Window Replacement Guide



A Darn Good Window Replacement Guide

Time to replace your windows?  Get ready to learn a whole new language: constant force balancer, U-factor, block and tackle, Low E, argon and krypton gases, warm-edge spacer, neat glass, fusion welded corners, etc.

With your new vocabulary come window makers and window installers who have different ideas about vinyl vs. wood windows, wood vs. fiberglass windows, about what’s the best spacer or glass pack, about the least acceptable U-factor.

If that’s not enough, some of the outfits you’re considering hiring to install your new windows tell you you need to replace windows and trim, some will tell you leave the trim alone, just insert new replacement windows and save some money.  Or maybe they’ll tell you you need sash replacement.

What Features Should Your Replacement Windows Have?

How do you know which features are the most important?  And what, exactly, do you need to replace?

Well, windows have two functions: let light in (which is easy to figure out), keep cold air out in winter, cool air in in the summer.

Which means, off all the cool, new words and phrases you’re about to learn, the one to pay attention is the U-factor.  Because the U-factor tells you how well the window you’re contemplating insulates.

High U-factor means bad insulation, low U-factor means good insulation.

When we come out to give you your free estimate (you did set up an appointment, haven’t you?), ask us for the NFRC sticker. (The NFRC stands for National Fenestration Rating Council, website at: and this is the page where you verify ratings:

The difference in numbers is small, a U-factor of .27 is much better than one of .34, for instance.

And the full unit U-factor is what you’re after.  It doesn’t matter to you that the center of the window has a great U-factor but overall, the window has an average or poor U-factor.

Creating a window with a great U-factor costs more than creating one with a lousy one.  Some other window features you will come across are cheap to make / create / build even if they are great quality.  So, a window with a bad U-factor might come with some kind of weatherstrip.  It’s still not as good as one with a good U-factor.

So, the glass is the biggest factor that determines the U-factor of a window.  The spacers of double and triple-pane windows are another.  Spacers are the things that keep the panes in place (they run all around the edges of the glass).

Spacers are made of different materials, some better insulator than others, from aluminum to some kind of foam.  The foam ones reduce heat transfer along the edges quite nicely, which reduces condensation nicely.

Other factors that reduce heat transfer and condensation? Argon gas and, yes, low E (low emissivity) coatings.

Argon is a heavy gas that gets injected between the windows.  The trick is to have it stay between the panes.  So, no nails, not even by installers.  Don’t say Duh!, it’s been known to happen.

Low E means adding a coat of silver oxide particles to glass.  That’s useful because those particles reflect sun heat away from the window.  And, for course, the same particles reflect back into the room heat from your furnace or radiators.

The also help keep your things look young longer as they filter out most UV rays, which, as you know, fades wood, carpets, clothes, etc.

Speaking of panes, if double is better than single, triple is surely better than double, right?  Well, from the point of stopping heat transfer yes.  But double is heavier than single and triple is heavier than double.  So much heavier that it can damage the hardware, cause seals to stop sealing.

And that’s, obviously, bad.  When seals fail, condensation forms between the panes and, since you can’t wipe it away, it works to eat away at your window parts away.

Types of Replacement Windows

So, now that you know the main things to look out for as far keeping cold air out in winter, cool air in in winter, let’s talk window frame materials.

Vinyl Replacement Windows

There are way too many window makers out there to keep track of them.  You see ads for Andersen, Pella, and Marvin all the time around in and around Des Plaines, IL.

People who don’t like vinyl windows will tell you that they’re not as strong as other types of windows.  That wood windows look so much better.  That vinyl changes size with temperature.

But vinyl windows are less expensive than wood windows, or fiberglass windows.  And you don’t have to buy the cheapest ones.  Almost every company that makes vinyl windows makes 3 quality levels.

The top level use better everything, so you end up with pretty good windows.  Even though they’re vinyl.  Just don’t forget you want a U-factor of .30, at most.

As far as overall look (color), with a bit of effort, you can find a company that has something you like.

As far as expanding and contracting, vinyl does them more than wood, but with the quality vinyl windows not enough to cause you more headaches than some other kind of window frame material.

If you’re still concerned, plant trees to shade your windows, and don’t put heavy drapes (they trap heat around the windows).

I’m not being glib: with wood windows, you need to refinish them every 2 years; with vinyl windows, you need to re-caulk every now and again, and you may have to change the insulation around the windows (every few years).

Wood Replacement Windows

I love the look of wood windows.  Wood is just great: you can paint it, you can use it without painting, and you can have a light finish, a dark finish.  It goes with every color you paint your walls.  It’s strong as heck.  But it’s expensive.

And, these days, you can get the wood look without the wood. Almost every vinyl, aluminum, or fiberglass window can be clad with wood / wood-looking material.  Almost every wood window is clad with vinyl or fiberglass, or aluminum, as they’re easier to maintain.

As mentioned above, every 2 years or so, you should re-paint (re-finish) your wood windows.

The same thing applies here: low U-factor a good wood window makes.

Composite Replacement Windows

Composite is melted vinyl combined with wood fiber.  It’s sturdier than vinyl alone, cheaper than wood alone.  It’s more expensive than vinyl alone, weaker than wood alone.  Best of both worlds, in a way.  And popular these days.

Do I need to say it? Low U-factor?

Fiberglass Replacement Windows

Fiberglass windows frames don’t expand or contract much.  And they’re strong.  Strong means the frame and sashes don’t have to be wide, therefore they are not.  And you can clad fiberglass window frames so they look like they’re made of wood.

All those advantages come with a price.

Window Replacement Options

You have three options, depending on the condition of your existing windows, full window replacement, insert and sash replacement.

Full Replacement

This is when you remove everything, existing windows and trim down to the studs. You’re left with nothing but the rough opening.  Then you attach the new window to the exterior of the house and add interior trim.

This option keeps the size of the original window glass, is great for keeping things water-proofed and looking new.  It also costs more than the other one.  Especially if siding needs to be replaced in order to attach the window.

Full window replacement is your option if you’re getting bigger windows or windows of a different shape.

Insert Replacement

If the window frame has no rot and has maintained original shape (perfect square, perfect rectangle) you could insert a replacement window directly into the existing frame.

What you’re accomplishing is this:

You get a new window with less mess / headaches / change to your daily life as you don’t have to replace the millwork, disturb the interior trim or exterior siding and you can keep the same window treatments.

You keep the existing frame, exterior trim and siding and the interior casing.  In other words, you save money.

Sash Replacement

This is what you do when the frame looks OK but the sash does not (sash = the part the moves up or down or out – think double hung or casement windows).

Will window sellers and installers agree with you?  Many will not, many will tell it’s not possible.  Because they’d make less if they take the job.  But, if you’re right, if your frames are good, there’s no reason to replace them.  Unless you’ve got casement windows and the manufacturer is no longer around.  So, stand your ground.

Of course, if you get everything new, you have the ‘everything new’ look and feel.

Who’s The Best Replacement Window Maker Out There?

So, now you’re going to choose a brand.  How do you choose? Do you go for Pella or how about the menards window replacement cost you heard about or, you’ve heard the name many times over many years? Do you pick a lesser known company?  Some lesser known companies have been around as long enough, have delivered quality long enough that they should be considered.  And they have windows that have the same features as those made by Pella and Andersen and Marvin.

Back in college, I used to buy corn flakes in a white and green box, ugly thing but good corn flakes inside.  My brother bought his cornflakes from a white box with a much nicer look.  Same cornflakes inside.  But I paid half as much as my brother did.

One day, I did a taste test, I had him test his, then my cornflakes without telling him which came from where.  He thought he was eating the same cornflakes, couldn’t detect any difference.  So, I told him what I’d done and asked him to stop wasting his money.  He did not.  Because, according to him, when he paid more he was sure he was getting quality.

If you’re like my brother, you’re going to insist on one of the top brand name windows.  If you’re like me, you’ll compare features, and, if identical, you’ll get the ones that cost less.

But, having read this article, you are in a better position to get good replacement windows.  Because brand name or not, as mentioned before, not all the windows a company makes are excellent… even if some are.