Energy Efficiency in Historic Buildings: a Strategy to Increase the Sustainability of the Built Environment

Abstract

The paper aims to define the most appropriate energy and environmental retrofit on historic buildings, to enhance the historical value of a building, to reduce energy consumption and to improve human comfort, health and safety. It allowed the evaluation of the conservation risks, energy consumption, and maintenance procedures and also led to a proposal on the most appropriate energy actions. It also defines the difficulties of integrating green practices with historic preservation, and offers recommendations for ways in which sustainable standards could be more accommodating for historic buildings. The approach was used in the National Hotel building located in Port Said, Egypt.

Full text

PORT SAID ENGINEERING RESEARCH JOURNAL
Faculty of Engineering-Port Said University
Volume … No. … pp: …
Energy Efficiency in Historic Buildings: a Strategy to Increase the
Sustainability of the Built Environment
Osama A.El-Enein1, Ghada El Rayes2, Marwa Mostafa3, and Mohammad M. Refaey4.
ABSTRACT
The paper aims to define the most appropriate energy and environmental retrofit on historic buildings, to enhance the
historical value of a building, to reduce energy consumption and to improve human comfort, health and safety. It
allowed the evaluation of the conservation risks, energy consumption, and maintenance procedures and also led to a
proposal on the most appropriate energy actions. It also defines the difficulties of integrating green practices with
historic preservation, and offers recommendations for ways in which sustainable standards could be more
accommodating for historic buildings. The approach was used in the National Hotel building located in Port Said,
Egypt.
Keywords: Sustainability-Historic Preservation- Revitalizing-Energy Efficiency-High Performance-Urban Harmony.
1. Introduction
Before implementing any energy conservation measures,
the existing energy-efficient characteristics of a historic
building should be assessed. Buildings are more than the
sum of their individual components. The design,
materials, type of construction, size, shape, site
orientation, surrounding landscape, and climate all play a
role in how buildings perform. Historic building
construction methods and materials often maximized
natural sources of heat, light and ventilation to respond
to local climatic conditions. The key to a successful
rehabilitation project is to understand and identify the
existing energy-efficient aspects of the historic building
and how they function, as well as to understand and
identify its character-defining features to ensure they are
preserved. Whether rehabilitated for a new or continuing
use, it is important to utilize the historic building’s
inherent sustainable qualities as they were intended to
ensure that they function effectively together with any
new treatments added to further improve energy
efficiency.
1.1. Energy Efficiency in Historic
Building
Energy efficiency is a major topic in the world. The
directive on energy performance requires minimum
energy standards for new and existing buildings that
undergo major renovation. Despite the directive admits a
few exceptions for listed buildings, the international
energy standards cannot be completely ignored or
abandoned.
1 Department of Architecture - Faculty of Engineering - University
of Port Said, Port Said, Egypt, E-mail: aboeinen@hotmail.com
2 Department of Architecture - Faculty of Engineering - University of
Port Said, Port Said, Egypt, E-mail: ghadaelrayies@ymail.com
3 Department of Architecture - Faculty of Engineering - University of
Port Said, Port Said, Egypt, E-mail: m_mostafa31@hotmail.com
4 Department of Architecture and Urban Planning - Faculty of
Engineering - Sinai University, Arish, Egypt,
E-mail:muhammad.refaey@gmail.com
Recent European policy officially introduces the concept
of energy balance towards nearly zero-energy buildings
and incentives the decreasing of 20% of environmental
emissions and the increasing of 20% of renewable
energy technologies within 2020. (1)
To achieve these goals, it is necessary to reduce user
demand as well as to improve the efficiency of energy
systems and to use renewable sources. Heritage must
adapt to changes, physical and cultural, within its
environment. The decision, inevitably, must be faced
with the energy efficiency of existent buildings,
independently by local bounds. Therefore we should
develop techniques to maintain, refurbish and adapt the
existing buildings to new requirements.
1.2. Sustainable Building Practices
Integrated design means thinking about how all aspects
of a building are interrelated such as the structural
components, heating, cooling systems, lighting,
windows, walls, interior finishes, etc. By recognizing the
connections between these systems, integrated design
offers many benefits. For example, when operable
windows are considered as part of a building’s
ventilation system, expensive ductwork and air handlers
can be made smaller and less expensive. Planning on the
"thermal mass" of concrete structural members to slow
down indoor temperature changes can also reduce the
need for conventional air conditioning. These kinds of
"passive" or low-energy design strategies can only be
effective if the whole building’s energy performance is
studied together. (2) These checklists are offered to
encourage the use of sustainable building practices in
remodels or renovations:
 Create a sustainable community.
 Respect the existing sites and reuse it.
 Avoiding additional energy consumption.
 Avoiding negative environmental impacts.
 Save water and reduce local water impacts.

 Save water and energy in plumbing systems.
 Reduce, reuse, and recycle systems.
 Using sustainable materials and support the market
for recycled materials.
 Preserving architectural history.
 Reviving urban areas.
 Create healthy indoor environments.
 Save energy through passive design.
 Make a sustainable roof.
 Save energy in lighting.
 Save energy in equipment use.
 Replace fossil fuel use with alternatives.
 Use creativity and innovation to build more
sustainable environments.
1.3. Environmental Performance to
Achieve Sustainability Principles
Preservation-based sustainability is offered as a more
comprehensive approach to development, as it takes into
consideration environmental, economic, social, and
cultural implications of buildings. These principles
constitute the basis of the more important sustainable
tools. These programs emphasize design, construction
and operation for obtaining a "high green performance"
building to reduce environmental impacts through
energy efficiency, use of recycled materials, storm water
management, and other innovations. In order to confirm
that preservation promotes sustainable development
versus the environment, it must be demonstrated that the
reuse of buildings successfully reduces pollution and
promotes the conservation of nature. This section looks
at the energy savings associated with preservation, the
avoidance of additional environmental impacts, the
avoidance of generating waste through demolition, and
the ability of preservation to curb sprawl.(3)
1.4. The Positive Benefits Of
Sustainable Preservation
The positive benefits of sustainable preservation
identified through following points: (4)
 Minimizing Consumption of Energy;
 Reusing Existing Materials;
 Avoiding negative environmental impacts;
 Reusing Existing Sites;
 Reducing Construction Waste;
 Accommodating Human Needs;
 Meeting Performance Requirements;
 Preserving Architectural History;
 Reviving Urban Areas;
 Creating Economic Advantage;
 Time Saving for New Construction;
 Maintaining Traditional Standards.
1.5. Barriers To Achieve Sustainable
Preservation
There are also barriers to achieve sustainable
preservation, which invariably concern costs. However,
this is often a fake reason obscuring the real reason that
it is easier under current development processes to
produce a new building. Adaptation of existing buildings
is frequently considered to be less creative than
producing a new building and therefore attracts less
fame. (5)
The range of barriers to adopting sustainable
preservation for an historic and existing building
identified during through following points:
 Only being viable where the costs and benefits are
factored in over the life of the building.
 Building owners see no economic benefits in reuse.
 Older buildings may require extensive and costly
refurbishment.
 Inability to match the performance of a new building.
 Ongoing maintenance costs may be higher than a
new building.
 Older buildings may not be able to meet current
sustainability standards.
 Availability and price of matching existing materials.
 Difficulty of maintaining the structural integrity of
older buildings.
1.6. Sustainable Preservation
Principles
High energy and environmental performances may lead
the preservation of a building, but each action on historic
and listed heritage gives attention to the matter of
vulnerability, physical alteration, and decreasing of
immaterial and material value. The most important
principles for sustainable conservation regard:
 Compatibility: modern materials tend to be harder,
less flexible, and less moisture permeable than
traditional ones. For these reasons when are used in
direct conjunction with historic fabric can greatly
accelerate decay in the original work;
 Aesthetic integration: history and authenticity of
historic building should be respected as essential to
its significance;
 Reversibility: the unavoidable changes of the
building should wherever possible be made to be
fully reversible. Adopting this principle, the valuable
historic fabric can be returned to its original state
without damaging the building;
 Emphasis on effective maintenance: care, planned
conservation, and management should include
regular inspections so that defects can be discovered
whilst still small and easily fixable. This permits to
preserve historic fabric, minimize cost and disruption
to the building’s owners and users.

The retention of older buildings or the re-using of
components in-situ and allowing for their energy
upgrading that can provide excellent results which are
fully in accordance with the principles of building
conservation and sustainability (Fig.1).
Figure 1: Means of Conserving Historic Building
1.7. Standards and Bases for Urban
Harmony of Heritage Buildings
and Areas
It is considered the baseline to direct and adjust urban
development, conserve the unique urban heritage of
cities, spread knowledge and awareness about the
importance of heritage buildings and areas, guidance
towards procedures for conserving architectural and
urban heritage, and providing the scientific and technical
mechanisms for the protection and continuity of
urbanization as a principle base for developmental and
community service programs. (6)
1.7.1. Supporting the Urban Character
The urban character is the product of the prevailing form
characteristics that create groups of buildings, the urban
fabric, the natural surroundings, and the prevalent uses in
certain place. The urban character depends on a fully
integrated matrix of references that is known as
architectural character, urban space, urban fabric,
activities and uses; which are all components of the
urban language that defines the identity of the place. To
achieve the goal of supporting the urban character, a full
study should be presented and included the urban
character elements as following:
 The Urban Fabric of the Area;
 Roads' Network and Pedestrian Paths;
 Advertisements and Signs;
 Vegetation and Greenery;
 Paving and Tiles;
 Lighting;
 Street and Open Space Furniture;
 New Buildings;
 Building Heights Inside and Around Heritage Areas.
1.7.2. Support of the Architectural
Character
Architectural character is the product of the prevailing
external composition characteristics in forming the
building's facades at a certain place, which take it to
uniqueness and excellence. To achieve the goal of
supporting the architectural character, a full study should
be presented and included the architectural character
elements as following:
 Building Height;
 Building Facades and Type of Finishing;
 Projections (Towers-Balconies-Cornices);
 Architectural Style;
 Additions to Building;
 Architecture Elements and Treatments;
 Entrances of Buildings;
 Shops and Commercial Activities.
2. Methodology
Energy efficiency and environmental sustainable
programs should be developed on the basis of a thorough
knowledge of the property, blending technological and
landscape requirements. This means understanding
original construction, alterations, actual conditions,
qualities, material and immaterial values, lacks, and
retrofitting opportunities (Fig.2).The strategy aims to
assess the following points:
 Historical analysis of city, urban site and heritage
building;
 Analysis of functions, performance and needs of
users;
 Building energy audit;
 Evaluation of environmental performance;
 Individualization of energy and environmental lacks;
 Definition of possible retrofitting actions.

Figure 2: Method for Analyzing Energy and Environmental Performance of Historic Building.
3. The Case Study: National Hotel
Building in Port Said, Egypt
The city of Port Said considered an international heritage
value. The influences of culture and architecture of the
city have given a unique architectural value to the city in
the world. Port Said, located on the northeastern
Mediterranean coast of Egypt, contains an architectural
wealth, which will hopefully be saved by virtue of
Cabinet Decree No l096 for 20ll. The decree has
specified a list of 500 buildings classified as historic
based on their singular architectural style and age. Port
Said, Founded in l859 by the viceroy Said Pasha. During
the digging of Suez Canal in 1859, a new cosmopolitan
city formed for over a century. European memory and
French in particular, linked to its construction by the
Canal Company of Suez, still marks the appearance and
atmosphere of the city (Fig.3).
Figure 3: Current Condition of National Hotel
Building.
3.1. Historical Background
The Island of National Hotel is one of the oldest
buildings in the city still visible. The hotel building was
probably built in the 1880s on the island owned by Bazin
Marseille Soap Company. That had obtained the
concession docks of Port Said during construction the
channel. The northern part of the island also contained
cellars which were the imported goods stored. In 1866,
to facilitate unloading cargo the company had drill a
small canal that connected the island in the commercial
basin. In 1877, a bridge was erected over the canal and
ramps as it existed before an "impassable to cars"
gateway. This new bridge was made by the famous
company Gustave Eiffel. The island which enjoys a
remarkable position along the ship canal has always
maintained its commercial vocation. In the twentieth
century, it has hosted a series of small hotels for transit
customers as evidenced by the remains of Many brands
such as "Hotel de France and Hotel Belle Vue" To
celebrate its remarkable character, it is obviously noted
wooden galleries, but also its singular form "U", or
imported materials which have allowed its construction
(maritime pine, bricks and tiles Marseille). Its location in
the heart of the city, facing the pool with trade vis-à-vis
the captaincy of the authority of the Suez Canal, is also
very relevant to fact and provides maximum visibility to
this catering company (Fig.4,5).
Figure 4: Conception Drawings Addresses the Development of the Site Since 1869.

Figure 5: Conceptual Perspective for the Original
Case of National Hotel Island in 1877.
3.2. Evaluation of Energy
Performance for the Building's
Original Case
A software simulation with Autodesk Ecotect Analysis
allowed verifying the energy performance for the
building. (7) In this way, the proper interventions have
been selected in order to improve energy and
environmental efficiency of the building (Fig.6).
Figure 6: Modeling of the Building Using Autodesk
Ecotect Analysis Program.
3.2.1. Results: Thermal Analysis
The following figures represent the thermal analysis on
the building throughout the year, and are divided into
monthly heating, cooling loads and discomfort degree
hours analysis (Fig.7, 8).
Figure 7: Heating and Cooling Loads in the Building.
 Cooling loads: represents in blue and reach to the
maximum in July and is equal 1395 watts per square
meter.
 Heating loads: represents in red and reach to the
maximum in January and is equal 10336 watts per
square meter.
Figure 8: Discomfort Degree Hours in the Building.
 Discomfort Degree Hours: represents the total
discomfort degree hours throughout the year and are
equal 2298.5 Hour which represents 26% of the year.
 Too Cool: represents in blue and reach to the
maximum in January and the total too cool hours
equal 1891.8 Hour which represents 82% of these
hours in winter.
 Too Hot: represents in red and reach to the
maximum in July and the total too hot hours equal
406.8 Hour which represents 18% of these hours in
summer.

3.2.2. Results: Energy Consumption
Analysis The following figure represents the daily energy use for
the building divided into energy used for heating,
cooling and electricity (Fig.9).
Figure 9: The Daily Energy Used By the Building.
 Energy Used for Heating: represents in red and
shows the total energy used for heating the building
throughout the year and is equal 204452 kilo watt.
 Energy Used for Cooling: represents in blue and
shows the total energy used for cooling the building
throughout the year and is equal 16342 kilo watt.
 Energy Used for Electricity: represents in purple
and shows the total energy used for electricity in the
building throughout the year and is equal 274495 kilo
watt.
3.2.3. Analysis Of The Building Envelope
Without Changing The Style Of The
Building
The building envelope has to achieve thermal comfort
through controlling the temperature inside the building
by using materials which have efficiency of insulation.
Table 1: A Comparison between the Analysis Results
and the Egyptian Code Rates for Overall Heat
Transfer.
BUILDING ENVELOPE ANALYSIS
Constituent Materials for the
Building
Insulation
Analysis
Results
Insulation
Egyptian
Code
U-
VALUE
=KW/M2
U-
VALUE
=KW/M2
EXTERNAL WALLS:
1.740
0.9
Continued Table 1
INTERNAL WALLS:
2.330
0.9
PITCHED ROOF:
2.760
0.4
FLAT ROOF:
1.920
0.4
Floors:
1.540
0.4

Continued Table 1
Openings:
5.440
3.5
By calculating the overall heat transfer (u-value) and
comparing these results with the Egyptian code, the
results were higher than the code which means that the
building envelope layers should be modified to achieve
the heat transfer rates in the Egyptian code.
3.3. Revitalization Project Guidelines
First of all, it was necessary to understand how
traditional buildings behave as environmental systems.
The analytical study shows that the building envelope
requires applying of insulation systems. It is possible to
insulate with thermal plaster or internal rigid insulation
in transpiring materials. The roof has high energy losses
due to the missing of insulation. To insulate the lower
insole preserving the original floor, it is possible to add
rigid or sprayed foam insulation on the internal surface.
To insulate the roof could be installed underside
insulation or insulated ceiling characterized by
mechanical, chemical and physical compatibility with
the original roof. Transparent envelope has high thermal
losses and air infiltrations. For this reason, it is necessary
to evaluate the replacement of existent glasses and
frames with new windows (low-e glasses and wooden
frames) having better performances of thermal
insulation, air permeability, water resistance and UV
protection. For protecting the building from solar gain
and discomfort glare can be installed internal shading
devices and curtains, without adding radical and
mechanical changes to the original facades. The absence
of insulation, thermal distribution, climatic control and
heat accounting systems, Furthermore, air-conditioning
systems damages the artifacts and the buildings because
the movement of air masses soils and dusts the walls, the
frescoes, the inlays and the decorations. (8)
The intervention requires the evaluation of the insertion
of radiant panels on existing floor (not characterized by
particular historic value). Instead, it is necessary to insert
thermostatic valves on existing radiators and heat
accounting systems. The electric system not always is
safety from risks. The lighting has discrete energy
performances, guaranteed by the integration with
daylight, halogen lamps and periodic maintenance on
inefficient devices. To increase the level of light can be
installed diffusers on existent glasses of the office and
high efficiency sources. Solar energy technologies must
be integrated within buildings and their surrounding
landscapes, in order to obtain financial support and to
increase their efficiency. The use of photovoltaic panels
is recommended for decreasing the high electric
consumption.
3.4. Possible Retrofit Actions For
The Building Envelope
 Add rigid insulation under the pitched roofs;
 Apply sprayed foam insulation to the top of flat
roofs;
 Install insulated ceiling;
 Install underside insulation;
 Insulate with thermal plaster or double wall;
 Install high-efficiency doors and windows;
 Install low-e glasses on existing frames;
 Transparent Insulating Materials;
 Install selective materials;
 Install weather-stripping on windows;
 Install internal shading devices;
 Install diffusers on existent glasses ;
 Install interior curtain.
3.5. Possible Retrofit Actions For
Sustainable Technologies
 Install efficient air conditioning units and heat
pumps;
 Install an exhaust air heat recovery system;
 Replace existing systems with efficient systems;
 Install thermostatic controls;
 Optimize the operating temperatures;
 Install the most efficient lamps and ballast;
 Install dimmers;
 Maintenance of lamps;
 Install photovoltaic panels;
 Install solar heating panels.
3.6. Evaluation of Energy
Performance for the Building
after Revitalization Project
Evaluating energy performance for the building after
modifying the building envelope, according to the
Egyptian Code for heat transfer (u-value)
3.6.1. Results: Thermal Analysis After
Modification
The following figures represent the thermal analysis on
the building after modification throughout the year, and
are divided into monthly heating, cooling loads and
discomfort degree hours analysis (Fig.10, 11).

Figure 10: Heating and Cooling Loads in the Building after Modification.
 Cooling loads: represents in blue and reach to the
maximum in July and is equal 1277 watts per square
meter.
 Heating loads: represents in red and reach to the
maximum in January and is equal 1270 watts per
square meter.
Figure 11: Discomfort Degree Hours in the Building after Modification.
 Discomfort Degree Hours: represents the total
discomfort degree hours throughout the year and are
equal 466 Hour which represents 5% of the year.
 Too Cool: represents in blue and reach to the
maximum in January and the total too cool hours
equal 342 Hour which represents 73% of these hours
in winter.
 Too Hot: represents in red and reach to the
maximum in July and the total too hot hours equal
124 Hour which represents 27% of these hours in
summer.
3.6.2. Results: Energy Consumption
Analysis
The following figure represents the daily energy use for
the building divided into energy used for heating,
cooling and electricity (Fig.12).
Figure 12: The Daily Energy Used By the Building after Modification.
 Energy Used for Heating: represents in red and
shows the total energy used for heating the building
throughout the year and is equal 21988 kilo watt.
 Energy Used for Cooling: represents in blue and
shows the total energy used for cooling the building
throughout the year and is equal 22101 kilo watt.

 Energy Used for Electricity: represents in purple
and shows the total energy used for electricity in the
building throughout the year and is equal 112427 kilo
watt.
3.6.3. Analysis Of The Building Envelope
After Modification
The building envelope has to achieve thermal comfort
through controlling the temperature inside the building
by using materials which have efficiency of insulation.
Table 2: A Comparison between the Analysis Results
after Modification and the Egyptian Code Rates for
Overall Heat Transfer.
BUILDING ENVELOPE ANALYSIS
Constituent Materials for the
Building
Insulation
Analysis
Results
Insulation
Egyptian
Code
U-
VALUE
=KW/M2
U-
VALUE
=KW/M2
EXTERNAL WALLS:
0.340
0.9
INTERNAL WALLS:
0.160
0.9
PITCHED ROOF:
0.150
0.4
FLAT ROOF:
0.150
0.4
Continued Table 2
Floors:
0.150
0.4
Openings:
2.710
3.5
By calculating the overall heat transfer (u-value) and
comparing these results with the Egyptian code after
modification, the results were within the range stated in
the code which means that the building envelope layers
after modification have achieved the heat transfer rates
in the Egyptian code.
4. Conclusion
The objective of studying energy efficiency and
environmental quality in historic building can only be
achieved by:
 Combining a full study of the building envelope
condition and the energy efficiency of the building;
 Studying the thermal comfort inside the building;
 A proper actions and modifications can be applied to
the building envelope without affecting the
architectural style of the building or destroying the
heritage of the building;
 Energy efficiency in historic building can be
achieved by controlling the usage of energy inside
the building and diversification of energy production
from various renewable sources together with cutting
greenhouse gas emissions;
 The goal may be obtained only by an integrate
analysis of historic, dimensional, functional, energy
and environmental matter;
 A deep knowledge of a real need permits to propose
the most appropriate retrofit actions.
 The rehabilitation of existing structures is nearly
always superior to new or replacement construction
in terms of the various aspects of sustainability and
sustainable development.
 Rehabilitated projects provide many advantages,
including maintenance of historical and architectural
integrity, revitalizing urban areas, and avoiding
negative environmental impacts and unnecessary
consumption of materials and energy.
 In planning a sustainable rehabilitation project, it is
necessary to consider the surrounding context of the

project, potential impacts to the human and natural
environment, and economic viability compared to
other alternatives.
 Sustainability as a decision includes all of these
considerations, and can serve as a governing
objective for all project decision makings which will
help to ensure the survival of the earth and its
inhabitants into the predictable future.
 Although there are many factors, the concept of
revitalizing historic building has significant support
as a positive strategy to make the built environment
more sustainable.
 Revitalizing historic building enhances the longer
term usefulness of building and is more sustainable
than demolition or rebuilding.
 The positive benefits for revitalizing historic building
identified during the research also support the tenets
of sustainability and include:
 Reducing resource consumption, energy use and
emissions;
 Extending the useful life of buildings;
 Being more cost effective than demolition and
rebuilding;
 Reclaiming embodied energy over a greater time
frame;
 Creating valuable community resources from
unproductive property;
 Revitalizing existing neighborhoods;
 Reducing land consumption and urban sprawl;
 Enhancing the aesthetic appeal of the built
environment;
 Increasing the demand for retained existing
buildings;
 Retaining streetscapes that maintain sense of place;
 Retaining visual amenity and cultural heritage.
5. References
[1]Elena Lucchi," Energy Efficiency In Historic
Buildings: A Tool For Analysing The
Compatibility, Integration And Reversibility Of
Renewable Energy Technologies", World
Renewable Energy Congress, Sweden, May 2011.
[2]Jill Boone, "San Mateo Countywide, Sustainable
Buildings Guidelines and Checklist''. February
2004.
[3]Patrice Frey, Historic Preservation as Sustainable
Development, the Sustainable Preservation
Research Retreat, the National Trust for Historic
Preservation, October 2007.
[4]S. M. Mofidi," Assessing Sustainable Adaptation
Of Historical Buildings To Climate Changes Of
Iran",3rd Iasme/Wseas International Conference
On Energy & Environment, University Of
Cambridge, Uk, February 2008.
[5]M.Akhtarkavan,"WSEAS, International Conf. on
Cultural Heritage and Tourism (Cuht'08),
Heraklion, Crete Island, Greece, July, 2008.
[6]Soheir Zaki Hawas, Urban Conservation,
Regeneration of Heritage Areas in Egypt, Cairo:
Books, 2013.
[7] Autodesk® Ecotect® Analysis 2011 software,
Ecotect Analysis product web page
(www.autodesk.com/ecotect-analysis).
[8]U.S. Department Of The Interior National Park
Service - Technical Preservation Services, The
Secretary Of The Interior’s Standards For
Rehabilitation & Illustrated Guidelines On
Sustainability For Rehabilitating Historic
Buildings, Washington, D.C.2011.