ThermaStar by Pella Series 20 Windows Reviews From Lowes

Update: While this ThermaStar by Pella window review was originally written several years ago it’s been updated in 2021 as we continue to work to provide the best replacement window information on the entire internet in 2021 and beyond.  See info towards the bottom of this post for the most recommended window companies in 2021.  Be sure to post a comment or send us a message with any questions!

Today in the top secret WindowDog lair we have captured a ThermaStar by Pella Series 20 replacement window.  You can find these sitting on the shelves at Lowes stores all over the country.  We captured this one at a store in Maryland and the same line appears to be in all Lowes stores east of the rockies.

Pella ThermaStar replacement windows from Lowes
Here is the Pella ThermaStar 20 replacement window from Lowes.

These windows are cheap and that’s the point.  This one cost us about $125 and it includes low-e glass and a full screen.  That sounds like the best price you’ll find for replacement windows.

best replacement windows of 2015

Is it worth the cost?

There are a few distinct drawbacks to buying stock replacement windows from a big box store like Lowes and this window will illustrates them well.

First, as you can see on the label, this window has a nominal size of 24×38, and an actual frame size of 23.5″x37.5″.  If the holes in your house happen to be just that size then you’re in good shape.  If not, you’re going to get creative.  You can rip down some lumber and fill an opening by an inch or two to make a stock window fit, but you’re not going to have the prettiest results.

The biggest drawback is the most obvious.  They just won’t fit right.  You can get cheap custom sized windows from distributors that will still be flimsy, but at least they’ll fit right.

Why are these so cheap?

Here’s a good example, look at this screen.  As you can see in the picture below it has a roll-formed frame, the spline is on the outside, the corner keys are exposed, and on and on and on.

Lowes replacement windows by Pella
That’s a cheap screen on the ThermaStar by Pella series 20 window from Lowes.

If you install this window and never touch that screen for the rest of your life it might hold up.  If you try to remove it, or open it, or stare at it for too long it’s going to bend.  I’m not sure if I have the words to describe how flimsy it feels in your hands.

Next, let’s look at the quality control.  This is a picture of the meeting rail.  You can see the big black scratch that came with this window along with the big thick welds.

Pella ThermaStar windows reviews
This Pella ThermaStar 20 replacement window from Lowes is in our office today.

This was a brand new window and while things do get dirty it’s hard to imagine how it got that scratch.  It may have come from the shelves at Lowes, but it was under the plastic wrapping.  More likely it came from the Pella plant.  It will probably come clean with some soft scrub, but it’s a chore I’d rather not deal with.

As an aside: Soft Scrub will clean anything off of a vinyl window.  It’s amazing.

Here is a quick look at the night latches that can limit how far the windows open.  This mechanism looks similar to many others out there.  I sometimes prefer the type without the button as this seems like it may be a failure point in the future, but it works ok for now.

Night latch on the ThermaStar by Pella series 20 replacement windows from Lowes.

How about the warranty on the Pella ThermaStar 20 windows from Lowes?

As you’d probably expect the warranties on stock windows from box stores like Lowes aren’t the same what you’d find on nicer windows.  In this case you only get 2-years of labor coverage to fix a manufacturing issue and the non-glass components are only covered for 10 years if you don’t live in the home.  Many folks might use these windows in a rental property so that is a factor to consider.  If you get the fancy blinds between the glass you’ll only get a 5 year warranty.  That’s an expensive option to only last 5 years.

You can download the entire ThermaStar by Pella windows warranty right here.

What’s the bottom line?

Well, the price was about $125, the quality is questionable, the sizes are limited and the warranty is pretty weak.  As you might expect this one isn’t a great buy.

If you’re looking to install windows yourself post a comment and we’ll try to direct you to a local distributor that can help you with custom made windows.  For something like $25-$50 more per window you can get a MUCH nicer custom made window.

For now you might want to take a look through our detailed replacement window reviews to get a better idea of your options.  You’ll be glad you shopped around.

If you’re looking for a window company right now, the best advice we have is to check out our list of the best window companies all over the country.  You can find it right here.