TheMitchells Posted July 31 Share Posted July 31 Okay - we have the first quote for ashp, radiators to 2 beds, bathroom, shower room and hall. (thats 5 rads), HWC and ufh to the lounge and kitchen - even though we didnt ask for that. I plan to add ufh when we do the extension as we will be re-doing the whole back of the bungalow. So will get that taken off. But its rather a lot!! while the EPC shows D, the bungalow is only 68m2 with an additional 28m2 when we do the new extension. So it is not huge. And we plan to retrofit insulation and renovate to a better air tightness. Am I being taken for a ride! That seems a large ashp for such a small building. I can see the Grant ashp for sale for £4,266 plus £800 for the installation packhttps://www.plumbnation.co.uk/grant-aerona3-13kw-r32-inverter-driven-air-source-heat-pump-hpid13r32body-111-37273?gad_source=1. But adding in the rads, hiring a plumber and electrician, should I just bite the bullet and get it done? I do have a second chap coming tomorrow for another quote. Unfortunately CVC have still not come back with a quote. I asked them over 2 weeks ago but nothing yet. Link to comment Share on other sites More sharing options...
TheMitchells Posted July 31 Author Share Posted July 31 One more thing - is a 210 hot water cyinder normal? our current one is only 120l and that seems fine. There is only ever going to be two people living there. And we have an electric shower so that would not come from the cylinder. Link to comment Share on other sites More sharing options...
MikeGrahamT21 Posted July 31 Share Posted July 31 210 is a lot of hot water, especially with an electric shower, any bath? Have you had a quote from Octopus Energy, E.On? Any of the big players just to compare? I'd guess someone else installing UFH would add a fair chunk to the bill. Link to comment Share on other sites More sharing options...
TheMitchells Posted July 31 Author Share Posted July 31 1 minute ago, MikeGrahamT21 said: 210 is a lot of hot water, especially with an electric shower, any bath? Have you had a quote from Octopus Energy, E.On? Any of the big players just to compare? I'd guess someone else installing UFH would add a fair chunk to the bill. One bath but not used very often - once a week? I looked at Octopus for a quote but it looks like you have to pay £500 for it, which is then deducted from the cost. The ufh install will come with the extension but thats not for a couple of years time. I'm looking for a simple heat loss calculator that i can use myself. I know jeremy had one. Will look for that. Link to comment Share on other sites More sharing options...
JohnMo Posted July 31 Share Posted July 31 For me these are the steps I would take. Assuming you keep the existing electric shower. Keep existing cylinder and heat via immersion as and when you need it, a simple immersion timer. Note: At heat pump temps 210L is more suited to a 3 bed house. Use the heat pump for CH only Do not do UFH unless you have lots of insulation below it. Especially if you are going to rip up sooner than later. Do you have idea of how many kWh of electricity you use for heating? Being electric it should run close to 100% efficiency, unlike a badly setup boiler. Use the reference here to check your likely heat pump size https://protonsforbreakfast.wordpress.com/2023/04/02/another-heat-pump-spreadsheet-beyond-the-rule-of-thumb/ Link to comment Share on other sites More sharing options...
MikeGrahamT21 Posted July 31 Share Posted July 31 50 minutes ago, TheMitchells said: One bath but not used very often - once a week? I looked at Octopus for a quote but it looks like you have to pay £500 for it, which is then deducted from the cost. The ufh install will come with the extension but thats not for a couple of years time. I'm looking for a simple heat loss calculator that i can use myself. I know jeremy had one. Will look for that. https://www.daikin.co.uk/en_gb/residential/products-and-advice/heat-pump-calculator/residential-solution-navigator-air-to-water-heat-pumps.html?lead=4c1379d4-4f4e-11ef-8c16-85d62a454bf0 Hopefully should be easy enough to get something usable out of it. I also found the proper MCS spreadsheet, thats anything but simple!! Link to comment Share on other sites More sharing options...
TheMitchells Posted July 31 Author Share Posted July 31 (edited) Scarily, it looks like they use 10,000 kW per year for hot water and heating. 😬 They do like it hot! Hubby is asking why we cant just add the radiators and a simple gas combi boiler?? I guess the easy answer is that there isnt gas to the property and the supplier for their area is talking about installation 10-12 weeks after acceptance of the quote, which was £1200. Unless we are able to connect into the neighbours incoming pipe? But with the central warm air unit still working (just), we could manage for a few months, getting the radiators fitted so that as soon as the gas is connected, a combi boiler could be fitted. It goes agaisnt my principles to use gas/fossil fuel. But it would be easy to install and probablly the cheapest option. Urhghh! The bill below shows their day and night use. The only thing on the night meter is the heating (mostly off currently apart from a small night storage heater in the shower room, turned low) and the hot water heating. Edited July 31 by TheMitchells Link to comment Share on other sites More sharing options...
Mr Punter Posted July 31 Share Posted July 31 Why not get some quotes for the gas combi and rads option and compare to the ASHP? 1 Link to comment Share on other sites More sharing options...
Dave Jones Posted July 31 Share Posted July 31 please post your heat loss calculation. without this your pi$$ing in the wind. Link to comment Share on other sites More sharing options...
TheMitchells Posted July 31 Author Share Posted July 31 Just now, Dave Jones said: please post your heat loss calculation. without this your pi$$ing in the wind. I dont have one. I am trying to use Jeremy's spreadsheet but there are bits I dont understand. Here is my attempt. But as we dont nhave an mvhr, that may spoil any results. Heat loss calculator.xlsx Link to comment Share on other sites More sharing options...
Dave Jones Posted July 31 Share Posted July 31 if you have had a quote for ASHP its law they provide your heatloss calcs against which they priced. post them Link to comment Share on other sites More sharing options...
JohnMo Posted July 31 Share Posted July 31 7 minutes ago, TheMitchells said: But as we dont nhave an mvhr, that may spoil any results Add 0.3 to number of air changes per hour and change MVHR efficiency to 0%. 1 Link to comment Share on other sites More sharing options...
JohnMo Posted July 31 Share Posted July 31 Start with basics Look at your name plate on the hot air heating system - what is it's rated output in kW. If it well below 14kW the quote you received is a bit of a joke. I would suspect closer to 6 to 8kW. Have a look on this forum, there have been people replace the hot air heat with A2A heat pump, so no radiators required. Link to comment Share on other sites More sharing options...
ProDave Posted July 31 Share Posted July 31 I would simply ask them HOW can they QUOTE (note quote not estimate) the total cost before they have done a heat loss calculation and therefore before they even know what size heat pump they are fitting so they don't know the materials cost. Anyway it does not take a genius to realise they are taking the pee and that is a grossly over inflated quote. I would run a mile. The more I see examples like this, the more I know this is where all the former double glazing sharks have gone to try and rip off as many unsuspecting customers as they possibly can. Link to comment Share on other sites More sharing options...
Mr Punter Posted July 31 Share Posted July 31 The EPC says you only have 100mm loft insulation. Top this up to 300mm and it will pay back very quickly. Link to comment Share on other sites More sharing options...
SteamyTea Posted July 31 Share Posted July 31 I think there are a number of problems involved with retrofitting ASHPs. The biggest one is general ignorance of heating systems and how they work (why many on here are trying to help). Once a customer gets a good idea of what is really needed, then they can shop around with confidence. Do your own heat loss calculations, then you can discuss requirements. Link to comment Share on other sites More sharing options...
MikeGrahamT21 Posted July 31 Share Posted July 31 I wonder how feasible running a combi boiler on LPG would be cost wise? Link to comment Share on other sites More sharing options...
TheMitchells Posted July 31 Author Share Posted July 31 2 minutes ago, MikeGrahamT21 said: I wonder how feasible running a combi boiler on LPG would be cost wise? Oh no - please dont confuse me any more - there are so many options already!😁🫤 Link to comment Share on other sites More sharing options...
Marvin Posted July 31 Share Posted July 31 Hi @TheMitchells No matter what you do, increase the loft insulation to 300mm where you can. 3 hours ago, JohnMo said: Do not do UFH unless you have lots of insulation below it. Especially if you are going to rip up sooner than later. Ditto. 1 hour ago, Dave Jones said: if you have had a quote for ASHP its law they provide your heatloss calcs against which they priced. post them And yet they say they will do them after..... If you are going to increase airtightness I assume you are going to use or have trickle vents in the windows. I think this will assume that 1/3 of the volume of the air in the building per hour will be replaced by outside air and therefore in winter produce a calculable heat loss. Pipework from the outside ASHP would be better run inside the thermal envelope of the building unless wrapped in a layer of 300mm loft insulation. Can you mark the position of proposed outside unit on the plan? I see you need a hot water tank. Will you need a buffer tank as you have underfloor heating and radiators? Where are they proposing to put the underfloor heating manifolds? Good luck Marvin 1 Link to comment Share on other sites More sharing options...
Marvin Posted July 31 Share Posted July 31 6 minutes ago, MikeGrahamT21 said: I wonder how feasible running a combi boiler on LPG would be cost wise? Hi @TheMitchells This would depend on whether you have a tank in the grounds or if you have to use bottled gas. Having installed bottled gas boiler in our bungalow and replaced it with an ASHP, we prefer the ASHP. However we have PV on the roof which supplements the cost of running it, and a very well insulated bungalow. An ASHP is most efficient when the difference in temperature between the outside air and the temperature of the water leaving the ASHP is the smallest. The calculated size of the gas boiler radiators would be smaller than ASHP radiators because the water temperature is usually run lower for best economy. We have larger radiators (with obviously more surface for heat to come off of) that are cooler and this make for the best result. Good luck Marvin Link to comment Share on other sites More sharing options...
JohnMo Posted July 31 Share Posted July 31 15 minutes ago, Marvin said: calculated size of the gas boiler radiators would be smaller than ASHP radiators because the water temperature is usually run lower for best economy But for best gas economy you would size them the same, to get best of the condensing mode. Link to comment Share on other sites More sharing options...
SteamyTea Posted July 31 Share Posted July 31 23 minutes ago, JohnMo said: 40 minutes ago, Marvin said: calculated size of the gas boiler radiators would be smaller than ASHP radiators because the water temperature is usually run lower for best economy But for best gas economy you would size them the same, to get best of the condensing mode. Would that be the case if you wanted to deliver instantaneous hot water. A 14 kW heater does not deliver a great amount of flow. Link to comment Share on other sites More sharing options...
Marvin Posted July 31 Share Posted July 31 (edited) 49 minutes ago, JohnMo said: But for best gas economy you would size them the same, to get best of the condensing mode. err. not sure what you mean... Edited July 31 by Marvin further thought Link to comment Share on other sites More sharing options...
TheMitchells Posted August 1 Author Share Posted August 1 9 hours ago, Marvin said: If you are going to increase airtightness I assume you are going to use or have trickle vents in the windows. Pipework from the outside ASHP would be better run inside the thermal envelope of the building unless wrapped in a layer of 300mm loft insulation. Can you mark the position of proposed outside unit on the plan? the current windows do not have trickle vents and I would not want them in any replacements. we plan to add mvhr when we do the renovation in a couple of years. The bedroom windows front onto quite a busy road which for me means closed windows. My parents are both going deaf so its not a problem for them. I had planned to have the unit under the front bedroom window. But the company who gave the quote say the regs say it cannot go to the front of the building if it fronts a highway. however, looking at the regs, it says in the case of land, other than land within a conservation area or which is a World Heritage Site, the air source heat pump would be installed on a wall of a dwellinghouse or block of flats if— (i)that wall fronts a highway; and (ii)the air source heat pump would be installed on any part of that wall which is above the level of the ground floor storey. As ours will be on the ground, I read that under the front window would be acceptable. We are not planning ufh yet - thats for the renovation and then we'd have a utility room so hopefully the manifold would go in there? I believe there would be a buffer tank with the hwc. and that is all going into the cupboard in the centre of the bungalow, where the current heating system is. Once we get it removed. Still waiting for the 2 asbestos companies to reply to my enquiry. job for the morning - chase them up. Link to comment Share on other sites More sharing options...
Dave Jones Posted August 1 Share Posted August 1 12 hours ago, Marvin said: Hi @TheMitchells No matter what you do, increase the loft insulation to 300mm where you can. Ditto. And yet they say they will do them after.... Good luck Marvin that would be the end of conversation for me. Cowboy company alert. How can you size rads and a heatpump without doing heatloss calcs. run 1 Link to comment Share on other sites More sharing options...
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