Use heating and hot water systems efficiently

Heating and hot water systems usually form a significant part of a business’ energy costs. They also have a considerable impact on the environment in the form of carbon dioxide emissions.

Choosing, using and maintaining your heating and hot water systems effectively can enable you to both save money and help the environment.

This guide gives an overview of heating and hot water systems, and heating, ventilation and air-conditioning systems. It also explains how to choose the most efficient new boilers and which regulations you need to know about. The guide also contains information and contacts to help you use existing systems more efficiently.

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Benefits of improving heating system efficiency

Heating and hot water costs can account for half of a business’ energy costs and half its carbon emissions. You can maintain or improve the efficiency of your heating system by using it economically. For example, by turning down your heating just 1°C, you can cut your annual heating costs by up to 8 per cent. See the page in this guide on using heating equipment efficiently.

By developing your knowledge of energy efficiency, you can make more cost-effective choices when it comes to replacing or upgrading your system. See the page in this guide on installing efficient heating and hot water equipment.

Using less energy will reduce your business’ carbon footprint and help limit climate change. See our guide on cutting your carbon emissions.

Being an energy-efficient business can also help attract customers, employees and investors. See our guide on how to market your environmental credentials.

Energy efficient businesses should be better prepared to comply with existing and new legislation. For example, if you propose to carry out building work on a building greater than 1,000 square metres, you may need to comply with building regulation conditions relating to the efficiency of your heating and hot water system. You can download a guide to heating, cooling and ventilation requirements under the Building Regulations [opens in a new window].

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Installing efficient heating and hot water equipment

Whether you are investing in a new heating and hot water system for your building, or upgrading an old one, you should make sure your equipment is energy efficient.

When constructing or altering a building, you must ensure that any new heating equipment meets or exceeds the energy efficiency targets in Part L of the Building Regulations. You can download a guide to heating, cooling and ventilation requirements under the Building Regulations [opens in a new window].

It may be more efficient to install additional small boilers for use in the summer months. For example, installing a separate water heater will help you save money by letting you switch off the main boiler system during the summer.

Various types of energy-efficient equipment are available, including:

• advanced metering systems
• optimiser thermostats
• zone controls for space heating
• sequencing controls
• heat recirculating units to recycle warm air in roof spaces

Renewable energy systems, such as solar water heating and wood-fuelled boilers, are another way of increasing building energy efficiency. They can also help you reduce your business’ carbon emissions. See our guide on how to generate your own renewable energy.

You can get advice on the best type of equipment for your premises from the Carbon Trust. Alternatively, you can contact specialist associations, such as the Heating and Ventilating Contractors Association (HVCA) or the Council of Registered Gas Installers (CORGI).

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Energy assessments for heating and hot water systems

You could save energy and money by arranging a regular energy assessment of your building’s heating system efficiency. This should focus on:

• Boiler selection and system design – do you have the right type of boiler, and are your heating and hot water systems optimised for your property?
• System controls – are they working properly?

It is recommended that you have your system assessed if it has a capacity of more than 20 kilowatts, or is more than 15 years old.

After the assessment, your engineer will give you:

• an energy efficiency checklist
• an efficiency comparison of your existing system compared with a new one
• an assessment as to whether your system is the right size for your building

You can find an accredited energy assessor by contacting specialist organisations such as the Heating and Ventilating Contractors Association (HVCA) or the Chartered Institution of Building Services Engineers (CIBSE).

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Using heating equipment efficiently

To get the most out of your heating and hot water systems, it is recommended that you arrange for an energy assessment of your equipment. See the page in this guide on energy assessments for heating and hot water systems.

You can increase efficiency yourself by taking simple steps, such as:

• setting timer controls to operate heating only when people are present in the building and activate ‘frost protection’ at weekends and during holidays
• ensuring the hot water is not heated too much – water only needs to be heated to between 60 and 65°C to protect against legionella bacteria
• checking your heating bills regularly – this will help you spot any sudden increases in energy use, which may be caused by changes in the way a building is used

You should also make sure you:

• don’t turn up heating unless you really need to
• leave plenty of space around radiators
• don’t heat unused space
• keep doors and windows closed, and draught-proof, in cold weather
• ensure thermostats are not near draughts or hot and cold spots
• don’t put hot equipment, such as photocopiers, near cooling vents
• maintain equipment properly
• have enough insulation around your hot water and HVAC systems, including; boilers, pipes, tanks and ductwork

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Maintaining heating systems effectively

Regular maintenance of your heating and hot water system helps you maximise its efficiency, improve workplace safety and extend the lifespan of your system.

Professional servicing and maintenance checks should cover:

• combustion efficiency
• running repairs
• limescale checks
• advice to owners
• replacing worn or defective parts, such as boilers, water heaters, pumps and air heaters

You can carry out regular simple maintenance checks, such as:

• setting outlet louvres correctly for warm-air systems
• cleaning reflectors for radiant heaters
• keeping air vents clean
• checking for leaks

You should also monitor gas flues for efficiency, temperature and chimney conditions.

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Heating, ventilation and air-conditioning systems

Heating, ventilation and air conditioning (HVAC) systems control the temperature, humidity and air quality in buildings, according to a set of chosen conditions. They do this by transferring heat and moisture in and out of the air and by controlling the level of air pollutants by directly removing them or by diluting them to acceptable levels.

HVAC systems vary widely in 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 didn’t exist originally 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 the most common method of providing cooling to a building when the need arises.

Energy consumption of HVAC systems

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

• design, layout and operation of the building – this affects how the external environment impacts on internal temperatures and humidity
• required indoor temperature and air quality – 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

One of the best ways to control the cost of using HVAC equipment is to reduce the need to use it initially. It’s important to first take energy-saving measures such as insulation and draught-proofing around your building. Simple measures such as window blinds can reduce the amount of heat entering a building and reduce the need for cooling. Room or zone controls and thermostats allow people control over their immediate environment, although it may be necessary to reset controls to a default setting each day.

Other opportunities for saving energy include:

• the use of passive heating, ventilation and cooling
• night cooling – when cool air passes through a building overnight to remove heat that has built up through the day

Refurbishment and hardware opportunities

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

Energy-efficiency loans and other support

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 the application process is straightforward. You can apply for an energy-efficiency loan on the Carbon Trust website- Opens in a new window.

Enhanced capital allowances for energy-saving equipment

The enhanced capital allowance (ECA) tax relief scheme can be used to buy certain HVAC zone controls. These allow the conditions in a specific area or zone to be independently controlled rather than a whole building being heated or cooled to the same temperature. As a result, zone controls can contribute to energy savings.

You can read about how to claim the ECA on the page on how to claim an ECA for listed energy saving products in our guide on first-year allowances for energy saving products.

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Checking boiler efficiency

Heating engineers checking commercial and domestic boiler efficiency can get useful information from several sources, including the:

• Seasonal Efficiency of Domestic Boilers in the UK (SEDBUK) boiler efficiency database
• Council of Registered Gas Installers
• Institute of Domestic Heating and Environmental Engineers (IDHEE)
• Heating and Ventilating Contractors Association

Efficiency ratings (domestic installations)

The energy efficiency of boilers intended for domestic use is rated in bands:

• A – 90 per cent and above
• B – 86-90 per cent
• C – 82-86 per cent
• D – 78-82 per cent
• E – 74-78 per cent
• F – 70-74 per cent
• G – below 70 per cent

Boiler efficiency database (domestic installations)

To check the efficiency of a particular model of domestic boiler, you can consult the boiler efficiency database on the SEDBUK website- Opens in a new window. This contains efficiency data for current boiler models, and is updated monthly.

You can use the online calculator to work out annual fuel costs for domestic boilers on the SEDBUK website- Opens in a new window.

Calculating boiler size (domestic installations)

To calculate or check the correct boiler size for a particular building without using rules of thumb, there are online calculators which can help. You can use the online boiler size calculator on the IDHEE website- Opens in a new window. You can also access the domestic heating sizing wizard on the Energy Saving Trust website- Opens in a new window.

Efficiency ratings (non-domestic installations)

Detailed guidance on the minimum acceptable performance of heating, cooling, ventilation and hot water systems is available. You can download the non-domestic heating, cooling and ventilation compliance guide [opens in a new window].

The guide also specifies the minimum acceptable performance of other forms of commercial heating, such as warm air, radiant and heat pump systems.

Boiler checklists

Step-by-step checklists for monitoring boiler energy efficiency are available online for:

• homeowner gas-fired heating installations – you can download a checklist for domestic gas-fired heating installations [opens in a new window]
• homeowner oil-fired home heating installations – you can download a checklist for domestic oil-fired heating installations [opens in a new window]

Gas boilers and space heaters below 100 kilowatts should be assessed every four years. Oil-fired or solid-fuel boilers, and space heaters larger than 100 kilowatts, should be assessed every two years.

Energy Performance Certificates

Boiler efficiency forms part of a building’s overall energy performance, which must be displayed in the form of an Energy Performance Certificate. See our guides on Energy Performance Certificates – business properties and Energy Performance Certificates – domestic properties.

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Boiler efficiency finance and support

Financial support is available to help businesses invest in more energy efficient heating and hot water systems.

Enhanced Capital Allowances

The Enhanced Capital Allowance (ECA) scheme allows businesses to claim 100 per cent first-year tax relief for capital expenditure on heating system items that appear on the Energy Technology List. Read more about ECAs in our guide on first-year allowances for energy saving products.

Green finance

The Carbon Trust offers leases, loans and other financing options for businesses seeking to reduce their energy use. New, more efficient equipment should lower your energy bills and loan payments are calculated so that they can be offset by the anticipated energy savings. Read about finance for energy-saving projects on the Carbon Trust website- Opens in a new window.

Further information on boiler efficiency

For general advice on heating and hot water systems, you can find a local Heating and Ventilating Contractors’ Association (HVCA) member on the HVCA website- Opens in a new window.

The Council of Registered Gas Installers (CORGI) can also advise you about installing efficient and regulation-compliant boilers. You can find a registered gas business in your area by searching the database on the Gas Safe Register website- Opens in a new window.

For advice on solid fuel heating appliances, fuels and services, you can find solid fuel heating appliances guidance on the Heating Equipment Testing and Approval Scheme (HETAS) website- Opens in a new window or contact the HETAS Helpline on Tel 0845 634 5626.

You can also find energy efficiency advice on the Carbon Trust website- Opens in a new window.

The Chartered Institution of Building Services Engineers (CIBSE) accredits assessors who can carry out an assessment of your property, helping you save money and cut carbon emissions. You can find out how to get a low-carbon energy assessment on the CIBSE website.

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