By: Gordon Ferguson

Gordon Ferguson — Mon, 28 Feb 2022 00:08:39 +0000

I could not agree more that ‘thermal comfort’ is the correct criteria, however this is not either/or with insulation but both/and.
I read a story some years ago of a social housing program that wanted to offer houses that were cheap to heat. However, the builders were only required to obtain a sufficiently good ‘u-value’ for the entire house envelope, and it was cheaper not to insulate the ground floor. The new residents quickly complained that the houses were expensive to keep ‘warm’ – because one ‘thermal comfort’ factor requires the difference in temperature between one’s head and feet to be less that three degrees – and the floors were cold.
We live in a largish late Victorian terraced house with nine inch solid brick walls, and as I see it, the biggest problems with the house are draughts and damp, which have a direct impact on ‘thermal comfort’. When we moved in in 1997, my first task was to change the sash windows to opening casements – but whilst preserving the look from the street since we live in a prosperous area where fitting plastic double glazing units would actually reduce the value of the house. In my view, a significant amount of the improvement in comfort from fitting expensive upvc double glazing units was getting rid of the draughts from poorly fitting windows – which could have been done a lot lot cheaper. However, there was a lot of skilled detail work required to get our windows – and doors – draught proof, which also requires regular maintenance.
Draught proofing immediately leads to damp problems due to condensation so we have a strict regime of opening windows during the day in unoccupied rooms, even when it is freezing outside. Damp from condensation can significantly reduce ‘thermal comfort’, and just turning up the heating thermostat does not work.
However, the biggest improvement in ‘thermal comfort’ of our house was efficient insulation of the attic and roof space – between 100 and 125mm of pir (Kingspan) insulation. This required careful and detailed work to achieve an airtight seal since nothing was square or level in this old house. Now the upstairs heating only comes on when the morning outside temperature drops below 2 degrees. A further significant improvement was damp proofing and also insulating the kitchen, along with underfloor heating to keep our feet warm. This space is easily comfortable at just 16 degrees.
Right now I am carefully draught and damp proofing the north facing very large bay window and adjacent walls to try and achieve similar levels of ‘thermal comfort’ in this our main sitting room. At the moment this room is only really comfortable at over 20 degrees.
So there is a real need to consider ‘thermal comfort’ alongside simply retrofitting insulation, but modern expectations of such comfort are very different from when the houses were built. Sadly, it is my view that retrofitting old houses to achieve modern levels of ‘thermal comfort’ is a highly skilled task that I fear is beyond the capabilities of typical building practice in this country, especially with simplistic solutions such as double glazing and just insulation, but is nonetheless very important on the path to zero carbon.

By: What we learned this week – The Earthbound Report

What we learned this week – The Earthbound Report — Sat, 26 Feb 2022 13:00:09 +0000

[…] tactics, but the idea of insulation in the first place? Andrew Curry discusses an interesting response from a buildings scientist to my recent post on Insulate […]

By: andyextance

andyextance — Sun, 20 Feb 2022 11:58:14 +0000

But how do we get to this? And what do we do with the existing fossil fuel-inspired buildings? Presumably their embedded carbon is worth trying to work with? I’ll listen to Pender’s paper and perhaps come back to comment when I have but this view doesn’t seem greatly constructive, if you will excuse the pun.

Comments on: Rethinking insulation

By: Gordon Ferguson

By: What we learned this week – The Earthbound Report

By: andyextance