Heat Pump Size Formula:
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Definition: This calculator determines the appropriate size (in tons) of an AC heat pump needed based on your cooling load and the system's SEER rating.
Purpose: Helps homeowners and HVAC professionals properly size heat pump systems for optimal efficiency and performance.
The calculator uses the formula:
Where:
Explanation: The cooling load is divided by the SEER rating (adjusted for unit conversion) to determine the required system size.
Details: Correctly sized heat pumps operate more efficiently, provide better comfort, and have longer lifespans. Oversized units short-cycle while undersized units run constantly.
Tips: Enter your building's cooling load in BTU/h and the SEER rating of the system you're considering (default 16). All values must be > 0.
Q1: How do I find my cooling load?
A: Professional Manual J calculations are most accurate, or use our Cooling Load Calculator tool.
Q2: What's a typical SEER rating?
A: Standard efficiency is 14-16 SEER, high efficiency is 18-20 SEER, and premium units go up to 26 SEER.
Q3: Why is size in tons?
A: HVAC capacity is traditionally measured in tons (12,000 BTU/h = 1 ton), dating from when ice was used for cooling.
Q4: Does this work for heating too?
A: Heat pump heating capacity is related but uses HSPF rating. Use our Heat Pump Heating Calculator for heating needs.
Q5: Should I round up the calculated size?
A: Round to nearest standard size (0.5 ton increments), but consult an HVAC professional for final sizing.