When a boiler has been heating your home for around half a century, replacing it is a significant change.
For David Brown, it was also an opportunity.
His gas boiler needed replacing. Having previously worked in refrigeration and air conditioning, he already understood the technology behind heat pumps.
“Our 50-year-old boiler needed replacing. Having previously worked in the refrigeration and AC industry, a heat pump was a logical option.”
David chose an Adlår dual heat pump system: an Aurora II for heating his home and a separate Fjord for hot water.
After living with it through winter, he reported electricity bills approximately 10–20% lower than the previous winter’s combined gas and electricity bills.
He is also open about the improvements he has made since installation — and the work he still plans to do.
Now, he is willing to welcome people into his home so they can see the system and ask him about it themselves.
Understanding the home behind the old boiler
David lives in a three-bedroom, semi-detached home in Southampton with three other occupants.
Built in 1962, the property has filled cavity walls, double glazing, 100 mm of loft insulation and solar panels.
Its heating system had developed around the old gas boiler and an established radiator network.
That gave us two things to understand.
How much heat did the home need?
And how would the existing heating circuit deliver it?
Our room-by-room assessment calculated a peak design heat loss of 4.88 kW. That informed the selection of an Aurora II 6 kW, with a 50°C design flow temperature.
A Fjord 200L was specified for the household’s hot water.
The assessment also identified differences in radiator output and pipework around the home. Those details would become an important part of David’s experience.
Why two dedicated heat pumps made sense to David
David understood that heating rooms and producing hot water place different demands on a system.
With Adlår, each has its own heat pump.
The Aurora supplies warmth to the home.
The Fjord produces hot water independently.
That means a demand for hot water doesn’t require the Aurora to pause space heating and switch to heating the cylinder.
For David, the arrangement also offered a practical installation advantage.
“Having the dual system meant that installation was simpler and costs were lower.”
Because the Fjord produces its own hot water, the Aurora did not need a heating-water connection to the cylinder through a conventional hot-water diverter arrangement.
Each system could be connected and controlled for its own job.
The installation also included ductwork and controls to manage the Fjord’s cool exhaust air. That created the option to make use of the air produced as the Fjord extracts heat for hot water.
In summer 2025, air from the diverted exhaust created approximately a 4C difference between indoors and outdoors.
In summer 2026, David added radiator fans and ran the Aurora in cooling at 17C to further control the indoor temperature, using around 2-4kwh per day.
What happened to the existing radiators?
They stayed initially.
“The existing gas boiler was removed and the heat pumps installed. Initially, no other changes.”
That doesn’t mean every radiator was ideally suited to the new system.
The survey identified differences between the heat required by individual rooms and the output available from their existing radiators. Some of the older emitters had limited capacity at the assessed operating conditions.
After using the system, David replaced a couple of particularly old radiators before Christmas.
His experience is useful because it shows why radiator decisions need to be made room by room.
Some may be suitable. Others may benefit from an upgrade.
The important thing is to understand what each room needs and whether its radiator can deliver that warmth at the proposed operating temperature.
The pipework became part of the story too
David is candid about one aspect that has needed more attention.
“Balancing the temperature between upstairs and downstairs isn’t easy, due to having longer pipe runs in 8 mm downstairs and short runs in 15 mm upstairs.”
This was an issue with the gas boiler too, but closing TRVs upstairs overcame that problem. Doing the same with the Aurora reduced water flow to a less than ideal 6-8l/min.
The downstairs heating circuit has long runs of narrow microbore pipework. Upstairs, the runs are shorter and the pipes wider.
That difference affects how readily heating water moves through each circuit and how heat is distributed around the house.
David plans to replace the long downstairs runs with 15 mm pipework to help address the balancing challenge.
It is a reminder that choosing the outdoor unit is only one part of a heating project.
Radiators, pipework, water flow and controls all influence what happens inside the home.
David’s account gives another homeowner something useful to consider: the existing heating circuit deserves just as much attention as the new heat pump.
What did David notice in his winter bills?
Once heating and hot water had moved to electricity, David compared his winter electricity bills with the previous winter’s combined gas and electricity costs.
He reports that they were approximately 10–20% lower.
That distinction matters.
He wasn’t comparing the new electricity bill with the old gas bill alone. His comparison included both household energy bills before the change.
It is a reported winter saving, rather than a verified annual saving or a measurement of heat-pump efficiency.
The home also has solar panels, and weather, tariffs, household energy use and temperature settings can all affect the comparison.
With those factors understood, David’s experience offers a reassuring example for homeowners concerned that moving from gas to a heat pump will necessarily increase their bills.
In his case, he reported lower combined energy expenditure over winter.
Over the last year, overall utility bills are around the same as 2024, despite the price increases and now switching cars to EV with home charging.
What was the quoted installation cost?
David’s post-survey quotation recorded a total project value of £9,086.
A £7,500 Boiler Upgrade Scheme grant reduced his quoted contribution to £1,586.
Quoted project cost | Amount |
Total contract value | £9,086 |
Boiler Upgrade Scheme grant | £7,500 |
Customer contribution | £1,586 |
The quotation included the dual heat pump system, installation, site-specific hot-water ducting, magnetic filtration, water conditioning and the selected maintenance package.
These are the quoted figures for David’s project. They should not be treated as a current offer or the installation cost for another home.
You can ask David yourself
Perhaps the most interesting part of David’s story is what he chose to do next.
He registered his home with Nesta’s Visit a Heat Pump service, offering prospective customers the opportunity to see the installation and talk about his experience.
That conversation can cover the questions that matter when you are considering a change yourself.
- Why did he choose it?
- What happened during installation?
- How has it worked through winter?
- What would he improve?
David brings both technical understanding and day-to-day experience to those answers. He can discuss the benefits alongside the radiator changes and pipework challenge.
That makes his story valuable.
It gives people a chance to understand a heating system as someone actually lives with it.
A new chapter for an established home
David’s old boiler had served the house for around 50 years.
Its replacement gave the home a different arrangement: dedicated space heating, independent hot water and a heating circuit that David continues to improve.
His first winter brought reported savings. It also showed where further attention was needed.
Both belong in the story.
At Adlår, we believe confidence grows when homeowners understand how their system works, why particular choices have been made and what can help it perform well.
David’s experience brings those questions into a real home.
And, for anyone considering a similar change, he is willing to open the door.
Explore a heating system designed around your home. Book an Adlår home energy assessment.
Customer quotes and reported energy costs are drawn from the supplied account of David’s experience on Nesta’s Visit a Heat Pump service. The 10–20% reduction relates to his reported winter comparison, not an annual savings guarantee. Costs and savings vary with weather, tariffs, solar generation, occupancy, household electricity use and system settings.
