Fitting a Heat Pump to an Older Canadian Home

Should insulation and air sealing come first?

Often, yes, or at least in parallel. A leaky house needs a larger heat pump, and a larger heat pump costs more to buy and run. Sealing the attic hatch, rim joists and window gaps, then topping up attic insulation, can cut the load enough to change the equipment size. The sequence is covered in insulation upgrade priorities, and a home energy audit gives a measured starting point.

Ask the contractor for a heat loss calculation after upgrades, not before. See why the load calculation matters.

Can the existing ducts handle a heat pump?

Heat pumps deliver warm air at lower supply temperatures than a gas furnace, so they usually move more air to deliver the same heat. Older ducts are often too small, leaky or poorly balanced for that. Signs to watch: whistling registers, rooms far from the furnace that never warm up, tape-patched joints and a return that is a single grille in a hallway.

Ask the installer to measure static pressure and check duct sizes against the airflow the system needs. If the ducts will not work, alternatives include ductless indoor units, partial duct upgrades or a hybrid arrangement. Compare these on the same page when you compare quotes.

What if the house uses radiators or baseboards?

Radiator houses can work with air-to-water heat pumps or with ductless units serving key rooms, but hot-water radiators sized for 70 degree water may struggle at lower temperatures. The low-temperature hydronic heating guide explains the trade-off. Dlsc.ca's district heating page shows the same idea at neighbourhood scale: the Drake Landing loop ran at roughly 40 to 50 degrees Celsius because the homes were built to need little heat.

Do not assume radiators must be replaced. A heat loss calculation per room shows which ones are adequate at lower water temperature.

Is the electrical panel up to it?

A heat pump needs its own breaker, and some installs also need a larger service. Older homes may have 60 or 100 amp service, fused panels or little spare room. Ask for an electrician's assessment, or a load calculation covering the whole house, before you commit. Costs for upgrades vary by region and utility, so request a written number.

Also ask about the outdoor unit: clearance from walls and windows, snow and ice drainage, vibration and noise near neighbours. See heat pump defrost and noise for what to expect.

What should an older-home quote spell out?

• The heat loss figure and the assumptions behind it.
• The condition of the existing duct or hydronic system and what is being changed.
• Backup heat plan for the coldest nights.
• Panel capacity findings and any electrical upgrade, with cost.
• Where the outdoor unit goes and how condensate is drained.
• Permits, commissioning tests and warranty terms.

A quote that says only "supply and install one heat pump" skips the hard parts of an old house.

How long does a retrofit take and what disrupts the house?

A straightforward ducted swap may take a day or two. Jobs that include duct changes, a panel upgrade, new radiators or an outdoor unit on a wall bracket can stretch to several days across different trades. Ask for a sequence in writing: who does the electrical work, when the inspections are booked and when the heating is off.

Plan around the season as well. Installers are busiest just before winter, and a retrofit started in the cold with the old system removed leaves little margin. Many homeowners schedule the survey and quotes in spring or summer, so insulation work, permits and any incentive paperwork are settled before the heating season begins.

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