When we bring up heat pumps with SD&G homeowners, one of the first reactions is protective: "I'm not ripping out a furnace that works fine." Good news — you usually don't have to. The setup that keeps your furnace and adds a heat pump is called a dual-fuel or hybrid system, and for a lot of homes around here it's the smartest way to go.
Here's how it works, why it fits Eastern Ontario so well, and who it's actually right for.
What "dual-fuel" actually means
A dual-fuel system is exactly what it sounds like: an electric heat pump and a fuel-burning furnace (propane, natural gas, or oil), working as one system under one control.
The heat pump handles heating and cooling for most of the year. When the outdoor temperature drops to a point you set, the system automatically shuts the heat pump down and switches to the furnace for the coldest stretches. You don't touch anything — the changeover is automatic, and you often won't even notice it happen.
It replaces your air conditioner (the heat pump does cooling too) and takes over the bulk of your heating, while your furnace becomes a backup that only runs on the coldest days.
How the changeover decides which system runs
The handoff happens at what's called the changeover point (or balance point) — an outdoor temperature threshold programmed into the controls. Above it, the heat pump runs because it's cheaper and more efficient. Below it, the furnace runs because it makes more heat per dollar in deep cold.
Where that line sits depends on two things: the point where your heat pump can no longer keep up with your home's heat loss, and the point where furnace fuel becomes cheaper to run than electric heat. We set it for your specific home, your equipment, and your energy prices — and we can adjust it if propane or hydro rates shift.
Why this fits SD&G so well
Dual-fuel makes particular sense in our area for a few reasons:
- You already own the backup. Most homes here already have a ducted furnace. Adding a heat pump to an existing furnace is often a smaller job — and a smaller bill — than a full all-electric system with electric backup heat.
- It hedges energy prices. Propane and oil prices swing; hydro rates change. A dual-fuel system automatically runs whichever source is cheaper at a given temperature, so you're never fully exposed to one fuel spiking.
- It's easy on the coldest nights. Our design temperature runs to roughly -25°C. On those few brutal nights, the furnace simply takes over — no electric strips straining, no wondering whether the heat pump can keep up. (We get into that in our piece on whether heat pumps handle -25°C.)
- Propane homes save the most. If you're heating with propane, running an efficient heat pump for most of the season instead of burning propane can meaningfully cut your heating cost. That's where we see the biggest wins.
Who should consider dual-fuel
It tends to be the right call if:
- You have a relatively new furnace you're not ready to replace — keep it, add a heat pump, and get cooling plus lower heating bills without wasting good equipment.
- You heat with propane or oil and want to cut fuel costs without losing your cold-night safety net.
- Your home is already ducted, so adding a central heat pump is straightforward.
- You want lower emissions and lower operating cost but aren't ready to go fully electric in this climate yet.
Who might skip it
Dual-fuel isn't for everyone:
- If your furnace is already at end of life, it may make more sense to look at a full cold-climate heat pump with electric backup, or to replace the furnace as part of the project.
- If you don't have ductwork, a ductless mini-split setup is usually the better path.
- If you're already all-electric (baseboards, for example), there's no furnace to keep, so the comparison is different.
What about maintenance?
A dual-fuel system has two heating components, so there's a bit more to look after — but not double the work. The heat pump gets serviced like an AC plus a heating check, and the furnace gets its normal inspection. Most owners fold both into a single annual visit. If you're on a maintenance plan, we cover both in your scheduled service.
The bottom line
Going to a heat pump doesn't mean throwing out a perfectly good furnace. For a lot of SD&G homes — especially propane-heated, already-ducted ones — keeping the furnace as an automatic backup and letting an efficient heat pump carry the rest of the year is the lowest-risk, often lowest-cost way to make the switch.
If you want to know whether dual-fuel makes sense for your home, call us at (613) 363-9011 or request a free quote. We'll look at your existing furnace, your ducts, and your energy bills, and give you an honest recommendation — including telling you if you're better off with a different setup. See our heat pump and furnace installation pages for more.