The Myth of the Room Thermostat: Why It’s Failing Your Heat Pump
Heat pumps are rapidly becoming the go-to solution for low-carbon heating. But even the best heat pump will almost certainly, fall short—not because of the unit itself, but because it’s being controlled by outdated thinking. The heart of that problem?
The humble room thermostat!
It might be smart. It might be wireless. But if your entire heat pump system is being switched on or off based on the temperature in just one room, you're missing the point—and likely missing out on serious efficiency and comfort.
Why Single-Room Control Doesn't Work with Heat Pumps
Most thermostats - smart or not - are designed to monitor just one location. That’s usually the hallway, or sometimes the living room. When that one space hits temperature, the heat pump shuts off. Sounds sensible, right?
Wrong.
Here's what happens:
That one room may heat up quickly (especially if it gets sun, or has larger radiators versus heat loss compared to other rooms).
Meanwhile, other rooms remain cold - bedrooms, north-facing rooms, poorly balanced system or those with larger heat losses/smaller radiators (in comparison).
The system cycles on and off, trying to chase an average that doesn’t exist.
Homeowners bump up the flow temperature or leave doors open, chasing comfort.
Efficiency drops. Comfort suffers. Bills go up.
This might have worked with gas boilers that blast heat into a system. But with heat pumps - especially ones designed to run low and slow - it's a recipe for disaster.
What About Multiple Room Thermostats?
Some systems try to fix this by putting thermostats in multiple rooms, each one capable of switching the heat pump on or off when its room is calling for heat.
At first glance, this seems better - but in practice, it often creates chaos.
Here's why it fails:
Each room acts independently, without awareness of what others are doing.
The heat pump keeps starting and stopping in short cycles - every time any room drops slightly below its setpoint.
This constant on/off cycling reduces efficiency and wears out the compressor prematurely.
The system never achieves a stable flow temperature or operates smoothly in weather compensation mode.
In colder weather, the flow temperature often gets set too high “just to be safe,” again undermining the whole point of a heat pump.
In short, multi-zone thermostats that each control the heat pump turn a sophisticated system into a chaotic one. You get no coordination, no balance, and no optimisation.
The Problem Isn’t the Thermostat — It’s the Logic
Today’s market is flooded with so-called “smart” thermostats. They offer Wi-Fi control, geofencing, learning schedules... but nearly all of them are either:
Single-point systems (failing to see the whole picture), or
Multi-point triggers (failing to coordinate or optimise heat delivery)
Either way, the heat pump is reacting, not thinking. And your comfort, efficiency, and energy bills suffer as a result.
The Better Way: Room-by-Room Intelligence
To make a heat pump work as promised, you need coordinated, dynamic control - the ability to see what’s happening in each room and adjust everything together.
That’s where COP Angel comes in.
Our patented system uses:
· Motorised radiator valves with built-in room sensors
· Return water temperature sensors on every radiator (or uf zone)
· Dynamic control algorithms that constantly adjust the flow temperature
· Room-by-room data to prioritise underperforming spaces—not just one hallway or rogue thermostat
This allows the system to operate in its sweet spot, avoid short cycling, and keep all rooms comfortable at the lowest possible flow temperature—exactly where heat pumps perform at their best.
Smarter Control = Lower Bills + Greater Comfort
With COP Angel, your system learns how each room behaves and balances heat delivery automatically. The result?
Better comfort in every room
Lower energy bills
Longer life for your heat pump
Fewer call-backs and complaints for installers
We are currently developing the solution and have proved concept via digital twin. We hold the UK patent and have international patent pending. If you are interested in investing in this game changing solution get in touch with the inventor here mike.kellett@copangel.com