Heat Pump Cooling
The same pump that heats you in winter cools you in summer.
An air-to-water heat pump isn’t just for heating. Flip it into cooling mode and it gently chills your home through the very same underfloor loops and fan coils — whisper quiet, whole-home, and astonishingly cheap to run. No noisy wall boxes, no separate air-conditioner.
7.5
Real cooling COP*
1 unit
Heats & cools
Silent
No fans indoors
Whole home
Room by room
*Measured on a real monitored UK system — see the live results below.
The concept
Cooling is heating, played backwards
People are often surprised that the box on their wall can cool as well as heat. But a heat pump never really “makes” hot or cold — it just moves heat from one place to another. Reverse the direction and you have air conditioning built into your heating system.
It simply runs in reverse
A four-way reversing valve flips the refrigerant flow. In winter the unit pulls heat from the outdoor air into your home; in summer it does the opposite — pulling heat out of your rooms and rejecting it outside. Nothing else changes.
Chilled water, not cold blasts
Instead of blowing chilled air at you, the system circulates gently chilled water (around 16–18°C) through your existing wet emitters. The cool comes off large surfaces, so it feels like walking into a naturally cool stone building — even, silent and draught-free.
A free summer bonus
If your heat pump and emitters are cooling-capable, active cooling is effectively a bonus function of the kit you already installed for heating. One machine earns its keep all year round instead of sitting idle through summer.
The science, reversed
How a heat pump cools your home
A heat pump doesn’t make cold any more than it makes heat — it simply moves heat the other way. Flip it into cooling mode and the exact same sealed loop lifts warmth out of your rooms and rejects it outdoors. Watch the reversed cycle below.
Stage 01
Indoor emitter
Cool water is pushed through your underfloor loops or fan coils. Warm room air gives up its heat to that cool water — exactly the reverse of a radiator. The refrigerant behind it boils and carries that unwanted heat away. Your rooms quietly lose their warmth without a single blast of cold air.
One machine, two jobs — a reversing valve is all it takes to switch from winter heating to summer cooling.
How we achieve it
Getting cooling right is all in the design
Cooling with water is wonderful when it’s engineered properly — and risky when it’s not. It comes down to two things: choosing the right emitters, and rigorously controlling condensation. Here is how we do both.
The quiet all-rounder
Underfloor cooling
Chilled water runs through the same underfloor loops that heat you in winter. The entire floor becomes a huge, silent cooling surface that gently pulls the heat down out of the room. The monitored systems doing the most cooling in the UK are almost all underfloor — it is the most comfortable and efficient route.
The golden rule: never cool below the dew point
The one real risk with water cooling is condensation — if a surface gets colder than the dew point of the room air, moisture forms on it. We design that risk out. The chilled-water flow temperature is held safely above the dew point, humidity and surface sensors trim the system in real time, and fan coils handle any room that needs genuine dehumidification. It’s exactly the careful, monitored approach the best UK installers use — comfort with zero damp floors or dripping pipes.
The proof — real monitored data
What cooling actually delivers, measured
This isn’t theory. Right now, dozens of UK air-to-water systems are publicly sharing their cooling performance on open monitoring platforms. One example — a 6.5 kW air-to-water heat pump in Potters Bar, London — recorded these figures over a summer monitoring window.
7.53
Cooling COP
units of cooling per unit of electricity
31
UK systems
publicly sharing live cooling data
~6.5kW
Monitored unit
a normal domestic air-to-water heat pump
Whole home
Coverage
cooling delivered through the wet system
One machine, three jobs — measured efficiency (COP)
A cooling COP of 7.5 means the system moved 7.5 units of heat out of the home for every single unit of electricity it used — dramatically more efficient than a typical plug-in or split air-conditioner. Space-heating and hot-water figures from the same unit are shown for context.
Head to head
Heat-pump cooling vs traditional air conditioning
Traditional air conditioning bolts a separate system onto your home, with a cassette on every wall blowing chilled air. Heat-pump cooling reuses the heating system you already have. Here’s how they compare — honestly, including where a split system still wins.
The honest verdict: for whole-home, silent, efficient comfort that you already half-own through your heating system, water cooling is superb. If you need instant, single-room spot cooling or heavy dehumidification in a humid space, a fan coil — or occasionally a dedicated split — is the right tool. We’ll always tell you which suits your home.
Cool in summer, warm in winter
Want a home that’s comfortable all year?
Book your heat-loss survey for £250 — fully refundable when you go ahead. We’ll design a system that heats beautifully in winter and, where your home suits it, quietly cools you through summer too.