6.3 Heating system
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In the design of buildings, the energy efficiency of the heating plant is an important part of the package of measures which contributes to the overall building carbon dioxide emissions. In practice the backstop levels for appliance efficiencies and controls will normally be exceeded to achieve compliance with Standard 6.1. for new buildings.
Good control of space heating is essential for conservation of energy in buildings, as without it, the potential of energy efficient heating plant cannot be realised. Generally the system should have sufficient zone, time and temperature controls to ensure that the heating system only provides the desired temperature when the building is occupied. Such operating controls can be overridden however when heating is needed to protect the building's structure, services or contents from frost or condensation damage.
There are efficiency issues which go beyond the guidance to the standard. These include:
a heating system boiler should be correctly sized to ensure energy efficiency
where future heating capacity may be required consideration should be given to providing additional space for extra plant. The pipe-work or ductwork should be configured to allow for the future loading, and
other efficiency targets which may be appropriate for a system, to achieve improved performance under the requirements of government climate change and energy saving schemes.
Renewable Technologies - Directive 2009/28/EC (http://europa.eu/legislation_summaries/energy/renewable_energy/en0009_en.htm) promotes the use of energy from renewable sources. Where the building 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 Non-domestic Building Services Compliance Guide for Scotland http://www.scotland.gov.uk/Topics/Built-Environment/Building/Building-standards/techbooks/techhandbooks/ndbscg.
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.
Older buildings - in many cases heating system improvements to historic buildings will be more feasible than any other energy efficiency measures, for example 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.
Where work to an existing building is subject to a building warrant and includes the provision of new fixed building services or alters or extends the capacity of existing fixed building services, the opportunity should be taken to review and improve the performance of fixed building systems.
Guidance on the extent to which improvement should be made is given in annex 6.D – ‘Improvement to the energy performance of existing building services when carrying out building work’.