Historic Home, Modern Heating – A High-Efficiency Heat Pump Project by Option Energy Solutions
We’ve recently completed another rewarding installation this time on a historic home with wattle and daub walls, showcasing just how far intelligent design and planning can take a modern heating system, even in a building that’s several hundred years old.
This 12kW Vaillant Arotherm Plus air source heat pump was installed in partnership with our Heat Geek network, and the early results have been nothing short of outstanding. Within just five days of operation, we saw a measured efficiency (Coefficient of Performance) of 660%—and with off-peak energy rates, that meant this homeowner was heating their entire home for just 1.25p per kWh.
System Design & Specification
The backbone of this installation is Vaillant’s high-performing Arotherm Plus air source heat pump, renowned for delivering excellent output at low flow temperatures. We worked to a low flow temperature curve of 0.5 (pending final tweaks), to ensure the system would run at optimal efficiency with minimal energy input. The system was also paired with SensoComfort and SensoNet controls, giving the customer advanced functionality and remote access for full control over the system from anywhere.
Given the age and layout of the property, a full radiator and pipework upgrade was also carried out. This ensured all parts of the system were matched to the new lower temperature design, providing even, comfortable heat distribution throughout the home without the peaks and troughs you might expect in a heritage building.
Challenges of a Heritage Property
Installing a heat pump in a historic building is never straightforward, especially when working with traditional wattle and daub walls. These types of homes typically come with unpredictable construction quirks, limited wall insulation, and less-than-ideal pipe routes.
We began with a thorough on-site survey and used accurate U-value data from real testing studies to assess the building’s heat loss accurately. With Heat Geek’s cutting-edge design tools, we modelled the system to suit the property’s specific characteristics—balancing modern efficiency with the constraints of a listed structure.
Routing primary pipework proved tricky, as expected, but our team found a practical solution by relocating the hot water cylinder and adapting flow routes to minimise disruption and retain character features in the home.
Early Performance & Customer Outcome
The first few days of operation have exceeded expectations. At 660% efficiency, this system is performing exceptionally well—even in early winter conditions. The customer, who is on an off-peak tariff at 7.5p per kWh, is currently paying as little as 1.25p per kWh to heat their home.
It’s important to note that this performance is the result of careful planning, low temperature system design, and upgraded emitters throughout. The homeowner is now enjoying stable, consistent heating at 21°C, with full confidence in the running costs and future reliability of their new system.
Why This Project Matters
This installation is proof that heritage doesn’t have to mean high energy costs or old-fashioned heating. With the right design, attention to detail, and the latest heat pump technology, even the most character-filled homes can benefit from ultra-efficient, future-proof heating solutions.
We’ll be returning soon to gather more data and share a closer look at how this system continues to perform across the seasons.
Installed by Option Energy Solutions – Heat pump specialists serving Steyning, Brighton, West Sussex, Surrey, and surrounding areas.
