Sustainable refurbishment describes working on existing buildings to improve their environmental performance using sustainable methods and materials. A refurbishment or retrofit is defined as: "any work to a building over and above maintenance to change its capacity, function or performance' in other words, any intervention to adjust, reuse, or upgrade a building to suit new conditions or requirements".Douglas, J. (2006), Building Retrofit, Butterworth Heinemann, London. Refurbishment can be done to a part of a building, an entire building, or a campus. Sustainable refurbishment takes this a step further to modify the existing building to perform better in terms of its environmental impact and its occupants' environment.
Most sustainable refurbishments are also green retrofits: any refurbishment of an existing building that aims to reduce the carbon emissions and environmental impact of the building. This can include improving the energy efficiency of the HVAC and other mechanical systems, increasing the quality of insulation in the building envelope, implementing sustainable energy generation, and aiming to improve occupant comfort and health.
Green retrofits have become increasingly prominent with their inclusion in a number of building rating systems, such as the USGBC's LEED for Existing Buildings: Operations & Maintenance, Passive House EnerPHit, and Green Globes for Existing Buildings. Some governments offer funding towards green retrofits as existing buildings make up a majority of operational buildings and have been identified as a growing area of consideration in the fight against climate change.
Overview Sustainable refurbishment is the equivalent of sustainable development which relates to new developments of cities, buildings or industries etc. Sustainable refurbishment includes insulation and related measures to reduce the energy consumption of buildings, installation of renewable energy sources such as solar water heating and photovoltaics, measures to reduce water consumption, and changes to reduce overheating, improve ventilation and improve internal comfort. The process of sustainable refurbishment includes minimizing the waste of existing components, recycling and using environmentally friendly materials, and minimizing energy use, noise and waste during the refurbishment.
The importance of sustainable refurbishment is that the majority of buildings in use are not new and thus were constructed when energy standards were low or non-existent, and are otherwise incompatible with current standards or the expectations of users. Much of the existing building stock is likely to be in use for many years to come since demolition and replacement is often unacceptable owing to cost, social disruption or because the building is of architectural and/or historical interest. The solution is to refurbish or renovate such buildings to make them appropriate for current and future use and to satisfy current requirements and standards of energy use and comfort.
Sustainable refurbishment is not a new concept but is gaining recognition and importance owing to current concerns about high energy use leading to climate change, overheating in buildings, the need for healthy internal environments, waste and environmental damage associated with materials production. Many governments are beginning to realize the importance of sustainably renovating their existing building stock, rather than just raising standards for new buildings and developments, and are producing guidance and grants and other support and stimulation activities. Think-tanks, lobby groups and voluntary organizations continue to publicize and promote the need for and practice of sustainable refurbishment. For these reasons, multiple countries have started to develop demonstration projects.
The techniques of sustainable refurbishment have been developing over many years and though the principles are very similar to those used on new buildings, the practice and details appropriate for the wide range of situations found in old buildings has required development of specific solutions and guidance to optimize the process and avoid subsequent problems. Recently, many government-sponsored sources have developed technical guidance regarding sustainable refurbishment practices and have published their findings.
Retrofits
Most retrofits can be considered somewhat "green" because rather than constructing a new building, an existing one is improved. This saves resources that would otherwise be used to build an entirely new structure. A green retrofit typically aims to incorporate sustainability and save energy costs with each design decision.
Retrofitting a building inherently carries the constraints of the existing building and site. For example, the orientation of a building in regard to the sun has a great impact on its energy performance, but it's generally not within the scope of a retrofit to rotate the building. Budgetary constraints also often impact the energy conservation measures proposed.
Until recently, green retrofits have generally been considered as one-off projects for specific buildings or clients, but given the increased emphasis on improving the energy efficiency of existing building stock in the face of climate change, they are beginning to be reviewed systematically and at scale. The main challenge this presents for governments and advocacy groups is that the existing building stock is characterized by different uses, located in disparate climatic areas, and uses different construction traditions and system technologies. Because of these disparities, it is difficult to characterize strategies that apply to all buildings.
Green retrofits have recently garnered considerable research attention due to government emphasis on retrofitting old building stock to address climate change. It is estimated that up to half of building stock is always over 40 years old. Older buildings have significantly worse energy performance than their modern counterparts due to shortcomings in their design, deterioration in mechanical system efficiency, and increases in envelope permeability. The energy use intensity of houses in the United States dropped 9% from 1985 to 2004 due to improvements in end-use energy efficiency and code improvements.U.S. Department of Energy, Energy Efficiency Trends in Residential and Commercial Buildings, https://www1.eere.energy.gov/buildings/publications/pdfs/corporate/bt_stateindustry.pdf However, this is offset by the overall increase in the total number of houses.
Reasons
Climate Change One of the objectives of the United Nations Framework Convention on Climate Change (UNFCCC) is the mitigation of greenhouse gas emissions that contribute to climate change. More specifically, the UN supports the immediate reduction of building-related greenhouse gas emissions. Building refurbishment plays a key role in the decarbonization of the current building stock. Other than tearing down existing buildings, it is the only way to improve building performance or to develop zero-emission buildings. Energy-efficient refurbishments are a tool to reduce energy consumption in buildings, which will result in lower greenhouse gas emissions and resource use. Studies present the significance of the possible impact of widespread refurbishment implementation on individual GHG emissions, but also worldwide emissions and energy consumption.
Environmental Justice & Social Sustainability Social sustainability relates to the impacts of a building on the surrounding or occupying society, community, and individuals. This is considered in environmental impact assessment tools, such as life cycle assessment (LCA). Sustainable refurbishment integrates economic, social, and environmental needs to improve upon the existing building conditions. For example, sustainable buildings are socially sustainable because they are healthier for occupants due to the use of materials that do not negatively impact health.
Organizations such as 'Her Retrofit Space' in the UK, focus on empowering women professionals in the retrofit industry. By providing resources, training access, and networking opportunities, they aim to close the gender gap in the industry while advancing sustainable refurbishment practices. With the need to expand the workforce in many countries, advocating women in the workforce is an important aspect of driving workforce growth.
Indoor Environmental Quality The indoor environmental quality of the existing building stock is known to often be more unsatisfactory and unhealthy than the outdoor environment due to the design and materials used. The leading argument for sustainable refurbishment, and sustainable building in general, is the belief that green buildings are healthier and more satisfactory for occupants. The specifications for sustainable refurbishments take measures to ensure that the materials and building framework does not radiate dangerous particulates and gasses, like sulfur dioxide and nitrogen dioxide, into the indoor environment, and further measures are taken to filter indoor air for inhabitants.Sharma, Nitish Kumar. "Sustainable building material for green building construction, conservation and refurbishing." Int. J. Adv. Sci. Technol 29 (2020): 5343-5350. The "Citizen's Healthcare Principle" states that sustainable refurbishments must ensure that buildings are safe and improve living quality for those inside. The refurbishment design must consider both the indoor microclimate and the external environment around the building when developing the program. The microclimate parameters that should be considered include: Air velocity Humidity Dew point Lighting Air circulation velocity Acoustics Temperature
Historic Conservation The preservation of historic buildings is inherently sustainable since it maximizes the lifespan of existing materials and infrastructure. Conserving the materials and existing structures reduces waste and preserves the character of small historic communities. Many argue that the epitome of sustainability is to not build at all, which equites to preservation and refurbishment.
Finite Resources: Materials and Energy As a society, we have a finite amount of many resources, nonrenewable energy sources for example. Non-sustainable buildings, in terms of their operation, also consume a significant amount of non-renewable energy resources, relative to other industries. Again, it is necessary to increase the energy efficiency of the existing building stick to reduce non-renewable energy resource consumption, or even replace that with renewable sources entirely. Efficiency can be improved through sustainable building refurbishments that modify the building systems and building operations. With buildings becoming more energy efficient it is increasingly important to look at the life cycle impact of the materials that make up the building. Designing and constructing buildings that are not sustainable for long lifetimes allows for the construction and demolition of buildings with short lifetimes, which wastes construction materials that are not used for their entire lifetime capacity. Reusing existing buildings enables building owners to use the embodied energy that is already invested in the building composition, rather than wasting that embodied carbon and consuming more with a new building construction.
Development of the Goals of Sustainable Refurbishment This section lays out a timeline and progression of the development of the goals of sustainable refurbishment from a few different authors: