8.3.1 Space heating

Also see:

8.3.1.1 Requirements

When space heating is provided, it shall comply with the Technical Requirements and ensure safe operation. Issues to be taken into account include:

relevant standards
provision of heating

8.3.1.1.1 Relevant standards#

Relevant standards for space heating design used in domestic hydronic systems include:

BS 5410	‘Code of practice for oil firing’
BS EN 14336	Heating systems in buildings. Installation and commissioning of water based heating systems
BS 8303	‘Installation of domestic heating and cooking appliances burning solid mineral fuels
BS EN 12828	‘Heating systems in buildings. Design for water-based heating systems’
BSRIA guide BG 4/2011	‘Underfloor heating and cooling’
CIBSE guide A	Environmental design
CIBSE	Domestic heating design guide

Space heating and cooling appliances, including all components and controls, should be of a type approved by the relevant authority, including:

gas appliances – Assessment by an appropriate independent technical approvals’ authority accepted by NHBC confirming compliance with UK CA, UK NI or CE marking
solid fuel – Solid Fuel Association, Heating Equipment Testing & Approval Scheme
electricity – British Electrotechnical Approvals Board
oil – OFTEC
LZC technologies – should have a current certificate confirming satisfactory assessment by an appropriate independent authority acceptable to NHBC. Systems, products and installations assessed through Microgeneration Certification Scheme (MCS) will generally be acceptable to NHBC
certification and test documentation should be made available to NHBC upon request
other certification bodies or test documentation may be acceptable where they are considered by NHBC to be a suitable alternative.

8.3.1.1.2 Space heating provision#

The provision of whole home or central heating is discretionary. Where provided by Infrared radiant panels the system should be designed by a specialist and recognised standards, where provided by hydronic systems or convector panel heaters, it should be designed in accordance with Tables 1,2 and 3, recognised standards, and:

the number of air changes per hour from kitchens and bathrooms should account for any mechanical ventilation
where rooms contain open flued appliances, the rate of air change used for the design should be increased in accordance with BS EN 12831
room ventilation rates should be in accordance with recognised standards and guidance eg CIBSE domestic heating design guide or other approved by NHBC see table 1
design temperatures should be verified by calculations and not by performance tests
the main living room should have a heating appliance or a heat output as part of a whole home heating system
heat loss calculations should be based on external temperature in line with tables 2 and 3
the heating designs must include allowances where applicable for thermal bridging
the design may need to use elevated temperatures to take into account frail, elderly or the infirm.

Table 1: Ventilation rates per hour (CIBSE Domestic heating design guide)

Room	ACH	Room	ACH	Room	ACH
Lounge/sitting room	0.5	Cloakroom/WC	1.5*	Internal room or corridor	0.0
Living room	0.5	Toilet	1.5*	Bedroom/study	0.5
Breakfast room	0.5	Utility room	0.5*	Landing	0.5
Dining room	0.5	Study	0.5	Bathroom	0.5*
Kitchen	0.5*	Games room	0.5	Shower room	0.5*
Family/breakfast room	0.5*	Bedroom	0.5	Dressing room	0.5
Hall	0.5	Bedroom with ensuite	1.0	Storeroom	0.5

Notes

* where mechanical extract ventilation is to be installed and the value exceeds the natural infiltration then due allowance must be made for the air extracted from any connecting room or corridor as detailed in Approved Document F.

Table 2: Room temperatures, new build insulated to current standards

Room	Temp °C	Room	Temp °C	Room	Temp °C
Lounge/sitting room	21	Cloakroom/WC	21	Internal room or corridor	21
Living room	21	Toilet	21	Bedroom/study	21
Breakfast room	21	Utility room	21	Landing	21
Dining room	21	Study	21	Bathroom	22
Kitchen	21	Games room	21	Shower room	22
Family/breakfast room	21	Bedroom	21	Dressing room	21
Hall	21	Bedroom with en suite	21	Storeroom	21

Table 3: Outdoor design temperatures

Region	Latitude	Outdoor design temperature °C	Ground reference temperature (winter mean °C)
Scotland & Isles	56-60°N	-5	+5.5
Northern England & Northern Ireland	54-56°N	-4	+6.0
Midlands, Wales and ROI	52-54°N	-3	+6.5
London, SW England	51-52°N	-2	+7.0
Southern England	50-51°N	-1	+7.5

Last updated: 2nd January 2024