Get on the case

Unless you are poor or operating a steel mill, the cost of energy is a small part of the household or business expenditure. As such, it doesn’t get much attention. For those who want to reduce energy consumption this is a painful reality. The government is endeavouring to reduce consumption in buildings by legislation of mandatory minimum construction standards and by displaying the building’s energy consumption like a fridge. The latter, it is hoped, will expose the building’s performance to consumer choice and drive the market to lower-energy buildings, providing that the consumers are sensitive to energy being an important issue. The worthy aim is to get the consumption down without resorting to the normal market mechanisms of price and taxation.

Buildings are enclosures in which stuff happens. As services engineers, we make assumptions about the construction and running of buildings and design the services installations to meet the conditions agreed in the brief. With reasonably conservative assumptions and plenty of design margins, this is not a problem and the subsequent energy consumption was whatever it was. However, this approach is no longer acceptable as legislation is setting out absolute energy targets for buildings, and energy labelling is set to be a public display of compliance. As services engineers, we are often required to demonstrate how the building will comply with Part L at the start of the project, as this can affect planning, let alone a building regulation application. We have little or no control over the detailed design or the quality of construction of the enclosure, factors which will arguably have a bigger effect on the energy performance of a building.

When designing to low-heating loads, the infiltration levels and cold bridging really do matter. In controlling cooling loads, the shading does matter. In naturally ventilated buildings, the size and manner of openings must be correct. In a well-sealed building, the revenge effects of poor air quality and moisture control are real issues that need to be addressed. The reflectivity of a surface affects how well the lighting works, but we do not generally control these elements of the building. While one might make these assumptions clear at the start of a project, it is not currently the role or responsibility of a services engineer to ensure these are kept in the design. Generally speaking, variations to the performance of a building result in greater energy use.

The other factor crucial to a building’s performance is the running of the building. Again, we have no responsibility for this. At completion, having demonstrated that the building services installations are performing as they should, we can show a clean pair of heels. The people running the building are not experts and will run the facilities in the best way they can, but it is unlikely to be the way you had intended.

At completion, having demonstrated that the services installations are performing as they should, we can show a clean pair of heels

We could try to keep our heads down and take advantage of the fact that we can always legitimately blame others for the lack of performance. However, I am suggesting that we take on the leadership of this particular aspect of the environmental performance; this is an additional duty to see that the assumptions made in the energy model are safe. Our responsibility would remain as reasonable skill care and diligence. We would have the right to receive the information and to flag up variations in the design or construction that would change the energy model for the worse. We should also have a post-completion appointment to educate those running the building and modify the systems to suit the actual operation.

Building services engineers are well placed to provide this role, which is legitimately an additional duty and fee. I also believe that clients will be looking for someone with a real understanding of energy and how it can best be managed. Let’s get organised and offer the service. Because if we don’t, someone else will pick it up and tell us to do the work for nothing.

Bill Watts is a partner at Max Fordham LLP