1. What is Heat Pump Sizing?

Heat pump sizing calculates the appropriate capacity (in BTU) needed to efficiently heat or cool a space in New Zealand homes. Proper sizing ensures energy efficiency, comfort, and system longevity.

2. How Does the Calculator Work?

The calculator uses the basic heat pump sizing formula:

Where:

• \( Area \) — Floor area in square feet
• \( Factor \) — BTU per square foot (typically 20-40 for NZ conditions)
• \( Insulation\ Adjustment \) — Multiplier based on insulation quality (0.8 for well-insulated, 1.2 for poorly insulated)

Explanation: The calculation accounts for the space size, local climate factors, and the building's thermal efficiency.

3. Importance of Correct Sizing

Details: An undersized heat pump will struggle to maintain temperature, while an oversized one will short-cycle, reducing efficiency and lifespan. Proper sizing is crucial for New Zealand's variable climate.

4. Using the Calculator

Tips:

• Measure your room's floor area accurately
• Use 30 BTU/sq ft for most NZ homes (20 for warmer regions, 40 for colder areas)
• Choose 0.8 for modern, well-insulated homes; 1.0 for average; 1.2 for older, poorly insulated buildings

5. Frequently Asked Questions (FAQ)

Q1: Why is sizing important for NZ homes?
A: New Zealand's climate varies significantly by region, and many homes have different insulation standards, making accurate sizing crucial.

Q2: What's the difference between BTU and kW ratings?
A: 1 kW ≈ 3412 BTU. Many NZ heat pumps show both ratings - this calculator provides BTU for compatibility with sizing charts.

Q3: Should I round up the calculated size?
A: Choose the nearest available model size, but avoid going more than 15% over the calculated requirement.

Q4: Does ceiling height affect sizing?
A: Yes, for ceilings over 2.7m, add 10% per additional 0.3m to the calculated BTU requirement.

Q5: What about open-plan areas?
A: For open-plan living areas, calculate the entire space as one zone and consider higher airflow models.