Thu 27th Mar 2014

Part L Building Regulations Changes

Published: Monday, September 21st, 2009

New revisions to Part L of the Building Regulations covering the conservation of fuel and power will come into force in October 2010.

For those of you unaware of the significance of Part L of the Building Regulation, this is the section whose authority extends to the type of boiler that should be fitted into a house.

Part L states that unless otherwise possible, it is the law that high-efficiency condensing boilers be installed. In other words, boilers with an efficiency rating of over 86% are now de rigeur. Out go all the old type of boilers which struggle to achieve a return of 50% to 70%, and in come condensing boilers.

And for those unaware of exactly what is a condensing boiler and why it is so efficient, then read on.

A condensing boiler is so efficient because it grabs heat from both the combustion process and exhaust gases. The downside is that they are more expensive to install (requiring an outside wall fitting and drainage system and more complicated fan assisted flue), but cost less to run. They must always be used, unless the installation of a condensing boiler is not practical, say in a cottage, or terrace house which has to have a back-boiler configuration.

The new changes, say boiler manufacturer Worcester Bosch Group, start with gas-fired boiler efficiency. From October 2010, only SEDBUK ‘A’ rated boilers (over 90% efficient) will be allowed for all new and replacement installations. Currently, A and B (86% to 90%) SEDBUK levels are allowed.

SEDBUK (Seasonal Efficiency of Domestic Boilers in the UK) was developed under the Government’s Energy Efficiency Best Practice Programme with the co-operation of boiler manufacturers, and provides a basis for fair comparison of the energy performance of different boilers.

Other planned, but not finalised changes, focus on improving the level of efficiency of a home’s heating system in line with the Code for Sustainable Homes, which covers all new-build properties. And the Government has proposed two different options for calculating the statutory 25% increase in energy-efficiency: Option A (aggregate 25% approach) and Option B (flat 25% improvement).

Option A concerns the optimal building specifications for 2010 and are determined by equalising the Marginal Abatement Cost (the cost of eliminating an additional unit of pollution) across the component parts. This is then applied to an assumed new-build mix with the requisite 25% reduction delivered overall.

Thus, under the alternative aggregate approach for new homes, the 2010 targets are based on a common specification. The only exception being the heating system efficiency, which is varied if anything other than the conventional fossil fuels – oil and gas – are used.

However, there is a separate specification proposed for electric resistance heating. This electric resistance specification is intended to be temporary with the electric heating option eventually having the same fabric specification as other fuels and being based on a heat pump solution. This change would be progressive to allow the electrical heating industry some time to diversify into new product areas.

Option B is the Government’s preferred option. It is to take the 2002 notional building that meets energy-efficiency standards and to apply a larger improvement factor for new homes over the 2006 factor. The argument being that it is the simplest method and also generates the largest CO2 saving.

The Government is still seeking advice on the merits of both options.

Finally, it is worth noting that the Government are seeking views on whether to make compliance with Part L a requirement for all new conservatory installations.

Guest Article by Neil Camp

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