Storm Windows – are they effective?
davegmc
| Posted in Energy, Heating & Insulation on
I wondering what your experience with Storms is. We have an old Bungalow and we really want to keep the old wood sash double-hungs because they give the house so much character. But I can’t afford the oil. Have any of you found wooden home-built storms effective? I’ve read some material that seems to indicate they don’t do much good.
Dave
Replies
They do a lot of good.
It all depends how much they control infiltration. A windy cold day with ANY leaky window is a miserable one.
Adding interior storms and insulative curtains helps too.
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Yes I agree reducing infiltration is a big benefit. I wonder what the HVAC engineers would say about the thermal performance of wooden storms with 1/8 glass? Are they effective at reducing conduction heat losses?
You get so much conduction thru the glass that I don't see the various kinds as being all that different on that issue. If you were comparing to AL frame only with no storm, that woiuld be noticeable tho.I guess what you are getting at is that the wood frame is less of a conductor than AL for the storm potion...
I suppose it is better in that res[pect, but a wood storm will not genrally have as tight of a seal at the jamb edge for resisting the infiltration is my point. Six of one, half dozen of the other....You'll have to catch a window guy for studies to show it all on paper
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wood storm will not genrally have as tight of a seal
Learned when a little kid that that is what old newspapers are for. Applied right, just about like caulking the storm window in place.
Mom' house does have some of the storm siliconed in place.
They can be effective, if they achieve a tight seal. It's generally possible to make a storm seal quite a bit tighter than a weight-balanced double-hung. Even if not sealed tightly they do some good, but not as much. (Of course, you don't want them TOO tight. They need to allow any rain or condensation between the panes to escape, and some air exchange with the outside air is good to reduce condensation problems.)
Of course, they won't keep wind from blowing through the siding, etc.
Dave,
Here are some coefficients of transmission (U) of a few windows from ASHRAE:
Single glass: 1.13
Insulating glass with a 1/4 inch air space: 0.65
Window with storm window and a 1 to 4 inch air space: 0.56
If you want to know the R value of these windows, R=1/U. My experience is that storm windows make a big difference in the heat lost through a window. Wood storm windows require some maintainence whereas aluminum storm windows are maintainence free.
Chris
As a general guideline, the center-of-glass temperature of a single pane of glass (1/16" vs 1/8" makes no difference), is about 16 degrees when the external temp is 0 and the internal temp is 70 degrees. This does not take into account wind or solar gain - it is a base temperature comparison.
Add a storm window and the internal temp of the center-of-glass jumps to about 43 degrees - a significant improvement.
The edges of the glass will be cooler than the center - in some circumstances significantly cooler. Using wood for windows / storms will result in warmer edge temperatures than will using aluminum framing materials. Vinyl is comparable to wood for energy performance.
You might consider cellular blinds. They won't cut infiltration, but if they are properly sized they cut heat loss substantially.
We bought ours from JC Penneys. If you do this, go for the "top down, bottom up" feature. It is really nice. Penneys has these things on sale regularly for less than half the normal retail price.
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I have a house built in 1890. I have architecturally significant windows that I did not want to replace. I decided to add traditional wood storms. We installed them in the fall and they make a big difference because they eliminate infiltration through the old windows. When I installed my storms I put foam around the edges. When I pull the bottom of the storms tight the foam compressed and forms a tight seal. I used open cell foam at the bottom of the window to let out any moisture.
I got my storms from Adams Architectural (http://www.adamsarch.com). They make old fashioned wood storms that have screening on the outside and glass inserts that are installed from the inside. They are nice because because they can be installed once and left. On the windows that need to be opened in the Summer you simply remove the glass insert from inside the house.
IIRC the windows cost about $200-$300 each.