6.3 Heating system
In the design of domestic buildings, the energy efficiency of the heating plant is an important part of the package of measures which contributes to the overall dwelling carbon dioxide emissions. In practice the backstop levels given in this guidance for appliance efficiencies and controls will normally be exceeded to achieve compliance with Standard 6.1 for new buildings. The notional dwelling standard specifications already indicate this (refer to clause 6.1.4).
This guidance refers to main heating systems for dwellings. Both the primary heating and secondary heating systems are taken account of in SAP 2012.
When the guidance in Section 3 on heating requirements for dwellings is considered along with Standard 6.1, central heating (rather than using several individual appliances as primary heating) will usually be the most practical way to satisfy the standards.
Renewable technologies - Directive 2009/28/EC promotes the use of energy from renewable sources. Where the dwelling design will include use of renewable energy for heating, Article 13 of the Directive recommends, amongst other measures, consideration of use of the following:
for biomass equipment, conversion efficiencies of 85%
for heat pumps, those that fulfil the minimum requirements of eco-labelling established in Commission Decision 2007/742/EC (amended in 2011 & 2013) establishing the ecological criteria for the award of the Community eco-label to electrically driven, gas driven or gas absorption heat pumps, and
for solar thermal systems, those that are subject to EU standards, including eco-labels and other technical reference systems established by the European standardisation bodies.
Conversions - in the case of conversions, as specified in regulation 4, the building as converted shall meet the requirements of this standard in so far as is reasonably practicable, and in no case be worse than before the conversion (regulation 12, schedule 6).
The minimum performance of, space heating and hot water systems, heating appliances and controls is set out in the Domestic Building Services Compliance Guide for Scotland http://www.scotland.gov.uk/Topics/Built-Environment/Building/Building-standards/techbooks/techhandbooks/dbscgs.
The document replicates guidance published in support of building standards elsewhere in the UK and supports standardisation of the specification and expected performance of fixed building services throughout the UK. The guidance applies to new systems and replacement, in whole or in part, of existing systems. It also addresses improvement work to existing systems as a consequence of replacing components.
Clause 6.3.2 provides information on situations not addressed in that document.
Historic, listed or traditional buildings - in many cases heating system improvements to historic, listed or traditional buildings will be more feasible than other energy efficiency measures such as improving wall insulation. Where this is the case, systems which go beyond these minimum backstop levels may help offset the deficiency in other areas of energy efficiency and carbon dioxide emissions.
As a conservatory which is heated will be inefficient in energy terms, the general guidance to occupiers is that they should be heated as little as possible. In view of the fact that heating is often desired particularly at the start and end of the heating season, any conservatory with heating installed should have controls that regulate it from the rest of the dwelling e.g. a thermostatic radiator valve (TRV) to each radiator.