Comparison between energy usage and thermal comfort of typical masonry houses in Ireland before and after receiving retrofit
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Comparison between energy usage and thermal comfort of typical
masonry houses in Ireland before and after receiving retrofit
Dr Jamie Goggins
Lecturer
National University of
Ireland, Galway
Jamie.Goggins@nuig
alway.ie
Mr Alan Armstrong, National University of Ireland, Galway, Ireland a.armstrong1@nuigalway.ie
Ms Helena McElmeel, Helena McElmeel Architects, Ireland, helena@mcelmeel.ie
Short Summary
This research project examines the efficacy of typical insulation and building fabric upgrade works
of residential buildings in reducing energy and greenhouse gas emissions, as well as their affect
on the perceived thermal comfort of the occupants. This is achieved by monitoring 19 houses in
Ireland and assessing the internal environment, energy consumption, comfort and occupant be-
haviour, before and after typical residential insulation improvements. A full economic and environ-
mental lifecycle analysis is conducted, which considers both the energy consumption and carbon
emissions embodied in the retrofit works together with those associated with the operation of the
home. The houses are typical masonry construction used in Ireland. The retrofit provisions in-
cluded pumping the cavity walls with insulation and increasing the level of insulation in the attic
above the ceiling joists. The heating systems in the homes are a central heating system using an
oil-fired condensing boiling and a solid fuel open fire in the sitting room. The mix of fuel type em-
ployed varied in the different houses. So did the level of satisfaction expressed by the occupants in
relation to the thermal comfort conditions before and after the upgrade works? As expected, the
upgrade of insulation of the houses lead to increased internal temperature, but also in most in-
stances an expected decrease in overall energy consumption over the lifecycle of the building.
However, deeper retrofitting is required on houses in Ireland if the Sustainability Energy Authority
of Ireland’s target to reduce CO2 emissions of buildings by 90% by 2050 is achieved. This is a simi-
lar target set by the European Commission for reductions in emissions associated with buildings in
Europe.
Keywords:Lifecycle assessment; Retrofit; Embodied energy; Embodied carbon; Residential
buildings.
1. Introduction
As Ireland aims at limiting greenhouse gas (GHG) emissions to 113% of 1990 levels through Kyoto
Protocol commitments by 2020 [1], national GHG emissions associated with the residential built
environment will have a significant role to play. Due to recent deceleration in new EU construction
activity [2], it is widely expected that national retrofitting strategies of existing housing stock will
require significant investment if legal binding targets are to be successfully achieved, especially in
Ireland where a significant portion of Ireland’s total housing units were completed in the last
decade (see Figure 1). Considering the majority of existing housing units will still be active in 60
years time, a lifecycle perspective strongly suggests domestic energy performance retrofitting or
refurbishment schemes will be vital in achieving energy efficiency targets [3]. Hence, the
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importance of a lifecycle analysis study, in terms of energy and carbon, for retrofitting projects is
authenticated. Over a 60 year lifespan it is important perceived operational energy savings of
retrofit options are not outweighed by indirect embodied properties of installed materials or
services. Studies have highlighted challenges associated with examining retrofit options in Ireland
over a lifecycle period [4, 5].
93% of Irish housing units granted planning permission between 1977 and 2011 have initial energy
performance requirements compliant to 2005 Irish building energy performance regulations [6] or
earlier from collected Central Statistics Office (CSO) data [7], equating to an equivalent Building
Energy Rating (BER) [8] of ‘B3’ or lower upon construction assuming no subsequent renovations or
retrofitting. A BER is an independent national certification system used in Ireland to assess how
energy efficient a home is. An alphabetical rating scale from ‘A-G’ is utilised with an A rated home
being the most energy efficient [8]. A BER is based on the characteristics of major components of
the dwelling (wall, roof and floor dimensions, window and door sizes and orientations) as well as
the construction type and levels of insulation, ventilation and air tightness features, the systems for
heat supply (including renewable energy), distribution and control, and the type of lighting. It
covers annual energy use for space heating, water heating, ventilation, lighting and associated
pumps and fans, calculated on the basis of a notional standard family with a standard pattern of
occupancy [8]. It is important to note that a BER is only an indication of the energy performance of
a house. For example, a rating of B3 equates to a primary energy usage of between 125 and 150
kWh/m2/yr. Hence, logical conclusions suggest retrofitting packages (small, medium and deep) will
play a vital role in landscaping Ireland’s future housing stock. Previous Sustainable Energy
Authority of Ireland (SEAI) retrofitting scheme take-up has been welcomed in Ireland [9].Therefore,
implementation of the SEAI’s residential roadmap targets to sizeably reduce domestic residential
energy usage and carbon consumption by 2050 is imperative [10]. Various scenarios have been
developed with retrofitting to varying degrees of up to 1 million Irish homes in order to achieve
substantial Irish residential sector decarbonisation. Targets are in accordance with European
Commission 2050 goals to cut EU CO2 emissions by 90% and energy consumption by 50% [11].
However, it is important appropriate investigation into perceived operational saving benefits is
carried out assessing the true effect of residential retrofit financial grant packages offered by SEAI
[12]. Issues such as occupant and physical ‘take-back’, energy usage offsetting, tenant thermal
comfort level and internal temperature changes require attention. A 2008 SEAI residential sector
report mentioned data on comfort levels or internal temperatures for residential dwellings was
unavailable for Ireland with UK values assumed [13]. Without substantial quality thermal comfort
and internal temperature data on retrofitted residential buildings in Ireland, it is difficult to truly
assess the impact of future national retrofitting schemes.
Fig. 1: Housing unit completions from 1970-2011 according to Central Statistics Office data [14].
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Improvement of the energy efficiency of the existing housing stock is a core element of Ireland’s
National Energy Efficiency Action Plan [15]. 199 ktCO2 (CO2 emissions) of the currently proposed
reductions target relates to state incentivised insulation and heating system upgrades to existing
houses, over the life time of the plan. These savings accounts for 8% of the overall reduction
forecast for the residential sector. The Better Energy Homes and Better Energy Warmer Homes
are the primary grant schemes in operation in Ireland at present, targeting houses constructed
prior to 2006 and 2002, respectively [9, 12]. Anticipated energy savings are the primary motivating
factor for individuals part-taking in such state incentivised schemes with comfort gain forming the
second most important factor influencing any investment. Previous studies have highlighted
possible mean energy savings (21%) of natural gas demand through the SEAI Home Energy
Saving (HES) energy retrofitting scheme for a sample of homes when observed over a two year
period [16]. Interestingly, a lifecycle analysis retrofit study conducted as part of Rebound initiative
on common house types retrofitted to various degrees highlighted client ‘take-back’ as a concern
for residential retrofit project [17, 18]. In that study, the observed before and after works mean
temperature data was used to develop specific Dwellings Energy Assessment Procedure (DEAP)
[19] models to assess the impact of temperature take back on CO2 emissions savings resultant
from the works, determining the level of direct rebound effect, i.e. the amount of potential CO 2
emission reductions taken back as additional warmth in the properties. Unexpectedly high levels
of ‘take back’ were predicted, if the observed short range temperature increases were to be
sustained in the longer term [17, 18]. Furthermore environmental life cycle assessment (LCA)
studies on residential case study buildings highlighted the importance of actual operational energy
(OE) and carbon (OC) usage in home as a true carbon footprint indicator instead of current BER
system limitations [8, 20]. Therefore, before the largest national retrofitting scheme is undertaken in
Ireland it is imperative the true potential of retrofitting project initiatives is carefully assessed.
This paper presents findings from a case study set of typical masonry residential buildings in
Ireland to determine the efficacy of typical insulation and building fabric upgrade works of
residential buildings in reducing energy and greenhouse gas emissions, as well as their affect on
the perceived thermal comfort of the occupants. This is achieved by monitoring 19 houses in
Ireland and assessing the internal environment, energy consumption, comfort and occupant
behaviour, before and after typical residential insulation improvements. These houses are located
in a residential housing estate in Ballyshannon, Co. Donegal, Ireland. Operational monitoring
started from November 2012 with upgrade retrofit works completed in December 2012. This paper
contains provisional case study results as monitoring is ongoing. However, a full economic and
environmental lifecycle analysis is presented, which considers both the energy consumption and
carbon emissions embodied in the retrofit works together with those associated with the operation
of the home.
2. Case study retrofit project overview
2.1 General information
The Highfields residential housing estate in Ballyshannon, Co. Donegal consists of 19 masonry
housing units constructed in 2004. The estate is managed by the Cluid Housing Association, which
aims to deliver affordable homes to people on housing waiting lists all over Ireland [21]. Housing
estate building topology consists of the single-storey and two-storey units, as presented in Table 1.
The two-storey 3-bedroom semi-detached homes in this estate have typical average total floor
area (110m2) of semi-detached houses constructed in Ireland, according to CSO data [7]. The two-
storey dwellings contain on the ground floor a hallway, living room, combined kitchen and dining
room, utility and WC. On the first floor, they contain a landing, bathroom, hot-press (with hot-water
storage cylinder) and three bedrooms, The single storey dwellings contain a hallway, one bedroom,
bathroom, living room, combined kitchen and dining room, hot-press (with hot-water storage
cylinder) and a utility. All of the dwellings have an attic space. The heating systems in the homes
are a central heating system using an oil-fired condensing boiling and a solid fuel open fire in the
living room.
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Table 1: A breakdown of the Highfields Cluid housing estate by house type and total floor area.
2
House Type House Number Total No of Houses Total Floor Area (m )
Two-storey semi-detached 7,8,9,10,16,17,18,19 8 110
Two-storey mid terrace 2,3,12,13,14 5 110
Single-storey end-of-terrace 1,4,11,15 4 67
Single-storey semi-detached 5,6 2 67
Located north east of Ballyshannon, house orientation varies through the estate site layout, as
seen in Figure 2. Houses numbered 5 through to 10 are orientated in a north-south direction with
the front of the houses southerly facing. House numbers 11 to 15 are opposite in orientation.
House numbers 1 to 4 have front openings facing easterly, as seen in Figure 2, with Highfields 16
to 19 are not aligned with the other 15 homes. Their front openings are in a predominantly south-
westerly direction. A photo of houses 7 to 10 is also provided in Figure 2.
Fig. 2: Highfields estate orientation layout map and photo of sample masonry estate homes.
2.2 Upgrade retrofit works
Thermal upgrade retrofit works were completed in mid-December 2012 on all 19 estate homes. A
basic upgrade in thermal cavity wall and ceiling insulation was conducted in accordance with the
Better Energy Homes scheme offered by SEAI [12]. Theoretical U values of building fabric ceilings
and walls in all homes were improved as a result.
2.2.1 Pre-works BER
As seen in Figure 3, average pre-works BERs ranged from D2 to C3 for estate houses. BER
results are expressed in terms of annual primary energy consumption (kWh/m 2/yr) and annual
carbon dioxide emissions (kgCO2/m2/yr) based on input data to the Dwelling Energy Assessment
Procedure (DEAP) software calculation tool [19]. Depending on the intensity value achieved an
alphabetical grade rating is assigned to the assessed dwelling. For the Highfields estate pre-works,
annual primary energy consumption and carbon dioxide emissions varied from 185-294kWh/m 2/yr
and 47-75kgCO2/m2/yr, respectively, according to the collected BER certificates shown in Figure 3.
2.2.2 Post-works BER
As depicted in Figure 3, an expected improvement in BER is recorded in all homes post-works
following retrofitting. Average post-works BERs ranged from D1 to C2. For the Highfields estate
post-works, annual primary energy consumption and carbon dioxide emissions varied from 169-
267kWh/m2/yr and 43-67kgCO2/m2/yr respectively, according to the collected BER certificates as
shown in Figure 3. As a result, it would be expected that client perception of internal thermal
comfort would improve and average internal temperature increases would be experienced as a
result of insulation works.
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Fig. 3 Building Energy Rating (BER) of Highfields estate pre and post insulation upgrade works.
2.3 Data instrumentation/inventory
Pre-works residential analysis required installation of oil, temperature and relative humidity (RH)
recording devices. They were installed in selected estate homes, as indicated in Figure 4. Lascar
electronic temperature and RH sensors EL-USB-2 and EL-USB-2-LCD were installed in 15 estate
houses on November 22nd 2012. Devices were planned to be left onsite in all 15 homes for the
duration of the heating season and beyond. Intermediate downloading of data occurs on
subsequent site visits. 10 Apollo smart oil monitors were installed onsite in 10 houses that utilised
oil-fired central heating and water systems. Sensors to obtain real-time electricity usage were also
installed to obtain electricity usage in selected homes. A thermographic camera was utilised to
perform thermography both pre- and post-works on selected estate houses. Digital cameras and
camcorders were also used onsite were necessary.
Fig. 4: Location of temperature and relative humidity sensors, oil and electricity monitors.
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2.4 Occupants surveys
As part of the study, strategically designed surveys were conducted on tenants both pre- and post-
insulation works. Information was gathered with respect to number of residents per house, number
of years living at the dwelling, average time spent at home, average energy spending expenses
per house and existing appliance usage is collected. Other important issue such as internal
thermal comfort perception and relative tenant behaviour is regularly recorded. Continuous thermal
comfort surveys are carried out at every site visit to maintain a database of tenant internal comfort
levels.
2.5 Weather data
Weather data was gathered from a Met Eireann operated weather recording station at
Ballyshannon for daily rainfall, maximum and minimum temperatures for the available period from
January 2011 to January 2013, as seen in Figure 5. External temperature and/or rainfall, as well as
other external environmental conditions, may influence final result interpretation. Thus, further
data, such as relative humidity and global radiation, will be obtained from another weather station
operated by Met Eireann in the locality (Finner, Bundoran, which is 5km from the site).
(a) (b)
Fig. 5: (a) Maximum and minimum daily temperature data and (b) rainfall (mm) from a Met Eireann
Ballyshannon weather station from January 2011 until January 2013
3. Results and discussion
Provisional results from the installed data equipment and tenant surveys are presented in this
section.
3.1 Internal thermal comfort and temperatures
Figure 6 presents data from installed temperature and relative humidity sensors pre- and post-
retrofitting works from a number of case study homes. Three sets of results (kitchen, living room
and bedroom) are presented from a three bedroom two-storey semi detached house (House No 9).
Comparative kitchen and living room results are extracted from the adjoining two storey house
(House No 10), while a bedroom from House No. 3 (a two-storey semi-detached bungalow is also
displayed. The location and orientation of these dwellings can be seen in Figure 4.
Initial observation of provisional results suggests a slight immediate increase in internal
temperatures following insulation upgrade works completion. External temperature data
corresponding to period of analysis time suggests maximum values rarely exceeding 10 ºC and
minimum recordings peaking below 0 ºC. It is assumed home space heating requirements were
required during this period with home space heat retention an important building fabric factor.
Following retrofitting, relatively stable pre-works house internal temperatures are displayed in many
houses, such as all rooms in House No. 6 (see Figure 6 (a), (c), (e)), as well as the living room in
House No. 10 (see Figure 6 (d)), with peaked rises in internal temperature following retrofitting. On
the other hand, the internal temperature of the kitchen in House No. 10 has larger fluctuations
(Figure 6(b)), as well as the bedroom in House No. 3 (Figure 6(f)), as these houses rely more on
solid fuel heating in the open fire in the sitting room during the day, whereas the occupants in
House No. 9 have the oil-fired central heating on throughout most of the day. Furthermore, these
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rooms typically have lower internal temperatures, which is due to low space heating being used by
the occupants in these rooms. In some houses, internal temperatures reduce after a period, which
may be caused by user behaviour or external influences (for example, in House No. 9 – see Figure
6(a),(c),(e)). Thermal space heat retention building fabric properties improved after retrofitting.
Thus, after an initial increase in internal temperature in the house post-works, some occupants
reduced the amount of space heating they used (i.e. had the central heating system for shorter
periods of time or less often).
Average internal temperature, relative humidity and dew points vary substantial for individual case
study homes as Figure 6 demonstrates. Two similarly designed rooms can have significant
differences in internal temperature and relative humidity, as Figure 6 demonstrates. Therefore,
significant variations in user behaviour cannot be ignored when estimating actual energy and
carbon savings following retrofitting. Future analysis will investigate this effect further.
(a) (b)
(c) (d)
(e) (f)
Fig. 6: Provisional temperature and relative humidity results recorded in case study homes. Results
are taken from the following locations: (a) House No 9 Kitchen (b) House No 10 Kitchen (c) House
No 9 Living Room (d) House No 10 Living Room (e) House No 9 Bedroom (f) House No 3.
Bedroom.
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Tenant perception on the internal thermal comfort of their homes pre- and post-retrofitting reflects
favourably on the perceived benefit of retrofitting to the internal environment of houses. A
perceived general increase in internal thermal comfort standards by the occupants following
completion of the insulation upgrade works can be clearly seen in Figure 7. When residents were
asked post-works if the insulation upgrade works would be of thermal comfort benefit, 90%
surveyed felt the works would be of thermal comfort benefit.
(a) (b)
Fig. 7: Results from an occupant survey rating house internal comfort level (a) pre-works and (b)
post-works
3.2 Energy and carbon usage
One important energy and carbon usage analysis area is occupancy electricity usage habits and
trends. Estimated rationalised electricity usage data pre- and post-retrofitting works was collected
from all estate homes and is presented in Figure 8, where the average daily electricity usage is
given in kWhr per m2 of floor area of the dwelling. Three scenarios are outlined in Figure 8 – pre-
works, post-works and post-works excluding the three week Christmas period. Average daily
electricity usage for a period pre-works and average daily usage post works are calculated from
electricity usage data recorded. In some dwellings, electricity usage over the Christmas period
would not be typical of other periods during the winter. Thus, a special compensation period of 3
weeks over Christmas is excluded in the third scenario, which was post-retrofitting works.
Fig. 8: Average estimated daily electricity usage in each estate house for the period from
November 2012 to April 2013 per m2 of floor area.
As can be seen from Figure 8, the average electricity daily usage varied significantly between
dwellings in the estate, even for the same house type and occupancy level. For example, for the
one-bedroom single-storey dwellings (i.e. Houses 1,4,5,6,11,15) there was a difference of over
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3.75 times the average daily electricity usage between House no. 1 and 11 prior to retrofitting of
the houses. The reason for the significant differences is that some houses used personal electric
heaters for additional space heating in addition to the oil fired central heating systems and/or solid
fuel open fire (e.g. House 11 and 15), whereas others had a back boiler behind the solid fuel open
fire in the sitting room, which connected to the central heating system, and did not use additional
personal electric heaters (e.g. House no. 1 and 4). It is noteworthy that both House 11 and 15 had
significantly lower average electricity usage post-retrofitting works, which was due to lower use of
personal electric heaters.
From Figure 8, nine of the case study houses (Houses 3, 4, 7, 9, 11, 13, 15, 17 and 18) experience
decreases in average daily electricity usage per m2 of floor area according to collected data. This
represents half the assessed estate homes. It is not possible to assume electricity usage
decreases are caused solely by retrofit works although its impact on electricity usage cannot be
ignored. A pre-works survey noticed 40% of assessed estate dwellings used electric heaters in the
preceding week to the survey. No mention of electricity based heaters was recorded in post-works
surveys. Significant average daily electricity usage per m2 of floor area increases is recorded in
certain estate homes (House No 11, 15 and 18). No significant change in household appliance was
recorded in any assessed home after the works.
Estimated economic annual energy spending analysis for space heating in Highfields estate homes
is based on tenant survey answers and heating season assumptions both pre- and post-works.
Average estimated monthly and weekly spending was recorded before and after the works. A
heating season assumption of 6 full months and 6 half months of fuel spending is assumed.
Improved accuracy of monetary spending on fuel is ongoing with the continuous collection of data
through ongoing resident survey studies and increased fuel usage data recordings. Nevertheless,
some trends emerged with respect to estimated annual energy spending per m 2 of floor area
according to the two housing unit types, as shown in Table 2. For example, an average estimated
annual spending reduction of 9 per m2 of floor area is estimated for the one-bedroom semi-
detached bungalows from recorded answers before and after upgrade insulation works. Little or no
spending estimation savings are recorded for the larger semi-detached houses assessed based on
assumptions and gathered energy spending data. However, there are large variations in monetary
spending on each fuel type between similar homes, as indicated in Table 2 by the large coefficient
of variation (COV) values.
Substantial savings were recorded in coal usage amongst one-bedroom semi-detached bungalows
before and after the works. Slight decreases in average annual heating oil, peat and briquettes and
biomass are also recorded in the semi-detached bungalows assessed following retrofitting. A 22%
reduction in heating oil average estimated spending per m2 of floor is recorded for the larger estate
homes as seen in Table 2. However, a counterbalance exists with an increase in coal and biomass
usage in these homes according to data recorded. Such an offsetting of energy spending can often
not be represented in perceived operational energy or carbon savings.
Ongoing analysis aims to improve result validity. 60% of assessed estate tenants had found
noticeable savings in energy usage following the upgrade insulation works, while 30% had not
according to survey results. The remainder were unsure. Such results favourably represent the
client perceived residential retrofitting approach.
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Table 2: Average estimated annual spending by fuel type per m2 of floor area according to the two
predominant estate housing unit types.
Pre-Works Post-Works Difference
House Type Fuel Type Average COV Average COV Average
Heating Oil 6.6 0.93 5.1 1.07 - 1.50
Coal 11 0.8 5.4 0.87 - 5.7
Semi-detached bungalows Peat 0.5 2.24 - - - 0.5
2
(67m ) Briquettes 0.9 1.37 0.4 1.73 - 0.5
Biomass 1.2 1.63 0.6 1.18 - 0.6
Total 20 - 9 - - 9
Heating Oil 7.9 0.56 6.40 0.2 - 1.60
Coal 5.6 0.69 6.10 0.72 + 0.5
Semi-detached two storey Peat - - - - -
2
(110m ) Briquettes 0.2 3.16 0.1 2.65 - 0.10
Biomass 0.7 1.51 1.80 1.19 + 1.10
Total 14 - 14 - 0
Environmental lifecycle assessment (LCA), in terms of energy and carbon, found average initial
embodied energy (EE) and embodied carbon (EC) of installed building materials according to
acquired bills of quantity to account for 9% and 12% of lifecycle energy and carbon over a 60 year
lifespan pre-retrofitting works, respectively. Average operational energy (OE) and operational
carbon (OC) accounted for the majority of lifecycle energy and carbon of the estate homes.
Based on post- and pre-retrofitting works BER results, perceived annual OE savings (16-
27kWh/m2) and OC savings (4-8kgCO2/m2) in the estate houses should benefit residential
occupants financially in the long term. Theoretical annual energy savings should equate to
between 1696-2113kWh and 1769-2079kWh for larger and smaller estate homes, respectively.
Therefore, assuming a domestic delivered energy cost of 26 cent for electricity [22], annual
estimated energy savings range from 438-549 and 467-541 for larger and smaller estate homes,
respectively. Similarly, assuming a domestic delivered energy cost of 9 cent for oil [22], annual
estimated energy savings range from 151-190 and 162-187 for larger and smaller estate homes,
respectively. Over a 60 year lifespan, perceived financial operational savings are substantial.
Average estimated annual spending reductions estimated from surveys of occupants of the semi-
detached single-storey dwellings amounted to 9 per m2 of floor area for fuel requirements as a
result of retrofitting. All semi-detached single-storey dwellings have a total floor area (67m 2).
According to Table 2 results, average estimated annual spending savings as a result of the
retrofitting works will equate to approximately 603, which is substantially higher than the estimate
obtained using the assumptions in the Dwellings Energy Assessment Procedure (DEAP), which is
the Irish official method for calculating and rating the energy performance of dwellings. Thus, BER
retrofitting estimations are relatively conservative according to these results for the semi-detached
bungalows. An over-estimation in perceived operational savings for the semi-detached two storey
estate dwellings is recorded. Care must be taken with regard to perceived OE and OC results as a
result of retrofitting domestic buildings. Provisional results highlight the significance of perceived
operational energy savings when used as a benchmark. Issues such as physical and occupant
‘take-back’ and energy usage offsetting may have an impact in retrofitted results. Further analysis
over a longer period will highlight such issues.
4. Conclusions
In-depth analysis into the efficacy of residential retrofitting packages for Irish residential building
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was conducted on a residential housing estate in Ballyshannon, Co. Donegal. Noticeable
improvements in internal temperature and occupant perception of internal thermal comfort was
recorded in many homes following completion of basic cavity wall and attic (ceiling) insulation
upgrade works in December 2012. Provisional results recorded half the assessed homes held a
noticeable average daily electricity usage decrease per m2 of floor area following completion of
works. Provisional findings from occupancy surveys recognised the significance of perceived
operational monetary savings as a result of retrofitting compared to actual or relative occupant
savings. Care is needed when utilised as a retrofitting energy benchmark. The study presented in
this paper involved only short span monitoring of the houses before and after works, so it is difficult
to determine if the observed internal temperature and energy usage trends will be sustained in the
longer term. Future Irish retrofitting strategies may need to account for the actual operational
savings impact compared to the perceived for various retrofitting packages on Irish residential
buildings. Methods of engagement and more sustainable consumption behavioural models need
to be developed, including the communication of the link between behaviour and actual energy bill
reduction, which is the primary driver for individuals participating in home energy efficiency
schemes in Ireland [18]. Further research in this area is required and may help reduce the direct
rebound effect of occupants taking excessive levels of increased comfort. Such measures may be
beneficial in ensuring net CO2 savings are achieved after insulation works and that Ireland’s
national commitments in terms of CO2 emission reductions are met.
5. References
1. UNFCCC, Kyoto Protocol to the United Nations Framework Convention on Climate Change,
http://unfccc.int/resource/docs/convkp/kpeng.pdf, Editor. 1998.
2. European Commission (2012) Construction: unleashing the potential of low energy buildings
to restore growth.
3. DCENR, Delivering a Sustainable Energy Future for Ireland White Paper, D.o.C.E.a.N. Re-
sources, Editor. 2007,
http://www.dcenr.gov.ie/Energy/Energy+Planning+Division/Energy+White+Paper.htm.
4. Hernandez, P., et al., The challenge of refurbishing recently built apartments. A life cycle per-
spective, in Sustainable Building Conference 2010. 2010: Madrid.
5. Ahern, C., P. Griffiths, and M. O'Flaherty, State of the Irish housing stock—Modelling the heat
losses of Ireland's existing detached rural housing stock & estimating the benefit of
thermal retrofit measures on this stock. Energy Policy, 2013. 55(0): p. 139-151.
6. DECLG, Building Regulations 2005 - Technical Guidance Document L - Conservation of Fuel
and Energy - Dwellings, Department of Environment Community and Local Government, Edi-
tor. 2005: Dublin, Ireland.
7. CSO. Central Statistics Office (CSO) - StatBank. 2012; Available from:
http://www.cso.ie/px/pxeirestat/statire/SelectTable/Omrade0.asp?Planguage=0.
8. SEAI, A Guide to Building Energy Rating (BER). 2010, Sustainable Energy Authority of Ire-
land Dublin, Ireland.
9. SEAI, Economic Analysis of Residential and Small-Business Energy Efficiency Improve-
ments. 2011, Sustainable Energy Authority of Ireland Dublin, Ireland.
10. SEAI, Residential Energy Roadmap 2010-2050. 2010, Sustainable Energy Authority of Ire-
land Dublin, Ireland.
11. Energy Efficient Buildings Association (E2BA), Energy Efficient Buildings European Initiative.
2011.
12. SEAI. Better Energy Homes Scheme. 2013; Available from:
http://www.seai.ie/Grants/Better_energy_homes/.
13. SEAI, Energy in the Residential Sector, E.P.S.S. Unit, Editor. 2008, Sustainable Energy Au-
thority of Ireland
14. CSO. Housing Completion Statistics. 2012; Available from:
http://www.cso.ie/px/Doehlg/Dialog/Saveshow.asp.
15. DoCENR, Ireland's second national energy action plan to 2020. 2013, Department of Com-
munications, Energy and Natural Resources: Dublin.
16. Scheer, J., M. Clancy, and S. Ni Hogain, Quantification of energy savings from Ireland's
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Home Energy Saving scheme: an ex post billing analysis. Energy Efficiency, 2012. 6(1): p.
35-48.
17. McElmeel, H., rebound project: Preliminary findings, in RIAI 3Twenty10 Research Competition.
2012, RIAI: Dublin.
18. McElmeel, H., Impact of temperature take back on CO2 emission reductions achieved after
insulation upgrades to two detached Irish houses, in MSc Architecture: Advanced Energy
and Environmental Studies. 2013, Centre for Alternative Technology: Wales.
19. SEAI. Dwelling Energy Assessment Procedure (DEAP) - Irish Official Method for Calculating
and Rating the Energy Performance of Dwellings. 2007; Available from:
.
20. Armstrong, A. and J. Goggins, The assessment of embodied energy and carbon of residen-
tial buildings in Ireland, in BCRI 2012. 2012: Dublin.
21. Cluid Housing Association. Cluid Housing Association,. 2013 [cited 2013 8th May]; Available
from: http://www.cluid.ie/.
22. SEAI, Domestic Fuel Comparison of Energy Costs. 2012, Sustainable Energy Authority of
Ireland
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