Opportunity Cost of Retrofitting Buildings - PDF

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					                             RETROFITTING BUILDINGS
 ‘What is needed is nothing short of an energy revolution’. Not a statement from a ‘prophet of
doom’, but from the International Energy Agency in its 2008 World Energy Outlook. The IEA
states that current low oil prices are delaying much-need investment in energy, as global oil
reserves decline at an unprecedented 6.7% per year; when the global economy recovers, the
supply crunch may be worse than the problems that pushed oil prices to $147 a barrel in
summer 2008.

In sustainable design no one profession has the scope to provide all the answers and design
teams are increasingly being expanded to include sustainable design and building physics
consultants. However the professions are evolving in order to embrace the challenges of the
sustainability agenda. Many architects are increasingly aware of how the building fabric and
energy systems behave, and the effect basic design moves can have on these areas.
Detailing of buildings now prioritises insulation, airtightness and the elimination of cold
bridging. Mechanical and Electrical engineers are also starting to embrace the sustainability
agenda, looking at the potential for using passive and renewable systems. When the two
professions work effectively together improved quality of the internal environment and
reduced lifetime costings can be realised.

Specialising in sustainable design and 4D Planning, MCO Projects environmental engineers,
architects and project managers work together from the outset taking into account the effects
on energy consumption of different building fabric and energy systems. MCO Projects has
recently illustrated this type of information in a Building Design and Energy Index, published
in the MCO Projects Green Issue Journal that pools data from the UK and Ireland with the in-
house data in order to find average energy consumption levels and patterns for buildings.
These consumption figures are then multiplied by the most recent SEI fuel cost data to
produce an index of current energy costs for a variety of buildings.

The terminology used is taken from BRE conventions, as the BRE was both a source and an
inspiration for the Index. ‘Poor’ refers to un-insulated buildings constructed prior to 1974, or
later buildings in poor condition. ‘Typical’ refers to buildings constructed between 1974 and
1998, earlier buildings which have been up-graded, or later buildings which were poorly built.
‘Good practice’ covers buildings constructed to 1997 or 2004 Building Regulations. ‘Best
practice’ refers to up-graded post-1997 buildings, or buildings designed and built to higher
standards than the 2004 regulations. However the building ‘type’ should be considered
relative rather than absolute due to inevitable variability in buildings and their energy
systems.

The Index sets out clearly the relationship between the design of the building and its fabric
and systems, and the building’s energy running costs. For example, a recently surveyed
leisure centre, which had been demolished and rebuilt, indicated that although the building
was commissioned in 2006, its performance was comparable with a building built more than
ten years earlier. The survey included an audit of equipment and energy consumption, a
review of the building performance, and options for reductions in passive and active energy
consumption and cost. The result of survey figures from MCO's database suggest that
buildings such as hotels and leisure centres, when in poor condition, spend a significant
proportion of revenue on energy bills. As shown by the Index these running costs can be
halved by choosing the best fabric and system options, and ensuring the best workmanship.
Many of our European neighbours have upgraded their building stock to reduce energy
consumption. Although some individual projects have been undertaken in Ireland, the great
majority of our existing building stock is (as per the Index) in ‘poor’ condition. In cities such as
Berlin, most residential and office buildings have now been upgraded in a program which was
at its peak between 1992 and 1997. 13 - 14 Rykestrasse consists of 44 apartments, 4 offices
and a café, arranged around an open courtyard situated in the old centre of Berlin. The three
buildings making up the complex were built in the early 1900s. These ‘protected structures’
were renovated in 1993, and the energy conservation measures included a green roof,
courtyard and rear external walls insulated to reduce u-values from 1.7 to 0.27, a gas-fired
CHP providing electricity, heating and hot water to apartments and a cafe. The energy
measures reduce the buildings’ CO2 emissions by 100 tons per year.

Many Irish local authorities have initiated insulation programs, initially to fill the un-insulated
cavity walls of housing stock built from the 1950s to 1980s. However, insulation of walls of
protected structures in Ireland is almost unknown as the application of internal or external
insulation does not sit easily with current Irish Conservation conventions. This is in marked
contrast to developments in northern Europe where the application of reversible insulation
measures to protected structures, including external insulation and secondary glazing, are
now accepted and widely used. On the northern edge of Berlin, the Stadtgut in the village of
Blanckenfelde is an ensemble of 18th century buildings which formed the centre-piece of an
estate. These protected structures are currently being renovated, including external insulation
of walls to achieve a u-value of 0.12 W/m2K. Together with the use of high-quality double-
glazing units in refurbished windows, this will reduce the heating energy requirement of the
buildings by 93%.

Unlike Stadtgut, protected structures in Ireland cannot be easily altered to improve energy
efficiency within current Conservation guidelines. New guidelines on energy efficiency in
historic buildings and protected structures are being prepared by the DOEHLG. MCO
Projects has just completed the refurbishment and extension of St. Anne's Convent for the
Congregation of the Sisters of Mercy, in Booterstown, County Dublin. This is a grouping of
protected structures dating from the 1780s and 1840s and 2 new buildings. Works to improve
the energy performance of the protected structures has involved insulation under the new
ground floor slab, between floors and in attic spaces, new draught sealed sash windows and
new external and internal lime render to improve airtightness. Detailing around windows and
doors has been carefully considered and lobbies to external doors have been installed. The
U-value of the existing walls is estimated at 1.7W/sq.mK.

The 2 new buildings are of contrasting construction methods dictated by conservation
planning concerns. Both buildings have sedum roofs. The larger extension uses a masonry
full fill cavity wall construction with 120mm of insulation. This wall achieves a U value of
0.2W/sq.mK. The other extension is of poroton blocks with 120mm of external Insulation
protected by a render. This wall achieves a U value of 0.19W/sq.mK. A version of the
external insulation and render system could technically have been applicable to certain
external walls in the protected structures.

The energy systems are generally the same for all buildings. A wood pellet boiler in a
separate purpose built outhouse provides hot water. The ventilation in the new buildings and
the basement of the protected structures is controlled by a MHRV system, reducing heat loss
and any need for open windows or vents. The integration of this system into the protected
structures has to be carefully coordinated and is only really possible in areas without intact
ceilings. A good level of airtightness has to be achieved for this system to function effectively.
In new building projects decisions on construction methodology and energy systems are
interrelated and interdependent in many areas including location, orientation, utilities, access,
building volume, user requirements and the planning context. There is no universal solution
and each project has to be individually assessed and an appropriate and balanced solution
achieved. MCO Projects is currently on site with a technology enabled social housing
development in Dundalk which aims to allow elderly occupants to live at home for longer by
providing a flexible layout and integrating sensor technology into the units. The building will
have high levels of insulation and airtightness, use a passive ventilation system, and will be
heated by a CHP biomass boiler with associated district heating system.

The Index is designed to complement the new Building Energy Rating system which sets out
the theoretical energy consumption of a building built to a particular standard. Using SEI fuel
cost data, the Index sets out the actual measured energy cost of buildings in euro, rather than
in kW/hours. This format will make it clearer that energy-saving design, both passive and
active, is a prerequisite rather than an option for every new building. For operators or owners
of existing buildings the Index presents the opportunity to assess the present situation and
make decisions on how to save considerably on energy costs.

A mutual understanding and collaboration from the outset of the project between project
managers, architects and environmental engineers provides a unique, streamlined, co-
ordinated service that reflects the demands of the sustainability agenda and can deliver
optimal and holistic solutions with considerable lifetime savings and income for clients.

MCO Projects: An Integrated Design Office Delivering Sustainable Projects
Winners 2007 Sustainable Energy Ireland Award for Excellence in Building Design &
Specification


                                             END


Note to Editors
For more information please contact:
Susan Andrews, Marketing and Business Development Manager, MCO Projects Ltd.
Tel: 01 8870630
sandrews@mco.ie

				
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