I have 8 skylights in my house–2 in MBR, 4 in sunroom, and 2 in “Gathering Room.” Ceilings are sloped, approximately parallel to the roof pitch in each room, approximately 16″ below the roof. The skylights are sources of heat gain in summer and probably heat loss in the winter. I’m contemplating installing a single or double pane of clear glass at ceiling level in each of the skylight recesses to reduce energy loss/heat gain.
I would appreciate comments on the expected value of such an effort in terms of energy gain or loss. That is, would it be worth the effort?
Replies
To get an accurate "R" value we need to know what the "R" value of your current skylights.
Are they single pane, double, old fashioned bubbles et al.
The 16" gap in between the skylight & the ceiling glass can have a miosture & fogging problem.
“The world is a dangerous place, not because of those who do evil, but because of those who look on and do nothing.” —Albert Einstein
Good question. I think I have double pane because I can see condensation on the glass in a couple of them. I interpret that to mean that the seal has been compromised. I don't know the R value either.
Thanks for your reply.
I think I have double pane because I can see condensation on the glass in a couple of them. I interpret that to mean that the seal has been compromised.
If the condensation is between the layers of glass, then the seal is compromised.
Double-glazed units are less likely to experience condensation on the inside, but roof windows are often more likely to get condensation than sidewall windows, particularly in bathrooms.
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
Yes, there is a significant energy cost (both in terms of winter loss and summer gain) of roof windows.
You don't mention how many layers of glazing in the skylights currently, but a doubling of the layers will half the heat loss and gain.
If you don't need them for light or ventilation, I'd consider removing some.
Solar & Super-Insulated Healthy Homes
I cant speak to the energy savings, but I did something similar to solve condensation issues I had on my two kitchen skylights. These are active skylights, so I take the "storms" off in early spring. It must help with heat loss since the warm air isn't getting up into the well anymore, I just can't quantify it for you. I made the frame from azek, got the plexiglass cut to size at the local lumber yard. I attached a frame of brick molding to the inside wall of the well and screw the storm to it. Weatherstripping between the frame and brick molding gives it a good seal.
Here's a pic before final painting and trim.
Looks real good. A+ job. I like skylights. They can totally change a room if they are donw right.
I am a bit curios about this posting as well because we plan on having a few skylights on our new house. What should we be looking at? is there some specific brand or type of skylight we should be asking for?
velux with blinds if sloped ceiling & buy proper velux flashing kit, i have 7 installed in muy place
mine are opening style & work fine with no leaks installed on a metal roof 1873 home
they are not cheap but i tried the cheap ones and they all leaked or had bad codensation problems , i learned the hard way ( ; >
I concure with DUDE that Velux would be the preferred skylight. Mine are a step up from the "bubble" windows. They are fixed (can't be opened) and we have had to add permanent cloth shades in the wells I described to in order to block the sunlight and its "bleaching" effect of sunlight on furniture, floors, etc. With Velux one can purchase windows that open with remote control, change from clear to "blocked" by an electrical charge, or with remote control blinds or shades.
That sounds awesome. There are just some things that will go in my house even if they are expensive :-)
Thank you for your reply and the picture. You've done what I had in mind to do. I hadn't considered plexiglass.
Dreamer,
Don't use glass for a near-horizontal application like this unless it is laminated or extremely thick. Both are expensive.
Use polycarbonate. Unlike plexiglas, it doesn't yellow. You can easily use 1/8" here.
Ron
Just to clarify, I used the term plexiglas in a generic way. It could have been polycarbonate as someone else suggested, I can't remember for sure. After all, it's been a whole year and I can't remember what I had for breakfast yesterday!
I did that with my skylights too. Mine are single pane glass in copper frames. The inside window I made from a wood frame with clear plastic. The kind you can buy at HD for cheep and is shrunk with a hair dryer. It's all but invisible. I didn't try and make the wood frames fancy, I just wanted it to look like I only had the old copper skylight.