Ductless Mini-Split Heat Pumps

What a ductless mini-split is

A ductless mini-split is a heat pump without the ductwork. An outdoor unit, much smaller than a central air condenser, connects by a thin bundle of refrigerant lines, wiring and a condensate drain to one or more indoor heads mounted high on a wall or set into a ceiling. Each head has its own fan and its own setting. In summer it cools and dehumidifies; in winter a cold-climate model heats, often as the main heat for the rooms it serves.

Where they make the most sense

• Homes with boilers and radiators: much of Hamilton’s older housing in the lower city, Westdale, Dundas and the older parts of Burlington has hot-water heat and no ducts for central air.
• Electric baseboard homes: a mini-split can cut heating costs sharply and add cooling at the same time.
• Additions, sunrooms, finished attics and garages: spaces the main system never reached properly.
• The one room that never gets comfortable: a hot upstairs bedroom or a cold room over the garage.
• Cottages and rural properties: heating and cooling without running ductwork through an old structure.

Single-zone and multi-zone

A single-zone system pairs one outdoor unit with one indoor head and is the simplest and most efficient arrangement. A multi-zone system runs two to five heads from one outdoor unit, which saves space outside but costs more per head, and every zone draws from the same compressor. For a whole house, a contractor may suggest two single-zone systems, a multi-zone, or a slim ducted unit hidden in a ceiling to serve several bedrooms through short duct runs.

Heating with ductless in a Hamilton winter

Cold-climate mini-splits keep heating far below freezing, many to −25 °C or lower, with reduced capacity in the deepest cold. Because each head heats only the room it is in, a house heated mainly by mini-splits works best with an open layout or a head in each main area, and with some backup heat: the existing boiler or baseboards, left in place, often fill that role on the coldest nights.

Running costs and rebates

Against electric baseboard heat, a mini-split typically uses a third to a half of the electricity for the same heat, which is often the biggest saving any heating upgrade can deliver. Against natural gas, the saving is smaller, but you also gain air conditioning. Qualifying cold-climate mini-splits can earn a Home Renovation Savings rebate when the contractor registers the job first; see the heat pump rebate guide.

What installation involves

1. Choosing head locations: high on an outside wall, with a clear throw of air and not over a bed.
2. Mounting the outdoor unit on a wall bracket or raised stand, above the snow line.
3. Drilling a small hole per head and running the line set, cable and drain, usually covered outside with a neat line-set cover.
4. Vacuuming the lines, releasing the refrigerant and commissioning each head.
5. A dedicated electrical circuit for the outdoor unit, under an ESA permit.

Most single-zone installs take a day. Ask where the condensate drain will go: it needs to run where it will not freeze into a sheet of ice on a walkway in winter.

Looking after a mini-split

Common questions at the quote

Expect the contractor to ask which rooms matter most, whether anyone in the house is sensitive to drafts, and how you want the heads to look. Wall-mounted heads are the cheapest and most efficient; floor consoles suit rooms with low windows or sloped ceilings; ceiling cassettes disappear into a drop ceiling in a basement. Ask how the line sets will be routed on the outside of the house and what colour cover is used, because on a brick Hamilton century home that detail is what neighbours will notice.

Each indoor head has washable filters that should be rinsed every month or two during heavy use. Once a year, a technician should clean the indoor coil and blower wheel, which can gather dust and mould, and check the outdoor unit. Keep snow and ice clear of the outdoor unit in winter.

How the request works

You request a ductless quote once, and we pass it to one licensed contractor who installs mini-splits in your area. Say how many rooms you want to heat or cool, how the house is heated now, and whether you want it to be the main heat or a supplement. For a whole-house switch, compare with a ducted heat pump if you have ducts.