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Part L is Good for Gas

The revisions to Part L of the Building Regulations, which came into force on April 6, were far from radical and it could be said that the Government side-stepped some of the most difficult decisions. As a result, the new legislation merely tweaks energy efficiency standards, but the plus side is that these targets are eminently achievable and do take us a small step further towards a more efficient building stock.

The combination of a nine per cent overall improvement in energy efficiency standards in the new build commercial building sector with new fabric energy efficiency standards is something our industry can work with. The addition of energy efficiency improvements when a building has changes made to its lighting and air conditioning systems is also a positive move. The new Part L is very much in keeping with the current government’s ‘light touch’  approach to regulation and so gives engineers greater flexibility in how they achieve the most energy efficient solution.  As a result, the latest high efficiency condensing gas appliances can deliver much of what the legislators intend without prohibitively increasing the cost of projects or adding unnecessary complexity.


In order to achieve the most energy efficient solution, engineers need freedom to choose from a range of options, particularly for ‘hard to treat’ buildings like warehouses and retail premises. It is also a more positive situation to have engineers designing for the project in hand rather than simply trying to tick boxes to satisfy planning and regulatory officials. In the case of new build projects, condensing heating appliances will be required to satisfy revised minimum efficiency levels, with the exception of direct fired hot water appliances below 30kW. 

In the retrofit commercial heating and hot water sector there is some room for manoeuvre and design engineers have been given some leeway in this area as non-condensing appliances are still permitted Part L also encourages project teams to look at new and refurbished commercial buildings holistically and gives credit for adopting the ‘energy hierarchy’ which tackles energy efficiency from a ‘fabric first’ standpoint. Existing regulations have tended to favour the use of particular technologies to help a building meet mandated emission targets with not enough credit given to efforts designed to improve the performance of complete building systems.

By setting targets for fabric performance, Part L is starting to move the argument in favour of the whole building approach which favours the all-round expertise of building services design engineers. Adding renewables to a building should only be considered once improvements to the fabric and existing building services have been made and even then only where they are cost-effective and technically appropriate. Buildings constructed using advanced sustainable techniques that minimise heat losses and so reduce energy demand can easily meet new energy saving targets using conventional high efficiency gas-fired technologies.

Of course, our industry should aspire to go much further than the basic benchmark set by Part L, so we should continually look for the added benefits offered by renewables, but for compliance purposes good, basic engineering will take us a long way. However, a weakness of Part L has been the lack of robust enforcement on the part of some local authorities leading to concerns over non-compliance.

No matter how well intentioned and developed a regulation is, if it is not fully enforced then it will not be effective. The need to reduce energy costs is an important consideration for building owners and developers, but legal underpinning is a good way of discouraging excessive ‘value engineering’ that looks to strip cost out of a project often at the expense of the performance of the finished asset. The new Part L clearly does not go far enough to embed the very best in energy efficiency practice, but it is a step forward and, most importantly, an affordable and practical one.

Author: Jonathan Tedstone, Business Project Manager, Baxi Commercial 

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Jon Ponting

Author: Jon Ponting

This article was published by Jon Ponting on 04.07.2014.