1. What is Heat Pump Sizing?

Heat pump sizing calculates the required heating capacity (in kW) for a home based on floor area and heat loss characteristics. Proper sizing is crucial for efficiency and performance in UK homes.

2. How Does the Calculator Work?

The calculator uses the standard sizing formula:

Where:

• \( Area \) — Total floor area in square meters
• \( Factor \) — Heat loss factor (typically 50-100 W/m²)
• \( kW \) — Required heat pump capacity in kilowatts

Explanation: The formula estimates the heat energy needed to maintain comfortable temperatures based on your home's size and insulation quality.

3. Importance of Correct Sizing

Details: An undersized heat pump will struggle to heat your home, while an oversized one will cycle on/off too frequently, reducing efficiency and lifespan.

4. Using the Calculator

Tips:

• Measure your home's total heated floor area
• Choose heat loss factor: 50 for well-insulated, 70 for average, 100 for poorly insulated homes
• The result indicates the approximate heat pump capacity needed

5. Frequently Asked Questions (FAQ)

Q1: What heat loss factor should I use?
A: 50 W/m² for new builds/passivhaus, 70 for average insulation, 80-100 for older properties with poor insulation.

Q2: Does this account for hot water needs?
A: No, this calculates space heating only. Add 1-2 kW if the heat pump will also provide domestic hot water.

Q3: Should I round up the result?
A: Heat pumps come in standard sizes (e.g., 5kW, 8kW, 11kW). Choose the next available size above your calculation.

Q4: What about climate variations in the UK?
A: This calculation already accounts for typical UK climate conditions in the heat loss factors.

Q5: Should I get a professional assessment?
A: Yes, this calculator provides an estimate only. Always consult with an MCS-certified installer for accurate sizing.