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Originally Posted by Taf
We were part of a group of council homes that were moved from Baxi back boilers in the living room gas fire hearth to Baxi wall-mounted combi-boilers.
They all suffered problems, from minor to major and dangerous, with ours having every part, apart from the case and wall plate, swapped for new.
So the council changed to a single Worcester model which was overpowered for our home but just adequate for most.
All OK for a year or so, then drips and auto shutdowns started. It was always the same component that failed, a pressure bladder that developed pinhole leaks. Once their initial stock of spare bladders had been used up, the new ones all worked perfectly.
Our was installed as "on-demand" only on the downstairs loo wall, 6 feet from the kitchen tap and directly below the bath, so there are no long runs of pipe to lose heat when the boiler kicks into life when a hot tap is opened. We lost the attic cold tank and airing cupboard hot water tank, but a neighbour had the boiler fitted into the airing cupboard, feeding a pressurised hot water tank. They soon learnt not to leave the system keeping tank water hot 24/7! Their system is on a waiting list to be moved into their downstairs loo, losing the hot water tank and reducing their gas consumption significantly.
Moving the boiler into the downstairs loo is also a precursor to a heat pump being installed at some point, "when costs drop to an affordable level." A couple of test systems were fitted in the summer of 2023, using the existing 15mm pipe and radiators. The tenants complained that the pumps ran almost 24/7 during the colder months, achieving only 17.5c around the house and not providing enough water even for a shallow bath. And then there were the higher costs, as electricity is about 5 times higher than mains gas. And their neighbours were constantly complaining about the incessant noise.
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I’ve been following heat pump developments for around 20 years now, as when we moved to our previous house we were off mains gas and didn’t even have heating oil like most of the neighbours - the house still had an open coal fire with back boiler. Back then, air-source heat pumps just weren’t an option unless you lived in a small, hermetically sealed and super-insulated chalet of the sort common in Scandinavia but non-existent in the UK. They were returning an efficiency of 3:1 if you were very lucky. Ground source heat pumps on the other hand were 4:1 or maybe a little better.
We went some way down the road of planning just such an installation but the problems began to multiply. The first problem was, back then, the established big companies were only set up to design and install large commercial projects. In response to that there were a few cottage industries popping up trying to serve domestic customers, but largely they were trying to profit off knowledge they had initially gained doing an entirely DIY installation of their own. They were interested in selling equipment but less interested in end to end design and project management. So our ground source project went from horizontal loops to collect the heat, then a vertical borehole (once it became clear we didn’t have nearly enough garden to lay the amount of horizontal collector pipe we’d need), then two vertical boreholes, at which point the whole thing was prohibitively expensive. Had the company we’d been talking to been prepared to take the entire project on and begin with a heat loss assessment of the house a lot of time and effort could have been saved.
In the end we went with wood pellets and installed a very pretty Italian burner which lived happily in the hearth formerly occupied by a Rayburn stove, but like all things Italian it was fiery yet temperamental. And getting spare parts was a nightmare because the manufacturer had given sole distributor rights to a small company way up in the northern highlands. We had a ridiculous situation a couple of times where we had to have our repairer talk to them, to get them to order something from Italy, which would be onwards delivered twice within Scotland before someone brought it to the house. More than a fortnight with no heating on two occasions (thankfully, living in a rural community, it’s easy to borrow loads of electric radiators).
These days I see all the talk of life-expired gas boilers being replaced by air source heat pumps and I just know the next national scandal is going to be the noise nuisance caused by entire streets worth of the things all kicking in at the same time on winter evenings. Even the best-made ones are far from silent, and like all things that have fans that move on bearings, the older they get the noisier they get. If it came to it and I had to have one, despite the cost and the disruption I would probably still want to turn a third of my garage over to a ground-source machine with the largest heat reservoir I could afford, and feed it from a single borehole in the back lawn. Though I still think we are going to see a government u-turn on the phasing out of gas, and a move to mixing green hydrogen into the public gas supply, probably about 5 years after the first complaints about noise and electrical overload start hitting the headlines.