By Mike Berry, Apex Technology
Since the 2007 Florida Building Code (the first Florida code to have a separate energy-efficiency code book) there have been two paths to energy code compliance, the prescriptive path and the performance path.
However, since the 2007 code, the prescriptive path has included requirements for having all duct work in conditioned space. Here in Florida we have decided that the cheapest location (at least for those building the house) for our ducts carrying 55 °F cooling air is our 150 °F attic.
Don’t worry. We’ll save the E-Council rant on the energy wasted by ducts in attics for another day.
With that issue aside for the moment, since the prescriptive path has required ducts to be in conditioned space (not in the attic) no one paid attention to that section of the code, because no one was interested in moving the ducts.
Instead everyone demonstrated compliance via the performance path, which meant you had to model the house in a clumsy computer program called Energy Gauge, and it would tell you if your house was efficient enough to be code compliant.
There is a lot of data to enter, a lot of data to check by building departments and multiple opportunities for confusion and delays in the construction and inspection process.
But there is a new code coming this summer, the 2014 Florida Building Code, which has been modeled after the 2012 International Code.
And now the prescriptive path no longer requires that ducts be in conditioned space — a cause for celebration (cue angelic singing).
The tricky part is that no one has really paid attention to this part of the code for the past seven or eight years, so a serious refresher is needed for builders, designers and building departments.
A draft of the new building code is available online at bit.ly/2014buildingcode
Keep in mind, the prescriptive world is slightly different than the performance world. Simpler, yes, but different. Highlights of the key requirements are listed below:
• Insulation: R-38 ceiling, R-13 wood-frame walls, R-13 floors, and R-4 masonry walls (Table R402.1.1)
• Windows: 0.40 max U-value and 0.25 max SHGC (Table R402.1.1)
• R-8 insulation for supply ducts in attics (R403.2.1)
• Duct blaster test required to verify duct leakage ≤ 4 cfm per 100 SFAC (R402.2.2)
• R-3 hot water pipe insulation in certain situations (R403.4.2)
These are in addition to the mandatory requirements from the E-Council’s January Builder News report, and they still include Manual J load calculations and Manual D duct designs, blower-door tests on every house and mechanical ventilation.
The prescriptive path may not make sense for everyone, but it is worth another look.
Contact the E-Council NEFBA liaison Palmer Kuder at (904) 725-4355 or [email protected] for more information or to get connected to consultants who can help you navigate this new code and develop your energy strategy.
Mike Berry, EI, Mechanical Design & Building Science Lead with Apex Technology, is a member of NEFBA’s E-Council and regular contributor to Builder News. Contact him via email at [email protected].