Making light work of energy savings

Published:  10 November, 2010

MK Electric, lighting control
Using room sensors to control lighting can reduce energy consumption by up to 90%.

Controlling lighting is one of the most effective ways of reducing energy consumption and meeting Government targets for reducing CO2 emissions, argues Martyn Rowe.

The construction industry is under pressure from two sides to save energy — a Government that has pledged to tackle climate change and customers eager to minimise rapidly rising energy bills. The coalition Government supports a wide range of regulations and incentives to cut carbon emissions, and there are also increasing concerns about the security of energy sources and affordability. As a result, it is ever-more essential for construction professionals to understand how they can control the efficiency and environmental impact of buildings.

As part of its mission to reduce global emissions the UK has promised to decarbonise its economy — a promise reinforced with legislation. The 2008 Climate Change Act made Britain the first country in the world to set legally binding ‘carbon budgets’, at 5-year intervals, aiming to cut UK emission by 34% by 2020 and by at least 80% by 2050.

These targets affect the construction industry particularly as up to 40% of the country’s energy is consumed by its building stock, so the new Government will certainly employ Building Regulations as a key tool in achieving its aims.

Part L of the Building Regulations, Conservation of Fuel and Power, was amended in 2006 to align with the European Union, Energy Performance of Buildings Directive. This amendment was intended to save a million tonnes of carbon per year by 2010 so as to meet Kyoto targets.

But tighter regulations came into effect on 1 October 2010 that aim to improve energy efficiency by a further 25% as compared to the 2006 regulations.

Further revisions to Building Regulations are scheduled for 2013 and again in 2016. The 2013 version will drive a 44% improvement in energy efficiency compared to the 2006 regulations, and the 2016 version a full 100% improvement – achieving the first zero-carbon homes and zero-carbon non-domestic buildings in 2019.


The revisions to Part L have not been the only significant drivers for energy efficiency in buildings. Since 2006 the industry has seen initiatives such as the Code for Sustainable Homes, Energy Performance Certificates, targets for renewables along with The Feed-in Tariff and Carbon Reduction Commitment Energy Efficiency Scheme.

Spiralling energy costs


The drive for energy efficiency is not simply regulatory but also economic, with the Energy Retail Prices Index seeing a marked step change in 2006. Despite a slow-down in the pace of rise in gas prices during 2009 the nation is braced for further steep price rises in the coming years. Users are suffering not only from more expensive bills for the energy that they consume, but they are also hit as higher energy costs are passed to customers by manufacturers, retailers and other service providers. There are also wider, longer-term implications for economic growth as sectors such as manufacturing.

The result is that both the Government and the economy are emphasising the need to reduce energy consumption and to develop methods of producing energy that do not harm the environment.

Why stand-alone PIRs for lighting control?

MK Electric, lighting control
In virtually every type of building the largest single user of energy is lighting, making it an ideal target for reducing energy use.

Lighting has to be the first area to considered for anyone wanting to achieve more with less energy because it consumes a large proportion of a building’s total energy consumption. Installing effective and efficient lighting controls is crucial in cutting the energy bill which is why modern sensor ranges are ideal; they not only comply with the relevant regulations but are also an energy-conscious product choice.

The Building Research Establishment found that, across a broad selection of non-domestic applications, lighting represents 40% of a building’s total energy consumption. In each example (apart from catering) lighting was the function with by far the highest energy usage, also representing the largest opportunity for energy savings.

In another study, the late Department of Environment’s Energy Efficiency Office and the Chartered Institution of Building Services Engineers (CIBSE) showed that an office rest room can save up to 90% of energy consumed if its lighting is controlled by a PIR instead of a central control that switches it on whenever the building is occupied.

Sensors not only help realise the highest potential savings in energy consumption and energy bills, but they also offer the shortest payback periods. There is a variety of ways to make lighting more energy efficient, from changing to energy-efficient lamps to the installation of high-frequency electronic ballasts. However, the Building Regulations clearly state the need to provide energy-efficient fixed building services with effective controls.

The associated costs of specifying and installing lighting control products can be offset against the potential energy savings and, thus, associated costs. The potential energy savings are affected by a number of variables, including the type of space, the footfall within that space and the presence of ambient light or natural daylight. Low-usage areas such as bathrooms, corridors and stores have also been shown to offer significant savings.

Balancing these potential savings against the initial cost of specifying and installing lighting controls can produce some startling variations in payback periods —ranging from less than a year for room-sensor controls to up to five years for automatic lighting (building) controls.

Research by CIBSE shows the quickest payback period combined with the highest potential energy savings can be achieved by installing room sensor controls (Fig. 1).

Government action on cutting carbon emissions is not just regulatory — there are incentives as well.

Many energy-saving lighting controls and associated equipment not only have short payback periods but also qualify for tax breaks — or at least did at the time of writing — as Enhanced Capital Allowances (ECAs). ECAs enable businesses to claim 100% first-year capital allowances on qualifying investments via their Corporation Tax Return. In addition to equipment costs, installation charges and any changes to the building needed to install the equipment also qualify for tax relief.


The Carbon Trust offer interest-free loans of £5000 to £100 000 for energy-efficiency projects, repayable over four years. These loans are available to small and medium sized enterprises in England and Wales that have been trading for at least 12 months. Any project that saves energy and has a payback of less than five years may qualify, and the loan can cover installation and commissioning costs as well as equipment costs.

Martyn Rowe is Environment Manager with MK Electric.

MK Electric, lighting control
Fig. 1: This analysis from CIBSE of the energy-saving potential of a wide range approaches for lighting clearly shows just how effective room-sensor controls are.

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