I have been shifting my research from the actual construction of the house to now what windows to help to reduce the weak link as much as possible.  I have been reading a lot about the Equinox house, and I found this article very interesting.  My house will not have solar power, but I think the concept can be used with any sort of heating system for the house.  Reading this really made me think about dollars spend on "super windows"  (serious, fibertec, etc) compared to more typical windows such as Anderson, Marvin, Pella, etc.  This article uses Pella, which I would personally not, however the idea is the extra money spent on high end fiberglass windows cost you a lot more then you actually save on energy, design depending obviously. 

So my question is, have been done more research into this as well and have been finding the same thing?  For example, I have quotes from Anderson, Marvin Integrity, and Fibertec.  I like the Fibertec and the glazing options, but again, is the price worth it?

Here are some numbers to compare apples to apples as much as possible:

All windows and a sliding glass patio door- price was around $9500 from both Anderson 400 and Marvin Integrity, including between the glass grills, unfinished pine interior, all casement windows.

Fibertec was about $9200, but did not include a french patio door (add another 1500), was full fiberglass interior (for maple or oak add around 800), and the glass was the same as the above windows.
Now with the Fibertec I can make my south facing have high SHGC of around .5, and triple glaze the north ones.  high solar gain does not change the price, triple adds around 12% (which would be around $500 to the north, or 1000ish if all were triple glazed.  So now we are at $11,500 (including wood interior, no triple glazing). 

basically around a $2000 difference, however Fibertec also has a 20 year on glass, lifetime on frame.  I need to add up the sqft of the window and walls, check out my gains and losses, and then see if I can recover any of that $2000 by heat savings.  I am not sure that I can. 

Here is the article if anyone is interested.  I encourage you all to read it.  BTW I love this blog, I have read almost all of them.

http://www.newellinstruments.com/files/Equinox_House_Topic4_Windows.pdf

Where you can REALLY save money with super windows is when it makes the design difference as to whether you can completely dispense with (or radically downsize) heating & cooling mechanicals, and control interior temps with ventilation rates and a modest amount of cheap resistance electric. It's not about the energy-use cost, but the comparative up-front capital cost. (Being able to skip the heating & AC can buy a lot of window.)

Of course this is usually only the case when you have very low U-values on the walls/roof/foundation, and a modest fraction of glazed area.

In high heating degree-day, high-fuel/utility cost regions there can still be a positive lifecyle-NPV in many instances. With a low HDD climate & cheap fuel/electricity, probably not.

Izerarc-

I would review the discussion on this topic previously posted in this forum:
http://www.greenbuildingtalk.com/Forums/tabid/53/aff/16/aft/59040/afv/topic/afpgj/5/Default.aspx#57348

Rather than speculate on what windows might give the best energy performance, why not use RESFEN, available as a free download, to quanitify the energy tradeoffs. I showed data in the discussion referenced above that showed in my heating-only, high sunshine area, that going with high solar gain windows from a mass-production wndow manufacturer provided better energy performance than using super windows (in my example case, Serious Windows) in low or high solar heat gain coefficient. So I got superior energy performance at a significantly lower cost with the high solar gain, high production windows. In some specific instances, like high altitude applications where gas fills can be problematic, it can be difficult to meet code with the high solar gain windows due to slight increases in U-factor, but that may not apply in your case. In my high altitude case, I used triple-pane windows to address this specific problem.

By using RESFEN, you can personalize the results for your climate and your solar insolation levels.

Lee Dodge

thanks for the replies.  I have done just that, and alot of other research as well.  I have found that by paying another $2k for windows, for my super insulated house we would only be saving around $80-100/ year total, giving us around a 20-25 year pay off, more if you take added loan financing into the equation.
Doesnt make sense to me.  I think I will just stick with a good performance, and good looking window.  I really like the Marvin Integrity windows.  Fiberglass and wood. perfect mixture for my area.

Posted By lzerarc on 22 Nov 2010 09:34 AM
thanks for the replies.  I have done just that, and alot of other research as well.  I have found that by paying another $2k for windows, for my super insulated house we would only be saving around $80-100/ year total, giving us around a 20-25 year pay off, more if you take added loan financing into the equation.
Doesnt make sense to me.  I think I will just stick with a good performance, and good looking window.  I really like the Marvin Integrity windows.  Fiberglass and wood. perfect mixture for my area.

To expand on Lee's response, before we built I ran several different variations of window specs into RESFEN.  I discovered basically what you did - that significant differences in u-value don't translate to significant differences in overall efficiency.  The thing that does, though, is SHGC.  It depends on the orientation of your house, of course, but high solar gain windows WILL make a significant difference.  I posted a couple weeks ago that on Halloween in our area, it was in the low 40's, but very sunny.  Our house got up to around 75 with the furnace off, and we had to open the windows for a while to cool it down.  In my opinion, solar heat gain & air infiltration are much more important numbers to look at than u-value..

I think that the real question here is how much will the energy you use, cost in the future?! Today in the US we are still paying very very low rates for our energy. This paradigm will not hold forever. Remember when you could buy gas less than a dollar a gallon I do! I would take a look at European rates when you do these calcs and then reconsider. Just a thought.

Posted By passivesolar on 22 Nov 2010 10:37 AM
I think that the real question here is how much will the energy you use, cost in the future?! Today in the US we are still paying very very low rates for our energy. This paradigm will not hold forever. Remember when you could buy gas less than a dollar a gallon I do! I would take a look at European rates when you do these calcs and then reconsider. Just a thought.

Along those lines, how long do you plan to be in a house, realistically?  As much as I'd like to think that I'll be spending my golden years in the house we just built, history shows that's not usually the case.  Spending twice as much on your windows is probably not going to be a very high ROI if/when you sell..

I would really like to stress the concept of a house as a system. You can build a house at all different insulation levels from code required minimum to passive house levels. Windows should be neither the weak link nor far superior to the rest of the house. A window needs to satisfy a number of objectives, aesthetics , view of the outdoors, admitting natural light, passive solar gain, thermal properties, privacy, preventing sunlight fading carpets and interior surfaces, egress from bedrooms, providing ventilation, eliminating the cold feeling standing in front of a window.
There are many different tradeoffs.
In my own case after working the numbers, I used High solar gain argon filled low E doubles with appropriate overhangs for shading on the south side.
On the other 3 sides I used low solar gain double low e krypton filled triplepanes. Almost all the windows are casements.
The south facing glass is about 2/3 of the total glass. I supplemented the kitchen and bathroom lighting with tubular skylights to increase total daylighting on the north side.
When I plugged in the numbers, It did not make sense to change the south facing glass to high solar gain triples. It did make sense to change the others to triple pane windows.
There are other things that help make the case for very good windows. The first is that they are much more comfortable to stand next to in the winter. If you ever stand in front of a double pane regular glass window on a cold clear night, you know what I mean. Radiation is a drag. The second thing to consider is that you are no longer constrained to putting the radiators, or heating ducts directly below windows. Once you get up to around r 5-6 for windows, you don’t get the temperature difference across the room so you can put your heat source anywhere and not have parts of the room feel uncomfortable. To me this is a better comfort trade off then granite countertops or a gold plated Jacuzzi tub.

Passive solar makes total sense if designed correctly. It is Nov 22. I have not turned the heat on in my house yet this year in Connecticut. I have had to run the wood stove 8 times so far, mostly on evening when it was cloudy or raining all day. Sunny days the house heats itself. I came back Sunday night after being gone for 4 days and the house was 63 degrees . Good windows makes passive solar doable with less thermal mass.
Having the attitude that I am only going to live here X years so I can use lower quality stuff costs everyone more in the end

Eric mentions that if windows are used with R values of 5 or 6, that temperature gradients in the house are reduced. An approach that does not require super (expensive) windows that works well in my area is to use good-quality windows of lower R value than what Eric quotes, but to combine them with cellular shades with the side tracks to seal them up tight at night. Different from Connecticut, the daily high temperatures in my high mountain desert area average 32 F higher than the lows, so lots of solar gain in the day combined with sealed up windows at night works well. I am currently measuring the R values for the double-cell, cellular shades, and it is looking like R values of about 2.7 with the side tracks, and 1.3 without. Combined with the R values of the windows of about 3.3, this gives a total R-value for the combination (with side tracks) of 6, and the cost of the shades is about $120 each. This may be an alternative, less-expensive approach to very high effective R-value windows (at least at night).

The "super" windows tend to have slightly lower solar heat gain coefficients and lower visible transmission than the mass production windows that I have, resulting in a net increase in energy use with the super windows, and a slightly reduced view of the snow-capped mountain peaks, all at increased cost. Some people do not like to have to deal with shades, but for privacy I have always used shades or curtains of some sort that I close at night.

Lee

Posted By eric anderson on 22 Nov 2010 03:45 PM

I would really like to stress the concept of a house as a system. You can build a house at all different insulation levels from code required minimum to passive house levels. Windows should be neither the weak link nor far superior to the rest of the house. A window needs to satisfy a number of objectives, aesthetics , view of the outdoors, admitting natural light, passive solar gain, thermal properties, privacy, preventing sunlight fading carpets and interior surfaces, egress from bedrooms, providing ventilation, eliminating the cold feeling standing in front of a window.
There are many different tradeoffs.
In my own case after working the numbers, I used High solar gain argon filled low E doubles with appropriate overhangs for shading on the south side.
On the other 3 sides I used low solar gain double low e krypton filled triplepanes. Almost all the windows are casements.
The south facing glass is about 2/3 of the total glass. I supplemented the kitchen and bathroom lighting with tubular skylights to increase total daylighting on the north side.
When I plugged in the numbers, It did not make sense to change the south facing glass to high solar gain triples. It did make sense to change the others to triple pane windows.
There are other things that help make the case for very good windows. The first is that they are much more comfortable to stand next to in the winter. If you ever stand in front of a double pane regular glass window on a cold clear night, you know what I mean. Radiation is a drag. The second thing to consider is that you are no longer constrained to putting the radiators, or heating ducts directly below windows. Once you get up to around r 5-6 for windows, you don’t get the temperature difference across the room so you can put your heat source anywhere and not have parts of the room feel uncomfortable. To me this is a better comfort trade off then granite countertops or a gold plated Jacuzzi tub.

Passive solar makes total sense if designed correctly. It is Nov 22. I have not turned the heat on in my house yet this year in Connecticut. I have had to run the wood stove 8 times so far, mostly on evening when it was cloudy or raining all day. Sunny days the house heats itself. I came back Sunday night after being gone for 4 days and the house was 63 degrees . Good windows makes passive solar doable with less thermal mass.
Having the attitude that I am only going to live here X years so I can use lower quality stuff costs everyone more in the end

Eric, I respect your opinion, but I have to disagree with this statement.  My paycheck subsidizes enough things already, I don't need one of them to be utility bill of the person who buys my house...

Well this is the green building forum To me the whole premise of green building is building long lasting energy efficient, right sized structures. I will never apologize for advocating that.

The problem is the lowest cost mentality attitude permeates the whole building industry(and larger US sociaty).  From the builder who cheaps out on shower faucets, knowing they will have to be replaced in 5-7 years, or the 6 year electric water heater or the 15 year shingle. Home depot is filled with stuff advertized as “ contractors specials”.

One of my co workers is having to spend thousands of dollars on having their driveway fixed. The builder probably saved 400$ by burying the tree stumps where the inspector would never think to look, now 20 years later is a huge problem. A person can go through a house and save tens of thousands of dollars by doing everything as cheaply as possible and selling it quick before problems emerge. Hell most of the time a builder or remodeler is only responsible for a year or two so they can really cheap out. In the long run the total costs to the consumer are higher.
 
Wouldn’t it be nice to buy a house from someone who spent the money to do it right? 

Anyway I guess we agree to disagree.
Cheers,
Eric

Lee,
 you are right. Growing up my parents used ¾” foam inserts in the windows at night with insulated shades over that in their passive solar house. It worked very well but relied on quite a bit of effort every day. They gave up after about 5-6 years of doing it.   I am way to lazy to do that myself. I think this may be why I am so anti-window treatments! The only blind I have in my house is in the bathroom, because some guests found it unnerving to sit on the throne with a big window to look out.

Cheers,
Eric

Posted By eric anderson on 23 Nov 2010 03:40 PM
Well this is the green building forum To me the whole premise of green building is building long lasting energy efficient, right sized structures. I will never apologize for advocating that.

The problem is the lowest cost mentality attitude permeates the whole building industry(and larger US sociaty).  From the builder who cheaps out on shower faucets, knowing they will have to be replaced in 5-7 years, or the 6 year electric water heater or the 15 year shingle. Home depot is filled with stuff advertized as “ contractors specials”.

One of my co workers is having to spend thousands of dollars on having their driveway fixed. The builder probably saved 400$ by burying the tree stumps where the inspector would never think to look, now 20 years later is a huge problem. A person can go through a house and save tens of thousands of dollars by doing everything as cheaply as possible and selling it quick before problems emerge. Hell most of the time a builder or remodeler is only responsible for a year or two so they can really cheap out. In the long run the total costs to the consumer are higher.
 
Wouldn’t it be nice to buy a house from someone who spent the money to do it right? 

Anyway I guess we agree to disagree.
Cheers,
Eric

I really don't think we're disagreeing. I re-read your post about window selection. I'm not saying, "go cheap because you're moving soon". I'm saying, "if you really go over the top, you'll never get your money out of it".

In your other post, you said -
"On the other 3 sides I used low solar gain double low e krypton filled triplepanes. Almost all the windows are casements. The south facing glass is about 2/3 of the total glass. I supplemented the kitchen and bathroom lighting with tubular skylights to increase total daylighting on the north side. When I plugged in the numbers, It did not make sense to change the south facing glass to high solar gain triples. It did make sense to change the others to triple pane windows. "

I think we're saying the same thing. If this was a "money no object" project, you probably would have done triple pane, krypton gas windows everywhere - but you didn't. In every project, regardless of budget, regardless of the length of time you plan to be there...ROI has to be a consideration. That's all I was saying.