The Saga of the Heat Pumps

Here is the sorry tale of our heatpumps

  1. Our electricity consumption has been excessive from when the heat pumps were commissioned
  2. Our annual electricity consumption is well over double the projection at time of purchase from Eco Heat Pumps
  3. The excessive electricity consumption is clearly the responsibility of Eco Heat Pumps and Danfoss because of faults in specification and performance
  4. We have incurred substantial losses through excessive electricity bills as a result of the faults
  5. Danfoss claim that we are not entitled to any reparation as the guarantee period has expired yet the faults were reported within weeks of installation.
  6. Danfoss have benefitted from buying a business with a presence in the heat pump market. This also means that they have a responsibility to meet the contractual obligations of the company that they took over.
  7. The heat pumps have been very unreliable. We have had to repair them on many occasions at high cost. We recently had a compressor replaced at a cost of £1,608
  8. Danfoss’ approach discredits the industry as a whole. Customers are entitled to receive a service that delivers what it promises.


Data (readings taken 14/7/13)

Thermia Diplomat 10 – fully operational since February 2006

  • Heat Pump hours – 27635 @ Output capacity of 9.54 @ COP of 4.6-3.3
  • Add Heat 1 hours – 6047 @ 3kwh
  • Add Heat 2 hours – 1242 @ 1.5 kwh
  • Warm Water hours – 7269

Thermia Diplomat 8 – fully operational since January 2008

  • Heat Pump hours – 27591 @ Output capacity of 8.13 @ COP of 4.6-3.4
  • Add Heat 1 hours – 6133 @ 3kwh
  • Add Heat 2 hours – 2959 @ 1.5kwh
  • Warm Water hours – 1317

Electricity Use – kwh/annum

  • 2009       28,537
  • 2010       33,750
  • 2011       31,254
  • 2012       22,615

Eco Heat Pumps projected electricity use for the heat pumps     11,166 kwh per annum

This data does not fully represent consumption because we have 2 wind turbines and a solar power array. Prior to 2011 we had 1 turbine – 6kw Proven – which generates about 14,000 kwh per year.  This suggests that without the renewables contribution we would be consuming around 40,000 kwh per year. Eco Heat Pumps said that the system should cost about £670 per year to run @ 6p per kwh. On this basis we should be consuming 11,166 kwh per year on heating. Allowing a generous 6,000 kwh per annum for other electricity costs, we are clearly consuming well over double what we should be consuming.



  • September 2004 – quotes sought for heat pumps from various suppliers. Architects plans for renovation project supplied
  • Chose Eco Heat Pumps mostly because we chose to support a local business
  • 20/10/04 – Quotation received based on Eco Heat Pumps calculation of floor area of 450 square metres
  • 15/3/05 Final quotation received estimating running costs of system @ £670 per year based on electricity cost of 6p/kwh


  • Eco Heat Pumps provide specification for installation and approve our plan to self-install under guidance.  Install to be overseen and commissioned by their engineers (Alan Donald – based in Scotland)
  • Summer 2005 – Ground loops installed to a better than specified standard. Greater separation of individually dug trenches and slightly deeper than specified – 1.25 metres instead of 0.8 metres.
  • Plumbing and electrical installation inspected by Eco Heat Pump engineers
  • 8/2/06 – Heat pump system tested, passed and commissioned
  • Underfloor heating system tested and commissioned by Eco Hometec – at the time a partner organisation of Eco Heat Pumps


  • 17/4/06 – wrote to Eco Heat Pumps because of concerns about electricity useage mostly owing to considerable use of Add Heat functions
  • I have weekly data from the heat pumps stretching back almost to the time of installation.
  • 24/4/06 – reply received from Eco Heat Pumps saying that the poor performance was due to an incomplete renovation and the need for the building to dry out.
  • 7/1/08 – Letter to Eco Heat Pumps again complaining about under performance.
  • 28/4/08 – Danfoss acquires majority share holding of Eco Heat Pumps
  •  November 2008 – letter to Eco Heat Pumps/Danfoss again expressing concern about performance. Data provided.
  • 6/11/08 – Visit by Stephen Andrews and Mike Walsh from Danfoss. A very unprofessional visit as documented in a letter sent to Danfoss after the visit. Cursory inspection of the heat pumps with rude behaviour. No data recorded or analysed in anything but a superficial way during the visit. No historical data asked for. The exercise was an attempt to bully me into submission. The data provided in this submission shows how
  • 23/2/09 – Letter to Danfoss again expressing concerns about performance. This followed a visit from a Danfoss engineer Lee who was shocked by our energy consumption. He identified a particular issue about pipe sizing near to the heat pump units.
  • 3/4/09 – Letter from Stephen Andrews at Danfoss suggesting that we should bear the cost of replacing the pipe work identified by Lee as being too small – 28mm instead of 40mm. (The pipe sizing had been guided by the Eco Heat Pump engineers.)
  • 9/5/09 – Reply to Stephen Andrews at Danfoss which challenges the accuracy of his statements in the letter of 3/4/09 e.g. that he inspected the heat pump data during his visit. It also challenges his unprofessional and dishonest behaviour.
  • 11/5/09 – Receive email from Simon Pepper at Danfoss saying that they no longer were prepared to offer heat pump service beyond the guarantee period having moved to a ‘supply only business model’
  • 22/6/09 – Letter from Stephen Andrews rejecting my arguments and disowning the problem.
  • 26/6/09 – Reply to Stephen Andrews cataloguing multiple failure in performance by both Eco Heat Pumps and Danfoss management and staff
  • 16/7/09 – Stephen Andrews agrees to change the pipe work at Danfoss expense without accepting liability for failures
  • 19/7/09 – I signed an agreement that we would accept that the fitting of the new pipework would end the issue about the underperformance of the brine circuit.
  • 20/7/09 – confirmed in a letter that we accepted the agreement provided that the remedial work was effective
  • Spring 2009 – Danfoss replace some pipework at their expense – some metrics improve following this work but the core issue of excessive electricity consumption remains.
  • 15/4/13 – Spreadsheet sent to Stephen Bancroft  – now Technical Manager at Danfoss – with all our heatpump data for several years – includes the overall hours in use and the add heat hours.
  • 19/4/13 – Stephen Bancroft visits – spends about 2 hours on site discussing issues and looking at metrics
  • 20/5/13 – Stephen Bancroft sends a report to us which confirms underperformance and makes action recommendations. In the accompanying email he says  ‘Initially I think we need to get the buffer installed and monitor internal temps and run hours.’
  • 4/6/13 – letter from Stephen Bancroft saying that Danfoss can only offer advice as the products are beyond the guarantee period. It also says that prior to installation a SAP report should have taken place on the building and that the system was not designed well.
  • We identified the issues and complained within 2 months of the installation of the system. The complaint stems from then which means that the guarantee is valid. Eco Heat Pumps were responsible for the oversight of the project and at no time proposed a SAP report. They also designed the system. Danfoss is now responsible for their work.

Other information

  • The building has a floor area of approximately 510 square metres – therefore the pumps have been undersized
  • Over the past 8 years much time and money has been wasted in trying to get the heat pumps to perform properly

Green Directions – the beginning

So what happens next when you have just bought a farmhouse, circa 1800, with attached barns two other collections of outbuildings and 10 acres of land? This was the wonderful opportunity and challenge facing me and my partner Sarah Brown in November 2003. We had both renovated properties before including another barn conversion, a terraced house and a detached house but this was on a completely different scale.

I started to research ways of tackling the project and was soon spending hours at exhibitions, reading magazines, watching programmes such as Grand Designs and searching on the internet. It didn’t take long for me to realise that we would have to take a radical approach to the renovation if the family were to live in such a large property sustainably.

Walking into the National Homebuilding and Renovating Show at the NEC in 2004 I was completely overwhelmed by a vast range of unfamiliar technologies such as heat pumps, under-floor heating, electricity generators, mechanical ventilation and insulation systems. Piles of leaflets returned to Sheffield, followed by more research and meetings with potential suppliers until an outline plan started to emerge.

A core part of the plan was to put in under-floor heating driven by ground source heat pumps which I installed with the help of a friend, Clive Quarmby. We spent many weeks digging trenches, laying pipes, soldering, fitting valves etc., using 8 different diameters of pipe in the process.

Sarah was pregnant with Arthur (now 6 – birthday in February), while all this was going on. By the time she returned from hospital with the new baby most of the heating was working and some of the floorboards in the bedroom had been restored. She was not happy.

Heat pumps need electricity to work and so we decided that we would have to make our own electricity to meet our objective of becoming energy neutral. I researched solar and wind power during 2004. Solar panels were about 3 times more expensive than they are now and were much more expensive than wind turbines compared with the amount of electricity they were likely to make. So, we bought a 6 kilowatt Proven wind turbine expecting it to make about 10,000 kilowatt hours per year. It didn’t. It made 14,000 kilowatt hours per year – fantastic.

The only trouble was we were using a lot more electricity than I had anticipated despite investing thousands of pounds on insulation and high-tec glazing. More investment was needed – more insulation and more energy generating technology.

We now have a 4 kilowatt solar power system which generates about 4000 kilowatt hours a year and have just installed a 10 kilowatt Xzeres wind turbine which hopefully will take us to our energy-neutral goal.

Every week I write down statistics from our systems. This is hopelessly inefficient and so I am now trying to find a data-logging system that will record everything automatically.