The only question is what is the energy efficiency of the window now that you have holes in them?
How does it work if you have triple panes with the sheet of plastic up the center?
Good question.
With a 3 pane window, it may be necessary to do the same thing on the outside of the window. I've seen some of the service franchises doing their (e.g. Window Medics, defogit.com, etc.) process on both the inside
OR outside. For a 3 pane window with fog on both sides of the center pane, it may be necessary to do the same thing on both the inside
AND outside.
First of all, most windows only have an R-value of 2-to-4.
Expensive windows are only slightly better.
Compare those R-Values to that of a brick wall of about R-12.
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Table 1. Clear-Wall and Whole-Wall R-Values for Tested Wall Systems
#, System Description, Clear Wall R-Value (Rcw), Whole Wall R-Value (Rww), (Rww/Rcw) x 100%
1. 12-in two-core insulating units concrete 120lb/ft3, EPS inserts 1 7/8-in thick, grout fillings 24 in o.c.
, R=3.7, 3.6
, 97%
2. 12-in two-core insulating units wood concrete 40lb/ft3, EPS inserts 1 7/8-in thick, grout fillings 24 in o.c.
, R=9.4, 8.6
, 92%
3. 12-in cut-web insulating units concrete 120lb/ft3, EPS inserts 2 1/2 in thick, grout fillings 16 in o.c.
, R=4.7, 4.1
, 88%
4. 12-in cut-web insulating units wood concrete 40lb/ft3, EPS inserts 2 1/2 in thick, grout fillings 16 in o.c.
, R=10.7, 9.2
, 86%
5. 12-in multicore insulating units polystyrene beads concrete 30lb/ft3, EPS inserts in all cores
, R=19.2, 14.7
, 77%
6. EPS block forms poured in place with concrete, block walls 1 7/8 in thick
, R=15.2, 15.7
, 103%
7. 2 x 4 wood stud wall 16 in o.c., R-11 batts, 1/2-in plywood exterior, 1/2-in gypsum board interior
, R=10.6, 9.6
, 91%
8. 2 x 4 wood stud wall 24 in o.c., R-11 batts, 1/2-in plywood exterior, 1/2-in gypsum board interior
, R=10.8, 9.9
, 91%
9. 2 x 6 wood stud wall 24 in o.c., R-19 batts, 1/2-in plywood exterior, 1/2-in gypsum board interior
, R=16.4, 13.7
, 84%
10. Larsen truss walls 2 x 4 wood stud wall 16 in o.c., R-11 batts + 8-in-thick Larsen trusses insulated by 8-in-thick batts, 1/2-in plywood exterior, 1/2-in gypsum board interior
, R=40.4, 38.5
, 95%
11. Stressed-skin panel wall, 6-in-thick foam core + 1/2-in oriented strand board (OSB) boards, 1/2-in plywood exterior, 1/2-in gypsum board interior
, R=24.7, 21.6
, 88%
12. 4-in metal stud wall 24 in o.c., R-11 batts, 1/2-in plywood exterior + 1-in EPS sheathing + 1/2-in wood siding, 1/2-in gypsum board interior. NAHB Energy Conservation House Details
, R=14.8, 10.9
, 74%
13. 3 1/2-in metal stud wall 16 in o.c., R-11 batts, 1/2-in plywood exterior + 1/2-in wood siding, 1/2-in gypsum board interior
, R=7.4, 6.1
, 83%
14. 3 1/2-in metal stud wall 16 in o.c., R-11 batts, 1/2-in plywood exterior + 1/2-in EPS sheathing + 1/2-in wood siding, 1/2-in gypsum board interior. AISI Manual details
, R=9.9, 8.0
, 81%
15. 3 1/2-in metal stud wall 16 in o.c., R-11 batts, 1/2-in plywood exterior + 1-in EPS sheathing + 1/2-in wood siding, 1/2-in gypsum board interior. AISI Manual details
, R=11.8, 9.5
, 81%
16. 3 1/2-in metal stud wall 24 in o.c., R-11 batts, 1/2-in plywood exterior + 1/2-in wood siding, 1/2-in gypsum board interior. AISI Manual details
, R=9.4, 7.1
, 75%
17. 3 1/2-in metal stud wall 24 in o.c., R-11 batts, 1/2-in plywood exterior + 1/2-in EPS sheathing + 1/2-in wood siding, 1/2-in gypsum board interior. AISI Manual details
, R=11.8, 8.9
, 76%
18. 3 1/2-in metal stud wall 24 in o.c., R-11 batts, 1/2-in plywood exterior + 1-in EPS sheathing + 1/2-in wood siding, 1/2-in gypsum board interior. AISI Manual details
, R=13.3, 10.2
, 77%
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Windows with fog and water drops inside (moisture) have a slightyly reduced R-Value (than the same window with a dry airspace).
The holes are small (about 1/8 inch), and a one-way valve at the top, and a two-way valve at the bottom should restrict significant air-flow, but allow moisture to escape at the top of the window.
The R-Value (insulating quality) of the dry window (even with two small 1/8" holes (in upper-left and lower-right) covered with the one-way and two-way valves) may have a better (or equal) R-Value of a window full of fog and water drops.
The fact is, the R-Value of a fogged window is not too terribly less than an unfogged window (of the same quality).
The real problem is more of a cosmetic nature, and repairing the windows is preferrable to the cost of replacing 17 windows (with 34 separate window panes) if the R-Value of the window has not been significantly altered by the two holes.
I'll know in a few days if the one-way valves work. I also plan to try a simple bead of clear silicone caulk at the top hole, with a few pin holes in the caulk. That may be enough to allow moisture to escape, while being much less conspicuous than a small one-way valve (which came from a degassing coffee bag; see below).