Mini-split installation and replacement in Scarborough, Durham and the GTA
A ductless mini-split answers one problem: a room, an addition or a whole house with no ductwork to carry conditioned air into it. An outdoor condenser is joined to one or more indoor heads by a refrigerant line set, and each head conditions its own space. Metropolitan Heating and Air Conditioning has worked across Scarborough, Durham Region and the GTA since 1979, and we install Carrier, Lennox, Napoleon, Trane, Bosch and Daikin.
Call (416) 283-5698, weekdays 8:00 AM to 4:00 PM, to arrange an assessment.
What makes a ductless system behave differently
The first is the absence of ducts. Nothing is lost to leakage, and nothing cools off crossing an unheated attic on its way to the room.
The second is the inverter compressor. A conventional system has one speed: full output until the thermostat is satisfied, then off until the room drifts far enough to call again. An inverter varies compressor speed continuously, so once the space is at temperature it settles to a low output matching the rate the room loses heat — which is why a ductless head holds a room in a narrow band rather than swinging either side of the setpoint, and why it is quiet at part load.
Where a mini-split is the right tool
- Additions and conversions. A room over a garage, a finished basement, an attic bedroom. Reaching them with ducts means opening walls, and the furnace usually has no spare capacity anyway.
- Houses with no ducts at all. Radiators or electric baseboards and no cooling. A multi-head system adds both without building a duct system from nothing.
- The room that has never been comfortable. Coldest in winter, warmest in summer, usually at the end of the duct run. One head fixes it without re-engineering the house.
Where it is not the right tool: a house with sound, adequately sized ductwork, which is better served by central equipment or a ducted heat pump.
Sizing, zoning and how many heads
Capacity comes from a heat-loss and heat-gain calculation for the rooms being conditioned — floor area, ceiling height, insulation, window area and orientation, air-tightness, use.
Oversizing hurts a ductless system in a particular way. An inverter turns down a long way, but not infinitely. Put a head in a room needing less than its minimum output and it drops to that floor, satisfies the room and starts cycling — the behaviour you bought an inverter to avoid — and it removes less moisture in summer, because the coil never stays cold long.
Multi-head systems share one outdoor unit. Each head controls its own room, which is genuine zoning, but they share a compressor and on most systems cannot run in opposite modes at once — one room calling for heat while another calls for cooling. Where loads are genuinely opposed, separate single-zone systems are cleaner.
The line set, the condensate and the outdoor unit
The line set is the part of the job most likely to be done badly and the part you cannot inspect afterwards. Line length and vertical rise are limited by the manufacturer, and past certain lengths refrigerant must be added to the factory charge. Lines are brazed, pressure-tested, then evacuated with a vacuum pump to pull moisture and non-condensables out before the charge is released. A rushed evacuation gives you a system that works for two seasons and then does not.
Condensate is the other detail. A wall head produces water whenever it cools, draining by gravity through a line that must fall continuously to a legitimate discharge point. Where gravity is not available — a basement head, or a run that would have to climb — a lift pump is fitted, and it needs power and access for cleaning.
Outdoors the condenser goes on a pad or brackets, clear of snow shedding off the roof and raised out of melt water. A heat-pump-capable unit needs room underneath for defrost water to drain rather than ice up.
Commissioning is what decides how it runs
Heads are mounted, penetrations cored and sealed, and the system pressure-tested, evacuated and charged. Then the part that separates a working install from a correct one: operating pressures and superheat checked against specification, airflow and vane operation verified at each head, condensate flow confirmed, and both heating and cooling cycles run through. We show you the controller and how to wash the filters. Manufacturer warranties are written against the installation instructions, so those are followed as written.
Related services and booking
See also mini-split repair, all ductless services and whole-home HVAC.
Call (416) 283-5698 weekdays 8:00 AM to 4:00 PM, or send us the details. Licensed and insured, on Venture Drive in Scarborough since 1979. Financing is available through Vista.