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Nebraska Energy Building Code
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| HITCHCOCK COUNTY
ENERGY BUILDING CODES |
The Nebraska Energy Code applies throughout Hitchcock County. |
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Prescriptive Packages may be used to ensure compliance with the building envelope requirements of the Nebraska Energy Code, also known as the 2003 International Energy Conservation Code, for single- and multi-family buildings that have less than a thirty percent (30%) window-to-wall ratio and are being constructed with wood.
Option A: Prescriptive Package Tables
- Calculate the entire exterior wall area of the building, including window and door areas. Do not use basement wall areas.
- Calculate the window area using the rough opening dimensions including areas of all skylights, above grade windows and basement windows where the basement is conditioned. One percent (1%) of the calculated window area is exempt from the Glazing U-Factor requirement.
- Calculate the Glazing Area. Glazing Area equals window area divided by exterior wall area.
- Determine the Heating/Cooling Equipment Efficiency (See notes below).
- Select the compliance package number based on the calculations in #3, the equipment efficiency, the Ceiling and Wall R-values and the window products selected for the building.
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Note:
Glazing Area - The maximum glazing area is the sum of all glazing (including windows, sliding-glass doors, skylights, and windows in conditioned basements) divided by the gross wall area (excluding basement walls — walls more than 50% below grade) expressed as a percentage. The area of a glazing assembly is the interior surface area of the entire assembly, including glazing, sash, curbing, and other framing elements. The nominal area or rough opening is acceptable for flat windows.
The gross wall area includes the following:
All above-grade walls enclosing conditioned spaces (including attic kneewalls and skylight shafts) The peripheral edges of the floors (the area of the band joist and perimeter framing between floors) Walls of conditioned basements with an average depth less than 50% below grade (include the entire wall area — even the below-grade portions) All windows and doors (including windows and doors in conditioned basements).
The glazing area percentage is a MAXIMUM. Any building with a glazing area less than or equal to this value will comply with the selected code.
Up to 1% of the total allowed glazing area may be excluded from the U-factor requirement. For example, 3 ft2 of decorative glass may be excluded from a building design with 300 ft2 of glazing area.
Glazing U-Factor - Glazing U-factors must be tested and documented by the manufacturer in accordance with the NFRC test procedure or taken from the default glazing U-factor table in the 2003 IECC. Center-of-glass U-factors cannot be used.
Ceiling R-Value - Ceiling R-values represent the sum of the cavity insulation plus any insulating sheathing to be used. The ceiling R-values do not assume a raised or oversized truss construction. If the insulation achieves the full insulation thickness over the plate lines of exterior walls, R-30 insulation may be substituted for R-38 insulation and R-38 insulation may be substituted for R-49 insulation in the generated packages.
Wall R-Value – The wall R-values represent the sum of the wall cavity and continuous insulation values. Do not include exterior siding, structural sheathing, and interior drywall in the R-values. The wall R-value requirements are for wood-frame walls. Continuous insulation is continuous over framing members or furring strips and is free of significant thermal bridging. The R-values of other parts of the building assembly (e.g., gypsum board and air films) are accounted for. Insulating sheathing installed on the exterior of above-grade walls is an example of continuous insulation.
Floor R-Value - The R-value requirements apply to floors over unconditioned spaces (such as unconditioned crawl spaces, basements, or garages). Floors over outside air (such as cantilevers and floors of overhangs) must meet the ceiling requirement of the package.
Basement Wall R-Value - The entire opaque portion of any individual basement wall with an average depth less than 50% below grade is considered an above-grade wall and must meet the same R-value requirements as the above-grade walls. Windows and sliding-glass doors of conditioned basements must meet the package window U-factor requirement and must be included in the glazing area calculation. Basement doors must meet the door U-factor requirement of 0.35. Walls of conditioned basements below uninsulated floors must be insulated from the top of the basement wall to a depth of 10 ft below ground level or to the level of the basement floor, whichever is less.
Slab-on-Grade R-Value - The R-value requirements are for unheated slabs. Add an additional R-2 for heated slabs (slabs with ducts or hydronic heating elements in or under the slabs). Slab insulation must extend a total linear distance of 4 ft. The insulation must extend 1) down from the top of the slab, or 2) down from the top of the slab to the bottom of the slab and then horizontally underneath the slab, or 3) down from the top of the slab to the bottom of the slab and then horizontally away from the slab, with pavement or at least 10 in. of soil covering the horizontal insulation.
** Indicates no insulation R-value required
Crawl Space Wall R-Value - The Crawl Space Wall option should only be used for walls of an unventilated crawl space. Do not select this foundation option if you will be insulating the floor above the crawl space. The crawl space wall insulation must extend from the top of the wall (including the sill plate) to at least 1 ft below the outside finished grade. If the distance from the outside finished grade to the top of the footing is less than 1 ft, the insulation must extend a total vertical plus horizontal distance of 2 ft from the outside finished grade.
** Indicates no insulation R-value required
Door U-Factor - The U-factor for all doors in the building envelope (regardless of the package chosen) is 0.35. You are allowed to exclude one door from this requirement. Door U-factors must be tested and documented by the manufacturer in accordance with the NFRC test procedure or taken from the default U-factor table in the 2003 IECC. If a door contains glass and an aggregate U-factor rating for that door is not available, include the glass area of the door with your windows and use the opaque door U-factor to determine compliance of the door.
Heating/Cooling System Efficiency – Reductions in building envelope R-value requirements can be made by installing high efficiency heating and cooling systems. The minimum required installed system efficiencies are:
Normal – 78% or 80% AFUE gas- or oil-fired furnaces or boilers, electric resistance heating, 10.0 SEER air- conditioners and 6.8 HSPF / 10.0 SEER heat pumps
High Heating – 90% AFUE gas- or oil-fired furnaces or boilers and 7.8 HSPF heat pumps
High Heat/Cool - 90% AFUE gas- or oil-fired furnaces or boilers with 12.0 SEER air-conditioners and/or 7.8 HSPF / 12.0 SEER heat pumps |
Option B: Software Programs — REScheck and COMcheck
Software programs may be used to comply with the building envelope requirements of the Nebraska Energy Code. Two software programs, REScheck and COMcheck, make residential and commercial energy code compliance easy. Both REScheck and COMcheck are available for free at the
U.S. Department of Energy’s Building Energy Code Website. |
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When using REScheck to show building envelope compliance with the Nebraska Energy Code it is recommended that you download and use Version 3.6 Release 2.
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