A listed home in Marlow might not be the first place you picture a heat pump.
Solid-brick walls. Limited roof insulation. An EPC rating of E.
For many homeowners, those details can make the conversation feel over before it has started.
Harvey Leonard’s home had all of them. It also had annual energy bills of approximately £7,300, with LPG supplying the heating and hot water.
The question was whether a different approach could work for this particular home.
We started by understanding what it needed.
A year after installation, Harvey reports annual energy bills of approximately £3,500.
That’s £3,800 less across the year — a reported reduction of around 52%.
Starting with the home
Older homes have their own character. They also have their own heating requirements.
Harvey’s semi-detached property had uninsulated solid-brick walls and a pitched roof with limited insulation. In some sections, the recorded loft insulation was just 25 mm.
Its listed status meant potential changes to the building needed careful consideration too.
Inside, the existing heating system served a combination of radiators and underfloor heating. Hot water needed to meet the needs of four occupants.
All of that mattered to the design.
An EPC rating gives us useful background. But it doesn’t tell us how much heat each room needs, how the existing emitters will perform or how heating and hot water should work together.
For that, we look more closely.
Our room-by-room assessment calculated a peak design heat loss of 8.82 kW. That informed the selection of an Aurora II 10 kW heat pump for space heating.
The heating system was designed around a 50°C flow temperature, reflecting the demands of the property and its heat emitters.
Understanding those requirements gave us a practical basis for designing Harvey’s system.
Two jobs. Each with its own heat pump.
Keeping the house warm and providing hot water are different jobs.
In Harvey’s home, we gave each its own dedicated system.
The Aurora II supplies the radiators and underfloor heating.
The Fjord 200L looks after domestic hot water independently.
That separation has a straightforward purpose.
When one heat pump handles both heating and hot water, it typically needs to pause space heating while it heats the cylinder.
With Adlår’s dual system, a demand for hot water doesn’t require the Aurora to switch away from heating the home.
The house can continue receiving warmth while the Fjord gets on with its own job.
For a building that loses heat more quickly, avoiding those hot-water interruptions is a useful part of designing for steady warmth.
It’s an engineering decision with an everyday purpose: heating and hot water that can work alongside each other.
Making the whole system work together
The heat pumps were only part of the installation.
We also needed to consider how they would connect with the home’s existing heating circuits.
The specification included adaptations to the underfloor-heating pumps, a buffer tank with an inline immersion heater, system filtration and the associated installation components.
A noise assessment carried out during the survey recorded a pass.
These details rarely make the headline. But they are part of turning a selection of equipment into a heating system designed around a home.
Then came the energy bills
Harvey reports that his annual energy bills fell from approximately £7,300 before installation to approximately £3,500 over the following year.
Annual energy bills | Harvey’s reported figures |
Before installation | £7,300 |
After installation | £3,500 |
Annual reduction | £3,800 |
Percentage reduction | Approximately 52% |
For this household, that is a substantial difference.
The figures are Harvey’s reported before-and-after energy costs. They are specific to his home and circumstances, rather than a prediction of what another household will save.
But they make this project particularly interesting.
A listed, solid-wall home with an EPC E rating was assessed on its individual requirements — and Harvey subsequently reported a significant reduction in his annual bills.
What did the installation cost Harvey?
The project received a £7,500 Boiler Upgrade Scheme grant.
After the grant and agreed project adjustments, Harvey’s final contribution was £2,195.
Using the reported £3,800 annual saving, that gives an estimated simple payback of approximately seven months.
The calculation is straightforward:
£2,195 ÷ £3,800 × 12 = 6.9 months.
That is a calculation based on the reported annual saving, rather than a measured payback date. It excludes servicing, financing and other ongoing costs.
The grant and contribution relate to Harvey’s installation. Another home will have its own requirements, installation costs and grant eligibility.
An older home deserves a closer look
Harvey’s project offers a useful perspective for anyone who has been told their home is too old, too poorly insulated or simply unsuitable for a heat pump.
Those concerns deserve proper answers.
Insulation matters. So do radiator capacity, heat loss, operating temperatures and the way the whole system is designed.
In a listed building, improvements to the fabric also need to respect what is suitable and permitted.
Harvey’s home needed that careful assessment. Its characteristics shaped the design.
The result was an Aurora II for space heating, a separate Fjord for hot water and a system specified around the building’s particular demands.
That is where every Adlår project should begin.
With the home. With the people living in it. And with a clear understanding of what their heating needs to do.
Could your home have a different heating future?
If you live in an older home, you don’t need to work out all the answers yourself.
We can help you understand its heating requirements, explore what is possible and explain the design choices that matter.
Book your Adlår home energy assessment.
Figures are based on customer-reported annual energy bills and supplied project information. Individual savings vary with energy tariffs, weather, occupancy, indoor temperatures, system settings and the energy uses included in the comparison.
