dual pane energy efficiency
#1
08-10-05, 05:10 PM
dual pane energy efficiency
Hi,
I would like to know how much energy is saved by using dual pane windows.
A few of our dual pane windows have condensation between them. So, I was wondering how much energy we are losing because of this.
Also wanted to know, if we can just change the dual panes without repalcing the whole window frame because our windows are slightly odd sized.
Thanks
Anindita
I would like to know how much energy is saved by using dual pane windows.
A few of our dual pane windows have condensation between them. So, I was wondering how much energy we are losing because of this.
Also wanted to know, if we can just change the dual panes without repalcing the whole window frame because our windows are slightly odd sized.
Thanks
Anindita
#2
08-10-05, 05:48 PM
Group Moderator
That's a hard question to answer. Well, not so hard to answer, but hard to put it in a way that makes any sense. A IGU with a failed seal will not be as efficient as one that is still sealed. How much of a difference that is, I really don't know. When they go bad, most people replace them because they are sick of seeing the condensation between the glass. But as far as energy efficiency goes, one could compare single pane glass with a sealed IGU, and reasonably conclude that a failed IGU is not much better than 2 pieces of single pane glass put back to back.
Since heating is usually the biggest concern, one has to consider how the glass performs in the winter, when it is the coldest. These values represent that:
If the U-value of a single pane of clear 3/32 glass is 1.3, it has a net heat loss of -21,429 kBtu.
If the U-value of an IGU (two pieces of clear 3/32 glass) is .89, it has a net heat loss of -13,700 kBtu.
Since the seal on the IGU has failed, the U-value would not be the same as it was originally. Hypothetically, let's say it's efficiency has gotten worse, and it's u-value is now somewhere inbetween .89 and 1.3. it's net heat loss would be somewhere around -17,000 kBtu.
What that translates to in dollars and cents is beyond me.
At any rate, IGU's can almost always be replaced without having to replace the entire window. Glass companies are usually the ones to call for having new pieces ordered and installed.
Since heating is usually the biggest concern, one has to consider how the glass performs in the winter, when it is the coldest. These values represent that:
If the U-value of a single pane of clear 3/32 glass is 1.3, it has a net heat loss of -21,429 kBtu.
If the U-value of an IGU (two pieces of clear 3/32 glass) is .89, it has a net heat loss of -13,700 kBtu.
Since the seal on the IGU has failed, the U-value would not be the same as it was originally. Hypothetically, let's say it's efficiency has gotten worse, and it's u-value is now somewhere inbetween .89 and 1.3. it's net heat loss would be somewhere around -17,000 kBtu.
What that translates to in dollars and cents is beyond me.
At any rate, IGU's can almost always be replaced without having to replace the entire window. Glass companies are usually the ones to call for having new pieces ordered and installed.
#3
08-10-05, 07:40 PM
Member
pane energy efficiency
I don't know the details of the energy loss, but I know a good window will work better than a foggy one and same me some money. I like to see the birds and deer so that is why I am in the process of replacing a bad one.
I just got a quote today. One more to come tomorrow, but it should be cheaper by all indications. My quote today for a 33" x 75" tempered dual pane (1") patio glass installed was $395. They will come out, remove the slider, put it on a work bench, remove the old glass, replace with the new glass, clean the track, adjust and lubricate the wheels, reinstall and adjust the locking mechanism. They said they need two days notice.
I also have another sliding window that is cracked. It is 27" x 43". To replace this at the same time would be $175. To do it separately, the price would be $264.
I am in a townhouse so replacing the entire door to comply with the architectural standards seems a lot more expensive ($1200 for the whole door at HD plus installation). If I had a newer "standard" size door (smaller) it would be cheaper, but I don't know about the quality. All I know is that my 25 year old pation doors are heavy.
I don't know if this is a good price, but it seems reasonable. Tomorrow I will learn more. I still have 5 more yellow pages to go through if I really wanted to be cheap, but it doesn't seem worthwhile to do that. This is just some information to put things in perspective.
Dick
I just got a quote today. One more to come tomorrow, but it should be cheaper by all indications. My quote today for a 33" x 75" tempered dual pane (1") patio glass installed was $395. They will come out, remove the slider, put it on a work bench, remove the old glass, replace with the new glass, clean the track, adjust and lubricate the wheels, reinstall and adjust the locking mechanism. They said they need two days notice.
I also have another sliding window that is cracked. It is 27" x 43". To replace this at the same time would be $175. To do it separately, the price would be $264.
I am in a townhouse so replacing the entire door to comply with the architectural standards seems a lot more expensive ($1200 for the whole door at HD plus installation). If I had a newer "standard" size door (smaller) it would be cheaper, but I don't know about the quality. All I know is that my 25 year old pation doors are heavy.
I don't know if this is a good price, but it seems reasonable. Tomorrow I will learn more. I still have 5 more yellow pages to go through if I really wanted to be cheap, but it doesn't seem worthwhile to do that. This is just some information to put things in perspective.
Dick
#4
08-10-05, 07:58 PM
Group Moderator
Those sound like reasonable estimates Dick. It's hard to replace a piece of glass for less than $200. Most of that cost is the hour it takes to go out and measure the glass, then the hour or more it takes to come put it in. I recently had to replace a single piece of glass for someone who lived 30 miles away.
120 miles @ 7 mpg plus wear and tear on the van (two trips- one to measure, one to install)
1 1/2 hour to drive over, measure, drive back
2 1/2 hours to drive over, get the old glass out, clean up the frame, install new, drive back.
I think their bill was $220, which means we gave the glass to them at cost. We tried to take it easy on them. It's amazing what things cost anymore. Especially now that gas is $2.39/gal! It hurts to fill up that van.
120 miles @ 7 mpg plus wear and tear on the van (two trips- one to measure, one to install)
1 1/2 hour to drive over, measure, drive back
2 1/2 hours to drive over, get the old glass out, clean up the frame, install new, drive back.
I think their bill was $220, which means we gave the glass to them at cost. We tried to take it easy on them. It's amazing what things cost anymore. Especially now that gas is $2.39/gal! It hurts to fill up that van.
#6
08-11-05, 09:04 AM
Member
pane energy efficiency
Just an update -
I think IGU is insulated glass unit (guess).
I just had the slding door glass installed today.
The estimator/installered showed up and quoted $346.18 installed for a 33" x 75" x 1" thick tempered panel. He had a panel on his truck.
In 35 minutes it was installed, adjusted and he was gone.
I would imagine these prices are typical for decent sized metro area.
Dick
I think IGU is insulated glass unit (guess).
I just had the slding door glass installed today.
The estimator/installered showed up and quoted $346.18 installed for a 33" x 75" x 1" thick tempered panel. He had a panel on his truck.
In 35 minutes it was installed, adjusted and he was gone.
I would imagine these prices are typical for decent sized metro area.
Dick
