Steve Milner

Using the naturally occurring energy in the spring on his land, business owner Steve is now able to heat his home, all year round for a fraction of the cost of a fossil fuelled system, with a Water Source Heat Pump system.

After noticing that the water in the natural spring in his garden was warm, even in the winter, green thinking Steve contacted Pure Renewables to see if he was able to make use of this energy.

As experts in renewable heating systems, we designed an Open Loop Water Source Heat Pump system which will meet all of the heating and hot water demands of the property.


Water Source Heat Pump systems work in essence just like any other type heat pump system, though they have a number of unique advantages:

  • The rate of heat transfer is much higher than air and ground source
  • As the water flows, it constantly replaces the energy source available
  • Little to no trenching required and outdoor fan units
  • Typically of a Higher Coefficient of Performance (CoP) than Ground or Air Source

With an Open Loop Water Source systems such as this one, there are additional aspects that must be taken into account to ensure the installation goes well and the system runs efficiently.  For example:

  • Is an extraction license required?
  • Is there a risk of freezing the heat exchanger or the energy source?
  • What is the water quality like?

Our highly experienced design team were able to tackle all these queries and more to create an efficient system which is cheap to run and very reliable, with a long life span.


Installed in a phased approach to fit in with the schedule of the property renovation works, the installation took several weeks, including a new central heating distribution system made up of Underfloor Heating and new convector radiators.  The installation was completed to schedule, meaning that there was no unnecessary disruption to the other trades and the family.

Return on Investment

The system is expected to save 75% on running costs compared to the previously used fossil fuel burning system.  When coupled with the Renewable Heat Incentive (RHI) payments, the system offers an outstanding payback of less than 4 years.

It is estimated the heating bills for this very large, detached home will be in the region of just £1,400 a year (with temperature set at 21 degrees all year round). In addition, the system is eligible for RHI payments totaling nearly £60,000 over the 7-year scheme.

At a glance


Steve Milner


Near Harrogate, North Yorkshire



Renewable technology

Open Loop Water Source Heat Pump, Underfloor Heating and radiators

System used

Danfoss DHP-S Eco Heat Pump, Adapted for Open Loop Water Source

Deluxe Underfloor Heating system

Stelrad Compact radiators

Energy cost saving

Up to 75% a year compared to an Oil / LPG system

RHI payments

£8,500 for 7 years, index linked to inflation