C o s t – E f f e c t i v e n e s s M e a s u r e m e n t M o d e l
223
COST-EFFECTIVENESS MEASUREMENT MODEL FOR
SCOTTISH ENERGY EFFICIENT AFFORDABLE HOUSING
DESIGN
Anushree Rohatgi
1
, Kajal Dhamne
1
, Balachander Raidu
1
, Masa Noguchi
1
&
Hasim Altan
2
1
Mackintosh School of Architecture, The Glasgow School of Art, United Kingdom
2
BEAU, School of Architecture, The University of Sheffield, United Kingdom
Abstract
Scottish homes today are conspicuous energy consumers emitting on average 3 ton-
CO
2
per house annually. The figure indicates the operational carbon dioxide (CO
2
)
emission is much higher than the UK average of 2.75 ton-CO
2
. Moreover, approx. 30%
of the households today are facing fuel poverty. The Scottish Government has set a
green housing delivery target that all newly built homes would be carbon-neutral by
2016/17. Having recognised such imminent issues, NRGStyle Ltd. is taking the actions
towards the future delivery of zero-energy/carbon affordable homes in Prestwick,
Scotland. The planning of such challenging affordable homes may highly be based on
innovations and non-traditional practices. Thus, this feasibility study was the initial
attempt for the company to grasp how the relevant passive design techniques and active
renewable technologies should be identified and measured in view of the operational
energy use, cost and CO
2
emissions. Accordingly, it led to the development of a cost-
effectiveness measurement model which consists of (1) steps (process) towards the
identification of potential design options and the combinability and the assessment of
energy consumption, operational energy cost and CO
2
emissions, as well as (2) a value
visualisation analysis matrix (product). The energy-related assessment is based on the
UK Government’s Standard Assessment Procedure (SAP) for Energy rating of Dwellings
(2009 version). Moreover, in order to identify design options, the energy and resource
usage patterns of NRGStyle’s existing house were examined using EWGECO’s gas,
electricity and water monitor. Domestic energy wastes could be calibrated, reduced or
eliminated by displaying the energy and resource usage. The assessment of the design
options was tailored to meet NRGStyle’s expectation for the application to their new
housing prototype called ‘ZEMCH109’. The original design approach was considered as
the benchmark figure of this cost-effectiveness assessment where the operational
energy cost was highlighted in this study and the future value was calculated using a
future worth method based on the time value of money concept—e.g. a period of 10
years and 10% interest rate.
Keywords:
Affordable homes, passive techniques, active technologies, heating systems,
zero energy, cost effectiveness.
Introduction
Households who spend more than 10% of their total income may be experiencing fuel
poverty. It has been reported that from 1996 to 2002, the fuel poverty population fell from
36% to 13%; however, it again rose to 15% in 2003. Since then, it has been on a
constant growth with 33% in 2009 (Scottish House Condition Survey 2009). In 2010, the
carbon emission in the UK rose tremendously due to increased use of gas for heating
homes during the cold months. As per Scottish House Condition Survey, detached
houses are facing maximum fuel poverty (40%) as well as having high CO
2
emissions as
opposed to semi-detached, flats and apartments (30%). “Energy use in buildings
worldwide accounts for over 40% of primary energy use and 24% of greenhouse gas
emissions. Energy use and emissions include both direct, on-site use of fossil fuels and
indirect use from electricity, district heating/cooling systems and embodied energy in
