Diminishing returns

[tonyshouse]

How important a factor are diminishing returns. These are often used as a reason for not adding sufficient insulation

 

in my way of thinking a more important consideration is the alarming cost of retrofitting insulation. Factor that in and diminishing returns literally go out the window.

 

further there is a step change once insulation levels get above the point where an expensive to install, run and maintain, heating system is no longer needed.  

[Gone West]

11 minutes ago, tonyshouse said:

further there is a step change once insulation levels get above the point where an expensive to install, run and maintain, heating system is no longer needed.

That is why I ran lots of iterations of PHPP in order to design a house that didn't need an expensive central heating system.

[the_r_sole]

4 minutes ago, tonyshouse said:

How important a factor are diminishing returns. These are often used as a reason for not adding sufficient insulation

 

in my way of thinking a more important consideration is the alarming cost of retrofitting insulation. Factor that in and diminishing returns literally go out the window.

 

further there is a step change once insulation levels get above the point where an expensive to install, run and maintain, heating system is no longer needed.  

 

You've framed that in a very particular way - first of all, I don't think it's ever used for "not adding sufficient insulation" - that would imply that the heat loss of the construction is unacceptable, however many people get to the point where the difference in heat loss between a 0.11 and a 0.12 wall isn't worth the extra investment in terms of the capital costs are never repaid over the lifetime cost of the building.

 

 

[joe90]

It’s “sufficient insulation” if the building regs are good but “additional insulation “ if the building regs are  poor, which they are now IMO.

[LA3222]

I think everyone is getting hyper focused on the word 'insulation' in this thread. I suspect that the comment is more a general observation about  diminishing returns pertaining to a self buildnin general with insulation referred to as an example.

 

Self builders tend to be a more fussy lot, particularly the ones whom carry out alot of the work themselves, as such, self builders tend to go above and beyond with everything when it comes to build standards applied and material choices made.

 

I suspect diminishing returns is something that is individual to everyone and each of us will have our own limits as to what constitutes 'enough'.

 

As an example, I have probably gone way OTT with regards to taping and sealing joints to get my air tightness down, its not what everyone would do but I was happy to do it.

 

The way I approach my own build is to assess everything against if I dont do something what are the consequences if I want to do it later. Most things tend to fall into the 'do it now' category otherwise to do it retrospectively can be a massive problem.

 

Thats probably also a factor as to why self builders go above and beyond, with the bare bones of a house to work with it is very easy to implement things now rather than in the future. 

[Mr Punter]

Space heating in a properly built new house or flat is not tricky or energy hungry.  Hot water and solar overheating can be bigger issues.

 

Air tightness can be more significant than insulation.