Green Building Forum - Any downsides to replacing regular boiler with combi? Tue, 19 Dec 2023 06:23:19 +0000 http://www.greenbuildingforum.co.uk/newforum/ Lussumo Vanilla 1.0.3 Any downsides to replacing regular boiler with combi? http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17980&Focus=303682#Comment_303682 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17980&Focus=303682#Comment_303682 Tue, 03 Oct 2023 18:41:20 +0100 DannySheffield
We need a new bathroom and the fitter has strongly recommended we replace the heating system first as a) it is likely to go wrong and need work which might well involve digging into walls etc, so it's better to do that before we have a new bathroom (and plastering in other parts of the house) done. b) switching to a combi boiler would free up much-needed space in a relatively small bathroom.

I'm aware that we won't be on a gas boiler forever. My question is - is there any benefit to maintaining space for the hot water cylinder in the bathroom on the basis that we might need to move back to tanks if we move to e.g. an air source heat pump? The heating engineer said that's probably 20 years away in our 1930s house. We have a second (120 litre) tank in the crawlspace, which we'd keep either way (just because it's too much hassle to get it out!).]]> Any downsides to replacing regular boiler with combi? http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17980&Focus=303691#Comment_303691 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17980&Focus=303691#Comment_303691 Tue, 03 Oct 2023 20:37:52 +0100 djh Any downsides to replacing regular boiler with combi? http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17980&Focus=303696#Comment_303696 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17980&Focus=303696#Comment_303696 Tue, 03 Oct 2023 23:09:20 +0100 tony Any downsides to replacing regular boiler with combi? http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17980&Focus=303720#Comment_303720 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17980&Focus=303720#Comment_303720 Wed, 04 Oct 2023 15:00:38 +0100 Simon Still
Surely if you're replacing the heating system now is the time to think about fitting a heat pump.]]> Any downsides to replacing regular boiler with combi? http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17980&Focus=303723#Comment_303723 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17980&Focus=303723#Comment_303723 Wed, 04 Oct 2023 16:15:45 +0100 DannySheffield
Posted By: Simon StillOn the green building forum I don't think anyone should be considering fitting a gas boiler now - we're really at the stage where it's obvious that is not green, sustainable or a long term strategy.

Surely if you're replacing the heating system now is the time to think about fitting a heat pump.


Simon, I take your point. The heating engineer I spoke to said our property wouldn't be suitable in its current state as it's not well insulated enough. It's a 1930 with cavity wall insulation, but I think a solid wall on the front (I'm trying to address that through ECO4). We have underfloor insulation and an insulated loft conversion (albeit to 1980s standards). We can't afford a big increase in energy bills at the moment. Any recommendations for where to get a balanced opinion on suitability? All the people I can see locally either do gas boilers or air source heat pumps, so I'm assuming have a bias.]]> Any downsides to replacing regular boiler with combi? http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17980&Focus=303724#Comment_303724 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17980&Focus=303724#Comment_303724 Wed, 04 Oct 2023 19:54:59 +0100 Simon Still Posted By: DannySheffieldThanks everyone, I really appreciate your thoughts.

Posted By: Simon StillOn the green building forum I don't think anyone should be considering fitting a gas boiler now - we're really at the stage where it's obvious that is not green, sustainable or a long term strategy.

Surely if you're replacing the heating system now is the time to think about fitting a heat pump.


Simon, I take your point. The heating engineer I spoke to said our property wouldn't be suitable in its current state as it's not well insulated enough. It's a 1930 with cavity wall insulation, but I think a solid wall on the front (I'm trying to address that through ECO4). We have underfloor insulation and an insulated loft conversion (albeit to 1980s standards). We can't afford a big increase in energy bills at the moment. Any recommendations for where to get a balanced opinion on suitability? All the people I can see locally either do gas boilers or air source heat pumps, so I'm assuming have a bias.

I think there is a big issue with heating engineers repeating the scare stories from the press or that they've been fed by the boiler manufacturers who have a clear incentive to discourage heat pump sales.

This thread (on Twitter) says the sums add up right now both for capital and running costs of a heat pump -
https://twitter.com/janrosenow/status/1709555750291263846?s=46&t=dAsKuC7CSc6zyBFbJ0vjeQ

Capital costs only add up because of current subsidies but running costs:
"This means that already with a modest SCoP of 2.9 at current price cap electricity prices the running costs of a heat pump are a bit lower than a 85% efficient gas boiler. With existing time of use tariffs or the new
@OVOEnergy @_heatgeek offer much larger savings are to be had even at modest SCoPs. High SCoPs and those tariffs savings combined could be more than half of the running costs of a typical gas boiler.]]> Any downsides to replacing regular boiler with combi? http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17980&Focus=303725#Comment_303725 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17980&Focus=303725#Comment_303725 Wed, 04 Oct 2023 20:06:31 +0100 Simon Still
I've only just skipped through this one but he made huge savings by scaling back an overspeed heating system and adding weather compensation control. House had TWO oversized boilers, two 300l tank and excessive pumps....
https://www.youtube.com/watch?v=FaSHX5mhyDw]]> Any downsides to replacing regular boiler with combi? http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17980&Focus=303726#Comment_303726 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17980&Focus=303726#Comment_303726 Wed, 04 Oct 2023 20:34:04 +0100 djh https://www.urbanplumbers.co.uk/]]> Any downsides to replacing regular boiler with combi? http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17980&Focus=303743#Comment_303743 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17980&Focus=303743#Comment_303743 Thu, 05 Oct 2023 10:33:42 +0100 WillInAberdeen Eg
https://twitter.com/Damon_BPHR
https://twitter.com/Ainsdale_Gas
https://twitter.com/GSHPinstaller]]> Any downsides to replacing regular boiler with combi? http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17980&Focus=303745#Comment_303745 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17980&Focus=303745#Comment_303745 Thu, 05 Oct 2023 11:17:37 +0100 WillInAberdeen Any downsides to replacing regular boiler with combi? http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17980&Focus=303751#Comment_303751 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17980&Focus=303751#Comment_303751 Thu, 05 Oct 2023 11:31:11 +0100 djh Any downsides to replacing regular boiler with combi? http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17980&Focus=303758#Comment_303758 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17980&Focus=303758#Comment_303758 Thu, 05 Oct 2023 15:53:44 +0100 WillInAberdeen