A bit more on Air Source Heat Pumps (and all that Jazz).

Revisited, briefly..

I felt the need to write a short piece here, following conversations with my good friend Jim and some concerning articles on the BBC news website about recently fitted home insulation.

This is in regard to the English and Cymric Governments’ attempts to improve the sustainability of the housing stock by offering free grants for Air Source Heat Pumps (ASHPs), solar panels, insulation and the like. I raised several concerns in an article here on Substack. Also, after posting a link to the piece on Fatebook and picking up a surprising amount of flak, I wrote another piece in response to that.

One of my concerns was that the subcontractors who were employed to carry out each phase of the work were allocated very little time to do it in and I wondered what would be the consequences. Jim, my old friend, a pensioner and guinea pig in all this, had opted for an ASHP, radiators, extra insulation and ten solar panels. The work was duly carried out, though after completion, it took three additional visits before the ASHP actually worked.

When the contractors had finally gone, Jim noticed they seemed to have left quite a lot of stuff behind, including a decent pair of boots, a lot of useful sized screws (thanks Jim!) and plenty of pipe lagging. Intrigued by the lagging, Jim popped the trap on his floor and ventured down into the crawl space where he found that non of the new pipes running from the ASHP cylinder to the radiators had been lagged. Given that the efficiency of an ASHP is highly dependant on good insulation, this seemed like a basic error.

Being a practical sort of 75 year old, Jim set too and began doing the pipe lagging himself. He then found that where one pipe ran from a front room radiator to meet a pipe from the tank, they hadn't been lined up properly and the connection was leaking. In this instance he phoned the contractors and they made a return journey to put it right. Of course, if Jim had not been of a practical bent and not had a look under his floor, neither the lack of lagging or the leak would have been noticed.

Then, having a nosy around the back of the new ASHP cylinder (a very substantial, large affair), he found, dangling on some wires, a mysterious box with a hole in it which looked like it was meant to fit onto a splined shaft on the cylinder itself. So another phone call to the contractors and another visit and the box was firmly attached to the cylinder. Again, if Jim hadn't been the sort to have a good look this wouldn't have been fixed, though Jim is unsure what the box was supposed to do anyway, as the ASHP seemed to be working OK without it....

Given that several tens of thousands of these installations have now been carried out, it does make you wonder what else has not been done and is waiting to go wrong…

Finally, I also raised concerns about insulation and the problems that can be caused depending on where it goes in a wall- inside, outside or, in the case of cavity wall, in the cavity. Looks like I was right to be worried as several stories such as this one on the BBC web site confirm.

A cavity wall is exactly that, a cavity wall- basically, two walls with a cavity, an air gap, between them. If you then fill that air gap with insulation, it is no longer a cavity wall, it is a wall with a moisture barrier in it and that means a surface on which cooling, humid air from inside the house can condense and cause mould. Duh! The really depressing thing about this is that its a problem that was identified over a decade ago (check this story on the BBC) and yet the same or similar mistakes are still being made.

There's no doubt that much of the housing stock in the UK and especially in Cymru, is substandard in terms of insulation and heating but rushing to try to sort it with one-size-fits-all solutions without properly addressing each individual situation is, as usual going to create more problems and expense than it is intended to save.

Many years ago, when I asked another old friend, Jo, from CAT (the Centre for Alternative Technology, Machynlleth), what sort of heating should I put into our barn conversion, he said don't worry about that yet, first thing to do is to get as much insulation into the building as you can, in the right places.

We did. It works. We now find that the small wood burner we used in our caravan/shed dwelling for twenty five years, heats our new home perfectly adequately for less wood despite it being three times the volume of our old home.

Thanks for reading. Hwyl! Chris.