Energy Construction Codes
2012 Residential Energy Codes
With little fanfare, a new law went into effect on January 29, 2010, that will dramatically change home construction in Illinois in a positive way. Public Act 096-0778 amended the Energy Efficient Commercial Building Act to include residential buildings. The Act was written with wording that requires compliance with the current version of the International Energy Conservation Code (IECC). The reason the Act will dramatically change home construction is that the current IECC 2012 code was written to achieve a 15 percent improvement in home efficiency from the prior IECC 2009 Code.
The Act requires communities and counties with a building permit and enforcement program to enforce the current IECC standard. For those areas outside of communities or counties with an enforcement program, Bruce Selway with the Energy Office of the Illinois Department of Commerce and Economic Opportunity (DCEO) indicates the Act still applies. “The Law does require design and construction professionals to follow the latest published edition of the IECC. While communities and counties with compliance programs must mandate compliance, all other construction must still comply with the Code.”
Here is a list of some key changes in the Code.
| Ceilings | R-49 | Can be R-38 if raised heel trusses used at eaves. |
| Walls | R-20 or R-13 + 5 | Basically, exterior walls will have to be 2 x 6 or 2 x 4 with 1” of foam sheathing on the exterior. Corners and headers must be insulated. |
| Floors | R-19 | |
| Basement Walls | R-10/13 | R-10 if continuous insulation, such as foam board on the interior or exterior, R-13 cavity insulation if the wall is framed out. This applies to conditioned and un-conditioned basement walls unless the ceiling above the un-conditioned area is insulated to R-19 and other steps taken. |
| Concrete Slabs Floors | R-10, 2’ | Perimeter edge insulation of R-10 must extend to the bottom of the footing or 2’, whichever is less. This would include walk-out basement edges. |
| Crawlspace | R-10/13 | Same as basement walls. |
There are other significant changes in the Code.
Air Leakage
The Code requires significant reduction in air leakage through the building thermal envelope. To ensure this, the Code requires testing of the building envelope (by use of a blower door test) with leakage not to exceed specified limits.
To achieve this, a continuous air barrier must be installed in the building envelope, with all joints and seams sealed. The rough opening around doors and windows are required to be sealed. Duct shafts, utility penetrations, flue shafts or other openings between conditioned and unconditioned areas must be also be sealed.
Heating and Air-Conditioning
There are significant new requirements in the Code concerning heating and air-conditioning systems. One component with significant changes is duct systems. Under the new Code, if any of the duct system is outside the building envelope, such as an attic, it must be tested to air leakage criteria. Generally this requires testing similar to a blower door system.
To remain below the air leakage criteria, duct systems outside the building envelope must be sealed and insulated to R-8 for supply ducts and R-6 for all others. The air handler component of a heating or air-conditioning system must have a manufacturers designation for air leakage that is less than or equal to two percent of the design air flow of the air handler.
One item that will increase the cost of new heating and air conditioning systems is that building framing cavities can no longer be used as a part of the duct or plenum system. In the past, a common practice has been to use floor joists as a part of the return air system by what is called “panning”. Basically, installers would nail a piece of sheet metal to the bottom of floor joists and then use the space created as a return air plenum. Under the IECC 2012 this is no longer allowed.
Installers also frequently use the space between interior wall studs to form a cavity for return air vents located near the ceiling. Once again, the new Code does not allow for this type of construction.
New homes with a forced air heating system must now also have a programmable thermostat installed. In the past, many efficiency experts have been opposed to the use of programmable thermostats with heat pumps. Quite often the thermostat would cause the supplemental electric coils to run more than necessary when temperatures were rasied from a setback period. The Code however calls for a thermostat that will prevent the supplemental heat from operating when the heat pump compressor can meet the heating load.
To ensure building occupants are breathing healthy air, all homes must be equipped with mechanical ventilation that meets the standards of the International Residential Code (the Code that specifies how homes will be built) or the International Mechanical Code.
Finally, heating and cooling systems must be sized according to Manual J of the Air Conditioning Contractors of America standards. Most quality heating and air conditioning contractors have discontinued sizing systems by square footage, but the Code now mandates they be sized by an industry recognized calculation method.
While these new Code requirements may seem restrictive to some, in the long run they will ensure that our homes are energy efficient, sustainable and healthy. While they may cost more to build initially, with reduced energy consumption, they will be less costly to live in.
Anyone who is involved in the construction industry should make sure they are educated and informed about the new Code as it becomes applicable on June 30, 2012 and this article is not a complete listing of requirements of the IECC 2012. The Energy Office with DCEO has been offering free training sessions for those involved in the construction industry. If you are interested in attending a session, please visit www.ildceo.net/energycode.
