Choosing the best location for a heat pump outdoor unit

What does the outdoor unit need around it?

A heat pump moves a large volume of air through its coil, so the outdoor unit needs open space on the intake and discharge sides. Walls, fences, shrubs and stacked firewood too close to it make the fan work harder, cut efficiency and capacity, and increase icing. The installation manual states the minimum clearance on each side and above the unit, and those figures are the ones to follow.

Leave room for service as well, because the whole heat pump system depends on it. A technician has to reach the panels, the electrical disconnect and the refrigerant connections, so a tight gap between the unit and a wall is a problem even when the airflow is fine. Avoid enclosures and decorative screens that trap air, and never place the unit in a closed crawl space or under a deck without ventilation.

How do snow and ice affect the location?

In Canada this is often the deciding factor. Snow that piles against the unit blocks airflow, and meltwater or roof runoff dripping onto it can freeze into ice. Pick a place away from eaves, roof valleys and anywhere snow slides off a slope. A raised stand or wall bracket keeps the coil above the usual snow line, and the height you need depends on how much snow your area gets.

A heat pump also drains water in winter during defrost. Make sure that water does not run across a walkway, a driveway or a step, where it can freeze into a slip hazard. Details of the cycle are in the guide to heat pump defrost and noise. For cold regions in general, the cold-climate heat pump guide adds more on winter operation.

Where should it go for noise and neighbours?

Keep the heat pump outdoor unit away from bedroom windows, indoor living areas, patios and the shared fence line when you can. Sound bounces off nearby walls and corners, so an inside corner makes a unit sound louder. A side yard that narrows between two houses can funnel noise to a neighbour's window. Our guide to heat pump noise levels and fixes explains the sound sources and quiet mounting methods.

Municipalities may require a minimum distance to the property line and limit sound at the boundary. Check the local bylaw, the permit requirements and, for a condominium, the rules of the corporation before you fix a position.

Does the distance to the indoor unit matter?

Yes. The refrigerant lines between the outdoor unit and the indoor unit have a maximum length and height difference set by the manufacturer. Longer runs cost more and can reduce performance, and lines that cross finished rooms add work. The location should also allow a clean route for the electrical supply and condensate drain.

Older houses may make the ideal spot hard to reach, with brick, narrow side yards or no basement access. The guide to heat pump installation in older homes covers those cases.

What should you check before the installer decides?

Walk the property with the installer and look at the candidate spot in winter terms: where does snow slide, where does water drip, which windows face it, and can you clear it easily? A short list helps.

• Clearance on every side, as stated in the manual.
• Distance to gas meters, vents and windows under local code.
• A stable, level pad or a bracket rated for the weight.
• A route for the drain water that does not freeze on a walkway.
• A clear path for service access.

Ask for the chosen location to be written into the quote, and compare it with other quotes using the heat pump quote guide.

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