Building Science Corner:
IRC 2009 and What You Need to Know
Although IECC 2009 is shortly coming to most states, almost everyone is currently implementing IRC 2009 at minimum. Here are the highlights of what you need to know:
- R506.2.3 - Vapor Retarder under slab
- R703: Both wind and water resistant exterior barrier.
- N1102.2: Attic doors/hatches insulated to same R-value as ceiling
- N1101.4: Blown or Sprayed roof insulation - rulers every 300 sq.ft.
- Attic Ventilation: All cavities in attic to be ventilated
Download the GWS booklet: www.gwssi.com/news.html
GWS Improves Energy Rating Industry
with Geothermal HERS Inputs
GWS President Kelly Parker has been working hand in hand with geothermal manufactures and software designers to produce a more accurate representation of geothermal systems in the HERS Index software. GWS now has an approved, specialized method of entering ground source heat pumps into REMrate that produces a better HERS Index number. To generate this change in the industry, it took the perfect recipe of GWS experience, Climate Master engineering and Architectural Energy design. If you use geothermal, we encourage you to contact GWS about this new analysis procedure.
Climate Master is the world's largest manufacturer of geothermal heat pumps and Architectural Energy designs and maintains REMrate software, designed specifically for the HERS Rating Industry.
Emerging Products: Aeroseal Duct Sealing
|Duct Corner |
Lawrence Berkeley National Laboratory has developed a method for internally sealing HVAC ducts using a pressurized aerosol sealant.
Aerosol duct sealing forces vinyl acetate adhesive particles into heating and cooling duct systems via specialized equipment.
The adhesive particles are kept suspended by the airflow until they naturally try to exit the duct system through leaks. In the process, particles are flung a
gainst the holes where they adhere and build up until the leak is closed. The sealant only sticks to the holes in the air duct without coating the rest of the duct.
|Duct Corner |
Because the installation of Aerosol is internal, it can be done relatively easy on existing homes. The adhesive quality makes it a great plan B strategy new homes that have trouble passing a duct blaster test. You don't have to open walls, floors or ceiling cavities to access hard to reach leaks.
The initial cost for aerosol duct sealing is $300 to $1800 per home. According to Aeroseal, the vast majority of the product left in the duct system is VAP and 2E1H. VAP has been used in water-based paints, adhesives and hair spray and chewing gum. 2E1H has shown no ill effects after long-term exposure to concentrations of 200 pp million. The largest concentration of 2E1H during Aeroseal injection was 1 pp billion. For more information: http://www.aeroseal.com/
Photos courtesy of GWS HERS & Green Rater, Jim Conlon of Elysian Energy in Maryland. Elysian Energy is a certified independent Aeroseal installer. Thanks Jim!
Oklahoma Tax Credit
With up to $4,000 per home, Oklahoma is at the top of the list of states offering credit for energy efficient new building. This tax credit is available for single family and multi-family units under 2,000 square feet. Many other states have similar incentives for home builders. To see if you qualify, please contact Andrea Palmer at GWS.