Windows - Double or Triple Pane? And Other Questions.

[jyl]

Hi all, I am looking for some advice about windows. Most of the house's windows have already been replaced with double-pane vinyl windows, appx 10 years ago. We are looking to replace about 8 remaining single-pane windows (basically all of them, except the leaded glass ones).

Three main questions -

First, does it make sense to pay up for the "best-insulating" windows?

I used a infrared thermometer to measure the temperature on the inside of the existing windows. The old single-pane glass windows were appx 55F. The double-paned windows were appx 65F. The wall was appx 66-67F (lath and plaster). Outdoor temp was about 40F and windy at the time. I gather I can get triple-pane, krypton-filled windows that supposedly have a higher R-value than my walls (see "Penguin" below). My question is, if the double-paned windows are measuring within a degree or two of the walls, why should I go "better"? I have no plans to add insulation to the walls.

Second, is there any particular reason to favor casement, vs awning, vs hopper type? The windows in question are not suited for double-hung. Obviously I won't use outswing hopper type if there isn't good rain protection above the window . . . also, in-swing versus out-swing? We don't have an insect problem.

Third, anyone know a good window contractor in PDX area? I got a pitch from Penguin Windows yesterday, their product ("Uniframe"?) seemed good (unnecessarily good? see first question) but the price seems very high (appx $1,000 per window including the $1,500 federal tax credit) and the sales job, although well-executed and not too pushy, irritated me.

[vash]

never thought to put the IR themometer to use. i have two windows remaining to change. i DIY'd it with encouragment from Milt. i got Marvins. my old house had ghetto, horrible, wood double hungs. the best part of this nightmare allowed me to buy Marvin's Tilt-pac windows. not casements. i got it down to 45 minutes, demo and install.

two of my windows, huge ones, were not tiltpacs, and i installed standard casement (am i even getting the term right?), and it was a beotch!! measurements were unforgiving.

all my glass is double paned, argon filled. glazed glass. my home is quieter, and more comfy temp wise. also lath and plaster construction with negligable wall insulation. triple pane is BANK!

[jyl]

I miss milt.

[john70t]

It doesn't make economic sense to pay for the triples at this time. An insulation system is only as good as its continuity, it would be like the Hoover Dam having sections only a foot thick.

The attic is usually the best place to start insulating:
Insulation Fact Sheet

I've heard up to 30% of heat loss is through the basement. Concrete is a good absorber and it is surrounded by four feet of frozen ground:
Insulate Basement Rim Joists | thefamilyhandyman.com | DIY Projects | Reader's Digest
If you want to do insulating yourself:
Tiger Foam | DIY Spray Foam Insulation Kits

From a simple engineering perspective:
-Casements hang so the end is exposed to soaking up rain. The box relies on one side of vertical hinges attempting to keep their elongated shape box-shaped against gravity somehow. I've also experienced they tend to be caught by side air gusts and break off, considering the closer is usually a single one at the bottom of the rectangle.
-Awnings are a more stable design gravity-wise, but also can soak up rain at the ends, are nontraditional, and they still feel "closed" even when they're open.
-An inward-opening Hopper seems like it would be self-draining, and easier to clean the outside, but are also nontraditional, and would be a bumping hazard in a tight space.
-Double-hung are traditional, but can have snow/water build up on the top edge, have the line through them, and can bind and be difficult to lock.

I'd consider whatever is architecturally needed first.

[svandamme]

tripple pane usually is not worth the investment if the house isn't built for it. eg if it's not a newly built house, with insulation technology from this millenium.

The difference between Hi efficiency doubbleglazing, and triple glazing is next to nothing

Something like, if it's 0 degrees C outside
Then with high efficiency double glazing, you'll get 17 degrees C on the inside
with triple , that would be maybe 18.5 C on the inside...

If your walls aren't completely built with modern insulation, you won't get the better result anyway..

[island911]

Originally Posted by svandamme

...

The difference between Hi efficiency doubbleglazing, and triple glazing is next to nothing.....

....if you live in Hawaii.

Triple pane makes a huge difference in R-value.

The Q is; is the temperature difference big enough to offset the additional cost?

[svandamme]

those values i listed, are real, i just ordered my glazing last week.
So if you have a 1.5 C difference on the panes, and you install it in an old house that's not much difference, and it won't be worth the investments since the walls will be less insulated then the panes..

Tripple glazing is only cost effective if the rest of the house is built up to modern, passive house standards... or if you live in Scandinavia or Alaska (where the houses would also be built with better wall insulation anyway)...

[island911]

As Milt once pointed out, windows are NO Where near as insulative as a typical wall.

John is in Portland where I expect that R13 (min) is code. Even a triple pane won't match that number.

FWIW; What I noticed in Scandinavia was a pair of double pane, plus heavy curtains. seemed smart for the area.

[island911]

Originally Posted by svandamme

those values i listed, are real, i just ordered my glazing last week.....

Sooo... the guy sellling doublepane sez that his doublepane windows are better than triple-pane windows. Oh really?

[turbo6bar]

Don't see any reason to go with triple pane when the rest of your house has poor insulation. Your dollar goes furthest addressing the area with least insulation.

The triple pane I have seen start at R-4 and go up to R-6. A vanilla double pane is R-3. You're paying a large premium for 30-50% gain in insulation. Spend the bucks on sealing leaks, HVAC ductwork, and installing insulation where none existed before.

If you're really into crunching numbers, buy one of several HVAC programs that calculates heat loss/gain (Manual J calcs). You will get numbers and you can make changes in insulation levels/window R-value to see effect.

Agree with svan. Triple pane is best when used with a house design for high efficiency. Jurgen

[LWJ]

Here is what I know. I worked one hellish under-employed year for a large national window company (sounds like Hella) and know some very smart HVAC people that focus on energy efficiency. I currently have crappy aluminum double glazed windows. Aluminum transmits a ton of heat so is not a very good frame choice. The decision I made was that even with my crap windows, it did not make sense to replace. I focused on other, higher gain areas.

Summary:
1) Windows are not cost effective to replace regarding energy efficiency.
2) The biggest thing you can do to make your home energy efficient is mitigate air leaks.
3) Style of window is largely not relevant - all modern windows make a reasonably good seal.
4) Nathan Alicata is a window genius. He lives in Milwaukie. Not sure if he does residential work or not. He is one of the smartest guys around regarding windows. Don't know if I have his number but I can find it if you need it.

Good luck!
Larry

[turbo6bar]

Originally Posted by island911

As Milt once pointed out, windows are NO Where near as insulative as a typical wall.

John is in Portland where I expect that R13 (min) is code. Even a triple pane won't match that number.

FWIW; What I noticed in Scandinavia was a pair of double pane, plus heavy curtains. seemed smart for the area.

Sounds like you're looking for the ideal engineered solution with little regard for cost efficiency.

John L, what is the insulation in your house?

[island911]

Originally Posted by turbo6bar

Sounds like you're looking for the ideal engineered solution with little regard for cost efficiency....

Oh really?

Originally Posted by island911

....

The Q is; is the temperature difference big enough to offset the additional cost?

[turbo6bar]

We've already settled that question. It probably isn't worthwhile to use triple panes. Keep up, kiddo.

[island911]

Originally Posted by jyl

... I got a pitch from Penguin Windows yesterday....

Search "Penguin Windows reviews" ... I don't think that you want to use them. BTW, their product is apparently just a relabeled triplepane.

[island911]

Originally Posted by turbo6bar

We've already settled that question. It probably isn't worthwhile to use triple panes. Keep up, kiddo.

Well that's a strange way to say "oops"

Anyway, the cost is really a decision that only the buyer can make. It is too simple to just weigh the cost of fuel to the cost of the windows. There are other factors that may weigh differently for the particular buyer. ...Perhaps the buyer wants that extra layer of Low E glass (of triple) to help slow the fading of a heirloom carpet or chair. Perhaps they want to slow a draft that is put in motion by a large wall of window. Maybe the home-owner would rather spend to insulate windows, but allow air leaks to mitigate the build-up of radon gas. ...perhaps the owner can get the triple pane windows for the same price as doublepane.... etc.

[MRM]

To further complicate matters, you may want some solar gain during the cold months, which means double panes are better than triples. In my part of the country the conventional wisdom is that double pane makes most sense. During the winter you want the drapes down at night for extra insulation, open during the day to allow solar gain. During the summer you do the oposite.

Be careful buying replacement windows. There is a big variety in price and performance and there is not necessarily a coorelation between the two. I woud stay away from aluminum for various reasons. Wood framed windows with a vinyl cladding is generall considered the best but there are some very nice all vinyl windows out there. Shoot me a PM if you're interested in comparing brands. I know most of them, but there are so many mom and pop window manufacturers that I can't keep track of them all.

Remember to compare apples to apples. You need a remodeling product, which is why Marvin's custom sized vinyl clad wood windows is a good option. Their larger and better known Minnesota-based competitor is one of my clients, so I'm biased toward them, but anyone who makes windows to fit your rough openings should be considered.

Since you already have some vinyl windows in the home, matching appearance is probably more important than performance. That means you'll want to stay with vinyl windows that look pretty much the same, or even the same brand. One of the best value vinyl windows out there are Silver Line http://www.silverlinewindow.com/index_noflash.cfm As a disclaimer, I do represent Silver Line and their parent company, so take what I say for what it's worth, but do compare Silver Line when you're looking.

Edit, to answer your second question, casement windows are generally considered the best performing style, although any style should work just fine. Casements have the fewest moving parts and are an inherently stronger design. The sills are sloped so that water flows out of the window so the bottom of the casement isn't sitting in water. I would match the appearance of the other windows first but if style is an option, I'd choose casements.

[onewhippedpuppy]

You'd do better investing your money in a quality double pane vs a cheap triple pane. Cheap windows are just that, over time you will regret the decision. Don't go with the cheapest, be it the installer or product.

[jyl]

Thanks everyone.

I have wood siding over lath and plaster exterior walls, zero added insulation. I guess this is pretty typical of 100 y/o construction. I have no plans to cut holes in the walls and foam in insulation, because its so expensive that (so far) I can't see a financial payoff over 10 or even 15 years. The attic is finished so there is limited scope to add insulation there.

Since starting this thread, I've calculated that the windows we plan to replace represent appx 1% of the exterior surface of the house. I've also looked up the R-values of lath/plaster walls (around 5, supposedly), of good double pane windows (seeing a wide range of claims, from 3 to 6), and of the best triple pane, krypton filled, low E windows (also seeing a wide range of claims from 6 to 8). I'm thinking that even if the double pane is R=3 and the triple pane is R=8, the difference to my house's heat loss from replacing 1% of the exterior surface with triple pane rather than double pane is - well, pretty much nothing.

So my inclination is to look for a decent double pane low E argon filled vinyl window, ideally good enough to get the 30% tax credit, from a solid local installer - that is not Penguin.

[jyl]

And all this sort of begs the question, why should I replace the damn windows at all, even if they are single-pane? I will have to noodle over that one . . .