Building standards technical handbook 2020: domestic

The building standards technical handbooks provide guidance on achieving the standards set in the Building (Scotland) Regulations 2004. This handbook applies to a building warrant submitted on or after 1 March 2021 and to building work which does not require a warrant commenced from that date.

3.13 Heating

Mandatory Standard

Standard 3.13

Every building must be designed and constructed in such a way that it can be heated and maintain heat at temperature levels that will not be a threat to the health of the occupants.


This standard applies only to a dwelling.

3.13.0 Introduction

Heating in a building is necessary to provide suitable conditions in which to live. Heating, ventilation and thermal insulation should be considered as part of a total design that takes into account all heat gains and losses. Failure to do so can lead to inadequate internal conditions, e.g. condensation and mould and the inefficient use of energy due to overheating.

Whole house ‘central heating’ is now almost universal, particularly in new buildings and is regarded as almost essential in combating problems such as condensation and mould growth.

Normal activities within a dwelling add both heat and water vapour to the air. If the heating maintains comfort levels in the whole at all times, condensation problems will be minimised, but costs will be high. A reasonable compromise needs to be given to heating and ventilation to reduce the possibility of such problems and guidance is provided for both these issues in this sub-section. Section 6, Energy, provides guidance on the third issue, thermal insulation.

This guidance covers dwellings only as the heating of buildings other than dwellings is covered by the Workplace (Health, Safety and Welfare) Regulations.

Conversions - in the case of conversions,as specified in regulation 4, the building as converted shall meet the requirement of this standard (regulation 12, schedule 6).

3.13.1 Heating recommendations

The layout of a dwelling, the size and orientation of the windows, the thermal mass, level of insulation, airtightness, and ventilation can have a significant affect on the demand for heat. The performance of a heating system will also have a major affect on energy efficiency. Section 6, Energy provides guidance on these issues.

Heating a dwelling will normally be tailored to personal comfort taking cost into consideration. However in addition to comfort, the heating should reflect the combined effects of occupancy pattern, ventilation provision, building mass and insulation to reduce the possibility of producing excess condensation that might damage the building fabric.

Every dwelling should have some form of fixed heating system, or alternative that is capable of maintaining a temperature of 210C in at least 1 apartment and 180C elsewhere, when the outside temperature is minus 10C.

There is no need to maintain these temperatures in storage rooms with a floor area of not more than 4m2.

3.13.2 Alternative heating systems

Alternative heating systems may involve a holistic design approach to the dwelling and can include the use of natural sources of available energy such as the sun, wind and the geothermal capacity of the earth. Passive design, such as use of the orientation of glazing for solar gain and of the building mass to store heat with controlled heat release may only need minor supplementation from a lower output fixed heating system. Active heating systems, such as heat pumps that extract heat from ground, air, water or geo-thermal sources, can limit emissions of carbon dioxide and reduce the use of fossil fuels. Complementary systems can also be used, to heat water using solar energy or generate electricity using solar or wind power.

Where there are elderly or infirm occupants in a dwelling the capability of the heating system to maintain an apartment at a temperature higher than 210C is a sensible precaution. Since it is not possible to determine the occupants at design stage the heating system should be designed with the capability of being easily upgraded at a later date.

If an existing heating system is to be upgraded to provide higher temperatures the boiler size may not need to be replaced, provided it was correctly sized originally. The upgrading may necessitate the replacement of some pipes and radiator in one or two rooms and accessibility will need to be considered. Such modification could result in a small increase in the recovery time of the hot water supply for bathing and washing.

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