# Presentation: 291434

## National Workshop on State Building Energy Codes 

- Jim Benney
- Director of Education
- National Fenestration Rating Council

## Rating the Energy Performance of Fenestration Systems

- How windows perform
- What the NFRC standards represent
- What the codes/programs say
- What do changes to the standards denote
- What does this mean to you?
- Q/A

## How do windows perform

- Energy from the sun is either transmitted, reflected or absorbed (and transmitted or reflected) by windows.
- This energy is ion the form of waves:
- Short wavelengths (UV)
- Medium wavelengths (Visible)
- Long wavelength (IR)

## U-factor (thermal transmission) 

- The rate of heat transfer through the fenestration product
- The lower the U-factor the more efficient the energy performance of the unit
- Depends upon size, temperature and components in the window
- Component properties include;
- Conductivity
- Emissivity

## Solar Heat Gain Coefficient

- The rate of heat transfer through a window product depending upon both directly transmitted solar gain and absorbed solar gain.
- The lower the SHGC, the lower the heat gain through a window.
- (SHGC is a ratio based on 0 to 1)
- Depends upon size, temperature and components in the window
- Component properties include:
- Emissivity
- Transmittance

## Visible Transmittance

- The amount of visible light transmitted through the window unit.
- Depends upon unit size, glass-to-frame ratio and transmittance of the glass.
- Important for determining the potential for daylighting.

## NFRC Standards

- NFRC 100 – U-factor
- NFRC 200 – SHGC
- NFRC 300 - Optical Properties
- NFRC 400 – Air Leakage
- NFRC 500 – Condensation Resistance

## What Codes/Program Say

- IECC Requirements: (fenestration)
- U-factor and SHGC shall be determined in accordance with NFRC 100 or 200 by an independent accredited laboratory (or through use of limited default tables)
-  -	products must be labeled and certified
- US DOE/EPA ENERGY STAR WINDOWS
- - Requires NFRC _Certified_ Products

## Changes to NFRC Standards2001

- Why did we change?
- New algorithms (latest technology and updated to ISO)
- Industry finally agreed upon one rating size (in unison with North American Standards)
- Addresses  a multitude of products in one document (not only windows, but TDD’s, garage doors, site-built products, etc.)

## Changes to NFRC Standards

- Biggest change = the rated size (both 100/200):
- 	Go from two sizes (residential and nonresidential to _One Size_
- For example: (*1997 standards*) =
- 			Casement Window
- Residential = 24” x 48” (610 mm x 1219 mm)
- Nonresidential = 36” x 60” (762 mm x 1524 mm)
**	****	****	**_**New **__NFRC size __*(2001 Standard)*__ =_
- 			_600 mm x 1500 mm_

## Changes to NFRC Standards

- What does this mean to you?
- U-factor and SHGC ratings may change for individual products
- It is the most up-to-date and accurate ratings available
- New NFRC Label will show only ONE rating (less confusion in the marketplace)

## Changes to NFRC Standards

- What does this mean to you?
- Watch the NFRC website for up-to-date information (_[www.nfrc.org](http://www.nfrc.org/)__) _
- Note when the new ratings become effective
- Review the impact on your local energy codes

## For additional help

- NFRC Silver Spring office:
- 301-589-1776
- Jim Benney
- Kansas Office
- 785-862-1890
- jbenneynfrc@aol.com