The role of aesthetics in energy-retrofit strategies: the case of solid wall houses in the UK

Seifhashemi, SM

Abstract

Solid wall dwellings are responsible for 36% of the carbon emission from the
domestic sector in the UK. Among energy retrofit measures, Solid Wall
Insulation (SWI) is the most effective in reducing energy demand. However,
the current rate for insulation of solid walls is lower than desired in the UK, and
only 9% of solid wall houses are insulated. To meet the 2050 net-zero
emissions target, a higher rate of insulation is required to improve the energy
efficiency of old stock. Innovative and encouraging retrofit plans are urgently
required to unlock the demand for SWI, which will improve the energy
performance of old dwellings. This study aims to contribute toward an
innovative solution for the uptake of Internal Solid Wall Insulation (ISWI)
demand in the energy technology industry.
Two interconnected gaps in the literature were identified. One gap is the lack
of clear information on the performance benefits of SWI as a single retrofit
measure in solid wall homes, which is a cause of uncertainty for householders.
This uncertainty about potential energy savings arising from the U-values of
walls in solid wall properties has led to under- or over-estimation of SWI
performance. The second gap is the need for innovative solutions to unlock
the demand for slow progressed SWI in the UK. In home improvement, the
aesthetic factor is seen as a trigger for renovation to start. Aesthetic renovation
is more of an issue for internal spaces and is happening routinely as a
voluntary approach by residents. Hence, the idea of integrating the aesthetic
factor in ISWI is recommended in this study for the first time, and its importance
in renovation for householders and in the uptake of ISWI is evaluated. To
address the knowledge gap about ISWI energy-saving benefits, an energy
assessment phase is designed in this research to contribute to providing clear
information about the benefits of ISWI itself for a variety of identified U-values
for solid brick walls using the developed validated model of the Salford Energy
House testing facility with a negligible model performance error. For the
second gap, aesthetic inclusion in ISWI and its impact on householders’ views
towards the uptake of ISWI is evaluated using an online survey. The results
from both phases of this research are then used to provide recommendations

for policy makers, the retrofit industry, and designers, in support of the
acceleration of ISWI in the uninsulated UK stock.
The focus of the energy assessment phase (Phase 1) was on U-value variation
as the key parameter for energy-saving evaluations. The energy performance
of pre-and post-IWI in the Salford Energy House (SEH) is investigated; this is
a replica of a pre-1919 Victorian solid wall terraced house. The modelling
software IES-VE was used to develop a model for the SEH, and this model
was validated against collected experimental data. The baseline solid wall Uvalue for SEH changed between 0.64-2.48 W/m²K to model different solid walls
before insulation and the benefits of insulation assessed. The result of this
phase contributes towards a better understanding of the energy saving
potential of IWI within the UK and provides a more realistic picture of its
benefits for policymakers and relevant stakeholders. Based on the results, the
annual heating energy saving varies significantly depending on the baseline
wall U-values, ranging from 19% to 46.2%. The difference of cost saving
potentials between the cases with the lowest and highest baseline wall Uvalues is also high, with variance per year being £228. Thermal comfort
(18°C<T<=23°C) was also evaluated for the selected case study with different
baseline wall U-values. It was found that the thermal comfort improved with
wall insulation while at the same time overheating is not significant for the case
study using Manchester weather data.
In the aesthetic evaluation phase, the second phase of this research, people’s
preferences for aesthetics in renovation and its potential in promoting SWI was
explored using an online survey. The data from the collected validated 273
responses was analysed using SPSS software. The results show that
aesthetics is a very important factor for most of the participants, since the
aesthetic is found to be rated more than 90% important to participants, which
is in line with cost and energy saving factors in internal renovations. This result
also confirms that including the aesthetics of wall insulation can challenge the
negative view of participants on losing internal space, where the disagreement
level is only 10%. Additionally, the preferences of participants towards
aesthetics can surpass the concerns of cost since 88.6% of participants are
willing to pay more to achieve an aesthetically appealing insulation product.

Furthermore, the views of participants were explored with respect to insulating
the walls with internal aesthetic panels, which offer aesthetic and energy
saving in a single package, and more than 50% of participants stated their
willingness. From the results, more than 2/3rd of participants also agreed with
delivering both aesthetic and energy improvement in combined retrofit plans
by established organisations. The significance of the aesthetic factor in
renovation and its inclusion in planning the SWI strategies, especially for IWI,
are proven by the results of this study.
In conclusion, it is necessary to boost the SWI intake with the highest potential
energy saving compared to other retrofit measures in treating the uninsulated
properties. It is recommended that policy makers include the aesthetic in
planning the SWI strategies to trigger its uptake. It is beneficial when interior
designers and product designers contribute to the engagement of
householders to raise awareness of the benefits from Internal Aesthetic Wall
Insulation (IAWI). This will unlock the demand for IWI by increasing the number
of potential customers and lowering the financial concerns of households. It is
also recommended that financial support be extended to cover the
redecorating cost after installation of IWI. Home improvement and energy
retrofit companies should come together to work closely in an integrated
approach to encourage IAWI for retrofitting old houses. IAWI does not only
provide energy saving but also the aesthetic improvement of internal spaces
can be achieved. Furthermore, establishment of organisations to centralise the
retrofit measures of old housing stock is recommended to offer both energy
saving and aesthetic incentives to householders at the same time. This is to
ensure that householders are supported during the entire retrofit process in
the design, supervision, after care process, professional-quality delivery of the
project, subsidies application, cost and time frame of the retrofit project while
receiving the aesthetic and energy saving benefits at the same time.

Citation

Seifhashemi, S. (2021). The role of aesthetics in energy-retrofit strategies: the case of solid wall houses in the UK. (Thesis). University of Salford

• Thesis Type: Thesis
• Deposit Date: Oct 13, 2022
• Publicly Available Date: Sep 27, 2024
• Award Date: Nov 26, 2021