Use air conditioning systems efficiently

Air conditioning can be a major source of energy use at business premises. You must have your air conditioning system serviced regularly to ensure it continues to be energy efficient. You must also ensure that it is serviced by authorised personnel and that it is not leaking fluorinated gases or ozone-depleting substances.

Choosing, using and maintaining air conditioning systems effectively can also benefit your business by cutting your costs and improving your image to customers, investors and employees.

This guide explains when you should have your system inspected, how to find an inspector and how to use the inspection report. It also covers how to use and maintain air conditioning systems efficiently and buying new equipment.

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Benefits of efficient air conditioning

With the UK’s 25 million buildings accounting for almost half of the national energy use and carbon emissions, energy efficiency is vital at a national level. To help improve efficiency, businesses are required to carry out a range of duties – eg having their air conditioning systems inspected.

You can find more information in the page in this guide on inspecting your air conditioning system.

Air conditioning can account for a third of annual electricity costs for an individual business. Improving the efficiency of your air conditioning can therefore lead to significantly lower energy bills.

Other benefits of efficient air conditioning systems include improved staff comfort and productivity, and general benefits of reducing your environmental impact, such as a better image for your business among customers, investors and employees.

Improving your air conditioning can improve the efficiency rating that your building receives when an Energy Performance Certificate is required. For more information, see our guide on Energy Performance Certificates – business properties.

Replacing refrigerants

For air conditioning equipment that contains fluorinated gases (F gases) such as hydrofluorocarbons (HFCs) or ozone-depleting substances such as hydrochlorofluorocarbons (HCFCs), you may have further obligations. This may be another incentive to improve or replace older systems with more modern units.

For more information, see our guide on managing fluorinated gases and ozone-depleting substances.

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Inspecting your air conditioning system

Air conditioning systems in buildings must be inspected regularly as part of the UK’s effort to improve the energy efficiency of its buildings and meet carbon emission reduction targets.

Air conditioning inspections give building owners and their tenants information and advice on how to improve energy efficiency and reduce electricity use, operating costs and carbon emissions.

Your system must be inspected by an accredited air conditioning assessor. See the page in this guide on checking your air conditioning inspection is valid.

Air conditioning inspection deadlines

All existing air conditioning systems over 12 kilowatts must have had their first inspection by 4 January 2011.

After the first inspection, your air conditioning must be inspected every five years. If your system was installed on or after 1 January 2008, the first inspection must take place within five years of installation.

There will also be a statutory requirement to lodge all air conditioning inspection reports on the central Non Domestic EPC Register from 6 April 2012.

Generally, a 12-kilowatt cooling capacity air conditioning unit is used in the following types of premises:

• general office spaces up to approximately 200 square metres (m²)
• offices with high levels of IT and electrical equipment up to 100m²
• retail spaces with average levels of display lighting up to 250m²
• retail spaces with high levels of display lighting and illuminated cabinets up to 150m²

An office building of 2,000m² is likely to need air conditioning with a 250-kilowatt output.

All air conditioning equipment must be maintained and serviced by personnel with the appropriate certification. This is to keep systems running efficiently without emitting fluorinated greenhouse gases (F gases) and ozone-depleting substances (ODS). F gas and ODS leaks are most likely to occur as a result of:

• gradual leakage during normal operation from joints, valves or compressors
• major failure – eg a burst pipe during normal operation leading to leakage of all the refrigerant
• emissions during plant maintenance
• emissions at the end of the equipment’s life

For more information, see our guide on managing fluorinated gases and ozone-depleting substances.

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What an air conditioning inspection involves

An energy inspection of your air conditioning system involves a visual assessment by an accredited assessor. For more information on accredited assessors, see the page in this guide on checking your air conditioning inspection is valid.

Inspectors will examine the air conditioning equipment, air movement systems and controls. They will need to inspect equipment located in plant rooms or on rooftops.

Once the visual inspection is finished, the inspector gives a detailed report to the person responsible for maintenance of the building’s air conditioning system – ‘the operational controller’.

Using the air conditioning inspection report

Air conditioning inspection reports contain:

• information on the current efficiency of your equipment
• suggestions for improving the efficiency of your equipment
• advice on replacing inefficient equipment and/or refrigerants
• any faults identified – such as the condition of air filters – and suggested actions
• information on the adequacy of your equipment maintenance and how to improve it
• advice on reducing your need for air conditioning

You do not have to act on the inspection report, but you may cut energy use and costs if you do.

For more information on equipment efficiency, replacement and maintenance, see the pages in this guide on using your air conditioning system efficiently, buying efficient air conditioning equipment and maintaining your air conditioning system.

You can find a guide on energy saving for offices on the Carbon Trust website (registration required)- Opens in a new window.

Responsibilities of air conditioning controllers

If you control an air conditioning system that requires an inspection, you must make sure that it has been inspected by the appropriate deadline. For information on deadlines, see the page in this guide on inspecting your air conditioning system.

If your responsibility for controlling the system passes to someone else, you should provide them with any inspection reports you have.

From 4 January 2011, if you do not provide an inspection report, the new controller will be legally required to ensure the system is inspected within three months.

Inspection reports should be kept with maintenance records in the building log book. You can read advice about building log books on the Chartered Institution of Building Services Engineers (CIBSE) website- Opens in a new window.

For more information on inspections, you can download the guide to air conditioning inspections [opens in a new window].

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Checking your air conditioning inspection is valid

An energy inspection report can only be produced by an accredited air conditioning energy assessor who must be a member of an approved accreditation scheme.

Approved accreditation schemes for air conditioning inspections are run by:

• Chartered Institution of Building Services Engineers (CIBSE) – find details of energy assessor accreditation schemes on the CIBSE website- Opens in a new window
• Royal Institution of Chartered Surveyors (RICS) – find details of energy assessor accreditation schemes on the RICS website- Opens in a new window
• ECMK Ltd – find details of energy assessor accreditation schemes on the ECMK website- Opens in a new window
• Quidos – find details of energy assessor accreditation schemes on the Quidos website- Opens in a new window
• Building Engineering Services Competence Accreditation (BESCA) – find details of energy assessor accreditation schemes on the BESCA website- Opens in a new window
• Heating and Ventilating Contractors’ Association (HVCA) – find details of energy assessor accreditation schemes on the HVCA website- Opens in a new window
• Sterling
• Stroma
• BRE
• NES
• Northgate

Problems with air conditioning inspection reports

If you have any problems with the quality or validity of your inspection report, you should first contact your energy assessor.

If you are still not satisfied, you should contact your energy assessor’s accreditation scheme, which will be listed on your report.

Refrigerants

All air conditioning equipment must be maintained and serviced by personnel that are authorised to handle fluorinated greenhouse gases (F gases) and ozone-depleting substances (ODS). For more information, see our guide on managing fluorinated gases and ozone-depleting substances.

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Maintaining your air conditioning system

Poorly maintained air conditioning can use up to 60 per cent more energy. Air conditioning units are subject to regular assessments, as part of the UK’s effort to improve the energy efficiency of its buildings and meet carbon emission reduction targets.

After each inspection, you will receive a report containing information on the energy efficiency of your air conditioning system. This will include information about the adequacy of your maintenance programme, as well as advice on how to improve it. You do not have to act on this, but it may cut your energy use and costs if you do.

You can find out about air conditioning energy assessments in the page in this guide on what an air conditioning inspection involves.

Air conditioning maintenance checklists should cover:

• refrigeration equipment
• condensers
• pipework insulation
• fans, filters and air ducts
• thermostat and controls calibration and settings
• safety – including keeping heat exchangers and cooling towers clean and free from legionella

You should also include refrigerant charge and leakage tests in maintenance schedules, as some refrigeration systems are subject to testing under regulations controlling fluorinated greenhouse gases (F gases) and ozone-depleting substances (ODS). For more information, see our guide on managing fluorinated gases and ozone-depleting substances.

Sources of advice on air conditioning maintenance

You can get advice on maintaining air conditioning equipment from several professional bodies, including:

• Chartered Institution of Building Services Engineers (CIBSE)
• Heating and Ventilation Contractors’ Association (HVCA)
• Institute of Refrigeration (IOR)
• Air Conditioning and Refrigeration Industry Board

CIBSE and HVCA publish useful information for building owners or operational controllers who are preparing a maintenance plan. For example, you can:

• buy a copy of Guide M – Maintenance Engineering and Management on the CIBSE website- Opens in a new window
• buy a copy of Standard Maintenance Specification for Building Services on the HVCA website- Opens in a new window

The Institute of Refrigeration (IOR) publishes information on the maintenance of refrigerants in air conditioning systems. You can find information on maintaining refrigeration systems on the IOR website- Opens in a new window.

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Using your air conditioning system efficiently

The efficiency of your air conditioning system partly depends on how you operate it. By setting controls correctly and reducing the need for cooling, you can save energy and cut the operating costs of your system.

Air conditioning controls the temperature, humidity and quality of air in your building. This is more accurately referred to as a heating, ventilation and air conditioning (HVAC) system.

HVAC systems vary widely in terms of size and function. If they were designed and installed during the building’s construction, they will be larger and a key component of the centralised building services. They will use ventilation to deliver both heating and cooling to the building.

Other systems provide heating through boilers and radiators, with some limited ventilation to provide fresh air or cooling to certain parts of the building.

In many buildings, individual comfort cooling units have been added to address a specific overheating problem that originally didn’t exist or wasn’t apparent at the time of the original design. For example, the huge increase in the use of computers, which generate a lot of heat, has meant that many older buildings now need additional cooling or ventilation. Comfort cooling units, are often the most common method of providing cooling to a building when the need arises.

There are five important factors that determine the energy use of an HVAC system. These are the:

• design, layout and operation of the building, which affects how the external environment impacts on internal temperatures and humidity
• required indoor temperature and air quality, as more extreme temperatures, greater precision and more refined air quality are all factors which lead to the HVAC plant consuming more energy
• heat generated internally by lighting, equipment and people
• design and efficiency of the HVAC plant – which provides heat, cooling and moisture control exactly where it is needed in the building
• operating times of the HVAC equipment and functionality of the controls – these limit operation to exactly when the system is needed

You can improve the efficiency of your air conditioning system by:

• turning cooling thermostats up and heating thermostats down so that the two systems do not operate at the same time
• reducing excessive draughts
• switching off unnecessary electrical equipment
• letting the building cool naturally overnight by allowing cool air to pass through the building to remove heat that has built up through the day
• placing heat-emitting equipment in a separate, naturally ventilated area
• servicing computer server rooms separately
• keeping windows closed when the air conditioning is on
• using external shading and window blinds to reduce heat entering the building
• encouraging staff involvement and feedback
• keeping a log book

You should also check your energy use on your energy bills and any other meters that have been fitted.

You can find information on using air conditioning systems efficiently on the Carbon Trust website- Opens in a new window.

Refurbishment and new installations

If you are refurbishing or putting in a new HVAC system, it is worth using the most efficient system available.

The more efficient the HVAC system is, the less expensive it is to run, which is an important consideration as the day-to-day running costs are far greater than the initial costs of installation.

When choosing an HVAC system you should:

• choose the system that is best suited to your needs
• prioritise energy efficiency in the design and installation stages
• implement and maintain good system controls
• set up and maintain the system effectively – and consider a maintenance contract

For more information, see the page in this guide on buying efficient air conditioning equipment.

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Buying efficient air conditioning equipment

There are several forms of financial support to help businesses to invest in more energy-efficient systems.

Enhanced Capital Allowance scheme

Under the Enhanced Capital Allowance (ECA) scheme, you can get 100 per cent first-year tax relief when you buy any air conditioning system equipment that is included on the Energy Technology List (ETL).

The ECA scheme allows businesses to write off the cost of air conditioning equipment on the ETL against taxable profits in the year of purchase.

For more information, see our guide on first-year allowances for energy saving products.

Energy efficiency loans

Eligible businesses that have been trading for at least 12 months may be able to borrow from £3,000 to £100,000 to buy energy-saving equipment. Loans are unsecured, interest-free and repayable over a period of up to four years. There are no arrangement fees and application is straightforward. You can apply for an energy-efficiency loan on the Carbon Trust website- Opens in a new window.

Consequential improvements

Under Part L of the Building Regulations, if you carry out improvements to buildings, you may have to improve your heating, cooling or hot water systems as well. This is known as the ‘consequential improvement requirement’.

The consequential improvement requirement applies to buildings over 1,000 square metres, where you are:

• building an extension
• installing fixed building services – such as heating, ventilation and air conditioning – for the first time
• expanding existing building services

You can download guidance on the conservation of fuel and power in new buildings (approved document L2B) [opens in a new window].

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