two to five indoor heads. The trade-off is that all heads share one compressor, so on some models the zones must be in the same mode — you cannot heat one room while cooling another. We flag that limitation when it matters to how you actually live in the house.
Is a mini-split cheaper than adding ductwork?
In a finished older home with plaster walls, almost always. In a house with an open basement and an accessible attic where ductwork can run easily, conventional central air is often the better value for whole-house coverage. The honest comparison depends on your house, and we quote both when both are viable.

Talk to a technician

Tell us what the house is doing.

Describe the problem and we will tell you what it usually means, what it typically costs to diagnose, and when we can be there. No obligation, no scripted sales call.

Call (301) 555-0182 Request a quote

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