Volume 7, Issue 9 - October 2006

A Welcome Change
New Florida Energy CodeGives Efficient Windows a Competitive Edge

by Arlene Zavocki Stewart

Energy-efficient windows tested to National Fenestration Rating Council (NFRC) standards will have a competitive edge in the Florida market, when the 2006 Florida Building Code supplement goes into effect on December 8, 2006. Savvy manufacturers will take advantage of the domino effect caused by federally mandated changes to heating, ventilation and air conditioning systems (HVAC) requirements that will leave the building industry looking for more cost-effective ways to meet the Florida Energy Code. The NFRC estimates that close to one million products already fit the bill by exceeding 0.87 U-factor and 0.55 solar heat gain coefficient (SHGC). These are the best code default performance values for double-glazed, tinted windows. 

Implications for Builders
A study commissioned by the Florida Home Builders Association (FHBA)1 estimates that 60 percent of housing starts (135,000 houses) will need to consider reconfiguration for cost-effectiveness. Florida’s highly flexible energy code gives builders infinite ways to comply, allowing them to trade off less cost effective options for ones with more bang for the buck. In years past, builders have preferred using high-performance HVAC equipment, allowing them to trade down from more expensive, efficient window options to less efficient, cheaper ones. 

As the market shift in HVAC continues, shortages in new high-performance equipment with adequate moisture removal capacity will become more apparent. Florida HVAC industry representatives report that not only is there a lack of Seasonal Energy Efficiency Ratio (SEER) 14 or better equipment, but that 50 percent of those units have a sensible heat ratio (SHR) of 0.7 or lower, a necessary factor in Florida’s hot, humid climate. The current up-charge for high-performance HVAC runs between $1,000 and $3,000, sending builders back to the drawing board to explore other options.

Arguably, the most cost-effective option for builders is to return to the original window and wall provisions they traded-off in favor of HVAC equipment. In fact, builders may not realize that they have been trading off thermal envelope efficiency in favor of HVAC options, since the original measures will not be printed in the Energy Code until December 8. 

Original window measures, found in the ‘baseline’ or model house, have been 0.5 U-factor, 0.4 SHGC since 2001. In December, the Florida code baseline will align itself with Zone 2 of the International Energy Conservation Code, maintaining a 0.4 SHGC and reversing to a 0.75 U-factor throughout Florida. By selecting windows that meet or exceed these baseline characteristics, builders neutralize the need for high-performance equipment, allowing them more HVAC options with better moisture control capacity. Furthermore, windows with advanced solar control allow knowledgeable air conditioning contractors to reduce the size of the HVAC units, right-sizing for comfort, longer unit life and fewer callbacks. Some contractors pass the $250 savings from the reduced size onto builders, while others up-sell other features to control humidity like variable speed air handlers. In either case, efficient windows can help contractors provide better products and service to their builder clients during their own market transformation.

However, selecting the right window is only part of the equation for successful window sales. The FHBA study also determined that none of the 2004-2005 energy code submittals used any NFRC-tested values, instead using one of four default entries that did not require labeling for thermal efficiencies. Like most energy codes, windows that meet the Florida baseline exceed the default performance. Therefore, even if builders are purchasing better performing windows, they are not claiming the benefit of that purchase. In order to claim such benefits, two steps are needed. First, U-factors and SHGC must be entered into the energy calculations. It is important to note that windows are the only thermal envelope provisions that have such defaults in the software used for Florida compliance (called Energy Gauge/FlaRes, www.energygauge.com). Wall, ceiling and floor insulation levels must be manually inputted with a specific R-value for each submittal. Second, the labels must stay on the windows through the framing inspections at least, so enforcement officials can verify the performance against the calculation (kept with other construction documentation).

Manufacturers Must Educate Others
The success of advanced window sales in Florida relies on the fenestration professionals’ ability to increase the awareness and distribution of their products’ energy performance. Architects, HVAC professionals, energy raters and insulation installers, all of whom provide builders with energy calculations, must be able to input appropriate U-factors and SHGCs with ease, in order to change the practice of relying on window defaults. In fact, inputting any NFRC value that exceeds the defaults for unlabeled windows helps the builder with compliance, reducing the need to purchase other energy- efficient measures. This is especially good news for monolithic impact products—some of which report performance better than the best double-glazed, tinted default. 

Awareness of this code change has been increasing steadily in the last six months. Code questions on window requirements were prominent at the quarterly FHBA meeting in August. State FHBA headquarters reports an average of five calls per week on the topic and several local chapters have requested that experts on the subject matter attend the monthly meeting to update their members. Building officials received a day of window training at their annual conference in June with several follow up sessions to local chapters in the following months. The American Architectural Manufacturers Association’s Southeast region presented a session at its fall conference while the Fenestration Manufacturers Association offered a course to manufacturers to prepare products to meet the code. However, confusion still occurs as builders report that they are being told that the federally mandated change is for windows, not HVAC systems. Fenestration sales can reduce builder concerns by noting that efficient windows provide more cost-effective flexibility in meeting the HVAC change. The “frequently-asked-questions,” posted at FHBA.com (click on “features” then “energy”) should explain the differences.

Arlene Zavocki Stewart is the principal for AZS Consulting Inc., a firm specializing in sustainable building advocacy, certification, training and promotion. 

1Based on the official Florida Department of Community Affairs energy submittal database for 2004-2005.

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