A heat pump works well when the whole heating system is designed around the needs of the home. That means understanding heat loss, choosing the right capacity, checking radiators and pipework, designing for appropriate flow temperatures, considering hot-water demand and commissioning the system properly.
A heat pump is an important part of the system.
But it is only one part.
On 21 October, organisations across Europe will mark Heat Pump Day — an opportunity to increase understanding of heat pump technology and recognise the people and expertise behind it.
There is plenty worth celebrating.
But for homeowners considering a heat pump, knowing that the technology works is only the beginning.
Because choosing a good heat pump doesn’t automatically create a comfortable home.
The experience you eventually have — how warm the house feels, whether there’s enough hot water, how often you need to adjust things and how efficiently the system operates — depends on decisions made long before the heat pump is switched on.
So this Heat Pump Day, we’d like to answer a slightly different question.
What actually makes a heat pump work well in a home?
A good heat pump system starts with understanding your home
It can be tempting to begin a heat pump conversation by asking which model you need.
We think there is a more important question to answer first:
What does your home actually need?
Every home loses heat differently.
Its size matters, but so do its construction, insulation, windows, ventilation and location. Individual rooms can have different heating requirements too.
Then there are the people living there.
How warm do you like your home? How much hot water does your household use? When are you normally at home? Are there rooms you use differently from others?
All of this matters because a heating system isn’t being designed for a number on a spreadsheet.
It’s being designed for a home.
A proper assessment should therefore build an understanding of the home’s heat loss, existing radiators or underfloor heating, likely operating temperatures, pipework, electrical capacity and hot-water requirements.
Only then can the system itself be properly considered.
This principle is reflected in UK heat pump design guidance too. MCS guidance uses building heat-loss calculations as part of correctly sizing and selecting a heat pump and the components around it.
For homeowners, the principle is simple:
The recommendation should follow the understanding of the home — not the other way around.
If a particular heat pump is being recommended, you should be able to understand why it is appropriate for your home.
Correct heat pump sizing matters more than simply choosing a bigger unit
Many homeowners replacing a boiler naturally look at its output and assume the new heating system needs a similar number of kilowatts.
But that isn’t how a heat pump should be selected.
The relevant question is how much heat the home actually needs under the conditions the system is being designed for.
That’s why heat-loss calculations matter.
They help establish the heating requirement of the home, which can then inform the size and design of the system.
More capacity isn’t automatically better simply because the number is bigger.
A good design is about selecting equipment appropriate to the home’s calculated requirements and considering how the complete system will operate.
We’ve seen this in our own projects.
In one recent Adlår installation, a 188m² home moving from gas heating was assessed through heat-loss-led system design. The resulting heating requirement led to the selection of a 6kW heat pump rather than simply using the output of the previous boiler as the starting point.
That’s the difference between replacing a product and designing a system.
Every recommendation should have a reason behind it.
Do you need new radiators for a heat pump?
This is one of the questions homeowners regularly ask when considering a heat pump.
The most useful answer is neither yes nor no.
It’s: they need to be assessed.
Radiators need to be capable of delivering enough heat to keep individual rooms comfortable at the temperatures the new system is designed to operate at.
In some homes, that may mean changing certain radiators.
In others, existing radiators may already be suitable.
The important thing is that somebody has worked it out rather than assumed the answer.
In the same Adlår project mentioned above, the existing radiators were assessed against the requirements of the home and ultimately retained. The completed heating design operated at a 35°C flow temperature without replacing them.
That doesn’t mean every home can do the same.
It means every home should be assessed individually.
So rather than simply asking whether heat pumps need new radiators, a better question might be:
“Has somebody checked whether my radiators can deliver the heat each room needs at the proposed operating temperature?”
That’s a much more useful conversation.
Why heat pump flow temperature matters
Once installed, a well-designed heating system shouldn’t demand constant attention.
You should be able to get on with living in your home.
One of the ways a heat pump can achieve this is by changing how it operates as conditions outside change.
When the weather becomes milder, your home generally needs less heat.
When temperatures fall, it needs more.
Rather than repeatedly asking the homeowner to intervene, the heating system can respond to those changing conditions by adjusting the temperature of the water flowing through the heating system.
This is known as weather compensation.
The engineering sounds technical.
The experience shouldn’t.
Ideally, what you notice is simply a home that remains consistently comfortable as the weather changes.
The temperature of the water flowing through the heating system — known as the flow temperature — matters for efficiency too.
Heat pumps generally operate more efficiently when they can meet the home’s heating needs without having to produce unnecessarily high water temperatures. That’s one reason the heat loss of the home and the capacity of its radiators or underfloor heating matter so much.
That doesn’t mean there is one flow temperature every home should use.
The appropriate operating conditions need to be designed around the individual property, its heating requirement and its heat emitters.
The goal isn’t to chase the lowest possible number.
The goal is to deliver the comfort the home needs without asking the system to work harder than necessary.
Hot water should be part of heat pump system design
There is another part of heat pump design that deserves more attention.
A homeowner doesn’t experience a heating system as separate engineering calculations.
They experience warm bedrooms on a cold morning.
A comfortable kitchen.
A hot shower.
Enough hot water when several people need it.
That means understanding hot-water demand should be part of understanding the home from the beginning.
Household size, routines and expected hot-water use can all influence the design.
The right answer won’t necessarily be the same for a couple living in a small home and a family where several showers, baths and other hot-water demands can happen within a short period.
This is why we believe heating and hot water should be considered as parts of one complete home-heating experience.
The technology exists to serve the people living in the home.
Not the other way around.
Why heat pump commissioning matters
There is an important distinction between a heat pump being installed and a complete heating system being ready to perform as intended.
That’s where commissioning comes in.
Commissioning is the process of checking that the different parts of the system are working together correctly and that its settings reflect the home it was designed to serve.
The homeowner shouldn’t need to become a heating engineer to benefit from this.
Think of it as careful tuning.
The system has been designed and installed. Commissioning helps translate that design into the way the system actually operates in the home.
And that thinking doesn’t necessarily need to stop on installation day.
Weather changes. Seasons change. Families’ routines change. And once a system is operating in the real home, there can be opportunities to understand its performance more closely and refine how it responds.
At Adlår, this is why we think about home heating beyond installation.
Monitoring can help our engineers understand how a system is behaving. Optimisation can then help refine settings where appropriate, supporting comfort and performance throughout ownership.
The technology stays in the background.
The homeowner should simply feel looked after.
Good engineering should eventually become invisible
There is a lot of technology involved in a modern heat pump system.
Compressors.
Sensors.
Controls.
Flow temperatures.
Heat curves.
Weather compensation.
Performance data.
But homeowners shouldn’t have to spend their lives thinking about any of them.
The purpose of all that engineering is something much simpler.
A warm home.
Reliable hot water.
Comfort through changing weather.
Confidence when winter arrives.
And eventually, perhaps the best outcome of all:
You stop thinking about your heating because it simply does its job.
That’s what good home heating should feel like.
Seven questions to ask a heat pump installer before choosing your system
If you’re considering a heat pump, you don’t need to become an expert in heating-system design.
But asking better questions can help you understand the thinking behind the system you’re being offered.
How will you calculate how much heat my home actually needs?
Ask how the heating requirement will be established and whether this includes a room-by-room heat-loss assessment.
How will you determine whether my existing radiators are suitable?
The answer shouldn’t automatically be “keep them” or “replace them”. Their suitability should be assessed against the requirements of each room and the proposed system design.
What operating temperature is the system being designed around?
You don’t need to specify the temperature yourself. Ask the installer to explain the proposed design and why it is appropriate for your home.
How have you accounted for our hot-water requirements?
Explain how your household actually uses hot water and ask how that has influenced the design.
How will the heating respond as the weather changes?
Ask how controls such as weather compensation will help the system adapt to changing outdoor conditions.
What happens during commissioning?
Ask how the installer will check that the complete system is operating as intended once installation is complete.
What happens after the installation?
Understand what support is available once you’re living with the system, particularly if settings need refining or you have questions during your first heating season.
None of these questions requires you to understand the engineering yourself.
That’s the point.
A good conversation should help you understand why decisions have been made without expecting you to become an engineer.
Frequently asked questions
What makes a heat pump efficient?
A heat pump’s efficiency depends on more than the unit itself. The heating requirement of the home, system design, flow temperature, radiators or underfloor heating, controls, outside conditions and the way the system is commissioned and operated can all influence real-world performance.
That’s why efficiency should be considered as an outcome of the complete system rather than simply a characteristic of the heat pump.
Do I need to replace my radiators when installing a heat pump?
Not necessarily.
Existing radiators should be assessed against the amount of heat each room requires and the temperatures the new heating system is designed to operate at. Some may already be suitable; others may need changing.
The important thing is to calculate rather than assume.
Why does flow temperature matter with a heat pump?
Flow temperature is the temperature of the water being supplied to your heating system.
Heat pumps generally operate more efficiently when they can meet the home’s heating needs at lower flow temperatures. The appropriate temperature, however, depends on the property, its heat loss and the radiators or underfloor heating being used.
What should I ask a heat pump installer?
Start by asking how your home’s heating requirement has been calculated, why a particular heat pump has been selected, whether your existing radiators have been assessed, what flow temperature the system is designed around, how hot-water demand has been considered, how the system will be commissioned and what support is available afterwards.
You don’t need to know the right technical answer yourself.
A good installer should be able to explain the reasoning behind the design clearly.
Better heat pump decisions start with better questions
Heat Pump Day rightly puts the technology in the spotlight.
But perhaps one of the most useful things we can do with that attention is raise the standard of the conversation around it.
The heat pump matters.
So does understanding the home.
So does system design.
So do the radiators.
So does hot water.
So do controls, commissioning and what happens after installation.
Because ultimately, homeowners aren’t choosing a heat pump for the sake of owning a heat pump.
They’re choosing how their home will feel on an ordinary Tuesday morning in January.
So if you’re considering making the change, don’t only ask:
“Which heat pump are you recommending?”
Ask:
“How has this heating system been designed around my home?”
The answer will tell you much more.
Considering a heat pump for your home?
At Adlår, our process begins with understanding the property and the people who live in it before recommending a system. Explore what happens during an Adlår home survey and why those details matter when designing heating around your home.
