should I replace my windows?

My house was built in 1996 and has unglazed double-paned windows with aluminum frames. We heat our 2300 ft2, 2-story house with a woodstove and really try to avoid using our gas furnace. So, some of the rooms in our house get really cold, due to the woodstove heat not being able to get to those rooms. Another issue is that the majority of our windows are on the north and east sides of the house. sigh.

We've received some insurance money to replace a few of the windows (hail damage), and now we are considering replacing all of them with energy-efficient vinyl windows, hoping those would help keep the house warm. But, it's such a significant cost. Does anyone know how much of a difference newer energy efficient windows would make, since I already have double-paned windows? Thanks!

I don't have an answer for you on the windows, but I use to live in a house heated by only a woodstove that also had the problem of some of the rooms bring too frigid. We installed a computer fan in the upper corner of living room doorway (the woodstove was in the living room) that led to the hallway and bedrooms. We placed a second on the hallway ceiling and directed it towards the dining room/kitchen. They were enough to move the hot air from the ceiling into the colder rooms. Perhaps not a perfect solution, but they were cheap, inexpensive to run, and very quiet to run.

New windows are so expensive. If you can't afford them, I suggest making insulated covers for the windows in the cold rooms. We do this in our bedroom every winter. Bubble wrap is easy to put up on the windows, and lasts multiple seasons. Other insulated covers can be used, but bubble wrap has the advantage of admitting light.

In terms of bang for your eco-buck, new windows seem to have a rather poor return because they have a high level of conspicuous conservation. In other words, they look nice and you can show them off to your friends when they come over. Check out the less noticible improvements (mastic on ducts, attic insulation, looking for drafts/air leaks) before spending the big bucks on windows.

One suggestion would be to run your gas furnace's blower to help equalize the temperature differences in the various parts of your house.

A very cheap double pane window, with a "bad" aluminum frame will perform at about r-1.23. A really good double pane with insulated vinyl frame will be r-2.94, or 2.4 times better insulation. That would cut your heat loss through the windows by 2/3.

This site lists typical insulation values for various kinds of windows. Note that they list u-values, not r-values. The u-value is just the inverse of the r-value, and vice versa. To conver, it's just 1/u = r

If the u-value is .46, the r-value is 1/0.46 = 2.17

https://www.energyguide.com/info/window2.asp (this link stopped working, here is another)

http://www.allweatherwindows.com/the-pros/architect/glass-performance-chart/



A "bad" aluminum frame means no insulation between the inner aluminum frame and the outside part of the aluminum frame. The aluminum goes all the way continuously from the inside to the outside. There's probably a manufacturers name on the window somewhere, and you can email them or find the product specs online. A "good" aluminum frame has insulation in the middle, so the highly thermally conductive aluminum doesn't suck the heat out of your house and send it to the great outdoors. They refer to the good kind as, thermally broken.


Cutting your heat loss by 2/3 is meaningful. But r-3 is still terrible. You could add a 1" rigid styrofoam insulating panel and jack it up to r-6 or r-7, which is better than the thousand dollar, best of the best, replacement window.

Adding a layer of bubble wrap adds about r 1.5 and you still get light through it. Just cut to size, spritz a little water (with a tiny bit of soap) on the glass and it will cling nicely with no fasteners. This guy does a nice how to video:

https://www.youtube.com/watch?v=JqD5fdEj8t8

You might scrounge enough bubble wrap to do it for free. The big 1/2" bubble wrap is more effective than the cheapo small bubble wrap.

If you want to do a whole house, it's not that expensive to buy new from ebay. Here's one example:

http://www.ebay.com/itm/Large-Bubble-Wrap-1-2-x-125-ft-x-24-Inch-Bubble-Wrap-Large-Bubbles-Perforated-/290603620210?hash=item43a9535772:g:dL8AAOxyMxpRqL7q


The general consensus is to put the bubbles toward the window and the flat sheet toward the room.

The market has turned to vinyl but I'm not convinced of the longterm durability of them. Especially where they get full sun. With aluminum you have relative confidence it will last your lifetime.

Past that I agree the payoff will be nonexistent. I would make sure there are no drafts between the window and wall. If there is, fix that, and call it a day.

Tyler Ludens wrote:New windows are so expensive. If you can't afford them, I suggest making insulated covers for the windows in the cold rooms. We do this in our bedroom every winter. Bubble wrap is easy to put up on the windows, and lasts multiple seasons. Other insulated covers can be used, but bubble wrap has the advantage of admitting light.

Yep. Drafts are also a huge problem. We took an incense stick around to all wall outlets including interior walls and wherever we saw the smoke moving in any direction but straight up we removed the box and installed installation into the cavity. But the biggest draft areas were around the windows which were very old wooden frames. The windows (not the glass) were loose and rattled so we found some 1/4" wide moulding with a 1/4" felt type backing. We tacked this to the side frame up against the window so that it no longer rattled. The draft was gone and the windows didn't rattle. A coat of paint on the wood bit of the insulation strip and you couldn't even see them. There's a lot of different product available to you have to figure out exactly what the problem is and find the product to match. We notice a huge difference in temperature once the house was properly sealed.

I understand about the cost of new windows etc. Hence some suggestions. (1) Try covering the windows with bubble wrap (just cut to size of windows, use a spray bottle with some water and spray the windows and place the bubble wrap over the moistened window. It will add about 2 more R value to the window. The only thing you may not like is that you can't see out the window but light gets through easily etc. (2) Another option is to form a 'third' window by stapling up some plastic. You are basically creating 'dead air space' in addition to the double glass.(again, it may not be esthetically pleasing but it will add to heat retention of the house. (3) A third option is heavy curtains. (Will look pretty)... Again, saving on heat being transferred through the windows.

Thanks folks. I actually have been doing the blow-dry plastic coverings for a few years now. Not only did that provide insulation, it also revealed that several windows were leaking air; the plastic would bow outward. So I sealed all the leaks. However, the cold still persists.

But, I totally did not think of bubble wrap, and I have a ton of it!

Troy Rhodes wrote:A very cheap double pane window, with a "bad" aluminum frame will perform at about r-1.23. A really good double pane with insulated vinyl frame will be r-2.94, or 2.4 times better insulation. That would cut your heat loss through the windows by 2/3.

This site lists typical insulation values for various kinds of windows. Note that they list u-values, not r-values. The u-value is just the inverse of the r-value, and vice versa. To conver, it's just 1/u = r

If the u-value is .46, the r-value is 1/0.46 = 2.17

https://www.energyguide.com/info/window2.asp (this link stopped working, here is another)

http://www.allweatherwindows.com/the-pros/architect/glass-performance-chart/



A "bad" aluminum frame means no insulation between the inner aluminum frame and the outside part of the aluminum frame. The aluminum goes all the way continuously from the inside to the outside. There's probably a manufacturers name on the window somewhere, and you can email them or find the product specs online. A "good" aluminum frame has insulation in the middle, so the highly thermally conductive aluminum doesn't suck the heat out of your house and send it to the great outdoors. They refer to the good kind as, thermally broken.


Cutting your heat loss by 2/3 is meaningful. But r-3 is still terrible. You could add a 1" rigid styrofoam insulating panel and jack it up to r-6 or r-7, which is better than the thousand dollar, best of the best, replacement window.

Adding a layer of bubble wrap adds about r 1.5 and you still get light through it. Just cut to size, spritz a little water (with a tiny bit of soap) on the glass and it will cling nicely with no fasteners. This guy does a nice how to video:

https://www.youtube.com/watch?v=JqD5fdEj8t8

You might scrounge enough bubble wrap to do it for free. The big 1/2" bubble wrap is more effective than the cheapo small bubble wrap.

If you want to do a whole house, it's not that expensive to buy new from ebay. Here's one example:

http://www.ebay.com/itm/Large-Bubble-Wrap-1-2-x-125-ft-x-24-Inch-Bubble-Wrap-Large-Bubbles-Perforated-/290603620210?hash=item43a9535772:g:dL8AAOxyMxpRqL7q


The general consensus is to put the bubbles toward the window and the flat sheet toward the room.

Thanks for all this info. My windows currently have frost on the inside of the aluminum frame, so I'm assuming they are of the "bad" variety? I've already repaired the drywall a few times due to condensation issues. I like the bubble wrap idea for some of our windows, particularly since according to your stats it would double the r-value.

Since you seem to know a lot about windows, do you know whether I should bother with argon? I hear conflicting opinions on this. I know that I'll lose 1/4 of it due to my elevation (if the argon was filled at sea level), and that some will leak out over time. I've also heard from other sources that it is still beneficial, and doesn't leak out as much as people claim. I do have to replace some of my windows because I had to file a homeowners insurance claim.
Thanks!

If you put bubble wrap against the pane, and plastic over that, on the frame/wall, you'd trap even more of an airspace. Then have insulated drapes for night time, and you should be experiencing significant extra warmth.

John Wolfram wrote:In terms of bang for your eco-buck, new windows seem to have a rather poor return because they have a high level of conspicuous conservation. In other words, they look nice and you can show them off to your friends when they come over. Check out the less noticible improvements (mastic on ducts, attic insulation, looking for drafts/air leaks) before spending the big bucks on windows.

One suggestion would be to run your gas furnace's blower to help equalize the temperature differences in the various parts of your house.

somewhat off topic, but I found the conspicuous conservation concept somewhat funny, as I drive a 23 year old car with dents all over it that gets 45 mpg. Since I do all highway driving, I believe that isn't too far below a Prius. Can we call that inconspicuous conservation?

I see what you mean, and yes, windows are a last resort.

I was thinking about easier ways to apply plastic to the windows and thought of screen kits. Turns out someone has already done as much:

Add flexibility to plastic windows kits

My house has aluminum storm windows and 100 year old single pan windows, yet we still hear the panes shake in their frames when the wind blows hard enough.
I think I will re- putty the glass, and try that removable caulk I have seen sold as a sealant between the frame and the sash.

A interior storm window made of pink foam insulation board would be nice. It could have cut outs for light, covered in clear vinyl on both sides.
The problem with these is storage- where fo they go the rest of the year?

Argon...or not argon.

By the straight up math, the high end argon filled windows will probably pay back after 10 years, or not, depending on how expensive energy gets and what you use to heat your house.

But it will make the room more comfortable, so that's worth something.

The newer argon filled window reportedly do hold the argon better over time than some of the older units.

If you keep the literature, you might make the money back on resale, that these are not cheapo windows. People often look for that now.

I would. We did and it made a very noticeable difference.

If I had an old house with inefficient windows, I would keep the ones on the south side and get or make window quilts that add much more r-value than new windows. I made the mistake of getting the low e windows in my house and it is blocking out too much sun in the winter. For the others, I would use old fashioned storm windows (sealed well), either inside or out. The double paned ones lose their seal too often and have to be fixed or replaced. I would probably keep these up all year, unless I need to open the windows for cross ventilation in the summer.

This idea looked really promising:

I did an article for Mother Earth News on interior storm windows. They make a big difference (100% better performance plus sealing maybe $5/window)for a little money and if done right you can barely see them. Vinyl in general is not a good product.