Air Source Heat Pump Size Calculator

BTU Calculation Formula:

\[ BTU = Area \times Factor \times Insulation\ Adjustment \]

Area:

sq ft

BTU Factor:

BTU/sq ft

Insulation Adjustment:

Recommended Heat Pump Size:

Unit Converter ▲

Unit Converter ▼

From:	To:

1. What is the BTU Calculation?

The BTU (British Thermal Unit) calculation estimates the required capacity of an air source heat pump based on the area to be heated/cooled, climate factor, and insulation quality. Proper sizing is crucial for efficiency and performance.

2. How Does the Calculator Work?

The calculator uses the BTU formula:

\[ BTU = Area \times Factor \times Insulation\ Adjustment \]

Where:

\( Area \) — Square footage of the space (sq ft)
\( Factor \) — BTU per square foot (typically 20-40 BTU/sq ft depending on climate)
\( Insulation\ Adjustment \) — Multiplier based on insulation quality (0.8-1.2)

Explanation: The calculation accounts for the size of the space, local climate conditions (through the factor), and the building's insulation quality.

3. Importance of Proper Sizing

Details: Correct heat pump sizing is essential for energy efficiency, comfort, and system longevity. An oversized unit will short-cycle, while an undersized one will struggle to maintain temperature.

4. Using the Calculator

Tips:

Measure your space accurately in square feet
Use higher BTU factors (30-40) for colder climates
Select insulation adjustment based on your building's insulation quality
Consider professional assessment for complex spaces

5. Frequently Asked Questions (FAQ)

Q1: What's the typical BTU factor range?
A: 20-40 BTU/sq ft. Use 20-25 for mild climates, 30-35 for moderate, and 35-40 for cold climates.

Q2: How do I determine my insulation quality?
A: Poor insulation (1.2): older homes with minimal insulation. Average (1.0): standard insulation. Excellent (0.8): well-insulated modern homes.

Q3: Should I round up the calculated size?
A: Heat pumps come in standard sizes. Choose the next available size if your calculation falls between standard units.

Q4: Does ceiling height affect the calculation?
A: Yes, for ceilings over 8 feet, increase the area proportionally (e.g., 10 ft ceilings = area × 1.25).

Q5: What about windows and sun exposure?
A: Large windows or significant sun exposure may require adjustments. South-facing rooms may need 10% more capacity.