mk1_man

They also do the training remotely via Microsoft teams. I have been incredibly impressed with AltoEnergy and their feedback is excellent. After a bit of back and forth have decided on final spec, cost etc. What are peoples views on the R32 Mitsubishi Ecodan heat pumps, especially the 8.5kW unit ?

Hi all, just wondered if anybody had any experience with the Ecodan pre-plumbed hot water cylinders. They use an external heat exchanger instead of an internal coil for faster re-heat times (supposedly) https://les.mitsubishielectric.co.uk/products/residential-heating/cylinder/ecodan-r32-ftc6-monobloc-pre-plumbed-standard-cylinder Am I asking for trouble going this route or are they a good option alongside quoted 8.5kw Ecodan heat pump.

Its a minefield out there. At the mo I am likely to follow my gut and purchase my own solution and that's likely to be a Vaillant Arotherm (7kW) or possibly the new Samsung R290 unit (8kW) instead of the 11 - 12kW units that are being quoted. Nobody appears to pay much attention to the fact that I have been a little anal with the air tightness measures and insulation to way past building reg standards and the fact that we have an mvhr installed and triple glazed Internorm passive standard windows and doors throughout. They just go by the fact that its a 1960's house .... heat loss on recent quote has come down to 7.8 from the 10.5 the other two mcs companies quoted but they are still insisting that I need to add another 3kw for hot water capacity and that I have to replace my cylinder even though it is a twin coil (solar) 250litre and reheats very quickly at the moment. Going my own route allows me to keep my gas boiler and use it to heat the water and as a backup to space heating via a couple of shut off valves. If I have my calcs wrong when its -2 etc I can simply revert to gas for the few days !

Thanks all and I appreciate the feedback. My issue is that I currently heat house and hot water with a 19kw system boiler (Viessmann) that majority of time modulates down between 10% & 30% so outputting around 1.9 - 5.7 kW The heating also runs infrequently apart from the 04:00 - 08:00 start time each day. My rooms are between 20.5° & 22° I just can't get my head around the fact the mcs figures are saying that I need to input 8kW or so 24 x 7 Maybe I am worrying too much, just need to clarify what the minimum output is for an 11.2 Ecodan so as not to be cycling all of the time.

Hi, I am still somewhat confused as to why the heat pump has to be bigger to support hot water. With the diverter it is either space heating or hot water but not at same time. With our current boiler setup system turns itself off for quite a bit of the day once slab (85 - 90mm) is heated up, and there is never demand for heat between 22:00 - 04:00 as heat loss appears minimal i.e. temps drop form around 21 - 19 so doesn't that leave plenty of time for heat pump to heat the dhw? My concern about a more powerful pump is that for 95% or higher time it is over sized so not efficient. I would prefer to just add a jumper or except a slightly colder house when temps drop below zero etc, it appears mcs don't allow / permit this approach?

Just had my quote from Alto Energy, 11.2kw Mitsubishi Ecodan, new 250 litre cylinder with 28mm 3m2 coil, all of the required bits and pieces £1500 once BUS grant removed. They operate what I feel is a unique and sensible approach, they do the heat calcs, mcs certification, commissioning etc but let the home owner / self builder either use their own plumber or install themselves if you are hands on build. All you need to do is attend their training course which can be done in physical classroom or via teams. Post install you still get the 5 or 7 year warranty. heat loss calculated so far at 8kw, not sure why 11.2kw heat pump being specified, do mcs add 20% or so wiggle room? My preference is to have a more suitable sized heat pump for majority of the time and if the rare occasions it drops to around -2 or less then we simply have a slightly colder house or wear a jumper.

Correct, would have to pay plumber, however my plan is to plumb myself, not complicated and have already done majority of existing. Even if you were to pay plumber it is at around £200 - £250 per day for a couple of days, much cheaper than the the £4k - 5k other 'mcs' companies are ripping people off to the tune of. Alto Energy run their own free training, so as long as your installation plumber or you yourself as the self builder attends the installation still qualifies for the Mitsubishi 5 - 7 year warranty.

I have had the quote back and I have to say really happy with proposal. Basically it is proposed as an 11.2kw Mitsubishi Ecodan along with all associated wifi adapter, fixing, valves etc also a new 250l stainless cylinder with 28mm 3m2 heat pump specific coils - spec looks really good. This is for either myself or a local (non mcs) plumber to do install and then company comes and commissions it. Cost all in is £9000 but with the £7500 back from grant I pay £1500 The Mitsubishi wasn't on my radar and had looked for the new Samsung R290 unit. What are peoples thoughts on the Ecodan, will I get decent figures if installed correctly. I am looking to have no buffer / LLH, no mixers or pumps on the underfloor manifolds (ground and 1st floors) single large zone with no actuators etc I understand this gives best efficiency? Appreciate peoples views, especially those with Mitsubishi units. I still think the 11.2kw is on the large side, curious as to know what it will modulate down to ?

Hi, I notice on the picture it has a small buffer / low loss header installed. Is this a specific requirement for Mitsubishi Ecodans? My preference for our install is open loop no low loss header, underfloor manifold pumps, mixer etc. Price wise look at other thread, just about to update with brilliant quote / method of obtaining BUS grant etc

just checked again and it is showing as 4.97 m3 / day which I think works out as 56.5 kWh? That then equates to 56.5 /24 = 2.35 kW each hour to heat house. Does that mean heat loss is around 3Kw per hour? I am getting so confused with all of the data being thrown at me recently ! House is 250m2

Apologies, I should have said 150m2 underfloor on the ground floor, also have 100m2 1st floor but we never have heating on that apart from bathrooms

Why would you need to add hot water, surely the pump is either heating water or underfloor but not both at the same time? Also how many days of the winter is it -3, I know its a little risky but I would rather either wear a jumper or add a fan heater for a few days of the year as opposed to being oversized for the majority of the time ? The benefit I guess of being forced down the route of self purchase and install is that I could also keep the gas boiler as a reserve, easy enough to plumb this way with a couple of valves or if I keep my small LLH I can have both plumbed in parallel

Hi, size of the heat pump is a frustration. I have had two companies that both say I need a 12kw heat pump as heat loss is between 10 & 12kw I keep challenging them by saying current modulation on gas boiler doesn't support that. Our boiler generally heats underfloor slab from 04:00 to around 08:00 and then stays off for most of the day. I am sure with a heat pump if running continuously it would just need to trickle the heat in. Even if I do me own heat pump calcs the companies don't budge, the only route is to purchase unit myself and if I went that route its either the 8kw new Samsung R290 or the Vaillant 7Kw I have 150m2 underfloor flooring in 11 loops. Plan is to ditch all the current actuators and the mixer valve & pump and run as open loop with no buffer. Any suggestions on best option for doing calcs myself. I have looked at heat punk and also Heat Engineer so far.

Sounds promising. At the moment my thoughts are new Samsung R290 pump controlled via homely or Vaillant unit on native control.

I am finding that the MCS route to market is a complete rip off, more akin to ambulance chasers. I am doing a self build with the intention of installing a heat pump at some stage so all main flow and returns are 28mm copper to tank and underfloor manifolds. The mains cable and 2 wire control cable is already run, I have an existing 250l twin coil cylinder that they have confirmed is suitable for heat pump so they have agreed not to swap etc. They have said that my install should be really simple and take no longer than a day possibly two. The quote is £13,250 of which I can claim £7,500 back. This is for a 12kw Vaillant which retails around £5700 and I am sure they pay much less. The only additional materials is a few valves, possibly antifreeze valves and a couple of meters of copper, interface, rubber feet etc. Say that amounts to an additional £1000 that would take a total of £6700 in goods. How on earth do they justify £6.5k for possibly two days work ! All of the companies appear to be the same. I obtained a few quotes last year before government increased grant to £7.5k, the difference I had to pay hasn't changed, it appears companies are able to just pocket an additional £2.5k in their pockets. How on earth does the government expect people to migrate from gas boilers to heat pumps with this closed shop racket going on !

Hi guys, my last 60 days gas consumption averages 1m3 for hot water and 6.5m3 for heating - Viessman boiler gives gas consumption for heating and water separately which is handy also verified against meter readings. So if my logic is correct 6.5m3 x 1.02264 (correction factor) x 40 (calorific value) / 3.6 (kWh conversion factor) = 74 Kwh per 24 hour period. Divide that by 24 = 3.08 Kwh Appreciate my boiler is not on 24 hours a day but to keep house warm at 21 degrees if it was on trickle heating this would be true? If that is the case then how have two MCS companies say my heat loss is between 10 & 12 Kw ? is my maths / logic correct? My own calculations marry up with my gut feeling that a 7kw Vaillant should be more than sufficient.

Hi all, my brain is hurting after trying to work out my heat loss as there is so much conflicting data. On the one hand I know that I run our underfloor generally at 35 degrees via gas boiler. We don't run weather compensation, system based on room thermostats / load compensation ? That said the heating is mostly on in the morning from around 4am where it heats the 80 - 90 mm screed after that for large amounts of the day the boiler is switched off, house stays around 20 - 21 degrees most of the time and even when heating is turned off at night it only drops to around 18.5 - 19.0 degrees or so, our setback is set at 18 and I don't think it has even kicked in. Its a fairly sophisticated Viessmann boiler and can modulate down to around 10% of its maximum i.e. it is a 19kw system boiler but most of the time it never seems to run over 30% modulation, often much less. House has been insulated to what i think is a high standard and very air tight, mvhr etc however heat loss calculations from companies are showing around 10 - 12kw which conflicts what I feel it is. Assuming it is 10Kw does this mean I need a 10Kw heat source running 24 hrs a day so with a COP of 4.0 that would be a consumption of 2.5Kw per hour 24 hours a day? Thanks

Hopefully get quote back soon, they are taking their time to do the heat loss so hopefully that may be a good sign. i will post findings once they arrive. I was certainly impressed with their approach to me installing myself when we discussed option on the phone, they even do free vendor training so you can still access longer warranties etc If it wasn't for trying to access BUS grant then I would simply purchase the heat pump and install myself keeping the boiler in situ for possibly the hot water heating. My Viessmann boiler is currently setup as a 4 pipe system anyway, 22mm hot temp circuit for uvc and a 28mm circuit at low temp for underfloor.

Hi, we are looking at installing either a Vaillant Arotherm or one of the new Samsung Gen7 R290 pumps. I am aware Vaillant has pump in the unit and Samsung have an external pump that the user suppliers? Our unvented cylinder is in the loft 2 floors up, is this going to pose a problem as we are looking to go fully open loop with no mixer or pump on the manifold. We have underfloor on 1st floor so plan is to run same temperature throughout. Keep it nice and simple. Just uncertain if pump has enough head to push water around ?

I have been having similar experience / frustrations with obtaining quotes for ashp. We are currently heavily renovating / extending a 1960's detached property. It is now circa 150m2 ground, 100m2 1st floor. All floors have been dug out and then new slab, insulation, underfloor (16mm @ 200 centres) , liquid screed etc. We have also installed overlay underfloor on 1st floor but only ground floor heating active at moment and bedrooms fine with no heat. Majority of walls are Plasmor Fibolite (0.24 - brilliant blocks) on internal and external skins, 100mm cavity with 75mm insulation, air tight parge coat and then 40mm closed cell xps foam board glued to block and then plasterboard glued to insulation. Roof is warm with 300mm pir insulation under osb skin. We also have mvhr being installed - project on going. Triple glazed Internorm Passive level windows and doors throughout. Basically aiming for as close to Passive i.e. lots of attention to sealing everything. The generic heat pump suppliers don't seem to take much of this into consideration and seem to be able to do a heat loss in a few mins with a couple of questions. Heat loss comes back around 11Kw, I challenge this and say our existing 19kw viessman boiler runs at 35mm flow and majority of the time modulates down to around 20% i.e. 3.8kw Personally I would like to install a Vaillant 7kw hp but nobody will budge. I have also built house with heat pump in mind and have already installed with brand new 28mm copper flow and return to boiler, heat pump would be fitted the other side of the cavity wall to where boiler is now, electrics are also in as is the 2 core comms cable, we have an existing 250 litre UVC in loft, so a really simple job. Quotes are coming in at around £14k before grant. When I challenge them about max 2 days on site for literally £7k of labour they just say " thats the way it is " I have recently found a company that do MCS installs under an umbrella scheme. They do the calcs, specify heat pump, do the grant application etc but then let your local plumber or even the self builder to install the system. They then commission it afterwards. just waiting on quote but keeping fingers crossed that this is a common sense approach and much more cost effective approach for may people who are self building etc - They are called Alto Energy

I have installed a Wundasmart heating controller with my Viessmann 100-W and it works great using Opentherm. It controls the water and underfloor heating and allows full modulation. I have plumbed the boiler in a 4 pipe configuration, one circuit for cylinder and the other for heating. Heating is set at 40 degrees and water at 60. I am very impressed with the system.