Windows - Double or Triple Pane? And Other Questions.
 

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.

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!

I miss milt.

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.

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..

....if you live in Hawaii. :rolleyes:

Triple pane makes a huge difference in R-value.

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

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)...

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.

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

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

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

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?

Oh really?

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

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

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

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.

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.

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.

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.

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 . . .

John, your a smart guy. That's exactly what I would do. You will not get much of a return at all by going triple pane. Go the route that offers the biggest return, and the plus is you can can the tax credit.

John. another thought is installing 'storm windows."

Because installation is often so easy, the bang for the buck may be better than replacing the originals. --really depends on the window type.

In your sutitation, double is the way to go. You do not need triple because it really doesn't do you any good. Save your money.

I like out swing windows because they can catch a draft during the hot months. they also do not take up space when they open outward,

Our house was built in 1926. House is brick exterior, plaster interior. Windows are a combination of doublehung and casement. I checked into the cost of replacement and it just wasn't going to be cost effective. Not to mention I love the look of the old windows. Instead I added insulation to the attic and sealed every gap I could find. The old double hung windows tend to leak a fair amount. You can get a weather stripping kit for the sashes that will seal the leaks. This Old House magazine has a great online how-to on doing this: Airtight Windows in 9 Steps | Windows | This Old House - 1

Frankly, I thought you were doing it for the appearance so that the windows matched the vinyl replacement windows you had done previously. If you are satisfied with the look and the windows are working well, I wouldn't replace them. If

i lived in a house that was in the flight path for seatac airport.
they port paid for the upgrade so they could add the third runway.
they put in @25k in sound insulation into the house
this included triple pane windows throughout.
sure the added insulation to the walls and roof we a big part in the sound and a byproduct was amazing heat savings.

but if the windows were closed you couldnt tell a plane was over head...with them open you couldnt hear yourseelf yelliing

Get the windows that are a close match the ones you have. Go over the rest of the house.

A do it yourselfer can blow in cellulose for a major increase in efficiency, for a minimal cost. Rent the biggest HP machine you can get, and use the largest nozzle. Pour in foam is notorious for leaving large voids, and is harder to install. Cellulose blown in properly can be packed quite tightly, and most has an adhesive element in it now as well.

Just be sure that you do any wiring upgrades in your outer walls before you insulate. I did cellulose with an installer when I was young, and the transformation of a house was really remarkable, especially if we did one in the winter.

If you already have a storm window on the outside, and the window can be made fairly air tight, you don't need to. Bare single pane is quite cold, even on a non-insulated house.

+1 on the storm windows
+1 on reducing air infiltration/leaks

If you decide to change the windows, I'd go with double paned factory sealed units that have the metal separators (not the caulking type) and casement style; imo.

Check your attick?
Properly vented and insulated.... biggest bang for your buck right there!
Cheers

John
Are you replacing the single pane windows because they are rotten? I'd only replace them in this case. Add a storm window that fits properly as others have said. If the existing original windows are solid and you have an old house with lath/plaster there is something to be said for that. Scrape and paint and keep all of your money and forget the grant unless the windows are truely shot.

Last time I checked, I would be dead before the upgraded windows would pay for themselves.

plastic sheets on the windows in winter ;) -- great ghetto look but does work a bit.

+1 insulation

double check around the window, leaks are nasty

Only one of the windows is not working, it is a double hung and I could repair the sash cord. The others are casements and working okay, not rotten. I was going to replace them for heat/cold reasons. But I am now reconsidering that. Maybe I will clean them up and repair what needs it, and call it good. I can't really put storm windows on them because we do need to open them sometimes during winter. I wonder if I can get double pane glass panels made to fit the existing window frames, I think I could make a thicker pane work.

When you get it all done and rub some paraffin wax on the edge of the sash and they will slide like if they are on rails. The old man I use to work for in college use to charge 40 bucks using this trick to make old windows work again. You can get a thin 1/4" or 5/16" thick dual pane glass insert made from a glass shop. check if your rabbet is deep enough.

One must remember glass panes are 1/8" or thicker and the usual airspace in an insulated unit is 1/4" or more so from my experience you would expect a unit to be 1/2" thick overall which is probably too thick unless your sash are 1 3/4" thick. Also, the 100 year old windows were not made to house the weight of double glass units (twice as much).

Reg

I'm surprised your local utility won't give you a freee energy audit and help with window costs as well - they do here, and all your & my area is under the same BPA parent program...

at any rate, I agree with your inclination - 2 panes, Argon fill, e-coating. This will do more than reduce your heating/cooling costs - it will make the house more comfortable. The reason why is complicated and somewhat distinct from the mere insulation value. But it deals with radiative losses from your body and the so-called 'radiative view factors." Anyway, I would particularly address any windows that you can see much of, when you are sitting on the couch, etc. - your normal places to be in the house (in front of computer, reading spot, dining areas, TV/video viewing or stereo listening areas).

you really need to get the walls insulated!

finally, the installation is very important - here, the utility certifies only ceretain contractors for their program

one thing is found out, is that some will cut off window fins and just push the repl. unit to make it quick and easy for them -- this will ruin the U-value of high $$ window unit, as air infiltration will be high.

you could ask; watch them; or even DIY - I did on some lower floor windows. Time consuming but it will keep you off the streets & out of trouble for a while.

Good Luck!