Measuring energy efficiency effectivness

Sigh. Radiant energy isn't just just in the visible spectrum.

I think more work/thinking needs to go into some sort of compromise. With around 10m homes needing *something significant* doing, a measure of retrofit has to be tabled as a decent option. I've done a fair bit to this Victorian terrace - and some of it has felt intuitively wrong. The reason this house has fared so well for 100+ years has been down to the lack of insulation - mainly ventilation/gaps and porous materials. As it becomes more energy efficient the fabric is going to suffer - but there must be ways to minimise that and reach a middle ground.

I'm told that to insulate/heat/cool a large 'heritage' terrace to gold standard Passivhaus is the best part of 200k. So that's not going to happen. Forsake mechanical ventilation, cut a few corners, DIY, decent incentives (VAT free, sensible FIT, etc.) - maybe half-a-Passivhaus - £20,000?

In the process, hit COP targets, save construction/demolition costs, communities thriving and intact, heritage remains, and homes that people actually enjoy.

The disabled use is something that I'd be concerned about - having overseen some home-wrecking adaptations. The rest can be bridged by acceptable compromise. IMO.

Remove the internal materials back to brick - gain 2". Insert 75mm celotex,

Net loss of internal space = 2", likely along 1 or 2 (external) walls only. Totally worth it.

Just 30mm of Celotex is the same as 60mm rockwool inside a cavity, so it can be done even on smaller terraced houses. These tend to be longer front to back so losing 2 to 3 inches off the front and rear walls isn't an issue especially if a full refurb with new kit and bathroom is being done.

older buildings didn't use plaster board. Plaster was direct to brickwork ½" max.

But the reality is that while we have certainly seen a massive hike in atmospheric CO2 levels, we might have seen a 1C rise in average temperatures and its very far from clear that that is actually a bad thing.

The Thames used to freeze over in some winters. It doesn't anymore and it is far from clear that that is a bad thing.

Sigh, ArtStudents. Let's try a physics experiment.

Take a thermionic valve, wire up the heater. Does the glass of the valve get warm to the touch? If we paint it so the glass is opaque, does it change?

The heater coil is in a vacuum, so there is no conduction of heat to the glass (beyond the wires, which are tiny). There is no convection inside either, because it's a vacuum. The paint stops the visible light.

So all we're left with is thermal radiation.

If you have a thermal camera it's measuring long wave infra red... radiation.

Theo

Thanks no I know they weren't built with it - removed enough of the stuff they did use :-)

A special combo of horse hair, fine rubble (10-20mm), some sort of binding agent, and an eggshell-like c.3mm 'plaster'. FYI 1 rubble sack per m2.

As for depth - in the Victorian homes I've lived (4) in 1" to 2". Never seen

Well, in that case it probably is, and more generally the ill effects are clearly documented through news programmes most evenings if nothing else.

And even if it couldn't be proven beyond the doubt of the most hardened cynics, is it worth taking the chance?

Yes, I just tacked 25mm to the (passageway) alcoves. A solid 3C difference over untreated surfaces. Except around the sockets - lesson learned ;-). Cheap and quick.

I put 50mm in the bathroom during a refit. That room (a N and shaded W facing offshot) went from the coldest room in the house to the warmest - the radiator barely comes on except in the coldest snaps. Did the same at my sister's - 2 bedrooms - anecdotally, they're well chuffed. Just as well as they've just had an air source heat pump fitted to their otherwise poorly insulated 17C farmhouse ;-)

So while older homes *are* tricky to insulate, significant gains are there for the taking. Just not Passivhaus gains.

I remember reading long ago, that the freezing of the Thames stopped because the flow changed after the newer replacement of the Old London Bridge was built in 1831.

Remove internal materials back to single 4" brick, lose 15mm

Insert 75mm celotex,

lose 75mm

Depends if the rooms started out any decent size.

I added 3mm or cork tiles to a house with only 4" of brick walls. That helped amazingly.

Exactly

The point is however, that the gains are illegal under building regulations. Any 'material change' must be to full modern regulations. So what? 75-100mm celotex?

Oh dear.

I am not even going to comment.

It varies. I've seen plaster 1/2" thick and 2" thick. In some cases, it has been 1" at the bottom, 1/2" in the middle and 2" at the top, straightening up a wall. Presumably not built straight in the first place, as the plaster looked to be original.

It's only for 'major renovations' or 'replacement of more than 50% of the thermal element’s surface area' - part L PDF page 70:

(a 'thermal element' is something like a wall or a roof - ie a replacement would be you knock more than 50% of the wall down and rebuild it. It would not count as replacement if you insulated an existing wall or replaced the existing insulation)

Theo

Yes, it's probably safer that way. Less foot in mouth or art student style reply.