jit

i agree. the system on Vaillant schematic book are design in consideration of all the property in uk . while most of property don't need it if your good installer. the way i see buffer is, it is made for diy installer which allow error and high tolerance in incorrect sizing but reduces efficiency of heat pump

i got 10kw solar panel and 16kw battery pack installed. in summer is no issue at all at it produce 60-90kw and in winter i am starting to see drop but even bad days producing between 15kw - 30kw. i can also charge from grid at 7p with my 16kw battery. there lots of option when it comes to cheaper fuel . and the heat lost calculation might be 7kw or even less if surveyor not input right U - value. this is why i am prepare to take risk. i just needed profession opinion to confirm if i am on right track or if i should do somethign different i am not installing buffer. totaly against. if its needed . i can alway install it after. my brother in law is plumber. so if any work need to be carried out after then can be done .

that gona require disruption. i just done full refurb last year. at the time i did not think about heat pump otherwise i would have done heating and plumbing according to that

no point in investing into product if recovery time is slower. every chance product to go faulty before recovery time and then i am having to spend the money for replacement

its loft conversion . so 150mm pir insulation, warm deck i predict 350-450ltr at estimate 55-65 degree temperature . it difficult to know exact volume as it store at different temperature and mixed with cold. but i know 1 full tank is not enough in morning so i run additional 30min i am tilting toward 7kw as all the engineer suggest 7kw is sufficient . i also had doubt as well so i did my calculation through heat punk with heating and dhw load with heat lost and that suggested 7kw is 127%. and if it not sufficient it would only struggle for month max when temperature is 0 to -2 degree. i can always option to using immersion at 7p which is not high considering scop is low when it cold (i also have 10kw solar generation system) atm i can sell to grid but that might not be the case in future so i can potentially use extra generation in immersion . in result i can save £1000 for not going with 10kw pump. i think it might be good idea to go for larger cylinder. then decide to go heat pump ready or PHE . cost is similier to both as PHE is expensive . if installation work out then i might not need to all the extra hack to meet demand. i am only turning heating on 45min in morning and 1hr in evening. it hold heating well.

no space for 2 tank. either i use exisiting 300ltr tank and PHE (hofuly reduce heating time and reduce cost.) or install 400-500lt new cylinder. and invest the PHE money on larger heat pump if 7kw does not meet heating and dhw load. (7kw to 10kw is £1000 more for heat pump cost)

£2500 after grant. when actual material cost is less then £5k as no new cylinder. if plate heat exchange is added to new cylinder. should this resolve issue? as plat heat exchange known to improve efficiency or i should get 500l tank . 7kw vaillant output 10kw at -2. this should still be ok or i should not consider output?

thank you for feedback everyone currently 300l i have to run 1 and half cycle in morning and 1 cycle in afternoon is enough water for bathing and cooking. 165m2 is heating space . kitchen, hallway on 1st floor and loft is excluded as there no radiator and its in center of all the rooms. 200-210m2 is actual space. the house 200mm solid wall but has external wall insulation 100mm all around old walls. loft is 150mm solid insulation . all windows aur new double glassed and 3 glazed extension. i had heat loss done by 2 separate companies . room by room and editing exact material and size. they both come up with heat loss 6.98-7kw. my aim is to run 2 cycle in morning as night terrif cheaper (7p) and 1 cycle in afternoon .also i am only using half the energy my solar is producing atm. 1 of the engineer made comment about heat pump not having enough time for heating if its working on hot water twice in morning. as 300l would take 90min estimate time heat up at 45degree. i don't mind installing 500l cylinder if it required but if plate heat exchanger resolve issue then i rather option for that as the cylinder is only 3month old . most of the engineer suggesting new cylinder and their not much information out to compare 'new cylinder vs small coil cylinder with plate heat exchange. i can always get new cylinder and sale old cylinder to builder for 20-30% discounted price. space is not issue and installation is very straight forward. i want to select engineer who know what they doing but it has to be in my budget. pipe work from cylinder to heat pump and consumer unit is only 2m max. no radiator replacement. still costing £10k. is this fair price?

i am electrical engineer , wanting to understand heat pump schematic and how system perform. i am in the process off having my heat pump installed. i had 3 heat pump engineers turning up with all different design. the house is fully insulated . 165m2 heating space and 7kw heat lost. 300l new cylinder (not 3m coil). ground floor UFH, 1st floor radiator circuit, 2nd floor radiator circuit (loft) from my reseach and what i understand. i want to install 7kw vaillant heat pump, open loop and no buffer/volumiser. engineer1 said. install bufffer. and new tank engineer 2. install bufffer. and new tank + zone radiator circuits engineer 3. suggest open loop system with no buffer and use existing cylinder with plate heat exchanger . from my research and what i understand . i want to avoid buffer and have open loop installation with balancing valve to control flow. i am not sure if i should plate heat exchange on existing cylinder as it 10 people and 3 bath. and do i need volumizer as their is plenty of volume being 3 circuit. i have boiler room outside and all the pipework run separate . the pump can be installed on same wall. what would be the good and high efficiency set up?