This will be interesting.

If government rhetoric on the number of heat pump installations is to be met then it's mostly about retrofits rather than original installations. I think it would be really helpful for those contemplating a retro-fit to learn what the realistic performance expectations (and potential pitfalls) are of connecting a heat pump up to existing radiators, for example. Those of us with (bitter?) experience even of original installations know that performance in use can be very different from theoretical maxima under controlled test conditions.  A bit like car fuel economy - WLTP figures are achievable but not in the real world if you drive with your pedal to the metal.

Mike

@mike-patrick, thank you. Some great and valuable points. I can think of two guests we are going to pose this question to. 

Hi Mike,

You analogy of car fuel consumption is perfectly correct in relation to ASHP. A correctly specified, installed and optimised ASHP system will perform much better than one that has not had the benefit of personnel who fully understand the problems and how to resolve them. An ASHP needs to modify it's operation to maximise its efficiency under changing operating conditions. Just like driving a car more economically.

The inherent weakness with an ASHP based heating system is that the primary energy source is not consistent. An ASHP extracts energy from the outside air, which of course the temperature of which keeps changing. This is similar to the calorific value of the fuel to a gas or oil boiler reducing with falling outside air temperature, so to output the same amount of heat energy it would be necessary to burn more fuel. This in turn occurs as the heat demand increases with lower outside air temperature, so you end up with a lose - lose situation.

I am in the process of documenting the results of the analysis that I have been performing on detailed manufacturers operating data, I hope to post the results in the near future.

Hi Mars,

Can you ask whoever you think suitable what, if anything, is being done to improve the efficiency of ASHP based heating systems when operating at ambient air temperatures below +5C.

@derek-m, will definitely ask. We have our first interview on Wednesday and a packed schedule of interesting guests throughout September. I think it's going to be super interesting.

Our first video has been recorded and we’ll start the edit tomorrow. A big thank you to Bob Beattie (@bobbt9866) for being our first guest and for sharing his insights and answering our questions. 

Our interviews have been going incredibly well. We have finished interviewing our first three guests who have provided some incredibly useful information, and we are hoping to post our first interview with Jan Rosenow on Monday, with interviews from Graham Hendra and Bob Beattie following on respective Mondays. 

If you haven't done so already, please head over to our YouTube and subscribe so that you don't miss the interviews: https://www.youtube.com/channel/UCik3JUx29XhSgEWKv7MUv8w?sub_confirmation=1

We're super excited because our first interview with Dr. Jan Rosenow is now live.

@editor Hi Mars,

An excellent video, though I'm afraid it did not fill me with confidence for the future. Virtually all the areas discussed were ones that we have explored on the forum for quite a number of months.

As was pointed out on several occasions during the interview, at the moment there is no real incentive for homeowners to spend £10k or more for a technology that will be more expensive to run.

I still feel that more effort should be made to encourage energy efficiency, which would probably be more cost effective, than pushing ASHP's at the moment.

@derek-m, I agree. Energy efficiency is key and more has to be made of insulation.

It’s difficult to see how dependence on fossil fuels will be severed in a significant manner.

Our interview with Graham Hendra is out and he makes some bold predictions about the future of renewables and heat pumps, and shares some really interesting insights about the industry.

It’s a fun, candid and entertaining interview. Sit back, relax and enjoy.