Patent ID: 7851034

Claim:
A window unit, comprising: at least first, second, third and fourth substantially parallel spaced-apart glass substrates arranged in this order so as to form a center gap between the second and third, or two inner, substrates and first and second outer gaps respectively between each of the two inner substrates and the two outer substrates; one or more spacer elements provided to maintain the first, second, third and fourth substrates in substantially parallel-apart relation to one another; a sealant provided proximate a periphery of the window unit so as to at least partially seal the window unit, wherein the center gap between the two inner substrates is provided at an inner gap pressure, the inner gap pressure being a pressure less than atmospheric pressure, wherein the first and second outer gaps are provided at pressure(s) greater than the inner gap pressure, wherein the window unit has an R-value of at least about 11 measured at a center thereof, and wherein the sealant extends between the first and fourth glass substrates so that the second and third glass substrates are interior of the sealant.