1. What is a Heat Pump Radiator Calculator?

Definition: This calculator estimates the actual heat output of radiators when used with low-temperature heat pump systems.

Purpose: It helps HVAC professionals and homeowners properly size radiators for efficient heat pump operation.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• Output — Actual heat output (Watts)
• Nominal — Rated output at ΔT=50K (Watts)
• ΔT — Temperature difference between water and room (Kelvin)
• n — Radiator exponent (typically ~1.3)

Explanation: The formula adjusts the nominal output for lower temperature differences typical in heat pump systems.

3. Importance of Radiator Calculation

Details: Proper radiator sizing ensures efficient heat pump operation, comfort, and prevents short cycling or insufficient heating.

4. Using the Calculator

Tips: Enter the radiator's nominal output, the actual ΔT (typically 30-40K for heat pumps), and exponent (default 1.3). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: Why is this calculation important for heat pumps?
A: Heat pumps operate at lower temperatures than boilers, so radiators deliver less heat than their nominal rating.

Q2: What's a typical ΔT for heat pump systems?
A: Typically 30-40K compared to 50K for conventional boilers.

Q3: Where do I find the nominal output and exponent?
A: These values are provided by the radiator manufacturer in product specifications.

Q4: What if I have underfloor heating instead?
A: This calculator is for radiators. Underfloor systems use different calculations due to larger surface areas.

Q5: Should I oversize radiators for heat pumps?
A: Generally yes - larger radiators compensate for lower output at reduced temperatures.