Window Shade Study Shows Positive Results

(This is from Robb Aldrich of Steven Winter Associates.)


It’s no secret that windows are a liability when it comes to heat loss in homes. Conductance of quality insulated, low-e windows is typically 0.30-0.35 Btu/ft2hr°F, or about R-3. If installed in a wall that performs at R-20, heat lost through windows is 6-7 times higher (per unit area) than heat loss through the rest of the wall. Various window treatments have been used for years to reduce this loss
and make homes more comfortable. Working through the DOE Building America Program with partner Comfortex Window Fashions, SWA performed a simple study measuring how much window treatments can reduce heat loss.


SWA and Comfortex installed double-honeycomb shades in four windows in a relatively new Connecticut home. Two of the shades were equipped with “ComforTrak Plus™” – a system that includes side-tracks and a simple gasket to reduce air movement around the shade (see image). The two other shades did not have any side tracks.


SWA installed several temperature sensors behind each shade, in the rooms, and outdoors; temperatures were recorded for 3 weeks during February and March. Based on these temperature
measurements, SWA calculated approximate, effective R-values for the shades. When shades were installed without side tracks, the shades seemed to add R-1.2 to R-1.5 ft2hr°F/Btu to the window assemblies. When side-tracks were installed, effective R-values were typically between R-4 and
R-5. It’s clear that limiting air movement around the shade assembly has a dramatic effect on heat transfer. Infrared images corroborate this.


In the image below, taken from inside the house when both window shades were closed, the window shade on the left has side tracks; the shade on the right does not. The warmer temperatures behind the shade without tracks – along with the cold edges near the bottom – are a result of much more warm air moving in behind the shade and cold air moving back into the room near the bottom.



While the numbers generated from this simple study are approximate, it’s clear that insulating window treatments can make a big difference in cutting heat loss through windows. Systems like the ComforTrak Plus tested here – which limit air movement through the shade – can reduce heat loss even more.




Views: 213

Tags: Home and Garden, Window blind, Windows

Comment

You need to be a member of Home Energy Pros to add comments!

Join Home Energy Pros

Videos

  • Add Videos
  • View All

Twitter

Latest Activity

Luis Imery added a discussion to the group Job Board
Thumbnail

Hiring: Construction Manager with High Performance Custom Home Experience

POSITION DESCRIPTIONJob Title: Construction ManagerDepartment: Construction –…See More
13 hours ago
Profile IconLuis Imery and Quinn Korzeniecki joined Diane Chojnowski's group
Thumbnail

Job Board

This group is for posting jobs related to all aspects of the home performance industry including…See More
13 hours ago
Colin Genge posted an event

Retrotec is attending the NEBB Testing and Balancing (Tab) Certified Professional Review Seminar in Chicago, IL at Hilton Chicago O’Hare Airport

June 6, 2016 at 8am to June 8, 2016 at 5pm
Building owners and tenants are concerned that the environmental performance of buildings must be…See More
17 hours ago
Colin Genge updated an event
Thumbnail

Retrotec is exhibiting at the NFPA Conference & Expo-Booth 1355 at Mandalay Bay Convention Center

June 13, 2016 at 8am to June 16, 2016 at 5pm
NFPA's Conference & Expo is widely regarded as the most comprehensive industry event for…See More
17 hours ago
Tom White posted a video

Hayward Healthy Home Principles and Products

Bill Hayward discusses the principles that were used to build the first Hayward Healthy Home and how the products were evaluated for toxicity before they wer...
18 hours ago
Tom White's video was featured

Building Science Insights -- To Vent or Not to Vent

Building Science Presentation with Dr. Joseph Lstiburek.
19 hours ago
Quinn Korzeniecki added a discussion to the group Job Board
19 hours ago
Profile IconIan Smith, Brett Slezak, Autumn Secrest and 6 more joined Home Energy Pros
20 hours ago

© 2016   Created by Lawrence Berkeley National Laboratory.   Powered by

Badges  |  Report an Issue  |  Terms of Service