Andrew Posted July 10, 2020 Share Posted July 10, 2020 Before we started, in fact, before we bought the plot I obtained plans from all the utility companies and the nearest gas main was a very long way up the road. No problem, we made all of our plans based on only having electricity. That included ASHP for UFH and hot water with an immersion boost. We were pleased that there is potential for lower carbon emissions with an ASHP, especially as the grid continues to de-carbon. We had an as-designed SAP done, with an A 94 rating including the ASHP, our Ecology mortgage has a discount if we achieve this. The plan was made, all was good. So I was talking to my neighbour the other day (who is building on a plot next door) and, with a glint in his eye, he said I'm getting a gas supply. I immediately asked the obvious questions, "How much?" . "£800" he said, clearly delighted with this small victory. Turns out a couple of new builds up the road had paid mega bucks to bring the gas main down the street and as such my neighbour had benefitted with a relatively modest cost for his gas supply. Now this got me thinking, surely given that they will need to extend down to my neighbour, my cost to connect gas should be similar to his, so I've submitted an application for a quote. But, I'm really in two minds - I was set on having an ASHP and whilst I know the running costs with gas will be lower, the higher environmental cost really troubles me. Moreover I think there's an element of being reluctant to change plans at this late stage. I have already buried all the ASHP ducting and piping through the slab, researched and selected the ASHP unit and supplier, the plumbing tender has gone out with the ASHP in it and our accepted electrical quote includes connecting the ASHP up. So I'd welcome any thoughts, am I just been too inflexible, unwilling to make a change at this late stage or is there merit with sticking with electricity only. What's the likely impact on the SAP assessment, will using a gas boiler lower our rating massively? Link to comment Share on other sites More sharing options...
jamieled Posted July 10, 2020 Share Posted July 10, 2020 I'd generally avoid making decisions based on what it does to the SAP rating unless your financing is dependent on it. As has been discussed elsewhere on here, SAP has some flaws in low energy housing. The only benefit you mentioned in using gas is the potentially lower running cost, but even that is only based on current prices and you can't guarantee it would continue. Like everyone on here, we've made many decisions based on what's important to us, rather than trying to cost-benefit everything to death. Assuming your house is fairly well insulated I'd imagine your all electric costs would be pretty low in an absolute sense ? If that's the case, I'd not be considering gas. 1 Link to comment Share on other sites More sharing options...
Mr Punter Posted July 10, 2020 Share Posted July 10, 2020 I am in the planning stage for 3 new flats which will be build to let. I really wanted to go no gas but there was no way to sensibly achieve it without impoverishing myself and the tenants. For a house, with the space for tanks and plant it must be a closer call. Combi gas boilers for me though. Link to comment Share on other sites More sharing options...
Nickfromwales Posted July 10, 2020 Share Posted July 10, 2020 (edited) Install the gas for now, and leave it all set up ready in anticipation of the fitting of an ASHP later down the road if the numbers make more sense then. If it's not a massive property you could get away with a decent high-flow combi boiler at £1500-£1800 plus fitting. Do you have rads or UFH? Most other M&E's I've spoken with still advocate using gas if it is available.... Your conscience is your's to deal with and your's alone. Also your money is your's to spend, and not others who may aspire to better things ( when it's not at their expense ). Do what is right for your budget and expected living costs, and if it becomes viable later, you or a new owner could retro fit the ASHP with ease. Edited July 10, 2020 by Nickfromwales 1 Link to comment Share on other sites More sharing options...
A_L Posted July 10, 2020 Share Posted July 10, 2020 1 hour ago, Andrew said: What's the likely impact on the SAP assessment, will using a gas boiler lower our rating massively? SAP is a COST index, given the current price of gas vs daytime electricity switching to gas could increase your SAP score. https://forum.buildhub.org.uk/topic/11185-what-is-the-effect-of-epc-changes/?tab=comments#comment-188312 Link to comment Share on other sites More sharing options...
epsilonGreedy Posted July 10, 2020 Share Posted July 10, 2020 I though SAP was an eco goodness index that does not track cost directly? Link to comment Share on other sites More sharing options...
joe90 Posted July 10, 2020 Share Posted July 10, 2020 With gas comes another standing charge and servicing costs and what is the life of a decent gas boiler these days? (I had to go ASHP as no gas near me but very glad I did). Link to comment Share on other sites More sharing options...
JFDIY Posted July 10, 2020 Share Posted July 10, 2020 Get the gas piped to the property, you don't actually have to get the meter fitted and it made live. My parents did that (along with ducts for all the other services) to one of the outbuildings when we did some sewer works. Link to comment Share on other sites More sharing options...
Andrew Posted July 10, 2020 Author Share Posted July 10, 2020 Interesting comments, thanks. Its quite a big house, 320 m2 with 6 bathrooms, so a combi probably isn’t going to do it. We’ve UFH throughout the ground floor but no plans for radiators upstairs. We’ve just finished the roof, doors and windows are going in now, so could easily change plans at this point. Even keeping the unvented cylinder, a decent sized system boiler seems to be less than half the cost of the ASHP, so I’m sure there’d be a saving on the build cost as well as the ongoing running costs. We’re not in passive house territory, although the house will be fairly well insulated (it’s a 140mm open panel timber frame fully filled with frametherm + 50mm PIR on top across the studs) and good airtightness. According to the SAP calcs we need about 12,000 kWh of heat input per year for space heating and hot water, so with some rough calcs using a very conservative COP for the heat pump, I reckon there’s about £200 annual saving for gas. But as some have said it’s not just about the pounds and pence and electric has much more potential to allow us to meet some of the environmental goals of the build. Hopefully the gas connection quote will come back really expensive and it’ll be decision made! 1 Link to comment Share on other sites More sharing options...
A_L Posted July 10, 2020 Share Posted July 10, 2020 34 minutes ago, epsilonGreedy said: I though SAP was an eco goodness index that does not track cost directly? Not the main SAP Index, but there others within SAP that have 'eco goodness'. Fabric Energy Efficiency (FEE), Environmental Impact Rating (EI), Dwelling Emission Rate (DER) Link to comment Share on other sites More sharing options...
Nickfromwales Posted July 10, 2020 Share Posted July 10, 2020 39 minutes ago, Andrew said: Hopefully the gas connection quote will come back really expensive and it’ll be decision made! Lets wait and then make some further recommendations. Your build sounds like it could easily accommodate an ASHP and it would be better suited to drive that type of heating. Link to comment Share on other sites More sharing options...
shuff27 Posted March 23, 2021 Share Posted March 23, 2021 Hi @Andrew what was the conclusion of your gas vs elec conundrum? I'll be facing the same issue soon. Link to comment Share on other sites More sharing options...
Big Jimbo Posted March 23, 2021 Share Posted March 23, 2021 I would bring the gas in if it were me. Just because i hear that the gas may at some time be changed to hydrogen or something ? If you don't bring it in, and somebody want's it in the future, it will be a total pain to bring in. Link to comment Share on other sites More sharing options...
TonyT Posted March 23, 2021 Share Posted March 23, 2021 I would try and have a small plant room so that changes to any type of heating system are minimised to the whole house. a few spare ducts from the plant room to outside for future will save a lot of grief. oh and a drain connection too! Link to comment Share on other sites More sharing options...
Andrew Posted March 23, 2021 Author Share Posted March 23, 2021 I didn't bother in the end, mainly as budget is under stress and whilst the quote was only £1500, all these 'only' 1500 quid items add up. I have laid a duct from the plant room under the driveway to the boundary so if the ASHP turns out to be a disaster we can connect it without digging up the drive. Link to comment Share on other sites More sharing options...
epsilonGreedy Posted March 23, 2021 Share Posted March 23, 2021 2 hours ago, TonyT said: oh and a drain connection too! Is there a new heating technology around the corner that needs a drain? A cooling circuit for a domestic nuclear fusion reactor? Link to comment Share on other sites More sharing options...
TonyT Posted March 23, 2021 Share Posted March 23, 2021 Condensing gas boiler- condensate requires to go into drain. also if it was a proper plant room a drain connection or floor drain is a plus, makes things easy,draining down cylinders, leaks etc Link to comment Share on other sites More sharing options...
epsilonGreedy Posted March 23, 2021 Share Posted March 23, 2021 2 minutes ago, TonyT said: Condensing gas boiler- condensate requires to go into drain. Is an external wall a viable substitute for the condensate drain, freezing risk aside? Link to comment Share on other sites More sharing options...
TonyT Posted March 23, 2021 Share Posted March 23, 2021 Sure, but if the condensate is going outside you have to increase the diameter of the condensate pipe to prevent freezing. Link to comment Share on other sites More sharing options...
epsilonGreedy Posted March 23, 2021 Share Posted March 23, 2021 Just now, TonyT said: Sure, but if the condensate is going outside you have to increase the diameter of the condensate pipe to prevent freezing. Good to hear, I thought I had a made a design mistake. When I first read your post I began to think that a hydrogen boiler might generate a lot more water and require special drainage arrangements. Link to comment Share on other sites More sharing options...
TonyT Posted March 23, 2021 Share Posted March 23, 2021 https://condensatepro.co.uk/drift-kit/ Link to comment Share on other sites More sharing options...
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