Thursday, December 13, 2007

Drawing Windows

One of Kevin's favorite books is the "children's" book "Harold and the Purple Crayon". Harold was able to draw his world, including his house, bed and windows. If a monster started to chase him - all he had to do was draw his way out of it. If he wanted some pie, a few marks with the crayon and voila, he was hungry no more. Sometimes being an architect is just like that- you just draw the picture and it will eventually become real. But most of the time it takes a whole lot of drawing, erasing, drawing and erasing.

One of the things we've been drawing and erasing are the windows for our new house. In our perspective, windows are a crucial element that we won’t cut corners on. They must meet both our esthetic and performance goals. They must be energy star rated. We’ve looked at Marvin Integrity, Accurate Dorwin and Fibertec and InLine Windows. These are all pultruded fiberglass windows, which we are selecting for their strength, durability and great performance from an environmental and energy point of view.

The Marvin windows were in the original bid, but we realized that they do not have the awning and casement windows we need. We are going with a white frame to match the existing windows and to create a modern, clean interior look. If we went with wood clad, they do have the types of windows in that line, but we don’t want wood - wood warps our current wood clad windows don't perform as well as we'd like them to.

The Accurate Dorwin windows are out of Canada they are a great window- but the lead times are crazy right now. It would be 12-14 weeks out and we just can’t afford that kind of time.

Inline and Fibertec windows are also out of Canada and have great performance. It will come down to a question of pricing and schedule. (Don’t be scared off by the castle-like monster home on their web home page!) We’ve gone back and forth with them to establish the size and functioning of the windows and have learned a few lessons:
1. Customize glazing and Low E coatings depending on the orientation of the window: We are likely going to go with triple glazed units with 2 low e coatings and argon filled cavities. On the north facing units (very few of those) we may use 3 low e coatings on different surfaces of the glass. The low e coatings will be slightly different, depending on the direction they face. The goal is to optimize the window's performance depending on the orientation and what we hope to accomplish - passive solar gain in the winter from the south is critical - so we're fine tuning the glazing to make sure that happens. The cost increase appears to be minimal to move from double glased to triple glazed units and as we will own this house for a long time, we want the extra performance - even if the payback in energy savings is 10 years out. Our triple glazed units will feature u values in the .15 to .20 range which gives us and Rvalue of R6 in most cases.
We shouldn't feel a draft off these windows at all - even on the coldest Minnesota winter days.

2. Think carefully where you need operable windows. We were originally showing nearly all windows being operable. For example on a typical casement window of 48” wide x 36” high, we were showing 2 operable sides. By having only 1 operable side, it saves over $500 per window.
2. Consolidate. Less is more (and it will cost you less). We had 4 small operable windows. Each of them was over $800 each. We combined them into 2 larger windows and will save significantly. We don’t want all the design decisions to be driven by cost, but “simple” usually means less cost and “simple” is often the better design decision.
3. The weak dollar sucks. The price for products from outside the US have increased significantly due to the weak dollar.

Look for some revised elevations soon!


Kyle said...

Interesting! I'm in the middle of looking for windows also and am currently looking at a European line, Gaulhofer I think. They seem pretty high performance but they aren't fiberglass like you are looking for.

SC said...

I'm also an Architect and in Canada. I just ordered windows from inline (fibretech was more expensive quote) and I was able to get them for very little more than good vinyl windows. I also visited inline operation, they also sell the equipment to manufacture fiberglass windows (pulltruders). Really interesting stuff. I didn't opt for the triple glazing because i think the payback vs being able to do other work energy saving work like spray foam insulating the entire attic.

Let us know how your windows turn out.

Kevin & Roxanne said...

Hello SC -
I found the same issue with Fibertech. The windows are installed and though we haven't realy begun using them - I really like their feel and operation.
It's taking too long for them to deliver the NRFC ratings to us, but I'm still hopeful.
The payback on the Triple vs the Double glaze doesn't always amake sense and sometimes you must spend the money elsewhere. Better insulation in the walls and ceiling is something I would opt for also. the triple glaze made sense for us - it won't be an immediate payback, but it's in the 10-12 year range. My brother has owed me $10 for the better part of 20 years so I'm used to waiting.

Jeet Khosla said...

We are looking into replacing the windows and patio door in our house. We live in Ottawa, Ontario, Canada where the climate in wiinter is fairly cold. A majority of our windows face south or southwest. However, there are mature trees in our yard and so heat gain during summer is not an issue (we rarely need to run our air conditioner). In winter the trees being free of leaves we do get sun though at a lower angle. We want sufficiently high energy efficiency from the windows (without them being gold plated). The issues we are struggling with are: fiberglass vs vinyl windows; double vs triple glass and hard vs soft coatings. Any advice/comments would be highly appreciated.

jorgnorth said...

Very helpful discussion.

Kevin- can you tell me how you were able to calculate the cost savings of triple vs. double glazing?


Tracy said...

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