Many modern air source heat pumps can provide cooling as well as heating, but turning it on isn't always as simple as flipping a setting. Here's what actually determines whether it will work well, or at all.

How Heat Pump Cooling Works

A reversible heat pump can run in two directions. In winter, it moves heat from outside into your home. In summer, it reverses the cycle and removes heat from inside, transferring it back outdoors, effectively cooling your home using the same unit you already have.

Not Every Heat Pump Supports It

Some units are cooling-capable straight from the factory, while others are heating-only by design. Even where the heat pump itself supports cooling, the rest of the system, controls, pipework, and emitters, also needs to be assessed.

Why Your Emitters Matter

Underfloor heating can provide gentle whole-house cooling, but only if the floor temperature stays above the dew point to prevent condensation. Fan coil units are purpose-built for both heating and cooling and generally perform best. Standard radiators without fans typically offer very limited cooling benefit.

The Condensation Risk

This is the part most commonly overlooked. Cooling surfaces can cause moisture in the air to condense onto pipework, manifolds, or floors if the system isn't properly protected, which can lead to hidden damage inside walls or floors over time.

What a Proper Cooling Design Accounts For

A safe, effective cooling setup needs to consider indoor humidity, dew point calculations, flow temperatures, pipe insulation, control strategy, suitable emitters, and heat pump compatibility, not just whether the unit itself "does cooling."

Cooling vs. Air Conditioning on Cost

Because a reversible heat pump uses equipment you already own, adding cooling is typically far cheaper than installing a separate air conditioning system, no second outdoor unit, no separate refrigerant circuit, and no additional standing electricity draw.

If you're considering switching cooling on, or planning a new system and want cooling built in from the start, getting the design properly assessed first is the difference between a comfortable summer and an expensive condensation problem later.