Best Double Interior Storm Window Inserts: Save Money on Heating

[@HartzHomestead]

Note: To shrink the film tight with a hair dryer like Window Insulation Shrink Kits, I'd suggest 1 or 2 mil film, if you can find it. I've found the folded up 0.75 to 1.5 mil film that comes in shrink kits is not very clear, and even after shrinking the creases still show. The 3 mil polyester film I use comes on a roll so it's not creased, and it's a little wavy but very clear, and a hair dryer isn't necessary. If you're determined to shrink it tight, you can do it with a heat gun, but be careful not to melt a hole in the plastic doing that, and if your frame is too flexible it may bow in from the tension.

[@drencrum]

Does the thickness of the film affect R value?

[@HartzHomestead]

@@drencrum Good question. It's primarily the air spaces that provide the insulation. The thickness of the film may make a small difference, but not much - I have not found any data on that. More important is to have air spaces between 1/2" and 3/4". Much more than that and you get convection currents that transfer heat. A thicker film will reduce sound transfer though, if noise is a concern.

[@SJ_fornow]

12 minutes and 45 seconds of high density information. No frills or filler. Good information, great delivery, answers all questions. Pack it in folks, this is the winner on the topic. Very good job, sir!

[@HartzHomestead]

Thanks so much for the compliment. This video was 2 years in the making, shot over 300 video clips and spent several weeks editing. Hoping it really helps people save energy on heating.

[@c-linnd606]

Agree 💯 !

[@robinbirdj743]

Im so excited to try this. You’ve made it clear and simple. Even nonwoodworkers can do this! For about $35 per window I will save enough in one year to pay myself back. THANK YOU

[@HartzHomestead]

Glad to hear it! That's my goal, that this video gives you enough information to build them yourself. It's true that the savings are tremendous.

[@rocktman81]

Absolutely fantastic. This needs WAY more views and thumbs up.

[@HartzHomestead]

Thanks! Comments like this help make it worth all the time I put into making the video.

[@Klis1517]

I truly appreciate your workmanship and the effort put into explaining it all. This video was a masterpiece!

[@HartzHomestead]

Wow, Thanks for the compliment. A lot of effort did go into producing this, to make it as easy to understand as possible. I do think these storm windows are pretty amazing, and I want other people to be able to build them too.

[@R3noire]

This video has exactly the information I was looking for. Guess I’m going to use mylar instead of acrylic. Thank you!

[@annewithrow826]

So helpful! Thank you. My home is older. Replacing windows would be ideal, but quotes I’ve gotten are eye-popping. My DIY skills are not yet up to replacing them myself. This is a terrific option.

[@HartzHomestead]

And since adding double storm windows gives you a total of 3 layers with 2 air spaces, it may be warmer than if you just installed double pane glass.

[@EpicMother249]

After years of trial and error. This guy is spot on. Thank you so much. Winter is coming..... and I am excited

[@HartzHomestead]

Thanks, a lot of effort went into developing these, and making the video. Glad you appreciate it! They really do make a difference.

[@92nredrappini84]

Very well covered I don't think you missed anything, thanks for the Video.

[@lifted4evr]

Immaculate job explaining all the ins and out of this job. The attention to detail is 10/10, even the links to materials are all listed out in perfect order. Thanks for sharing the knowledge. Power bills from heating costs with the single pane windows in my place currently gets out of hand fast with the cold. This is definitely the way to go to save big.

[@HartzHomestead]

Thank you, these storm windows have made such a difference in our house that I had to share it so others can do it too. Making this video was indeed a big effort over 21 months, using 162 video clips. Glad you appreciate it!

[@carolinemiller7774]

Brilliant! Thank you for sharing your knowledge and great detail.

[@richardmalmberg7722]

I watched this and built some they work really well. My wife insisted that they look nice so I took the extra time to sand and paint them. Very expensive double pane windows are only R3 at best and will only last so long. I'm getting R4 to R5 way cheaper with this method. Brilliant explanation of the whole process.

[@HartzHomestead]

Great to hear! Yes, these storm windows make a pretty amazing difference and last a long time, well worth the effort it takes to build them.

[@chaosplan]

Thank you for the comprehensive video, I’ve watched a lot of them and yours is by far the most succinct. Love your idea of using Mylar, it looks absolutely crystal clear and the thicker weight will last more than one season. Also, never thought about using two layers of film, this is brilliant because it exponentially increases the insulation value for a small amount of extra effort and material cost.

[@isaacs6193]

I made mine with pvc trim and duck brand max shrink plastic window kits, supposedly 1.5 mil. I really like the idea of polyester film, wish I'd thought of that. Great idea, thanks man

[@sunnifreyer2759]

Brilliant help!! Love the details. I came here as I am trying to insulate my sliding glass doors using magnetic strips but now you've created another project for my other windows. You did a great job with this video.

[@AlistairLindsay]

I learned so much from this- thank you!! 🤩

[@johnmerkel756]

This is such a thoughtful video- great job

[@steveforbes7718]

This is definitely a much better method of making up storm windows without going totally broke! I was wondering if such plastic was available and how it might be done. You answered all of my questions easily and quickly with no fluff. Thank you.

[@HartzHomestead]

Thank you! It's a very practical, cost effective way to save heat. I prefer the stronger 2-3 mil plastic over the very thin stuff. The frame design may depend on your particular windows.

[@Elizabeth-n3v2u]

Thank you sir for this wonderful demonstration. I cant afford to run the heat in my house above 45 degrees f because it has huge single pane glass windows. My power bill is massive and im so so cold all winter. I can build these with the tools i have. Thank you!

[@HartzHomestead]

Yes adding 2 or more layers of plastic will make a huge difference, especially starting with single pane. You can add a spacer if necessary to keep them 1/2" to 3/4" from the existing glass, adding as many layers as you have time and money for materials. There may be surfaces you can tape 1-2 layers to, as long as you have the right air space. I find up to 4-5 glazing layers is not overkill - each air space gives you more insulation.

[@BrandonGee]

This is great! Thank you for putting together all this information with links to the materials.

[@ChrisKChandler]

Excellent video, thank you for sharing material links!

[@doc2945]

Great informative video. Thanks.

[@tjtexas5130]

Thank you. This is one of the best videos on this topic I’ve watched so far. Hoping to help my daughter make these for her house. Possibly looking at using Mylar or something similar. Live in Texas - so might use year round. Cut heat in summer and cold in winter. Thanks again

[@HartzHomestead]

Glad it was helpful! For keeping the heat out in summer, also be sure to have some external shading, like awnings or solar screens, to block the sun before it shines through the window. I plan to do a video on that next spring.

[@MissRuddy]

Thanks

[@DogTrots]

I'm thrilled to get started on a few windows for my house! Happy to support you by purchasing your recommendations via your links. I appreciate the exceptional video!

[@HartzHomestead]

Thanks for your support!

[@LisaMarselle]

Thanks for this - this is the most comprehensive video out there! Questions - how long do the films last when directly applied to the window frames? And do they remove the paint? Also, is all mylar the same? Thanks!

[@HartzHomestead]

The 3 mil film should still last 30+ years taped directly inside a window frame. A thinner .75 to 1.5 mil shrink film may not last as long. It's possible the tape can come loose sooner depending on the quality of tape and surface you tape it to. The 1/2" tape with red backing from ePlastics (link in video description) is very good. If you have good quality paint, you can likely peel, scrape or rub the tape off like rubber cement without damaging the paint. The 3 mil clear polyester films I've gotten from ePlastics and Grafix Dura-Lar from Amazon were both equally good. Some reviews for shrink film kits said the clarity of the .75 and 1.5 shrink films varied. They come folded up so shrinking with a hair dryer is needed to get rid of the wrinkles, while the films I've gotten came smooth on a roll.

[@Abijah12411]

I might try this when I can afford it.😊

[@ItchyKneeSon]

Awesome, in-depth description! Thanks so much!

[@F.Reyes39]

Awesome video I appreciate your help. You covered everything.

[@slushyslushfund9626]

Thank you so much for sharing this! Our house has a screen room with 4 track windows. It's great May-Sept but the vinyl has no r-value to speak of. It just keeps the wind out. I got quotes for putting in proper glass windows and that's way out of our budget. This seems like a good way to extend how long we can use the porch.

[@HartzHomestead]

Yes, adding more layers of plastic will make a huge difference. Just be sure they are attached well enough so the wind doesn't blow them out.

[@JW-qp5uf]

Just my opinion on using mylar, I found it reflects light/glares. I made several inserts with this method and during the day, they look good. But at night they reflect any imperfections and light. It was distracting in my living room. I had to scrap the mylar part and rebuild using acrylic. Costs more up front (and I ended up wasting $ on the mylar and adhesive) but I couldn’t get along with the reflection. It seemed like a cost effective solution but I ended up spending more…Good video though!

[@HartzHomestead]

Yes, polyester film does reflect indoor light at night in a wavy pattern. I don't mind it at all, and some think it looks "pretty", reflecting various colors in the room. One option is to use a lighter weight, like 1 mil or less and heat shrink it so the plastic is tight, though that puts more tension on the wood frame, which could cause it to bow in on larger windows. Of course the other solution is what you have done, with rigid glazing like acrylic, which costs more but is more durable and blocks noise better.

[@GoggleAX]

Wonderful video, very clear, easy to understand, and follow, instructions! Quick question: understanding it may cost more, why not use aluminum window screen framing in place of the wood? It would likely need a horizontal support but also is lighter, thinner, comes in several relevant colors, corners and connecting “T’s” are readily available and may remove the need for most tools to make and install the window. No disrespect at all intended, just an honest, question. Thank you!

[@HartzHomestead]

The main advantage of a wood frame is it's easy to get a 3/4" spacing between 2 layers of glazing by taping film to both sides of a 1x2 frame. You certainly could use aluminum screen framing, but you'd only get one layer of film per frame, plus aluminum conducts heat much faster than wood, so you'd get some heat loss and likely condensation on the frame. For any climate that's cold in the winter, it's well worth having double pane glass plus at least 2 layers of film inside that.

[@GoggleAX]

Well, I am indeed in a cold climate (MN, USA) so it seems as though wood is the way to go for me! 😇. Thank you. 🙌🏼

[@JUDALATION]

cant wait to build these for my house!

[@ksnax]

I went with 12 mil vinyl for my inserts for high durability, but they are also covering 123 year old single pane wavy glass, so optical distortions from it aren't a problem. I think the vinyl also provides some sound attenuation as well, but I have not measured it.

[@HartzHomestead]

Thanks for the report! Vinyl is very durable, and I would think that would help with sound.

[@DivinityHealings]

Thank for sharing!

[@GinaKayLandis]

Such great info!! I didn't know about using open cell foam. My utility bills are pretty low, even though I have two huge windows! I do have a question - A Japanese content creator used two shower curtains for hrr sliding glass doors - didn't tape them up, just hung them on one of the drapery tracks. While on the surface this seems like it might work, is convection a culprit in this scenario? I just wonder if that may be a minimally effective solution for peoplr who aren't really in a position to cut wood or assemble things (small homes, few tools, no saw). I know there's no guarantee of efficacy, but sometimes even a little result is better than none. Thanks for your video!

[@HartzHomestead]

Yes, any kind of curtain is better than none, though the better sealed it is around the edges, the more good it will do, and it helps to have a layer of bubble wrap, batting or foam insulation in there. We have just a double heavy sheet that lays flat over one window and it's noticeably cooler behind the curtain.

[@beemaningi]

Great information!! Thank you.

[@AnnD2023]

I can never get that type of foam insulation to stay stuck well enough onto the wood. I wanted to compress slightly when I install the window and it just pushes the insulation strip off.

[@HartzHomestead]

Be sure to sand the wood if it's rough, and wipe any dust off with a tack cloth. Even if it doesn't seem like there's dust on it, the tack cloth leaves a very clean surface for the tape to stick to. Press the weatherstrip on very firmly - I go over it with the back of my fingernail. Weatherstrip will stick best if the wood is varnished with clear polyurethane, even just one coat, or painted. Weatherstrip varies a lot in quality, so you could try some different brands. I have not had it come off that easy, so it may depend on the wood and weatherstrip you're using.

[@CoreyFeldman]

I accidentally bought closed cell foam and had this problem. It's exposed surface is tacky enough to grab the foam and pull it from the frame. Getting the open cell weather strip fixed this problem.

[@colinrichardson5507]

Great video, many thanks! Already made the frame with shrink film. One question, I'm looking for an alternative to the polyster film which I can get in Europe as the provided links does not ship to Europe. How does .003 inch translate to 3 milimeters? according to my calculations 0.003 * 25.4 = 0.0762 milimeter?

[@HartzHomestead]

The phrase "3 mil" refers to 3 Thousandths of an inch, not to millimeters. Especially in North America, the word "mil" refers to 1/1000 of an inch. So yes, 3 mil plastic is 0.0762 millimeters thick.

[@colinrichardson5507]

Ah now I understand, thanks for the reply!

[@beemaningi]

Thanks! Do you recommend a type of 2 sided tape? (I'm going to try the frame but there's a door where I would need to tape directly onto the door/painted wood. I suppose any tape can mess up a painted surface. Just wondering if you've had any luck with one that came off without taking too much paint with it! or do you leave the clear layer/film on permanently? Thank you for a great video.)

[@HartzHomestead]

I really like the eplastics.com 1/2" double sided tape with the red peel off backing. It's rubber cement based, so you can usually rub it off, though it may depend on the quality of the paint on the door and how long it's on. I do leave the plastic on as long as it's in good shape - usually 30 years or so.

[@john707070]

I have problems in my bedroom with sunlight and streetlights. It gets very bright and it’s not very dark. I’m trying find ways to make it better for sleeping. This plastic will will be ideal in the summer heat and winter cold in NY. I’ve seen other ways to make it black out. I wonder if this could be used with plastic that is black to block out light? Any idea about black plastic?

[@HartzHomestead]

You could use any plastic. I've seen tinted mylar (polyester film) with a reflective surface on one side, which you could face out, so you could still see through it, but it would be much darker. Black plastic would give you total blackness. It's usually polyethylene, and comes in 3 - 10 mil. Not sure if it would last as long as polyester, but you'd still get the heat saving benefit in winter. If the sun shines on it in summer it would heat up the black, so a shade outside the window would be best for keeping cool.

[@john707070]

Thank you! Very excited to build some frames. My home is going to be warmer in the Upstate winter.

[@steveforbes7718]

You may consider investing in what are known as "Blackout Curtains". The good ones definitely stop all light and also add an insulation factor. Then, if and when you want light all you need to do is push them aside until no longer needed. They are quite popular with third shift workers.

[@bookkeepingtipswithty]

Great video, I am going to try this. My question is I have a 54 inch by 54 inch picture window. I do not want to split it into two. Where can I find a piece of duralar wider than 4ft?

[@HartzHomestead]

Eplastics.com stocks clear polyester film 48" wide, and their website says they can special order custom widths up to 60” wide, so I would call them (they're in CA and TX). I don't know if they can do a small quantity, and shipping will likely be more on a wider roll. If not, search for other companies that make clear polyester film, or if there's a good local hardware store they might be able to help. Let me know what you find.

[@mknmike]

What kind of plastic is that at 9:17 that you are cutting? Do you have a link to where it can be purchased? I'm looking to create an interior storm for a 10'x4.5' picture window.

[@HartzHomestead]

That is 3 mil clear polyester film (0.003"). Amazon has 40" wide rolls. ePlastics.com has 48" wide rolls. See links in video description. You could search online for wider rolls, but may pay quite a bit for shipping. Another option is to break it up into multiple storm windows - then you could make 3 inserts 42" x 54" or 4 inserts 28" x 54" and use narrower plastic. Since a 10' long insert would be hard to store, and you'd need 1-2 vertical bars to keep the top and bottom from bowing in, if it doesn't open you might be better off permanently attaching the plastic to the window frame.

[@TheAndrewWScott]

Awesome video! Do you happen to have data on heating/cooling costs before and after installing these?

[@HartzHomestead]

Not precise data. When our house had single pane aluminum windows, adding double storm windows cut our firewood use literally in half, and the house stayed noticeably warmer. I've since installed vinyl frame double pane windows, and mostly switched to electric heat. Without these storm windows, we had a hard time keeping the house warm with electric heat during a cold spell. Adding storm windows again made the house noticeably warmer and dropped our electric bill by at least $30 a month.

[@sarahengland1843]

Thanks for the video! Have you tested the sound blocking effect of these film inserts by any chance? ...or do I need to use Perspex for that? Thanks for any advice on sound blocking.

[@HartzHomestead]

I think our house is quieter with the inserts, but haven't tested it in a tangible way. Thicker plastic would be better. A solid glazing like glass or acrylic would be best.

[@lizs1865]

Nice video. Did you notice any reduction in the noise level?

[@HartzHomestead]

Yes, we live near a river that is a constant background sound, and it's definitely quieter when our double 3 mil storm windows are in. Thicker plastic like 5 mil would dampen sound even better, but costs more. Solid acrylic or glass panes are best at blocking sound, especially 1/4" thick or more, but more expensive and harder to cut.

[@lizs1865]

@@HartzHomestead Thank you!

[@anaesterhazy631]

Will it stop noise, too?

[@HartzHomestead]

They will help reduce noise some. A thicker plastic like 5 or 7 mil is better for noise, though it costs more. You can get much thicker vinyl, but it's not as clear. If you really want to reduce noise a lot, use a solid acrylic sheet or glass, but they are harder to cut and cost more.

[@anaesterhazy631]

@@HartzHomesteadThank you.

[@nika_vodvud]

bless you man

[@leosarrade8995]

(slow clap) Verry well done sir! Great instruction and great information.

[@HartzHomestead]

Glad you appreciate it! This video was 21 months in the making, about 200 hours editing, from 340 clips I shot down to 94, plus 124 titles. The subject is dear to my heart, since these storm windows have made a huge difference in having a warm house, and not enough people know about them. I love the way they look, and could save the world significant amounts of energy.

[@joshuatoral5105]

Can this be done with glass instead of plastic film?

[@HartzHomestead]

Yes, glass is heavier, needs to be cut to size, and you have to be careful not to break it. Glass does block noise better than plastic, and can be put either outside or inside your window. It costs more new, but there are plenty of old windows for free if you take out the glass and cut it yourself. If you were to put two panes on a wood frame you're basically building your own insulated glass unit, which would be quite heavy to take in and out.

[@joshuatoral5105]

@@HartzHomestead thanks for the reply! I didn’t know a wood frame could be used to build an insulated unit. Everything I’ve seen looks like it has metal or plastic spacers before going in any kind of frame. Do you have any suggestions on how to do it with wood?

[@HartzHomestead]

@@joshuatoral5105 I've never done it, not sure how well it would work. I'm just saying if you did it would be heavy for a storm window. The main concern would be moisture, as wood expands and contracts, so the wood would need to be well sealed. To use glass for a storm window it would be better to build a wood frame for each piece of glass.

[@eh_bailey]

R5 to R9 from an R2-3 is totally ridiculous. Where do those numbers come from? I think you would be lucky to get even 1 additional R.

[@HartzHomestead]

An argon filled double pane window with a low E coating is about R3. The air space between two ordinary panes of glass, or plastic, is about R2. Adding 3 layers of plastic 3/4" apart, those 3 air spaces will add R2 each x 3 = R6. Over an R3 window makes R9. I can tell it works because it has cut our heating bill in half, from $100 to $50 a month in the winter. A triple pane window salesman shot my storm windows with a temp gun, and said they were as good as his R-8 windows that were $1,000 each.

[@gregcorwin8316]

@@HartzHomestead I really enjoyed your video. Very well done information for people who want to find a simple and relatively inexpensive upgrade for their window performance in winter. However your R value calculations aren't quite right. For example, as you mentioned, one lite of uncoated glass - R1, two lites uncoated and no argon, R2, three lites R3, and so on. In simplest terms, adding each additional layer adds an additional R1 to the stack. Forgetting R value completely, since ultimately it's just a lab calculation, adding 2 or more layers of plastic (tight is crucial) is without doubt going to make a very noticeable improvement in winter time performance and comfort. Summer improvement is more hit or miss, depending on other factors, but for winter it's a great idea. each ad

[@HartzHomestead]

@gregcorwin8316 This is debatable - I've not found any real studies on it. It is not the film but the air space that creates the insulation. Filled with air, one airspace is about R-2, filled with argon that same airspace is R-3. My logic is the airspace between 2 layers of glass creates an R-2, so each additional airspace adds another R-2. I've also noticed that plastic feels warmer than glass to the touch, and moisture does not condense on plastic as readily, indicating it is warmer, so the plastic itself may add a tiny amount of insulation. I do know that our house is much warmer with these installed.

[@gregcorwin8316]

@@HartzHomestead Consider that a single sheet of glass in a window is an R1, you mention that in the video and I agree 100%, so no dispute. Two lites in an IG or dual pane unit, without LowE coating or argon, or even a single pane with a storm window attached is an R2. That is also well established, and was also mentioned in the video, so once again we agree there too. However three lites in a triple pane configuration, with no coating or argon, is an R3, again this is a well-tested and well established performance value, yet if each airspace in a triple is independently an R2 as you suggest, then why is the actual triple an R3 and not an R4? And why is a single pane R1 if it has no airspace at all? As a quick aside, actual window glass energy performance when clear (uncoated) glass and with no gas infill (other than ordinary air), in multi pane configurations, will vary slightly based on the width of the airspace as well as glass thickness. Using R1, R2, R3, in examples is for clarity and will vary slightly real time based on the factors mentioned. Using R 2.02 versus R 2.04 based on different airspace depth or variations in glass thickness, rather than just generically keeping it at R2, would be cumbersome IMO and not really add anything to the discussion. However if you prefer to be more precise, then I would suggest using U factor rather than R value for more precision....but that might be overkill without adding anything really beneficial to the overall discussion. The ideal width of an airspace for maximum energy performance varies depending on whether or not it's filled with air or argon, and/or based on the LowE coating used, and/or on the thickness of the glass. As you mentioned in the video, 1/2"-3/4" works great for the application that you describe, no disagreement at all, I think 3/4" is ideal because you can put film on both sides of a 1x2 (again as you describe) and end up with a very workable internal storm window, with a solid R2 as constructed. But, if the airspace is the main consideration, then why is it necessary to have multiple sheets of plastic rather than just a single sheet of plastic installed several inches from the original window? If airspace is the insulator, then why do you get better performance (and you do) from having multiple chambers rather than a single wider airspace without the additional layers if the plastic sheet versus the single wider air space?

[@HartzHomestead]

@@gregcorwin8316 The problem with an air space over 3/4" is that there's room for convection currents down the colder surface and up the warmer one within that space, thus transferring more heat. I've seen charts that show 5/8" as optimal, and over 1" is not so good. A single pane is near R-1 because of a thin film of air on both sides of the surface, which might be reduced if it's very windy out. You might be right about the R values, though from experience it seems plastic insulates better than glass. I've never seen a scientific study on it. One chart I saw showed 2 panes of glass at R-2 and 3 panes at R-3.2, with just air between them and no coating, so each space would only add R-1.2. Another website lists 2 panes at R-3 to 3.8 and 3 panes at R-7 to 8, so that second space adds as much insulation as the first, but those are argon filled with Low-E coatings.

[@roughcut4683]

Why did you choose open cell weatherstripping rather than closed cell?

[@HartzHomestead]

The weatherstrip needs to condense enough to get the window in and out and compensate for variations in the space between the storm window and the window frame. Closed cell does not compress enough, so the space would have to be an exact fit. Though it's possible open cell may allow a tiny bit of moisture and air through, cutting the inside film slightly larger makes an air and moisture barrier all the way around.

[@CoreyFeldman]

I accidentally bought closed cell and it feels a bit rubbery on the surface, so it doesn't slide in, but sorta grabs the window frame and peels/rolls the foam off the insert. Besides compressing more easily, the Open cell is more of a smooth/slick surface, so it slides into the opening without pulling off the insert.

[@brianbailey462]

10-20 dollars a window?? how is this possible?? The foam weatherstripping alone is that much!

[@HartzHomestead]

I should have said $10 to $40 - it depends on the size. I did find 3/8" x 1/2" x 17' MD weatherstrip at Home Depot for $2.07, and 1/2" x 3/4" x 17' Frost King on Amazon for $4.65. Search for "Open Cell Foam Tape" or check your local hardware store. A 3' x 4' double storm window takes 14' double stick tape x 2 sides = 28'. A 36 yard roll from ePlastics is $12, = $0.12/ft x 28' = $3.36. 3 mil Dura-Lar on Amazon is $61 for 40" x 50', or $1.22/ft x 8' = $9.76 for 2 layers. So Foam $4.65 + Tape $3.36 + Film $9.76 = $17.77 for a double 3' x 4'. I built mine with scrap lumber I already had. Buying 1"x2"x8' lumber runs $2 - $8 each, so that adds $4 to $16, total $22 to $34 plus screws, varnish etc, more or less depending on the size of your window.