Case Study
Oil to Vaillant Heat Pump with Solar: Lincolnshire Case Study
A low-temperature heat pump upgrade designed to work beautifully with existing underfloor heating, solar panels and battery storage.
Published by Vector Heat
This Lincolnshire homeowner wanted to move away from domestic oil and make better use of an existing solar and battery installation. The property already had underfloor heating, giving us an excellent foundation for a carefully designed, low-temperature air source heat pump system.
Project at a glance
| Previous heating | Domestic oil |
|---|---|
| New system | Vaillant air source heat pump |
| Design flow temperature | 35°C |
| Guaranteed efficiency | 450% |
| Funding | £9,000 BUS grant |
| Heat emitters | Existing underfloor heating |
| Controls | Wireless sensoCOMFORT and myVAILLANT app |
From oil heating to a joined-up home energy system
This was more than an appliance swap. The new heat pump needed to complement the home's solar panels and battery storage while delivering dependable heating and hot water.
The project was completed through the Heat Geek platform, with the customer receiving a £9,000 Boiler Upgrade Scheme grant and the added reassurance of the Heat Geek Guarantee.
Designed for a 35°C flow temperature
Liam designed the system around a 35°C flow temperature. Lower flow temperatures help a heat pump work efficiently, and the property's existing underfloor heating was well suited to distributing gentle, even heat.
The completed design carries a guaranteed efficiency of 450% through Heat Geek. In practical terms, that means a seasonal design target equivalent to 4.5 units of heat for every unit of electricity used by the heat pump.
Converting the underfloor heating to open loop
We converted the heating system to an open-loop arrangement. Removing unnecessary hydraulic separation allows the heat pump to work directly with the underfloor heating circuit, supporting good flow rates, lower operating temperatures and straightforward control.
Simple Vaillant controls
The homeowner can manage the system using Vaillant's wireless sensoCOMFORT controller and the myVAILLANT app. The controls make everyday adjustments simple while allowing the weather-compensated system to do the important work in the background.
Designed, installed and commissioned by people who care
Liam carried out the design and final commissioning. The Vector Heat installation team completed the physical work, transforming a tight utility space into a neat, accessible plant area and installing the outdoor Vaillant unit cleanly against the brick exterior.
The customer's verdict
“Only a couple of days to install completely. I would thoroughly recommend Liam and his team… They were kind, polite and respectful. We have gone from domestic oil to a system that benefits us financially and environmentally.”
Peter, Google review
FAQs about moving from oil to a heat pump
Can an oil boiler be replaced with a heat pump?
Yes. A heat-loss survey and room-by-room design establish the heat pump size, emitter requirements and suitable flow temperature.
Does underfloor heating work well with a heat pump?
Underfloor heating can be an excellent match because its large surface area can heat a home using low water temperatures.
What does a 35°C flow-temperature design mean?
It means the system was designed to meet the home's calculated heat loss with heating water flowing at 35°C at the design outdoor temperature.
Can a heat pump complement solar panels and battery storage?
Yes. Solar generation and battery storage can help provide electricity used by the heat pump, although the benefit depends on generation, storage, tariffs and when heat is needed.
How is a Vaillant heat pump controlled?
This installation uses Vaillant's wireless sensoCOMFORT controller, with the myVAILLANT app giving the homeowner convenient access from a phone.
Planning your move away from oil?
We design heat pump systems around the home, its emitters and the way you use energy—not just the outdoor unit.
Talk to Vector Heat