Fort Wayne Project
Glass product that brings year-round savings.
That’s something worth studying.
- Wood frame windows
- 4.0 ton A/C unit in clear double-pane window houses
- 4.0 ton A/C unit in high solar gain low-e houses
- 3.0 ton A/C unit in LoĒ² houses
Following the tests, the results from the houses using LoĒ² were as follows:
- $600 A/C equipment savings
- Heating and cooling energy savings vs. both clear and high solar gain low-e
- Improved comfort over both
Energy savings and comfort
The bottom line:
Measured temperatures support the comfort message
Throughout this 24-hour period, the heating energy consumption for the two glass types was nearly equal but not the comfort level inside the house.
At night, the clear glass starts out at 12°F colder than LoĒ². In order to match the comfort of LoĒ², the thermostat in this house should have been raised by 2°F.
During the day, the high solar gain that comes through the clear glass heats the room and the glass surface. The clear glass house sees a 40°F fluctuation in roomside glass temperature (cold at night and hot during the day). Discomfort concerns will prompt the homeowner to intervene, e.g. closing the blinds, opening the window to vent heat, and certainly challenges the notion that passive gains are “free heat”.