Heat Pump Sizing 101: How Many BTUs Does Your Canadian Home Need?
Introduction
Installing a heat pump in Canada isn’t just about choosing the most efficient model—it’s about choosing the right size. An oversized unit wastes energy and money. An undersized one will struggle on the coldest days. So how do you find the perfect fit?
The answer lies in proper sizing—a mix of square footage, climate zone, insulation levels, and heat loss. In this guide, we’ll walk you through the essentials of sizing a heat pump for Canadian homes, using industry-standard BTU calculations and Natural Resources Canada (NRCan) guidance. Whether you’re heating a 600 sq. ft. condo or a 3,000 sq. ft. family home, we’ve got you covered.
What Does “Sizing” a Heat Pump Actually Mean?
Heat pumps are rated by BTUs (British Thermal Units) or tons of heating capacity. The goal is to match the system’s output to your home’s heat loss load—how much heat it loses on the coldest days.
Common Conversions
- 1 ton = 12,000 BTUs/hour.
- 1 kW = 3,412 BTUs/hour (for electric comparison).
Bigger isn’t always better. A heat pump that’s too powerful will cycle on and off too often, wearing out components and reducing efficiency.
General Sizing Guidelines by Square Footage
These estimates assume decent insulation and airtightness. Always get a pro load calculation for accuracy.
Heat Pump Sizing by Square Footage
| Home Size (sq. ft.) | Suggested BTUs | System Size |
|---|---|---|
| 600–900 | 12,000–18,000 | 1–1.5 ton |
| 1,000–1,400 | 18,000–24,000 | 1.5–2 ton |
| 1,500–2,000 | 24,000–30,000 | 2–2.5 ton |
| 2,000–2,500 | 30,000–36,000 | 2.5–3 ton |
| 2,500–3,000+ | 36,000–48,000+ | 3–4+ ton |
Example: A 1,800 sq. ft. home in Edmonton typically needs a 30,000–36,000 BTU cold-climate system to handle -25°C temperatures reliably.
How Climate Zone Affects Sizing
In Canada, your regional winter lows directly impact heat pump sizing.
Climate Zone Table
| Region | Winter Low (°C) | BTU Multiplier |
|---|---|---|
| BC (Lower Mainland) | -5 to -10 | 20–25 BTUs/sq. ft. |
| Ontario/Quebec | -15 to -25 | 25–35 BTUs/sq. ft. |
| Prairies | -25 to -35 | 35–45+ BTUs/sq. ft. |
| Atlantic | -10 to -25 | 25–35 BTUs/sq. ft. |
Cold-climate models are a must in zones below -20°C. They maintain higher output and efficiency without needing constant backup.
Ducted vs. Ductless: How It Affects Sizing
Ducted Systems
- Designed for whole-home heating.
- Requires load calculation for each zone (floor, room).
- Sizing needs to account for duct heat loss and airflow balancing.
Ductless (Mini-Splits)
- Zoned systems; sized per room.
- Great for additions, small homes, or retrofits.
- Easier to oversize if not careful.
Example: A 3-bedroom bungalow in Nova Scotia used three 9,000 BTU ductless heads—one per zone—for targeted, efficient heat.
What Else Influences Heat Pump Sizing?
Even two homes with the same square footage can need very different systems. Why?
Factors That Affect Sizing
- Insulation levels – Older homes with poor insulation need more BTUs.
- Window size and quality – Large or single-pane windows mean more heat loss.
- Air leakage – Drafty homes require larger systems.
- Ceiling height – More volume equals more heating demand.
- Solar gain – South-facing rooms might need less heat.
That’s why NRCan recommends using a certified energy advisor or HVAC pro to do a Manual J load calculation—the gold standard for sizing.
Conclusion
Getting the right-sized heat pump is key to staying warm and efficient through Canadian winters. Oversizing or guessing based on square footage alone can lead to higher costs and poor comfort. When in doubt, consult a pro—or use Solenery Insights to match your postal code, climate zone, and home details to the best-fit system.
