Upgrading your home's heat pump can be confusing when faced with technical terms like "BTU" and "tons." This guide will help you understand heat pump capacity measurements and their conversions, making your purchasing decisions and rebate applications much easier.
Heat pump cooling or heating capacity is typically measured in either "tons" or BTUs (British Thermal Units). The "ton" measurement is more commonly used in the HVAC industry, while BTU represents a more fundamental unit of heat energy - specifically, the amount of heat required to raise one pound of water by one degree Fahrenheit.
The key conversion to remember is that 1 ton of cooling capacity equals 12,000 BTU per hour. This means:
1 ton = 12,000 BTU/hour ≈ 3.5 kW (kilowatts)
Residential heat pumps generally range from 1 to 5 tons in capacity. Selecting the right size depends on multiple factors including home square footage, insulation quality, and local climate conditions. An undersized unit won't adequately heat or cool your home, while an oversized unit will waste energy.
Many government rebate programs, such as Canada's CleanBC Better Homes and Home Renovation Rebate Program, require heat pump invoices to clearly specify capacity in either tons or BTUs. If your invoice only lists BTUs, you'll need to convert to tons to qualify for rebates.
Convert BTUs to tons using this straightforward equation:
Tonnage = BTU value ÷ 12,000 BTU/ton
For example, a 24,000 BTU heat pump converts to:
24,000 ÷ 12,000 = 2 tons
Here's a quick reference table for common conversions:
| BTU | Tonnage |
|---|---|
| 12,000 | 1 ton |
| 18,000 | 1.5 tons |
| 24,000 | 2 tons |
| 30,000 | 2.5 tons |
| 36,000 | 3 tons |
| 48,000 | 4 tons |
| 60,000 | 5 tons |
If your heat pump invoice doesn't specify capacity in either unit, contact your installation contractor immediately. Updated documentation showing heating capacity is required for rebate applications.
For accurate sizing, consult an HVAC professional who can perform detailed calculations based on your specific circumstances.
Beyond capacity, consider these key efficiency metrics:
SEER (Seasonal Energy Efficiency Ratio) measures cooling efficiency
HSPF (Heating Seasonal Performance Factor) measures heating efficiency
Higher SEER and HSPF numbers indicate greater efficiency and lower operating costs. While more efficient models may cost more initially, they typically save money long-term through reduced energy bills.