Posted by: @sapper117

This may be too late but having spent many weeks looking at various systems and looking for suitable contractors (very difficult) we have ordered our new system to be installed in 4 weeks

we are a 180 plus old random rubble cottage on the east coast of fife running north south so we get belted by the wind rain and snow. Current 38 yr old micro bore wet system using LPG (1/4 of the ch is almost dead) backed up by a very efficient 8KW wood burner. Hopefully the wood burner will just become a feature in the evening rather than 24/7 from Sept to Apl!

Having researched and done a lot of reading on this and other sites we decided to risk all and go for ASHP and rip out all of our existing wet systems and replace with ASHP compatible rads plus a 250 ltr tank. The firm installing visited twice first just to meet and talk and the to spend about 3 hrs taking measurements and details of construction etc and insulation (we have built 2 extensions over the years and i was clerk of works for both so could confirm construction, insulation etc. the number crunching cam to tight on 12 KWh so it was decide that we would install 2x7Kwh Valliant ASHPs plus the tank renew all rads and piping. The plan is to run the system 24/7 using weather compensation and adjusting the temp by using the flow temp and avoiding all TRVs buffer tanks and zones to keep it simple (i believe this is the common way on the continent) no doubt in 6 weeks i will be reporting back but in the meantime i have a new problem

one of the reasons for this very expensive operation is to future proof our property, both now being retired. A new EPC is required for the Scottish energy loan/grant but chatting to our very professional EPC reporter i think that by keeping things simple and no TLVs we are going to be marked down, equally because we are going for 14KWh it will be treated as 2 systems and we are likely to be better of by just replacing our current LPG with a new one!! So much for green drive in scotland. Anyone else had problems with EPCs? To be honest for 20 yrs I owned a property management and letting company and was very heavily involved in EPCs and the way they have been twisted by local authorities and Govt to control the lettings market and am concerned that this will move shortly to the private owned market by threats of limiting lending regs on mortgages linked to EPC ratings. At the moment it appears that what we are doing will penalise us rather than assist  

very reassured to see that there are similar properties to ours having good results and look forward to reporting progress

I suppose the easy answer would be to install the cheapest TRV's to meet the requirements of the EPC, and then wind them fully open when operating your system. I am assuming that your proposed system would operate using both 7kW ASHP's during the colder periods, but only one during milder temperatures, which I suspect would improve overall efficiency.

@derek-m I believe that is the plan  it seems a shame to outlay for some 12 valves then just not use them but it may come to that😡

Posted by: @sapper117

@derek-m I believe that is the plan  it seems a shame to outlay for some 12 valves then just not use them but it may come to that😡

I'm afraid that I have been awaiting an outbreak of common sense for many years, but I am not holding my breath. 🙄 

@derek-m

12 years as a Royal Engineer then 20 working in the scottish letting industry - part of that working as part of the policy committee of our association dealing with the scottish Govt on letting matters - I see no sign of common sense breaking out at all in the near or distant future.

When you spend well over £20k retro fitting a green eco heating system and the political system then down grades you and also threatens the likely hood that in the future your house might be unsaleable as a result of your doing what they tell you to do (and even provide a trounce of cash) because you have a lower rating than before you did the work.

Throws hands in air

It seems that without my having to take up petitions the light has been raised by the govt over EPCs  lets just hope that they sort it quickly and at the same time allow storage systems to be added to the epc that way even older properties stand a chance of getting B ratings 

Quick question. If you want 12kW of heating why on earth would you use 2 units? There are many units out there which will easily cover 12kW with one unit. 2units are more expensive, need planning permission and the DNO application is a nightmare. We designers always try to get you into one heat pump where possible. 

Maybe Variant is the wrong solution. In my humble and biased opinion the Vaillant is overpriced, over complex and bloody massive. 

@grahamh And Vaillant do do a 12kW single unit as well, why use two?

Thank you for both emails

1 i followed all the guidance i could which lead me to the conclusion firstly that most problems (excluding insulation) were caused by

  a poor design

  b poor / incompetent installation

have done a full check of all the makes i felt i was happiest with Valient. The check also involved looking at all the contractors in a radius of max 40 miles (ie local and easier to get back after installation again a problem with some i have seen who have been tempted by distant firms) a deeper investigation of these firms (ie not just reading the adverts and comments allowed on their sites showed several horror stories and several who when interrogated admitted that they had installed very few or in one case 1 set up before. One firm even quoted all the requirements for my property from an old EPC they got from the national site!

2 the firm due to install (mon) have put in 54/5 systems to date all within a 30 mile radius of us and are based 18 miles away. 2 site visits and a very long and detailed heat loss calc with my input as over 38 yrs i have carried out extensions and know the construction inside out) 

3 calls lead to the estimate just below 12kwh however in conjunction with my EPC officer we decided that we should leave an option to add a radiator to our bedroom at a later date (?on sale or just prior) which we like to keep cold (-2 last night!) and also to fit a radiator in the conservatory if we insulate the roof.

4 yes i am well aware that Valliant do a 12 however 

 a on speaking to the installers and later direct to Valliant the waiting list for 12s is very long and

 b RHI finishes 31 Mar and it was advised we were likely to miss the date if we went for the 12 KWh so looking forward we thought it would ensure RHI and allow additions if needed.

5 I am well aware of the additional cost for 2 pumps however my situation at present is such that this is not a concern, my concern is simply that the system works and to that end the complete wet system is being removed (easy job) and being replaced but high flow pipe work throughout the property and ASHP radiators (a very big and difficulty job) heated flooring is out of the question due to fairly new laid oak flooring

Many thanks for following my post and i appreciate your comments and suggestions. I hope that my due diligence in finding contractors will be worth the long hours researching but as you may be able to tell from my username I am a retire royal Engineer and the two directors of the installation firm are ex RAF Tornado technicians, we are from the same world and i recon if they can put a tornado together then they have a good chance of this, and for the last 18 years I ran my own property company maintaining 100+ student flats so have a good experience in most property maintainence (excluding ASHP!)

finally not mentioned in the post as it is very new but we are waiting for clearance from Scottish Power to add an 8KWh Solar system (in addition to 4KWh on the roof already) in the field with an 8.2 battery storage system to aid in the cost once or tariff runs out in 20 months

I will update how things are going as and when

mike

Hi @sapper117 

I presume that the control system will be arranged such that only one of the two heat pumps will operate during milder weather conditions, with the second one being used as the heat demand increases?

I believe that is the plan I have to say that i will be writing many notes once it is in when i get the handover!

@sapper117

Actually thinking about your proposed arrangement, with suitable control valves and logic, it would be possible to have one heat pump providing heating and the second one provide hot water when not required for heating. It may prove more energy efficient.

It would also probably be possible to have the heat pumps exchange duty when the running one needs to defrost, such that rather than using electrical energy to defrost, it defrost naturally when the outdoor air temperature is above zero. This arrangement also may prove to be more energy efficient.

I fully agree with your sentiment of using ex-forces trained personnel, because since the bean counters took over control of most industries and discovered that training costs money, there is very little carried out these days.