Why Dual Fuel Heat Pumps Need Proper Sizing in the Lower Mainland

Sizing starts with the home, not a rule of thumb

For the announced dual-fuel rebate, the existing primary gas furnace must be at least 15 years old.

A dual-fuel heat pump and furnace must be planned as one heating system. The announced FortisBC dual-fuel requirements call for a CSA P280-12 heat-load calculation. That calculation helps the contractor size the equipment for the home rather than selecting it from square footage alone.

Why the matched AHRI reference matters

The qualifying reference must cover the outdoor heat-pump unit, indoor unit and furnace model together. A compatible-looking collection of components is not the same as an AHRI-certified matched system. Confirm the reference before equipment is ordered.

Lower Mainland switchover setting

For the announced rebate, the maximum switchover temperature is 5°C or lower in the Lower Mainland and Vancouver Island. The control setting determines when the system changes from heat-pump heating to furnace heating. The contractor should record the intended setting during commissioning.

Records that support a rebate application

• CSA P280-12 heat-load calculation and supporting information.
• AHRI-certified matched-system reference.
• Equipment, invoice and installation details.
• DSMAlly commissioning records and required photos.
• Any current FortisBC forms or documentation requested for the application.

FortisBC announced residential dual-fuel support up to $4,000 and income-qualified support up to $8,000 for eligible installations after October 15, 2026. A correct size does not itself guarantee a rebate.

Explore heat pump services, heat pump installation, heat pump installation in Surrey, or use the rebate tool to organize your project questions.

Program information can change. Review the current FortisBC rebates page and the FortisBC income-qualification-code information before buying equipment or relying on an amount.