ThermaStar by Pella Series 20 Windows Reviews From Lowes

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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.

Pella-ThermaStar-20-Night-Latch
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. 

Update: We now have more recommend LOCAL window companies than ever before.   Click here to see who we recommend in your town.  It's 100% free.  You'll thank me.  There is no better resource; you're going to love it.  See for yourself right here.  

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49 thoughts on “ThermaStar by Pella Series 20 Windows Reviews From Lowes”

  1. Laura Adams says:

    I am replacing the windows in my 1977 built home. I will select the product BEFORE I hire a contractor or company to install. I am finding it difficult to compare products online. I don’t like vinyl windows at all, and I want to be sure that the glass in the windows I select is not distorted or too reflective as I have seen in some windows. I know that Guardian manufactures such a glass but am not sure if they have other glass that does not have this issue. To summarize; I want either thermally broken aluminum or fiberglass frame and at the right price point. Any assistance will be appreciated.

  2. “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. ”

    Can you provide information on local distributor for wood clad windows in the Wake Forest, NC area? (27587 zip in case you need it) I am looking at installing several myself, but don’t want to buy them from Lowe’s necessarily.

  3. Jennifer Beadling says:

    We are looking to replace all of our windows and want a product with between the glass blinds. I see your advice about selecting a contractor first. Lowe’s does have their own contractors, but I see you’re not too impressed with that idea in general. Any suggestions?
    Thanks.

    1. thewindowdog says:

      I know I mention it a lot, but I’d strongly suggest starting with Angie’s List (discounted rates here). It’s really the best way I know of to find a worthwhile company in your area. We’re going to be starting a recommendation section soon, but until then Angie’s List is your best bet.

  4. Ron Earyes says:

    Looking to install windows myself. Please direct me to local distributors that can help me with custom made windows.

  5. Mike Reibling says:

    Looking to install windows myself. Please direct me to local distributors that can help me with custom made windows.

    We are converting a screened in porch built in 1952. The spaces between the 4 x 4’s are all different which is why we need the custom windows.

    1. thewindowdog says:

      Hi Mike, I’m not really familiar with the distributors in your area. Maybe try for an ABC Supply or Roof Center. If they’re in your neck of the woods they can probably help.

      1. jdhansel construction says:

        Abc is great and big selection

  6. You left out the fact these windows have Argon gas also. Another thing that all Vinyl pella windows have over other companies is there is no way water can back up and into your home during a heavy storm. Many Vinyl Windows actually have an open line that if the weep holes can not keep up with the amount of water coming down, it will back up into the home.

    I do suggest for people to spend the extra 25-50 bucks per window to customer order the correct size.I also tend to do what I can to help them with savings depending on the size of the customers order.

    Also if the build in work is down right, you should have no added issues as long as you finished the outside correctly and fill any dead spaces with insulation of some kind. It usually cost about the same amount, or within $10 to build in as it would to order the custom size.

  7. James France says:

    I am looking to install windows myself. Can you direct me to a local distributor for custom made windows,

    1. thewindowdog says:

      We’ve sent Alside Mezzo windows to a few readers recently. Where are you located? We may be able to help out.

  8. My house is a 1959 build, it had the original windows. I replaced all 17 with Pella Thermastar units. Some of the openings were close to the standard sizes offered at lowes, some needed to be special ordered to get a close fit. The special order windows were only around an extra 20 bucks. 15 of the window’s are standard double hung, one is a slider, and the picture window in the Living Room is a 96×54 opening, has a double hung flanker on each side and a solid 52″wide glass in the center. The Living room window came as 3 units put together with vinyl strips and was very flimsy to mount.
    A common issue with all the windows is the screens. The screens are very cheaply made and do not fit well. Around here we have seasons for mosquitos, fly’s and lady bugs. Right now it is the lady bugs. There are 20 to 50 or more lady bugs inside the screens of each window right now. so now I wonder, whats the use of having screens on them at all ? They definitely do not do their job of keeping the bugs out.
    Mike

    1. thewindowdog says:

      I wasn’t impressed with the screens of the Pella Thermastar windows either. The best idea I can suggest is to try to get a good look at where they’re getting through and see if you can increase your defenses in that area. You may be able to put a wide white tape around the perimeter of the screen to seal it better. Just try to find one that won’t leave a sticky mess when you pull it off. Good luck!

  9. Michael Welsh says:

    Hello, Im looking to install replacement windows myself and am in the Westminster, MD area. Can you please point me to a distributor. Thank you.

  10. Brian Beeler says:

    I just bought 2 pella therms star 20 series, was going to try install myself this week, but am reading reviews after purchase! Should I return them, or roll the dice? I plan on selling house after kids get out of school? Btw, I have a total of 14 to replace

    1. thewindowdog says:

      Well, as you can tell I’m not a huge fan of that model. It is cheap so I guess it depends on your budget. Many people install those windows every day. It just depends on what you’re going for.

  11. I just purchased two Thermastar by Pella double hung windows. I didn’t realize it had full screens. Where can I purchase half screens for these windows?

    1. thewindowdog says:

      Great question. I don’t know, but I’d start with Lowes, then maybe call Pella. You may be out of luck as those windows have very few options. Be sure to let us know what you find out, I’d be curious to hear.

  12. We bought pella thermastar replacement windows in 2011. Double hung, single screen, joined vertically with a mullion to accommodate window openings. My husband is a builder and was here at install. Insulated well, finished outside well, level in the openings. We are replacing all windows again, as we noticed in the cold weather, a draft flows up the channels on both sides. We have to cover the windows with plastic in the winter because of the draft. Had rep from pella come to see them a few weeks after install. He suggested that we fill the frame as much as possible with foam insulation and then said they were not level in the openings. Having a level on hand, we showed him they were right on the bubble. No satisfaction from pella at a second call except to receive a bag filled with foam weatherstripping for all parts we could get to. Will never buy Pella thermastar again.

    1. thewindowdog says:

      I’m sorry to hear about your troubles.

  13. I ordered 13 Pella Windows from Lowes in April. Ordering was a nightmare dealt with Victor who had a huge chip on his shoulder from the start. Windows came in all were ordered wrong lowes fault. Ordered them again they came in all the jams were wrong. Lowes got the right jams, my contracted had to re cut all jams they were terribly off. I was having my roof siding and Windows done this kept my whole project from being done. Every time they screw up it takes another 21 days to get the item. Lowes and Pella do not ruch even when it is their fault. We called Pella they do NOTHINGto help you! Trust me go with Anderson Windows. We never got the trim for our last window a 31″x64″ double hung window with half circle window on top so we called Lowes for a price. It took two business days just to get a price from Pella. For inside trim that is $8 for an 8′ piece we would need 3 and the half circle. Lowes and Pella quoted a price of $633 dollars. Called Pella they said we had to go through Lowes maybe they could talk to the rep to get this for nothing after all the trouble we had. Called the manager at Lowes in Schenectady after hearing him tell Pella he wouldn’t even pay that kind of money for the trim he turned around and offered us 10 % off. Needless to say I will NEVER do business with Lowes or Pella again!!!!

  14. I installed Thermo by Pella in my house. new construction flange windows installed over existing 1956 single pane crankout aluminum frames. Had to rip the flange at the nail hole fin with a circular saw. Worked like a champ. Also installed new in 4 or 5 customers homes. Never a complaint. Saved my customers Hundreds.

  15. Carey Jones says:

    We are looking for replacement windows to install ourselves in Gainesville, GA. 1985 home has old pella casement windows that don’t crank or lock well. It’d be nice if we could find someone to repair the hardware since window quality is superior. Cost needs to be low, rental home to be sold in spring. Any help would be appreciated

  16. Hi Window Dog. We need to replace a big picture window/2 double hung on the sides, and 5 double hung windows. After getting 5 estimates, I ran across your website. It has been great! Wish I would have found it prior to the first estimate! Our last estimate is going to be from a general contractor, and I will have to find some “stock” window options rather than custom made…unless you have any ideas of companies in Central, Illinois? Bloomington, but no farther than Peoria, or, a 35 mile radius? Thanks!

    1. thewindowdog says:

      I wounldn’t suggest going with stock sizes as you’re much more likely to have issues caused by the windows not fitting right. Custom made windows don’t really cost much more than standard size windows so it’s typically not a big deal to get windows that fit right. Good luck.

  17. Ann L. Riling says:

    I had a recommended contractor come in to give me estimates for 7 replacement windows in my home. He highly recommended Harvey windows and told me the cost would be $500 per window, including installation. Are Harvey windows good quality and does this price seem extremely high.? I am retired on a fixed income and cannot afford to have poor quality windows and work such as was with my first floor windows 15 years ago. Please guide me.

  18. Robert Bayly says:

    Looking for replacement windows DIY. 3 units RO 42W x 54H, 3 units RO 36W x 54H, 1 unit RO 48W x 54H. to replace old wood single hung units except for the 48 x 54 which has a pivoting window but want a regular window for that too. Just don’t know if they make them that big. San Bernardino CA but I guess location doesn’t really matter since they can be shipped. I’m looking for best price no frills units.

    1. thewindowdog says:

      Hi Robert, I can help with an order in most markets, but I can’t ship to southern California. At least not yet. Sorry I couldn’t be more help!

  19. Hi,

    I’m looking to replace some aluminum frame window in mobile home that I own. This is rental so I’m looking for overall value. Can you recommend a local seller of custom windows in my area?
    I’m in the Portland, Oregon area.

    Thanks,
    Brian

  20. JOHN C GUEDRY says:

    I’m in South Texas 78504, looking to replace all windows from a 90s built home. Any recommendations on Windows?

  21. I’m looking for replacement windows in NE Ohio (Akron area). I’m in the process of getting prices from a couple of lumber yards that carry windows. I’ve been to the box stores. I would like your help finding other distributors in the area. Are there building supply companies or direct-to-customer distributors that would sell to an individual? Any recommendations for decent low-E double-hung vinyl windows with half or full screens? It can go from -15 to +100 degrees in this area on extreme days but generally hovers in the high 70’s, low 80’s in summer and teens in the dead of winter.

  22. My zip code is 85022. I’m looking to replace my windows. Any help with a manufacturer would be great.

    1. thewindowdog says:

      Hi Jack, I can help with a window order in Phoenix if you’d like. Check out this page for our listings of recommended companies.

  23. Hi my zip code is 02341 and I am Looking for a local distributor for my own installation.

    1. thewindowdog says:

      Hi Steve, I could help you with a window only order in Mass. Drop me a line if you’d like some options.

  24. I’d love for you to refer me to a local window manufacturer

  25. Hi,
    Any suggestions for local companies near Ocean City MD?
    I noticed you didn’t have any listed for the Eastern Shore.
    Tough area because house is north east facing on water… elements are a killer… really need a good window and excellent installation. Any suggestions?
    Thanks
    DS

  26. Ed Raskay says:

    I’m looking to replace a couple twin double hung vinyls. I live in the Philly area and was wondering if you could offer some distributor recommendations. Windows will be for my garage and a powder room. I replaced all my other windows with Simontons a few years back and was not very happy with a few of them – fogging and a broken sash mechanism.
    Thanks

  27. We live at 8,000 ft on Colorado’s Front Range (40 miles to Denver, 15 to Boulder). We’ll be installing the windows ourselves and most are fairly standard sizes. We’ve looked the Jeld Wens (Vinyl 4500) at Home Depot and the vinyl Thermastar’s by Pella at Lowe’s. As your reviews point out, these windows are workable but not of the highest quality. We’d maybe spend a little more per window ($25-50) for better quality. Do you have a list of distributors who sell to residential in the Denver/Boulder area. Thanks!

    1. thewindowdog says:

      Hi David, I could help you with a window only order without install in that area. Send us a message and we’ll be happy to help out.

  28. CALVIN SHAW says:

    I am looking to replace and install all my windows but one.. I would like to get info on custom windows…thx

    1. thewindowdog says:

      Hi Calvin, what’s your zip code? We may know someone who can help out.

  29. CALVIN SHAW says:

    I would like information on better windows than the box stores. I would install myself

  30. Joe Edwards-Hoff says:

    I’m hoping to replace windows in the Spring. The $308 price tag on the 95.5×47.5 Pella window at Lowes is tempting. With a local energy rebate, that’s a pretty cheap window. But we also want to be happy with them. I’m in SE Washington state. 98930.

    1. thewindowdog says:

      It’s hard to be happy with a product like that in my opinion. They’re super cheap for a reason. It might be worthwhile to compare a couple options so you can be clear about the differences. They’ll be in the house for decades so it’s good to get a good price, but not so good to be dealing with an inferior product for 20+ years.

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