Water efficiency – Do we realise its real impact on carbon emissions?
In the absence of strong water efficiency regulations it is easy to overlook specification of water efficient fittings. With rain bucketing from the skies in Ireland, water has tended to be considered much less important than energy efficiency. However water treatment was one of the highest sources of carbon emissions for local authorities, and hot water can now be the highest single source of energy use in homes built to current Part L energy regulations. If you consider that the least efficient showers use well in excess of 26 litres of hot water per minute, as opposed to 3 litres for the most efficient, you can understand how this could have a dramatic impact on energy use.
Indeed the fact that hot water is responsible for up to 80% of regulated energy use in apartments ( apartments have very low space heating requirements as surrounded by other apartments) will see the introduction of a credit in the DEAP software in the revised Part L building regulations which come into force in 2019, where flow restrictors are fitted to showers and taps. This also allows the BER assessor to input the actual water usage data for the taps and showers specified.
Luckily it is now very easy to specify and calculate water efficiency in homes. The Irish Green Building Council are scheme partners with the European water label ,which provides a label for water efficient fittings and fixtures just like the rating system for electrical goods. This contains data for most of the leading manufacturers of sanitary ware. It also provides a water calculator to assess the impact of the fittings on overall water usage in the home, just like the Building Energy Rating (BER) rating system does for energy. This allows the architect or specifier to use the drop down menu to pick specific products, which makes it very easy to calculate whether the benchmarks in the HPI have been met or whether alternative fittings need to be chosen.
This means that for architects it is simply a matter of searching for the most efficient fittings or better still if short on time asking the supplier to provide a sanitary ware schedule that meets the target benchmark within the Home Performance Index. This is what HPI intends to do, simplifying life for all by bringing state of the art tools to measure all the key performance indicators for quality housing.
For more infomation on the European Water label and to access the calculator see here.