Hi all,

I am researching how low u-values need to be to achieve CSH levels. I realise that this part of the code is based on a percentage DER/TER improvement but does anyone have a feel for what this translates to in terms of fabric u-values.

I am after Code 4,5 and 6 u-values for walls and ceilings and suspended floors. Anyone help?

Many thanks in advance. Mike

Thanks ST.

Been reading some more : From http://www.woodknowledgewales.co.uk/page.jsp?id=89

"Achieving Code 4 requires a mandatory minimum of 8 credits under section Ene 1 resulting in a DER/ TER improvement of ≥ 44%. Because of the design flexibility provided by Part L of the building regulations there is no defined U value for a wall element which would be required to comply with this reduction in the DER. In practice U values of 0.15 W/(m2K) or less are generally considered necessary to achieve such a significant reduction in the DER. In certain contexts, such as detached houses in an exposed setting, architects may wish to specify even lower U values than this, with U values as low as 0.1 W/(m2K) considered necessary"

The site doesn't really make it clear whether the improvement in wall u-value alone is typically enough to result in the 44% improvement; or whether improvements to the other fabric elements are also required.

Anyone add more meat to this?

Good point James.

Just go for the Lowest U value you can afford (be that cash or space). Heat Recovery is also worth thinking about. It is all about Carbon Reduction really.

As others have said there is no defined CSH level 4 = U values of x.

From what I have seen, csh level 3 is achievable with U values just under 0.2, but it really depends on heating and hotwater systems etc almost as much as the U values.

Timber