This guide provides detailed guidance for the installation of fixed building services in new and existing non- domestic buildings to help compliance with the energy efficiency requirements of the Building Regulations.
This edition covers the design, installation and commissioning of:
• conventional means of providing primary space heating, domestic hot water, mechanical ventilation, comfort cooling and interior lighting
• low carbon generation of heat by heat pumps and combined heat and power systems.
The guide sets out recommended minimum energy efficiency standards for components of building services systems, including the use of controls. For systems installed in new buildings, the standards are design limits (or backstop values). For new or replacement systems and components installed in existing buildings, the standards represent reasonable provision for complying with the Building Regulations.
It is important to note that standards higher than many of these recommended minimum standards will need to be achieved if:
• new buildings are to meet the the Building Regulations target carbon dioxide emission rate (TER) calculated using National Calculation Methodology (NCM) tools such as SBEM1
• systems (up to 45 kW heat output) are to comply with the Microgeneration Certification Scheme standards that enable building owners to receive payments under the Renewable Heat Incentive (RHI) and qualify for Green Deal funding
• products are to be recognised as renewable technologies under the Renewable Energy Directive.
The guide includes some supplementary information that identifies good practice design and installation standards that exceed the minimum standards in this guide. Microgeneration Certification Scheme standards2 are an example of good practice standards.
In relevant sections, the guide identifies additional non-prescriptive measures (for example additional controls) that can improve plant efficiency. These may be used to gain ‘heating efficiency credits’ to help meet the carbon dioxide emission targets for new buildings, or the recommended minimum energy efficiency standards set out in this guide for work in existing buildings.
A summary of recommended minimum energy efficiency standards is presented in Table 1 at the end of this section.
1.2 Innovative systems
It is also important to note that this guide covers a range of frequently occurring situations. It deals with the most commonly used fixed building services technologies. In doing so it neither endorses these methods and technologies nor excludes other more innovative technologies that may offer an alternative means of meeting the functional requirements of the Building Regulations.
Where the alternative technology has been the subject of a recognised testing procedure that assesses its energy performance, this may be used to indicate that the system is adequately efficient. In the event that there is no recognised testing standard, suitable calculations or modelling methods may be used to show the carbon performance of the system.
1.3 European directives
The design and installation of fixed building services products, such as boilers, circulators and heat pumps, shall at the appropriate time comply with all relevant requirements of EU directives as implemented in the United Kingdom. There are a number of directives with requirements that directly or indirectly control the energy efficiency of building services.
The Ecodesign Directive 2009/125/EC provides a framework for establishing requirements for ‘energy- related’ products placed on the EU market. Current requirements cover ‘energy-using’ products such as boilers, light bulbs and washing machines. In the future, requirements will also cover products such as windows, insulation material and shower heads whose use has an impact on energy consumption.
The requirements are set out in Commission Regulations listed in the document http://ec.europa.eu/energy/ efficiency/ecodesign/doc/overview_legislation_eco-design.pdf. Products covered by the regulations can only be CE marked and placed on the market if they meet the ecodesign standards specified.
At the time of preparation of this guide, Commission Regulations existed or were being developed for:
• space heaters and combination heaters
• water heaters and hot water storage tanks
• glandless standalone circulators and glandless circulators integrated in products
• water pumps
• air conditioners and comfort fans
• fans driven by motors with an electric input power between 125 W and 500 kW
• lighting products in the domestic and tertiary sectors
• electric motors.
The intention is that the recommended minimum product standards in this guide should at least match the energy efficiency standards set out in Commission Regulations as they come into force. For example, although the implementing regulations for hot water storage tanks were published in September 2013, the standards do not come into force until September 2017.
If in any doubt as to whether a product is subject to minimum ecodesign standards, check the Commission document above.
The Energy Labelling Directive 2010/30/EU complements the Ecodesign Directive by providing a framework for labelling of energy-related products including lamps, luminaires, household air conditioners and washing machines. The Energy Label classifies products on an A to G scale, ‘pulling’ the market towards more efficient products by better informing consumers. The Ecodesign Directive, by contrast, uses regulation to ‘push’ the market away from the worst performing products.
The Renewable Energy Directive 2009/28/EC provides a framework for the promotion of energy from renewable resources. It sets a mandatory UK target of 15% energy generation from renewable sources by 2020 – the ‘renewable energy obligation’ – as a contribution to meeting the EU’s overall target of 20%. Of relevance to building services is that it includes criteria for training and certification of installers of renewables. The directive also specifies in Annex VII the standards that heat pumps must achieve to be recognised as renewable technologies by the directive.
The Energy Efficiency Directive 2012/27/EU establishes a common framework of measures for the promotion of energy efficiency within the EU in order to ensure that the EU meets its target of a 20% reduction in primary energy consumption by 2020. Legislation to implement the directive in the UK will be published by 5 June 2014. Included will be requirements for public authorities to purchase only energy-efficient products, services and buildings; and requirements for heat meters to be fitted in apartments and buildings connected to a central source of heating or district heating network. For more information on the specific requirements and technical standards, see the DECC website3.
The Energy Performance of Buildings Directive 2010/31/EU is a recast of the original 2002/91/EC directive, which in 2002 introduced requirements for:
• the establishment of a methodology for calculating the integrated energy performance of buildings
• minimum energy performance requirements for new buildings, and, where feasible, for larger buildings undergoing major renovation
• energy performance certification of buildings, and
• inspections of heating and air conditioning systems.
The recast directive includes a new requirement to consider, in the design of new buildings, the feasibility of using renewables and other ‘high-efficiency alternative systems’. There is no mandatory format for this assessment, but it will now be necessary to declare (through a new field in the energy performance calculation software) that it has been carried out.
The Building Regulations, which already met the original requirements in many ways (for example by setting standards for new buildings), have been amended in some places to reflect the new requirements of the directive. For guidance on the changes affecting new buildings, see Approved Document L2A.
For guidance on the changes affecting major renovations, see Approved Document L2B. For guidance on other requirements relating to building certification and inspection of heating and air conditioning systems, see the DCLG website4.
1.4 Status of guide
The Building Regulations contain functional requirements, such as requirements that buildings must be structurally stable, constructed and fitted to ensure fire protection, and energy efficient. These functional requirements are often drafted in broad terms, and so it may not always be immediately clear to a person carrying out work how to comply with the relevant requirements. Consequently, theDepartment for Communities and Local Government issues documents, known as approved documents, which provide practical guidance on ways of complying with specific aspects of the Building Regulations in some of the more common building situations.
Approved documents are not always comprehensive and may contain references to other documents which will provide more detailed information and assistance on parts of the guidance. This guide is one of those documents: it provides more detailed information on the guidance contained in Approved Documents L2A and L2B about compliance with the energy efficiency requirements which apply when installing fixed building services in new and existing buildings.
If you follow the relevant guidance in an approved document, and in any document referred to in the approved document (such as this guide) which provides additional information to help you follow that guidance, there is a legal presumption that you have complied with the Building Regulations. However, in each case it is for the building control body (local authority or approved inspector) to decide whether work complies with the requirements of the Building Regulations. It is therefore sensible that you check with the building control body before starting work what they consider it is necessary for you to do to comply with the requirements of the Building Regulations.
1.5 How to use this guide
The guide is divided into the following sections:
Section 1: Introduction and summary of energy efficiency standards
Section 2: Gas, oil and biomass-fired boilers
Section 3: Heat pumps
Section 4: Gas and oil-fired warm air heaters
Section 5: Gas and oil-fired radiant heaters
Section 6: Combined heat and power and community heating
Section 7: Direct electric space heating
Section 8: Domestic hot water
Section 9: Comfort cooling
Section 10: Air distribution
Section 11: Pipework and ductwork insulation
Section 12: Lighting
Section 13: Heating and cooling system circulators and water pumps
Supplementary information is shown against a blue background. This may be further information to help with interpreting the minimum energy efficiency provisions needed to comply with the Building Regulations. Or it may be guidance on best practice that goes beyond the recommended minimum standards.
Key terms are printed in blue and are defined at appropriate points throughout the guide.
1.6 Key terms for space heating and domestic hot water systems
The following general definitions are applicable to the sections that deal with space heating and hot water. Further definitions are included in later sections as appropriate.
Heat generator means a device for converting fuel or electricity into heat – e.g. a boiler or radiant heater.
Heat generator efficiency means the useful heat output divided by the energy input in the fuel (based on gross calorific value) or electricity delivered to the heat generator, as determined by the appropriate test methods for that type of heat generator.
Heat generator seasonal efficiency means the estimated seasonal heat output from the heat generator divided by the energy input. This will depend on the heat generator efficiency and the operating mode of the heat generator over the heating season. For example, in the case of boilers it is a ‘weighted’ average of the efficiencies of the boiler at 30% and 100% of the boiler output. For other technologies the heat generator seasonal efficiency may be the same as the heat generator efficiency.
Minimum controls package means a package of controls specific to each technology that represents the recommended minimum provision necessary to meet the Building Regulations energy efficiency requirements.
Additional measures means additional controls or other measures that go beyond the recommended minimum controls package and for which heating efficiency credits are available.
Heating efficiency credits are awarded for the provision of additional measures, such as additional controls, that raise the energy efficiency of the system and go beyond recommended minimum standards. Different credits apply to the different measures that are available for heating and hot water technologies.
Effective heat generator seasonal efficiency is obtained by adding heating efficiency credits, where applicable, to the heat generator seasonal efficiency:
Effective heat generator seasonal efficiency =
heat generator seasonal efficiencyheating efficiency credits Equation 1
Where relevant, this guide sets standards for effective heat generator seasonal efficiency so that a heat generator with an inherently low efficiency may be used in combination with additional measures.
Space heating system means the complete system that is installed to provide heating to the space. It includes the heating plant and the distribution system by which heating is delivered to zones. Heat losses from the distribution system can be addressed by reference to guidance by TIMSA on HVAC insulation5.
Domestic hot water system means a local or central system for providing hot water for use by building occupants.
1.7 Summary of recommended minimum energy efficiency standards
Unless specified otherwise in this guide, it is recommended that, where applicable, building services are provided with controls that as a minimum correspond to Band C in BS EN 15232:2012 Energy performance of buildings. Impact of building automation, controls and building management.
****Table 1 Recommended minimum energy efficiency standards for building services****