What’s new for contractors?

Energy Star™ homes! As an IHP contractor, every new home NISEnergy services will receive a gold Energy Star™ certificate of efficiency and IECC 2012 compliance. The 2012 code requires better insulation, a tighter envelope, tighter ducts, better windows, and more efficient lighting than the 2009 code. Here is a summary of the important changes made for residential builders in the 2012 International codes:

•  Air duct tightness requirements have become more stringent.
•   Blower-door testing requirements have become mandatory and more stringent; the 2009 threshold of 7 ach50 has been changed to 3 ach50 for northern Illinois.
•  All homes in our area will be required to have a whole-house mechanical ventilation system.

The bottom line: Every new home will need to be tested with a blower door, and every cold-climate builder will need to come up with a strategy to stop thermal bridging through studs.

High-efficiency lamps

Section R404.1 of 2012 IECC requires that “a minimum of 75% of the lamps in permanently installed lighting fixtures shall be high-efficacy lamps.” That percentage has been raised from 50% in the 2009 code. The code defines a high efficiency lamp as either:

•  A compact fluorescent lamp (CFL);
•   A T8 or smaller linear fluorescent lamp; or
•  Any lamp meeting the following minimum efficiency requirements: 60 lumens per watt for lamps over 40 watts, 50 lumens per watt for lamps over 15 watts but no more than 40 watts, and 40 lumens per watt for lamps rated at 15 watts or less. LED

This definition excludes incandescent light bulbs. High-efficiency lamps are allowed to have any type of base; screw-base (Edison-base) lamps comply with the new code.

Air duct tightness testing

Like the 2009 codes, the 2012 IECC requires duct leakage testing unless the duct system is located entirely inside of the home’s thermal envelope. The new code has increased the stringency of the duct leakage thresholds. The code permits builders to test a duct system in one of two ways:

• One option is a “rough-in” test after the air handler is installed. While the 2009 code had a threshold of 6 cfm per 100 square feet of conditioned floor area for this test, the 2012 code has lowered this threshold to 4 cfm.
•  The third option is a “post-construction” test. While the 2009 code had a threshold of 12 cfm per 100 square feet of conditioned floor area for this test, the 2012 code has lowered this threshold to 4 cfm.

The bottom line: get out your tub of mastic, and seal everything well.

Better air tightness requirements

The 2009 International codes included provisions to improve the air tightness of new homes. Builders were given two compliance options: either follow a checklist of measures or have the home tested with a blower door. The new 2012 code doesn’t give builders a choice anymore; builders now have to comply with both the checklist requirements and the requirement to conduct a blower-door test.

The air-sealing checklist in the 2012 IECC is called Table R402.4.1.1, “Air Barrier and Insulation Installation.” The 2012 table is based on the earlier checklist (2009 IECC, Table 402.4.2); however, the 2012 version is written in mandatory language, and a few ambiguities in the earlier table have been cleared up. Table R402.4.1.1 requires:

•  A continuous air barrier shall be installed in the building envelope. Exterior thermal envelope contains a continuous air barrier. Breaks or joints in the air barrier shall be sealed. Air-permeable insulation shall not be used as a sealing material.
•  The air barrier in any dropped ceiling/soffit shall be aligned with the insulation and any gaps in the air barrier sealed. Access openings, drop down stair or knee wall doors to unconditioned attic spaces shall be sealed.
• Corners and headers shall be insulated and the junction of the foundation and sill plate shall be sealed. The junction of the top plate and top of exterior walls shall be sealed. Exterior thermal envelope insulation for framed walls shall be installed in substantial contact and continuous alignment with the air barrier. Knee walls shall be sealed.
• The space between window/door jambs and framing and skylights and framing shall be sealed.
•  Rim joists shall be insulated and include the air barrier.
• Insulation shall be installed to maintain permanent contact with underside of subfloor decking. The air barrier shall be installed at any exposed edge of insulation.
•  Where provided in lieu of floor insulation, insulation shall be permanently attached to the crawlspace walls. Exposed earth in unvented crawl spaces shall be covered with a Class I vapor retarder with overlapping joints taped.
•  Duct shafts, utility penetrations, and flue shafts opening to exterior or unconditioned space shall be sealed.
•   Batts in narrow cavities shall be cut to fit, or narrow cavities shall be filled by insulation that on installation readily conforms to the available cavity space.
• Air sealing shall be provided between the garage and conditioned spaces.
•  Recessed light fixtures installed in the building thermal envelope shall be air tight, IC rated, and sealed to the drywall.
• Batt insulation shall be cut neatly to fit around wiring and plumbing in exterior walls, or insulation that on installation readily conforms to available space shall extend behind piping and wiring.
• Exterior walls adjacent to showers and tubs shall be insulated and the air barrier installed separating them from the showers and tubs.
•  The air barrier shall be installed behind electrical or communication boxes or air sealed boxes shall be installed.
• HVAC register boots that penetrate building thermal envelope shall be sealed to the subfloor or drywall.
•  An air barrier shall be installed on fireplace walls. Fireplaces shall have gasketed doors.

Once you have completed the air-sealing checklist, you still need to conduct a blower-door test.

Northern Illinois is zone 5.

According to section R402.4.1.2 of the 2012 IECC, “The building or dwelling unit shall be tested and verified as having an air leakage rate of not exceeding 5 air changes per hour in Climate Zones 1 and 2, and 3 air changes per hour in Climate Zones 3 through 8. Testing shall be conducted with a blower door at a pressure of 50 Pascal. Where required by the code official, testing shall be conducted by an approved third party. A written report of the results of the test shall be signed by the party conducting the test and provided to the code official. Testing shall be performed at any time after creation of all penetrations of the building thermal envelope.”

NISEnergy, LLC offers builders consultation of the new energy code, site support, high-efficiency lighting, insulation installations, blower door and duct testing with Energy Star™ Home Performance certification.