Water efficient appliances for households

The AECB Water Standards and why we wrote them.

Another blog post based on my watery days. The Code for Sustainable Homes (CSH) was a UK government scheme designed to provide an ambitious standard for house builders who were trying to acheive low or zero carbon buildings. It included a range of requirements relating to CO2 emissions, material use, water efficiency, surface water run off, pollution etc. The scheme aims were laudable, its execution less so. The water requirements of CSH were particularly poor, being based on a whole house water use calculation. In this approach, appliances were traded off against each other, and multiplied by usage frequencies in order to reach a theoretical value of how much water an individual would use in a day. The approach was based on scant evidence and resulted in some laughably poor installations featuring dribbling taps, shallow baths and sacrificial appliances where it was clearly assumed the householder would remove them as soon as they moved in to the property.

After a good deal of sniping from the sidelines, in 2009 Nick Grant and I had a fit of constructiveness and took it upon ourselves to write what we thought would be a better approach, and produced a fittings based standard. This was adopted by the AECB, the Sustainable Building Association, and became the AECB Water Standard.

Because Nick and myself tend to rant, and the AECB were very tolerant, we took the opportunity to summarise a good deal of the background evidence within the standards. The final document is therefore split into two volumes. The AECB Water Standard Volume 1 provides the standard itself, with Volume 2 providing the rationale.

It is worth noting that Building Regulations represent a bare minimum, so when we are told a particular approach is “ok, because it complies with building regs”, all we are really saying is that we are doing something as badly as it is possible to do it without risking prosecution. Sadly, most houses are still built to this bare minimum approach. Whilst the CSH was abolished in 2015, the water calculator lives on in Part G of Building Regulations, so the critique of the approach within the AECB guidance still provides useful context. However, imitation is supposedly the sincerest form of flattery, and Part G of Building Regulations now includes the option of using a fittings based approach to calculating water use. Perhaps the Part G authors read the AECB water standard…

small bath

This man isn’t a giant, it is just that he is sitting in a short and very shallow bath specified as a result of using the water calculator to meet a whole house water efficiency standard.

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