Propane versus natural gas furnaces in BC

Natural gas is mostly methane, delivered by utility mains at low pressure, and priced per gigajoule by FortisBC in BC. Propane is a liquefied petroleum gas delivered by truck to a tank on the property, with about 2.5 times the energy per unit volume of natural gas, priced per litre. A furnace is configured for one fuel: the gas valve, orifices and pressure settings differ, and the manufacturer's product data states the configuration and its conversion path.

Heating values and pressures are why conversion is a kit-and-commission job, not an adjustment: the manufacturer's kit changes the components, the licensed gas fitter sets the pressures to the kit's figures, and the input rate is verified by meter or tank clocking.

Most Lower Mainland homes sit on FortisBC's natural gas network, which makes natural gas the default and usually the cheaper fuel per useful energy. Homes beyond the mains — rural properties, islands, some eastern valley acreages — use propane, delivered and stored on site, often with higher per-gigajoule cost and the logistics of tank supply.

The fuel decision is therefore usually settled by location first and price second. Where both are possible, the comparison belongs in a consultation with current delivered prices for both fuels.

Converting a furnace between natural gas and propane requires the manufacturer's listed conversion kit for the exact model number, installation of the kit, pressure set-up per the kit's instructions, input-rate verification and combustion analysis, all under a gas permit. This site's fuel-conversion service page documents the scope; the model pages state each furnace's fuel position and conversion accessory from the product data.

Field-fabricated conversions without a manufacturer kit are not performed: the appliance's certified configuration depends on the kit.

The cost comparison is per useful gigajoule delivered: natural gas at FortisBC's current residential rate versus propane at the delivered price per litre, accounting for the furnace's certified AFUE. Propane prices vary with delivery and contract terms, which is why the comparison uses current quotes rather than national averages.

Propane installations add the tank, its siting rules and the regulator set-up, which are separate from the furnace and its permit. The tank company and the gas fitter each have their scope, and the handoff between them is part of a clean installation.