NOTE: This section sets out minimum Building Regulations standards for fixed building services and other systems.
Best practice is to achieve higher efficiencies than these minimum standards.

NOTE: The Ecodesign for Energy-Related Products Regulations 2010 set the efficiencies and standards that must be met when introducing new energy-using products to the market. This approved document sets standards that should be met when installing fixed building services or on-site electricity generation. In cases where the Energy-Related Products Regulations and the Building Regulations both apply, both standards should be met.

Gas-fired heating systems

6.1 A gas-fired heating system should meet either of the following, in addition to the general requirements for heating and hot water systems in Section 5.

a. New dwellings should meet the minimum efficiencies in Table 6.1.

b. Existing dwellings should meet the minimum efficiencies in Table 6.2.

NOTE: The minimum system efficiency in Table 6.1 might need to be improved upon to meet the target emission rate and target primary energy rate for the dwelling.

Table 6.1 sets out minimum standards for services that are likely to be installed in new dwellings. If a service is not covered in Table 6.1 then it should meet either the efficiencies set out in Table 6.2 or an equivalent standard.

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Table 6.1 Minimum efficiencies for gas-fired heating systems in new dwellings

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Table 6.2 Minimum efficiencies for gas-fired heating systems in existing dwellings

6.2 If a gas-fired combination boiler is installed in an existing dwelling, at least one of the following energy efficiency measures, appropriate to the system, should be installed.

a. Flue gas heat recovery.

b. Weather compensation.

c. Load compensation.

d. Smart thermostat with automation and optimisation.

6.3 A gas-fired range cooker with an integral central heating boiler (within a single appliance body) that is either part of a new system or is a replacement component in an existing system should have two independently controlled burners (one for the cooking function, and one for the boiler).

NOTE: This paragraph does not apply to appliances with fully independent boiler and cooker parts within a shared case. In this case, the boiler should be treated as a conventional gas-fired boiler.

6.4 If a gas-fired warm air system is installed in an existing dwelling, all of the following should be met.

a. The system should be installed in accordance with BS 5864.

b. All new or replacement ductwork should be insulated in accordance with BS 5422.

c. Where controls are external to the heater, the system should be provided with a time switch/ programmer and room thermostat, or programmable room thermostat.

d. Where controls are integrated in the heater, the system should be provided with a time switch/ programmer and room temperature sensor linked to heater firing and fan speed control.

e. Independent temperature control of the hot water circuit should be implemented with a cylinder thermostat and a timing device. When there is no demand for hot water both the pump and circulator should switch off.

6.5 A gas-fired fixed independent space heating appliance that is installed in an existing dwelling should meet the applicable standard(s) as follows.

a. An appliance for primary space heating should meet standards (i) to (iv) below.

i. BS EN 1266

ii. BS 7977-1

iii. BS EN 613

iv. BS EN 13278.

b. An appliance for secondary space heating should meet one or more of standards (i) to (vi) below:

i. BS EN 1266

ii. BS 7977-1

iii. BS EN 613

iv. BS EN 13278

v. BS EN 14829

vi. BS EN 449.

6.6 If a gas fire is provided as a secondary heat source as part of a combined fire and back boiler unit in an existing system, the standards in BS 7977-2 should be met.

6.7 If a gas-fired fixed decorative fuel-effect fire is installed in an existing dwelling, both of the following should be met.

a. The standards in BS EN 509 should be met.

b. The number of appliances should not exceed one per 100m2 of dwelling floor area.

Oil-fired heating systems

6.8 An oil-fired heating system that is either part of a new system or is a replacement component in an existing dwelling should meet the minimum efficiencies in Table 6.3, in addition to the general requirements for heating and hot water systems in Section 5.

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Table 6.3 Minimum efficiencies for oil-fired heating systems in existing dwellings

6.9 An oil-fired range cooker with an integral central heating boiler (within a single appliance body) that is either part of a new system or is a replacement component in an existing dwelling should have two independently controlled burners (one for the cooking function, and one for the boiler).

NOTE: This paragraph does not apply to appliances with fully independent boiler and cooker parts within a shared case. In this case, the boiler should be treated as a conventional oil-fired boiler.

6.10 If a continuously burning oil-fired vaporising appliance is provided for secondary heating or hot water, one of the following should be met, depending on the type of appliance.

a. For a manually operated appliance, no further control is required above the integral manual controls that the appliance manufacturer provided.

b. For an electrically operated appliance, an integral remote or thermostatic control should be provided.

NOTE: This guidance does not apply to appliances that have been converted from another fuel.

Electric space heating systems

NOTE: Electric resistance heating is assumed to be 100% efficient, therefore no minimum efficiency is set for these types of system.

NOTE: This section of the guidance does not cover either of the following.

a. Electric heat pumps (guidance is provided in paragraphs 6.36 to 6.43).

b. Portable electric heating devices.

6.11 Electric heating systems should meet the guidance in paragraphs 6.12 to 6.14, in addition to the general requirements for heating and hot water systems in Section 5.

6.12 For electric storage heaters, both of the following should be met.

a. Automatic control of input charge should be provided.

b. The rate of heat release from the appliance should be adjustable, using an adjustable damper or other thermostatically controlled method.

6.13 For electric panel heaters that are either part of a new system or replacement components, time and temperature control should be provided to allow separate control for either of the following.

a. Each room.

b. Each appliance, where this meets the guidance for thermostatic room controls in paragraphs 5.20 to 5.22.

6.14 For an electric warm air system that is either a new system or is a replacement component, both of the following should be provided.

a. A programmable room thermostat or a time switch and room thermostat.

b. Separately controllable heating zones that meet the guidance for thermostatic room controls in paragraphs 5.20 to 5.22.

Solid fuel heating systems

6.15 Solid fuel appliances in new and existing dwellings should have a minimum efficiency (gross calorific value) as given in Table 6.4 for the category of appliance.

6.16 A solid fuel appliance belonging to category D1/2/3/4, F, G2, J2 or J5 of Table 6.4 that is used to deliver primary heating as part of a central heating system should comply with all of the following.

a. Meet the general requirements for heating and hot water systems in Section 5.

b. Have separate time controls for space heating and hot water circuits.

c. Have automatic control of the burning rate.

d. Follow the manufacturer’s instructions on the size and position of heat leak radiators designed to keep the system operating effectively by leaking heat.

6.17 A solid fuel appliance that is either part of a new central heating system or is a replacement component of a central heating system should meet both of the following.

a. The appliance should be from categories D, F, G or J in Table 6.4.

b. The appliance should have a ratio of room heat to water heat appropriate for the room and the total property.

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Table 6.4 Solid fuel appliance categories and minimum efficiencies

District heat networks and community heating systems

6.18 Paragraphs 6.19 to 6.25 apply when connecting dwellings to a district heat network or community heating system to which both of the following apply.

a. Has a central heat source, such as a boiler, combined heat and power unit or heat pumps.

b. Distributes heat to 15 or more dwellings.

NOTE: An existing district heat network is defined in Appendix A. A new district heat network should be taken as meaning any other district heat network.

Connecting to a new district heat network or community heating system

6.19 The central heat source should comply with the standards in Section 6 of Approved Document L, Volume 2: Buildings other than dwellings.

Connecting to an existing district heat network or community heating system

New dwellings

6.20 An existing district heat network that is being connected to a new dwelling should not have a CO2 emission factor for delivered heat to the dwelling which is greater than 0.350kgCO2/kWh or a primary energy factor for delivered heat to the dwelling greater than 1.450kWhPE/kWh. For dwellings, this should be calculated using SAP 10 or taken from the Product Characteristics Database.

NOTE: The same CO2 emission factors and primary energy factors used to calculate the dwelling emission rate and dwelling primary energy rate described in paragraph 2.8 in Section 2 of this approved document should be used to check against the factors for delivered heat.

Existing dwellings

6.21 When connecting an existing dwelling to an existing district heat network or community heating system, the carbon intensity and primary energy of the system should be assessed and the guidance in paragraphs 5.4 and 5.5 should be followed.

Emission factors and primary energy factors should be determined by a qualified person, based onthe details of the system and taking account of the annual average performance of the whole system, including distribution circuits and all the heat generating plant, combined heat and power, waste heat recovery, heat dumping, and evidence of future changes to the heat source, for example, replacing or adding new heat generating equipment.

Minimising energy used by pumps

6.22 New district heat networks or community heating systems should meet both of the following.

a. The design temperature difference for the community heating primary circuit should be a minimum of 20°C. Heat pump-led community heating systems may, however, need to run at a lower temperature difference.

b. Variable volume control systems should be used to reduce the volume of water and the pressure difference required from the pumps under part load.

Controls

6.23 For wet heating systems, the maximum design flow rate into the dwelling’s heating system should be limited by suitable control and balancing valves to maintain the overall balance in the network and to avoid excessive pumping energy.

6.24 For new district heat networks or community heating systems, the domestic hot water system should have variable volume controls to maintain low return temperatures in the primary community heating circuit.

Metering

6.25 District heat networks and community heating systems should be designed to accommodate heat meter(s) for each dwelling.

Micro combined heat and power

6.26 The heating plant emission rate of the micro combined heat and power system (micro-CHP) should be no greater than the emission rate of a regular boiler using the same fuel as the micro-CHP.

6.27 The heating plant emission rate should be calculated using all of the following.

a. The method in DEFRA’s Method to Evaluate the Annual Energy Performance of Microcogeneration Heating Systems in Dwellings.

b. The performance data for the micro-CHP packaged according to BSI PAS 67.

c. A plant size ratio that uses the nominal heat output of the heating plant divided by the average heat loss of the building when there is a temperature difference of 24.2°C.

Underfloor heating systems

Zoning and controls

6.28 New underfloor heating systems should meet all of the following, in addition to the general requirements for heating and hot water systems in Section 5.

a. All underfloor heating systems should have controls to adjust the operating temperature.

b. Room thermostats for electric underfloor heating systems should have a manual override.

c. Heating systems for screed floors that are greater than 65mm thick should automatically reduce the room temperature at night or when the room is unoccupied.

d. Heat loss should be minimised by following the guidance in paragraphs 6.29 to 6.32.

Minimising heat losses

6.29 Ground floors and those in contact with the outside of the dwelling should be insulated to limit heat losses to not more than 10W/m2. The heat loss from the floor should be calculated using the sum of the thermal resistance of the floor finish and the underlying heated layer, multiplied by 10.

6.30 Underfloor heating systems intended for intermittent or cyclical operation and/or installed over unheated rooms should be separated from the structural floor by a layer of insulation with a thermal resistance of at least 1.25(m2·K)/W.

6.31 The intermediate floor should have a layer of insulation to reduce downwards heat transmission with a thermal resistance of one of the following.

a. The performance in paragraph 6.29.

b. As specified in BS EN 1264-4, as follows.

i. For electric systems, not less than 0.5(m2·K)/W.

ii. For wet systems, not less than 0.75(m2·K)/W.

6.32 Distribution pipework which does not provide useful heat to a room should be insulated to the standards detailed in paragraph 4.26.

Specific standards for electric underfloor heating

6.33 Electric cables for underfloor heating should be installed within screeds as follows.

a. For direct electric systems, within screeds not exceeding 60mm.

b. For night energy storage systems, within screeds of at least 65mm.

6.34 Where electric cable underfloor heating night energy storage systems are used, both of the following should be met.

a. A minimum of 20% of the floor area of the dwelling should have fast-response systems, such as panel heaters.

b. Controls should be installed which modify the input charge in response to both of the following.

i. The room thermostat.

ii. Floor temperature sensing.

6.35 Programmable room thermostats with an override feature should be provided for all direct electric zones of the electric underfloor heating system. Thermostats should have air and floor temperature sensing capabilities which may be used individually or in combination.

Heat pump heating systems

NOTE: For heat pumps that provide comfort cooling, guidance is also given in paragraphs 6.49 to 6.53.

6.36 Electrically driven air-to-air heat pumps with an output of 12kW or less should follow the Ecodesign Commission Regulation No. 2016/2281 for air heating products, cooling products, high temperature process chillers and fan coil units.

6.37 For other types of heat pump, not defined in paragraph 6.36, the coefficient of performance should be both of the following.

a. For space heating, a minimum of 3.0.

b. For heating domestic hot water, a minimum of 2.0.

6.38 The heat pump unit should include controls for all of the following, in addition to meeting the general requirements for heating and hot water systems in Section 5.

a. To control water pump operation (internal and external, as appropriate).

b. To control either of the following.

i. For wet systems, water temperature.

ii. For air systems, air temperature.

c. For air-to-water and air-to-air units, to control outdoor fan operation.

d. For air-to-water and air-to-air systems, to provide a defrost control for the external air-side heat exchanger.

e. For air-to-air systems, to control secondary heating (if fitted).

f. To protect against water flow failure.

g. To protect against high water temperature.

h. To protect against high refrigerant pressure.

i. For air-to-water and air-to-air units, to protect against air flow failure.

6.39 The heat pump should have external controls that include both of the following.

a. Weather compensation or internal temperature control.

b. Timer or programmer for space heating.

6.40 For heat pump installations in which there are other heat sources available to the same building, each of these heat sources should be appropriately incorporated into a singular control system.

6.41 Heat pumps should be located and installed subject to the manufacturer’s guidance. In regard to air source heat pumps, this includes the consideration of factors that may adversely affect their performance, e.g. the avoidance of cold exhaust air recirculation and the removal of condensation from the outdoor coil during a defrost cycle.

6.42 Heat pumps should not be sited adjacent to sleeping areas, nor should they be located on materials that can readily transmit vibrations. Additionally, the location of external fans and heat pump compressors should be appropriately selected to minimise disturbance to neighbours, while remaining in compliance with planning requirements.

6.43 The installation of anti-vibration instruments and flexible hose connections should be in accordance with the manufacturer’s guidance in order to limit the effects of harmful vibrations on building structures.

Solar water heating systems

NOTE: The guidance for solar water heating in this document applies to indirect solar systems that supply domestic hot water and have both of the following.

a. A solar collector area of less than 20m2.

b. A solar heated water storage volume of less than 440 litres.

6.44 New solar hot water collectors should be independently certified as complying with all tests required by BS EN 12975-1 and BS EN ISO 9806 for both of the following.

a. Thermal performance.

b. Reporting and identification.

6.45 The electrical input power of the primary pump in the solar water heating system measured in watts should be less than the higher of the following.

a. 50W.

b. 2% of the peak thermal power of the collector.

6.46 For a heat exchanger between a solar primary and secondary system, a minimum of 0.1m2 or equivalent of heat exchanger area should be provided for every 1m2 of the net absorber area of the solar collector.

6.47 For work on new or existing solar water heating systems, controls should be fitted to or upgraded in solar domestic hot water systems to do all of the following.

a. Maximise the useful energy gain from the solar collectors.

b. Minimise the accidental loss of stored energy.

c. Ensure that hot water produced by back-up sources is not used when adequate solar pre-heated water is available.

d. Provide a means to control the adverse effects of excessive temperatures and pressures.

e. Where a separate domestic hot water heating appliance is pre-heated by a solar system, the appliance should be controlled to add no extra heat if the target temperature is met from the solar pre-heated vessel.

6.48 The dedicated storage volume of solar heated water relative to the area of the collector should be either of the following.

a. A minimum volume of 25 litres for every 1m2 of the net absorber area of the solar collector.

b. A volume equivalent to at least 80% of the daily hot water demand (as defined by the Standard Assessment Procedure).

Comfort cooling

6.49 The specification of comfort cooling systems should be based on a heat gain calculation for the dwelling. To calculate heat gain, both CIBSE’s Guide A and the manufacturer’s guidance should be followed. Systems should not be significantly oversized – in most circumstances, the cooling appliance should not be sized for more than 120% of the design cooling load.

6.50 The seasonal energy efficiency ratio of an air conditioner working in cooling mode should be a minimum of 4.0.

6.51 Comfort cooling systems should have both of the following controls.

a. For each control zone and for each terminal unit, independent control of both of the following should be possible.

i. Timing.

ii. Temperature.

b. If both heating and cooling are provided in the same space, the controls should prevent them from operating simultaneously.

6.52 For cooling systems that serve multiple dwellings, follow the guidance in Approved Document L, Volume 2: Buildings other than dwellings.

6.53 Exposed refrigeration pipework should be both of the following.

a. Insulated.

b. Enclosed in protective trunking.

Mechanical ventilation

6.54 Ventilation systems should meet the ventilation needs of the dwelling, in accordance with Approved Document F, Volume 1: Dwellings. Systems should be designed so that they can be commissioned to suitable ventilation rates so that spaces are not significantly overventilated.

6.55 The specific fan power for mechanical ventilation systems should not exceed the following.

a. For intermittent extract ventilation systems: 0.5W/(l·s).

b. For continuous mechanical extract ventilation systems: 0.7W/(l·s).

c. For continuous supply ventilation systems: 0.5W/(l·s).

d. For continuous mechanical supply and extract ventilation systems: 1.5W/(l·s).

6.56 All ventilation systems which provide both supply and extract ventilation within the same unit should be fitted with all of the following.

a. A heat recovery system with a minimum efficiency of 73%.

b. A summer bypass facility (giving the ability to bypass the heat exchanger or to control its heat recovery performance).

c. A variable speed controller.

Lighting

6.57 Any fixed lighting should achieve lighting levels appropriate to the activity in the space and spaces should not be over-illuminated.

NOTE: In many cases, it is likely that householders will be able to choose the lamp installed in the individual space.

6.58 Where installed in a new or existing dwelling, each internal light fitting should have lamps with a minimum luminous efficacy of 75 light source lumens per circuit-watt.

6.59 Where installed in a new or existing dwelling, internal light fittings should have local controls to allow for the separate control of lighting in each space or zone. Controls may be manual, automatic or a combination of both.

6.60 Where installed in a new or existing dwelling, fixed external lighting should have both of the following controls.

a. Automatic controls which switch luminaires off in response to daylight.

b. If luminous efficacy is 75 light source lumens per circuit-watt or less, automatic controls which switch luminaires off after the area lit becomes unoccupied. If luminous efficacy is greater than 75 light source lumens per circuit-watt, manual control is acceptable.

Building automation and control systems

6.61 Where a building automation and control system is installed, it should have appropriate control capabilities for the dwelling, based on the type of building, its expected use and potential energy savings.

6.62 The system should be specified and installed according to the manufacturer’s instructions to ensure that its overall performance meets a reasonable standard.

6.63 For large or complex buildings, the guidance in Approved Document L, Volume 2: Buildings other than dwellings should be followed.

On-site electricity generation and storage

6.64 Where on-site electricity generation and storage is installed, such as photovoltaic panels or battery storage, systems should be an appropriate size for the site, available infrastructure and on-site energy demand.

6.65 The system should be specified and installed according to the manufacturer’s instructions to ensure that the overall performance of the system meets a reasonable standard.

6.66 When replacing an existing system, the installed generation capacity of the new system should be no less than that of the existing system, except where a smaller system can be demonstrated to be more appropriate or effective (e.g. replacing an existing system with one which is better matched to the dwelling’s energy demand).

6.67 On-site electricity generation should be provided with controls to allow proper operation of the system without the need for user intervention. This is particularly the case where electricity generation and storage systems are used, such as batteries.

Section 6: System specific guidance