Okay, So I guess it’s about time to tackle the whole window issue. Windows are almost always the first thing people try to sell you when you are looking to cut energy costs. They tell you it’s the best investment you can make and it will pay for itself in no time. Hmmm… pay for itself… that’s a pretty steep claim … are they right? Probably, if you aren’t in a hurry to see your money back.
Windows … are a major expense. They just plain cost a lot. Especially good ones. So, how do you decide? Let’s take a look (you look, I’ll talk) at what you have now. You can get them as tight as possible first, and then decide if they still need to be changed. First, do they have sash weights? You’ll see either chains or ropes going over a pulley at the top of the window frames.
If they do, there is an uninsulated space about 2 inches wide on either side of the window. A cast iron counterweight rides up and down that space when you open and shut the window. This space can’t be insulated, However… you can air seal it a bit. Make sure there are no gaps or spaces between the inside window trim and the walls. If you stop the air flow, you’ll stop most of the heat loss.
Next, are they single pane windows? Single pane windows can function reasonably well as long as the have decent storm windows on the outside. If they don’t … you probably should consider new windows. Do they seal pretty well? Ignore the cold air from the glass itself and feel for drafts around all the edges of the sashes. If your storm windows are closed well and you still feel drafts … maybe windows should be on your short list.
Speaking of storm windows … Number one mistake people make is they caulk up the weep holes at the bottom of the frames. Those little holes or slots are there to let the condensation that accumulates on the glass drip out. If you seal them up your windows will rot out.
On double hungs, check the weatherstripping between the sashes. Is it still functioning? Do casements close evenly from top to bottom? These are signs that the windows are on their way out. Remember, your biggest concern is drafts. If you have already have double pane windows,even lousy ones, new ones should be down toward the bottom of the list. Sure, new ones will be better, but the amount you save will take a long time to make back.
NOW DON’T GET ME WRONG! If you have the cash, absolutely get new windows … sooner or later you’ll save enough in fuel to pay for them. But, if you only have a certain amount to spend, you can probably get better “bang for your buck” in other places. But hey …If nothing else … new windows are just nicer and they do add to the value of your home.
Sure, compared to the walls of the house, windows are a real energy waste. While your walls may be R-11 even really good windows are only R-3 or 4. Yes, they do lose a lot of heat… but… usually a lot more is lost through leakage than through conduction.
SO …. My point … (yes, I do have one …by now, most of you were starting to wonder) … is this… FIRST, put your money into air sealing. SECOND, put some money into insulation. THIRD, tackle the windows and doors and things like that. And FORTH, if you still have any money left … or your rich uncle dies and leaves you a big pile of it …go for a high tech heating and hot water system.
Now, assuming you ignore me completely and go buy new windows … what should you look for? When you compare them, you’ll see two numbers, one is a “u-value” the other is “solar heat gain coefficient”. U-value is the insulation value of the window. It is equal to 1/r-value. (I had to throw in at least a little math). To put it in perspective, a window with a U-value of .25 would have an r-value of 4. They typically have U-values of around .3 to .4 meaning r-values around 2 or 3. Not so good compared to walls. WIth U-VALUE … LOWER IS BETTER.
Solar heat gain is how much heat from the sun gets through. Depending on what climate you are in and which direction the window faces, you may have different needs for this number. Before you buy windows, do your homework and find out what is typical for your area.
AND NOW …. LASTLY … ( you can’t wait for it to end, can you? ) … Blinds and curtains. Most of the heat lost through the glass is caused by convection. The cooled air drops down and is replaced from the top with warm room air … which cools and drops … and … again. Anything in front of the glass… like curtains, blinds, shades, etc. will slow down this movement and cut down on heat loss. Consider closing them at night to keep some more of the heat in. Anyone remember those heavy old thermal curtains your grandma used to put up in the winter? Well, they worked. Dark as night inside …. but warm … And warm is good …