More building owners and managers are considering window, curtainwall and storefront renovation projects to increase both short-term tenant satisfaction and long-term building value.
The U.S. has over 5 million commercial buildings with 70 billion square feet. Many of these buildings have windows, curtainwall and storefront that are over 30 years old and use shades or dark film to control the heat and glare generated by the sun, thus affecting the appearance and views from the building.
Replacing your glazing products can attract potential tenants and employees, while improving their level of performance. One study from the World Green Building Council found:
- Employee productivity had a 4% reduction in cooler and a 6% reduction in warmer temperatures
- Employees with windows had 46 minutes more sleep
- Employees had a 66% drop in performance when exposed to distracting noise
Glazing products also provide improved aesthetics, clearer views, reduced outside noise and improved thermal comfort. The DOE estimates that roughly half the commercial buildings in the nation have single pane glass in mostly non-thermal aluminum frames. Nearly 60% of existing office buildings were constructed before 1980 and before low-emissivity (low-e) glass was in commonly use.
Today, window systems for commercial buildings typically feature high-performing insulated glazed units with low-e coatings constructed with aluminum frames and thermal barriers. The glazing options for modern window systems help manage unwanted solar heat gain, controls glare, mitigates damaging UV rays and increases natural light.
Choosing the most efficient window design can be difficult. Product information typically offers window properties such as shading coefficients, solar heat gain coefficients, U-Factors, or R-values, and air leakage rates. However, the actual importance of these properties depends on conditions specific to your building and site.
A range of 25-40% in energy savings is frequently cited by the DOE for whole building, energy-driven retrofits. Energy models can help predict payback periods in terms of energy savings specific to windows. Knowledgeable window renovation partners can offer energy modeling tools to compare performance data between the products selected for an individual building and can share location-based performance information on peak demand, annual energy, carbon emissions, daylight, glare and condensation predictions.
Replacing aging windows, curtainwall and storefront with modern, high thermal performance units also can significantly reduce HVAC workloads. The DOE estimates that windows account for 39% of the HVAC load for heating and 28% for cooling. Evaluating the benefits of a high-performance window renovation, prior to HVAC and lighting upgrades, will help save money on purchasing equipment that has been properly sized to meet the building’s reduced energy demands.
High-performance window renovations can contribute to achieving ENERGY STAR®, LEED® and other third-party certification and recognition for energy-efficient and environmentally responsible practices. U.S. buildings consume approximately 40% of the nation’s total energy, making them a target for savings through mandatory codes and voluntary incentive-based programs. A 2014 EPA study estimated that building retrofits could yield more than $1 trillion of energy savings over 10 years, mitigate 600 million metric tons of CO2 per year and reduce emissions by nearly 10%.
Sustainable, high-performing buildings also command a premium in the market. Studies of the value of green building show that ENERGY STAR Certification is associated with a range of benefits including:
- 5.8%-26% increase in property value
- 1.3%-11% increase in occupancy rate
- 3%-5% increase in lease rates
More and more jurisdictions are establishing green building labeling programs that require buildings to make energy performance statements available for all real estate transactions including sale, lease and financing, as well as to the public.
Many cities have implemented mandatory building energy use reports. As occupants’ green building knowledge grows, their expectations follow – especially if they are responsible for some of portion of their utility costs. Occupants are increasingly demanding evidence that their employers and building owners are exceeding minimum environmental standards. While some see third-party certifications as a stamp of approval for a goal achieved; others seek ongoing, visible improvements that address the whole building design and operation.
When vetting prospective partners for window renovations and retrofits, ensure they can provide energy modeling, product selection recommendations, design assistance and installation recommendations. Check that they can help navigate the aesthetic and code compliance criteria, as well as offer support for green certifications, tax credits and incentive programs. Ask how they stand behind their work and how the window systems are warrantied. Verify that the chosen manufacturer has the resources to help your team assess the relevant information for your return on investment analysis.
John Bendt is vice president of Apogee Enterprises, Inc.’s Building Retrofit Strategy Team. To learn more, please email email@example.com or call 715-846-3355.
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