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8741097 
Meetings & Symposia 
Construction methods which can achieve A3 rating at minimal extra cost 
Pike, J 
2008 
University College Dublin 
English 
Analysis of completed multiple housing schemes designed to achieve an A3 rating, using current standard construction methods, showing the additional cost of achieving the A3 rating, set against the potential advantages. The study will then show how these additional costs can be reduced and other technical problems solved, using off-site construction methods and advanced technical solutions. The first scheme is: A development of 67 dwellings consisting of 2 storey terraced houses and some 3 storey apartment buildings, built using a timber frame with brick or block rendered external walls. • Windows and doors with lower u-value (1.4Wm2K) • Increased insulation in the floors and lofts • Airtightness level of 1.5 a/c per hour • Heat Recovery Mechanical Ventilation • Hot water solar panels and twin coil copper tank • Energy efficient light fittings • Energy efficient gas boiler and efficient heating controls The study of alternatives will be based on the second stage of this development which is awaiting planning permission and will be on site before the autumn. The second scheme consists of 280 apartments in 6 and 7 storey buildings on a "brownfield" site. The construction is traditional blockwork walls with brick faced cavity walls. Energy Efficient Features: • Insulation specification 60% more than required in the building regulations • Heat Recovery Mechanical Ventilation to all units (individual air handling) • A high level of airtightness was achieved • Exposure was minimised by using natural shelter, woodlands and landscaping • Draught lobbies were designed into main entrances to minimise heat loss • District heating system utilises 10 gas-fired boilers in the basement to supply hot water and heat to units, gas bought at commercial rate therefore 30% saving to homeowners • An individual metering system for each apartment allows the management company to issue heating bills every 2 months, a laptop is simply plugged into the system and each bill printed instantly • Room thermostats allow individuals to control the level of heat they use, the 10 boilers operate on a 'when needed' basis, the greater the demand the more boilers fire up with the system falling back to 10 or 2 boilers at off-peak times just to supply hot water The study of the alternatives will be related to a similar development of apartments which will entirely use off-site construction and is currently at planning stage. Three other projects which are either on-site or pre-construction will also be analysed in conjunction with the 2 above. 
Airtightness; District heating; Heat recovery ventialation; Increased insulation; Metering system; Reduced energy consumption; Solar hot water; User friendly system