[orwin]

Insulation cut my mother's home energy costs by 60% this winter. And her home wasn't as poorly insulated as UK homes seems to be according to what I read (and in general, it was a bit above the average French home).

Granted, heating is around 15% of the total equivalent Co2 we use, but reducing that by 60% would prevent 8 to 9% of produced energy to be used. Also would cut costs for a lot of the poorest.

If insulating UK cost around the same price (or even more, because the windfall will be in UK taxpayer pockets), I think it should be done first.

[gerdesj]

UK home owner here. House is sticks and bricks, built 1920ish but heavily modernised. Insulated to modern building regs, including extra steels and structure to account for snow loading on the roof. When it snows here (very infrequent) our house is the only one that it sticks to. Also acoustically insulated between floors. Ground floor (first floor elsewhere) - we hung safety barrier netting between the joists and ran 125mm of loft insulation between the joists to insulate from below but still allows some air movement and avoid condensation.

Underfloor heating ... electrical underfloor heating - across the entire house. Now our theory was that if we got our 'leccy from renewables, we were pretty "green". We do have gas but that is only used for cooking (hobs only - not the oven) and hot water.

When say our kitchen floor decides to switch on, that's 4KW. Each room has its own circuit and we switch off the unused ones. After a power cut the blasted things revert to defaults and switch themselves back on, I have to cut them off at the consumer unit to be sure. I am three years into experimenting with Zwave zone controllers but they cost a fair bit and I need to be absolutely sure about safety before I deploy all 10 zones. I'll probably install a separate cut off switch per zone with a few temperature probes as well as the controllers with their own sensors but that is a while off for now. Home Assistant with Node-Red runs this lot and more. Safe power control does need some care ...

Electricity here is roughly three times more expensive and rising than it was before a bunch of homicidal Russians decided to fuck up their neighbours. My bills are quite heavy and it doesn't help that I run quite a lot of IT stuff here! I'm very lucky that I can afford all this but not everyone can.

I don't think that UK housing, in general, is any worse than the rest of Europe with respect to insulation. I lived in West Germany for some time back in the day and I studied Civil Engineering so I think I have a fair handle on the issues involved. We have just as many horrors in our housing stock as everyone else.

[cjrp]

Interesting, I'm in a house of a similar age/construction but not very well insulated apart from the loft. Have you written up any more information at all; costs too? Assuming you have a cavity wall, did you insulate that?

[gerdesj]

I'm a bit wary about filling the external wall with polystyrene balls or whatever. I need to determine whether there are enough brick ties installed and that they are working. Brick ties are basically bits of heavy wire that should be laid in the mortar that hold the two rows of bricks together.

The idea of filling the cavities of a fairly old brick built building with some form of insulation is sound but does need care. In the UK (and elsewhere too) we generally go for "sticks and bricks" construction. The external "box" is often a double skin of brickwork. My house is roughly six meters by 12 meters (20' x 40') in plan. Each storey is about 2.5m high - that's why you see wood in 2.4m lengths (allow for bits above and below).

So let's look at the structural components: Take a wall 12m long x 5m high. The wall is constructed of two skins of brickwork. Brickwork is very good in compression but not so good in response to a lateral force. If wind is allowed to whistle inside our brickwork it will basically raise the pressure inside the gap between the two skins of brick. If you pump something into the gap that will also exert a lateral force. To stop your walls collapsing outwards, you should have brick ties installed and they should be in reasonable condition and the mortar should be gripping them effectively.

You can go for external or internal insulation instead. External means cladding of some sort and internal means you will lose some internal floor space.

The biggest gain of all is insulating the loft - heat rises. You should aim for a good 250mm of "wooley" or equivalent.

In general I'd suggest looking for draughts and plugging them. Do be careful that ventilation is still maintained.