Radiator for a heat pump: what you need to know

A heat pump heats your home differently from a traditional gas boiler. That has direct consequences for which radiator you choose. Not every model is compatible, and the choice affects both comfort and energy efficiency.

How does a heat pump work differently?

A gas boiler heats water to 70–90°C. A heat pump works at lower flow temperatures — typically 35–45°C for air-to-water systems, sometimes slightly higher for hybrid setups.

At lower flow temperatures, a radiator delivers less heat. To reach the same comfort level, you need a larger radiator surface, a more efficient material, or both.

Why aluminium performs better at low temperatures

Aluminium has a high thermal conductivity. That means it transfers heat from water to air more efficiently than steel at the same temperature. At low flow temperatures, this difference is noticeable: an aluminium radiator delivers more heat output than a comparable steel model at the same flow temperature.

All Heatnest radiators are made of 100% aluminium and are well suited to use with a heat pump.

Key points when selecting a radiator for a heat pump

1. Calculate heat output at low temperature

For heat pump installations, radiator output is calculated at the lower flow temperature (LT value). Make sure your installer runs calculations at 35°C or 45°C flow, not at the standard 75°C figure.

Use our product advice page for guidance on sizing.

2. Check existing radiators

If you are switching to a heat pump in an existing home, existing radiators are often too small. They were sized for high temperatures. A conversation with your installer is wise before proceeding.

3. Combination with underfloor heating

Underfloor heating and heat pumps are a natural match. In rooms without underfloor heating — bathrooms, bedrooms, studies — a well-sized aluminium radiator is the smartest supplement.

Electric element as a back-up or shoulder-season solution

In spring and autumn, you may only want to heat the bathroom. An electric heating element lets you run a radiator independently from the central system. Practical and energy-efficient for rooms you heat selectively.

Which Heatnest models suit a heat pump?

All Heatnest models are aluminium and therefore compatible with heat pumps. For larger rooms, pay attention to available heat output at low flow temperature.

Popular choices for heat pump homes:

• Nexo — horizontal, strong heat output at LT
• Libra — vertical, compact, suited for bathrooms with heat pump
• Pure — slim vertical model for narrow wall spaces

See all models on the products page or ask for advice.