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Building Envelope Retrofits for Improved Energy Efficiency

 

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The median age of commercial buildings today is 32 years old. As commercial buildings age, their façades and systems start to degrade, malfunction, fall out of specification, or even change use. The effect of this enclosure performance degradation is poor thermal comfort, poor indoor air quality (IAQ), and wasted energy resulting in an increase of energy consumption over the coming years. With a push for commercial buildings to reduce the energy footprint, retrofitting a building enclosure has many benefits, including energy savings, improved overall appearance, and uninterrupted workflow for buildings occupants.

The trend in building construction is shifting from new construction to retrofits. According to McGraw-Hill data, the U.S. Green Building council observed that 61% of all construction projects today are retrofits. A building doesn’t have to be new to be efficient. Building owners are choosing to retrofit their facilities, converting them to sustainable commercial buildings. Smart owners package energy saving technology to get serious savings through lower energy consumption and operating costs. According to the U.S. Energy Information Administration, HVAC systems make up 51% of the total energy use while lighting represents 25%. With these two elements making up three-quarters of an office building’s energy use, it is best to focus retrofits on energy efficiency before cosmetic retrofits are fulfilled.

There is strong case for building owners to retrofit commercial buildings for energy cost savings alone, but there are many other quantitative benefits, including reduced operating and management expenditures, extended equipment life, increased property value, and improved occupancy rates.

Candidates For Retrofit

Many of the buildings we encounter today were built before 1980, which allows multiple opportunities for building enclosure companies to retrofit. Common candidates include hospitals, high-rise buildings and glass towers, and adaptive reuse buildings.

Hospitals. Facility management in hospitals benefit significantly from retrofitting their buildings. Poor thermal performance and poor IAQ can seriously impact the quality of patient care. Hospitals use a significant amount of energy not only because of the 24/7 operations, but because of the amount of air that must be conditioned. Ventilation systems must perform at optimal levels or mold can grow in high humidity areas, compromising the health of the facility occupants.

To ensure energy efficiency, a hospital retrofit should include overhauling the HVAC system, updating energy draining lights, and renovating its building envelope.

High-Rise Buildings. Large-scale commercial buildings in highly populated cities present an opportunity for improving energy performance and sound reduction of outside elements through a building enclosure retrofit. Many of high-rise towers in the U.S. were built 30 to 40 years ago with curtainwalls that are considered substandard today. The curtainwall technology wasn’t particularly robust when the buildings were initially built, resulting in failing sealants that lead to water penetration and air infiltration. In recent years, there have been many developments in curtainwall technology involving progressive design technique, high performance materials, and advanced fabrication processes.

The insulated glass installed on these buildings typically have a warranty of five to 10 years, with the products having a life expectancy of 20 to 30 years. Generally, the glass originally installed in these older buildings offered little protection for sound transmission from outside sources like traffic, nearby construction, and low flying aircraft. The building’s poorly insulated glass and building façade results in poor thermal performance that leaves its occupants uncomfortable and increases energy costs for the owner.

Renovations/New Use. It is inevitable that existing commercial buildings age and outgrow their original function. Changes in technology, lifestyle, and construction and design are constantly updated to meet modern demands. It is economically beneficial to adapt older buildings as opposed to constructing a new building. The demolition and reconstruction process takes more time and is wasteful. Additionally, historical buildings give a glimpse of the past, and repurposing a place with valued heritage makes adaptive reuse an essential component of sustainable development.

Adaptive reuse of an older building doesn’t mean restoration or preservation. Adaptive reuse changes the intent of the structure to meet the current needs of the building owner. Some adaptive reuse projects do include restoration to keep the building’s façade or interior looking similar to its past, but the overall purpose of the building serves a different need.

For example, the historically known Old Post Office and Clock Tower in Washington, DC was built in 1899. The property went through numerous renovations. In 2016, the historic building was transformed into the newest addition of the Trump Hotels. The historic building’s renovations included upgrades to the entry façades and canopies with modern materials, new acoustical cladding systems and the mechanical screen walls and installation of high-end panel systems in the entrance portals.

Location also plays a large role in the decision to renovate or adapt an older building for a new purpose. Factories are commonly adapted to provide residential housing, especially in the Northeast and the Midwest. The exterior building façade not only has to be retrofitted, but the HVAC systems, lighting systems, and overall structures will need to be retrofitted to provide an optimal performing building for its occupants.

Financing A Retrofit

As the urgency grows for reduced energy use, an increasing number of cities have made commitments to climate and sustainability goals. With a strong focus on codes, standards, and green building certifications, such as the U.S. Green Building Council LEED certification, there has been tremendous progress in the quality and performance of new buildings, but many building owners are reluctant to undergo retrofits on their existing buildings. For many building owners, capital costs are the primary barrier to investing in a retrofit causing slow implementation of large-scale adoption of energy conserving technology.

A traditional energy overhaul requires a significant investment; therefore it is often combined with a major renovation or an intensive building system replacement. This customized approach isn’t attractive to building owners; a more industrialized approach is recommended. An industrialized approach provides an immediate, low-cost energy savings to the building owner to simplify the decision-making process.

Many options exist for financing energy efficiency upgrades including commercial loans, energy performance contracts, utility rebate and on-bill finance programs, and government-supported low interest loans. There is a variety of tax incentives to further improve the economics of energy efficient upgrades. Additionally, the U.S. Department of Energy (DOE) have developed the Advanced Energy Retrofit Guides (AERGs) for existing buildings to help building owners, facility managers, and energy managers select efficiency improvements that best suit their building type and location. These guides provide examples of how implementing an energy efficiency upgrade makes good business sense.

The prevalence of green building programs and the availability of tax incentives make retrofitting building enclosures affordable for owners. Energy savings are valuable and offer building owners a low-risk investment that will reduce operating and maintenance expenditures and contribute to healthier environments and more competitive industries. A simple ROI analysis will demonstrate that the energy saved with a retrofitted façade will result in decreased operational costs over the long term.

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