Window Air Sealing Techniques | Ask This Old House

In this video, Ask This Old House home technology expert Ross Trethewey and master carpenter Nathan Gilbert share some cost-effective ways to seal and insulate existing windows without replacing them.
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Host Kevin O’Connor, contractor Nathan Gilbert and tech expert Ross Trethewey share some cost-effective ways to seal and insulate existing windows without replacing them. The team discusses efficiency ratings for older single-pane windows compared to today’s options and offers tips to seal your drafty windows from the inside. They explain different insulating techniques, including shrink wrap, weather stripping, and caulk. Anything you can do to decrease airflow and leakage will drastically increase comfort and energy savings.
Skill level: 1/5
Cost: Varies depending on the method of sealing air leaks
Time: 1-2 hours
Materials
Window insulation kit [thd.co/3uX6buP]
Foam sealant [amzn.to/3oQGTL7]
Fiberglass insulation [amzn.to/3gM1lbx]
Weatherstripping [amzn.to/351ECWs]
Caulking cord [amzn.to/3sCn9vC]
Tools
Caulking gun [amzn.to/36aKihf]
Putty knife [amzn.to/3rTbBoA]
Utility knife [amzn.to/3gKR2oh]
Try Sealing Air Leaks Before Upgrading Windows
Windows usually have an R-value of 1 to 2-walls generally have an R-value between 13 and 20. Before incurring the expense of buying a new window, homeowners should try to seal any air leakage around the existing window’s frame. Traditional New England homes usually have storm windows to create a bigger barrier during winter. Nathan also explains a newer style: screw-in aluminum with removable glass for spring and summer.
Where to find it?
When talking about shrink wrapping windows, Nathan refers to the Frost King [www.frostking....] Premium Cylinder, Heavy Duty, EZ Roll Shrink Window Kit [thd.co/3uX6buP]
When talking about feeling a draft in your window and removing window casing, Nathan suggests using a low expanding foam like GREAT STUFF™ [www.greatstuff...] Window & Door Insulating Foam Sealant [amzn.to/3oQGTL7].
All other tools used including caulking gun [amzn.to/36aKihf], fiberglass insulation [amzn.to/3gM1lbx], weatherstripping [amzn.to/351ECWs], and caulking cord [amzn.to/3sCn9vC] can be found at local home centers.
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About Ask This Old House TV:
From the makers of This Old House, America’s first and most trusted home improvement show, Ask This Old House answers the steady stream of home improvement questions asked by viewers across the United States. Covering topics from landscaping to electrical to HVAC and plumbing to painting and more. Ask This Old House features the experts from This Old House, including general contractor Tom Silva, plumbing and heating expert Richard Trethewey, landscape contractor Jenn Nawada, master carpenter Norm Abram, and host Kevin O’Connor. Ask This Old House helps you protect and preserve your greatest investment-your home.
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Window Air Sealing Techniques | Ask This Old House
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[@BlueStreak706]

Been watching this show since 95 when I was 13. Thanks to KZbin, we don’t have to wait until Sunday to catch it on tv.

[@cabooseocallaghan6229]

If anyone is wondering what kind of caulk to use, i used Dap Dynaflex 230 clear on my windows since it's pretty much invisible when it totally cures. It's white at first but don't worry, it'll turn clear in either a few hours to a few days depending on how thick the bead you lay is. My windows were having early morning frost build up on the inside, and after sealing the cracks with the Dynaflex there's no frost at all. It also comes off fairly easy with a painter's tool, caulk remover, or putty knife or some kind of flat scraper. Best of luck boys 👍

[@RobynJohnChrestman]

I am so glad you said something about what kind of caulk I need to caulk my windows and was at a loss of what kind to use. I have horrible condensation on the interior of my windows and the draft on this Reno house windows is well it actually will move the curtains. So it’s imperative that I find the right caulk. I love caulking but I have never caulked windows before so thank you!!!

[@rawbacon]

Stopping air infiltration and thick curtains can make a huge difference.

[@1stWorldProblemsSolved]

thick curtains make a huge difference.

[@wingking077]

Thank you for speaking to the average home owner who can’t spend 20-30 thousand for new windows.

[@MustPassTruck]

Inflation is making it more like 40-50 now.

[@rupe53]

@@MustPassTruck ... at a grand each (typical) you have 40 - 50 windows in your house?

[@MustPassTruck]

@@rupe53 I'm going off quotes I have gotten for my house with about 30 windows. Its about 1,500 to 2,000 per window with labor costs for nice casement windows.

[@cyrenedomogalla5127]

If you're at all handy, you can learn to do the install yourself (KZbin!). Then go to your local window supplier (not contractor) and order from them. Yes, it's a lot of work, but if it means new, efficient, functional windows for half the price tag - might be with it.

[@rupe53]

@@MustPassTruck ... ouch!

[@buckybarnes3803]

One year I did the plastic inside but I taped it over and around the trim. Then additionally I built an inexpensive exterior frame with 4 mil plastic on the outside. It was a particularly drafty window and room. Wasn't pretty but it worked

[@TrigunV4S]

Dang Bucky the military didn’t pay you much for your years of service! Tony didn’t have some type of payment plan for the avengers! 😆 Hmm perhaps your solution would work for my windows as well! My house windows are Original from 1949!

[@charlottelebrun]

Ok in

[@TheChupacabra]

I can’t get over how cool it is to see richard’s son jumping into the this old house cast!! The resemblance is so uncanny. Love how you all are keeping it in the family. I wish Roger’s kid could’ve jumped in when Roger had to step away. “There you are Peter!”

[@penske1]

Sick Hook reference!

[@TheChupacabra]

@@penske1 haha thanks!

[@frankiei755]

Dude needs to lay off the caffeine… he talks a million words a minute

[@TheChupacabra]

@@frankiei755 spreading the HYPE!

[@govinda102000]

I lined/wrapped my removable screens with thin plastic. It helped nicely especially when I used removable tape where the screen meets the window frame.

[@camicri4263]

That's good information, thanks guys! I've been watching your show since 1984 and always loved it! Is so good to see that is as relevant as January 1st 1979.....in my case 1984.🤗🤗

[@Stonewallx39]

With gas prices going the way they’re probably going to go this winter (‘22-‘23) this information could literally be a life saver for many! Frankly as much trust as most have in the power grid after the Texas fiasco a couple years ago it would be foolish not to think through some efficiency improvements in each of our homes to get through the roughest spots.

[@mikeylikesit6588]

This is the exact video I needed. Can’t afford new windows yet. Have other more pressing matters. This will help tremendously. TY

[@Ang.0910]

Keep your original wood windows! Salvage storm windows and use the plastic in the meantime

[@TheCimax1]

Hi. Thank you so much for your video. Do you have any suggestions for installing the window sealers to where windows would open in case of a fire? Thank you.

[@jennlo7293]

Replacement windows are not as infinitely repairable like the old wooden Windows. Storm windows, weatherstripping, work great for old windows and reduces drafts.

[@Lwnmwrboy5]

Window inserts are a good option if you have enough depth in the sill. Relatively inexpensive and don't look as cheap as a plastic film. Getting new windows is nice, but the return on investment takes quite a while. We have old single pane and a window installer came by to give us a quote and was quite honest and said if you aren't going to stay for at least 5 years after this, just band-aid it and save your money.

[@CertifiedMailSignatureRequired]

Where are you finding relatively inexpensive window inserts? I have found nothing of the sort, please do share! Considering making myself but not sure I'm 100% qualified so curious what you've found. thx. -tony

[@Lwnmwrboy5]

Agreed. If you pull off the molding around window and put backer rod or use spray foam in a can, that will likely solve most of the issues on older windows. Reality is that most installers will quote you for the simplest and quickest install for new windows, which generally means it won’t be done the proper way. For older wood frame single pane, you’re better off hiring someone to restore them instead of replacing. Bronze weatherstripping would certainly be added and lasts forever compared to brush/foam.

[@NOT_A_TOP_FAN]

@@CertifiedMailSignatureRequiredsame boat. Everything is so freakin expensive these days. Makes me not want to purchase anything big because products and services are so overpriced. There’s a couple good videos of guys who have made wooden ones and used the shrink wrap. But even then, depending on how many windows you have, the molding to build them isn’t cheap….

[@2-old-Forthischet]

I had double pane windows installed in my condo about 5 years ago. I haven't turned on my heater since. Of course I live in So Cal and I admit I'm a woos. One thing I found that helps in the winter and summer are sunblock curtains as a supplement to the vertical blinds. One thing to beware of when installing new windows is that if the walls are not perfectly flat to begin with, it's going to look like krap.

[@JEK]

Same here, one of the last apts. I lived in had all new double pane windows. Maybe 1 week out of the year we would turn some heat on. Otherwise, being an upper unit and heat rising was very nice savings on utilities.

[@CertifiedMailSignatureRequired]

lol - didn't know y'all had heaters in so-cal

[@2-old-Forthischet]

@@CertifiedMailSignatureRequired luckily these new fangled ones don't have pilot flames.

[@hardass912]

Projects for the spring, when it gets warmer, thanks!! Propane is costly, need to save everywhere i can

[@aaronhodgman]

I'm building my own wood framed storm windows using two layers of that plastic, and held in place with foam weather stripping. Luckily I only have three old single pane windows to deal with though.

[@CertifiedMailSignatureRequired]

nice - thinking of this myself. any more tips or advice for a fellow diy-er?

[@dimitardonev4507]

This type of window are full of design flows. In order to keep the convenience of low profile footprint when opened they said good buy to all ability to create tight seal between the panels.

[@warrenvalentino5763]

Thank You Very Much for this information in this video! i love watching all of your videos. :)

[@leohoward7282]

I remember a video from Norm where he talked about using different gasses toimprove insulation.

[@brewster102]

If you use window unit ac, take them out for the winter, they are very drafty

[@Okamika44]

I appreciate you showing cheaper options. thx

[@tycox8704]

I was told by a relative in the commercial building trade that windows have the highest markup of any building product. In other words, they are unnecessarily over-priced.

[@marklittler784]

Can get rubber beading for the two sides to replace the two wooden ones dividing the windows for a better seal.

[@bangbang-nm7hx]

I gotta say very informative and handy, call me old, Bobs where its at. Good man.

[@marklittler784]

Put up double curtains that go to the floor.

[@SeanBaker]

I just had three windows replaced last month. That's enough window replacement for me. I may consider storm windows in the future. I also have window inserts for some of my other windows. Much cheaper solution.

[@marklittler784]

If replacing putty put primer on the wood first to stop the wood absorbing oil out of putty and seal with paint when putty becomes firm after a week or two.

[@thomasgregory8941]

Money saving video. Thanks

[@Mr.Pop0]

It aint pretty but the best is foam insulated tape by frost king, it sticks to everything and its really easy to use.

[@TheChupacabra]

Are there any competitors to frost king? I’ve had mixed results with their products but they dominate the shelf space. Any hvac pro recommendations out there?

[@CertifiedMailSignatureRequired]

@@TheChupacabra frostking is fine, but it's cheap. it's scotch double sided stick tape + a thin ceranwrap...

[@pbenson56fran]

How would you weather strip a window that opens from the side of the wall?

[@coreylipford8905]

Probably the same put the weatherstripping seal on the part where it seals or closes

[@pbenson56fran]

@@coreylipford8905 thank you

[@mcbustnut8033]

Love this, thanks guys 🙏🏽

[@mileena7702]

Thank you I really appreciate this info.

[@svendolufsen849]

Aluminum storm windows are traditional now???

[@kw2080]

How much savings? How about some example numbers?

[@jenniferzennifer6949]

I have tho older metal storm windows. I was told one is supposed to be the bottom and one the top... but which way is it? The outer most storm window on top or bottom?

[@seanh3563]

Spring bronze is where it is at for air sealing. Lasts 100 plus years.

[@keradouglas6401]

@Sean H what's spring bronze and where can I purchase?

[@jasony9950]

Every, please don’t ruin your homes by putting vinyl windows, they are throwaways, 15 years from now. Keep the character of an old home by keeping the windows.

[@rupe53]

I said that years ago and everything I tried was "not quite right" so I took the plunge and replaced the windows. Having a home that was 100 years old took some head scratching, but I settled on doing the outside trim with 5/4" x 4" pine so from the street it looks almost the same. The bonus is I save quite a bit on heating costs due to lack of draft. BTW, they are vinyl on the outside and wood on the inside.

[@hosoiarchives4858]

I have never understood why people buy vinyl

[@chuckgordon8198]

Kept mine. However, I recommend more aggressive weather stripping and sealing. Gives you a chance to really fix it better. Also, exterior storms change the exterior. I opted to make removable interior inserts. Make them for about $100 a window in 2022. Table saw and hand tools. About 6 hrs to make per window excluding finishing. No modification of frame other than a few holes for pegs up top and latch on bottom. I suppose screws would work too. In and out in a few minutes. Summers I use a removable screen insert I get from any chain hardware. No visible mods. Works great. Seal seal seal.

[@Stoffmonster467]

You can get windows looking ecactly like your historic ones - but with wooden surface and triple pane glass.

[@mortensonaaron]

I thought Ross and Nathan were the same person until now. (Just kidding. Love you guys)

[@tdkaz]

1 stepler and sheet of plastic - will do

[@ewcamaewcama]

any ideas for weather proofing a patio sliding glass door?

[@rupe53]

you could caulk the stationary side and use that temporary calk on the moving side. Don't forget the gap where both sides overlap.

[@flybyav8tor]

Most modern windows are such a scam. R1 vs R3 compared to a R23-25 wall is less than a 3% improvement. Pop the sashes, install some good interlocking bronze weatherstripping, repair any broken parting beads, repair glazing. Add some inset storm windows and bam great performing window and most importantly they are still beautiful vs ugly chunky insulated glass with shallow muntin bars. My windows are 190yrs old and are in great shape. A modern window gets what, 30years at best?

[@paulkatz8250]

What about windows that open horizontally?????

[@edtalley]

my storm windows don't work worth a flip for insulation. Last winter i had ice on the inside of my windows.

[@cabooseocallaghan6229]

what kind of caulk is best to use so it isn't too sticky and a big hassle to remove come springtime?

[@markchallenge7949]

It’s called caulking STRIPS I believe. It’s like grey putty noodles. You shove in the cracks. I used them last year and after a few Kim ths they stopped working because they weren’t sticking to window anymore. So I won’t be using them this year

[@cabooseocallaghan6229]

@@markchallenge7949 Thanks Mark 🙂 i ended up using Dap Dynaflex 230 clear and it worked excellently. Totally invisible and it stopped up all the cracks. It's sticky enough but comes off fairly easy from the wood with a painters tool 👍

[@rebeccajohnson629]

So need to redo windows

[@bangbang-nm7hx]

I miss Bob and the good days!!!

[@globaltokyollc-f1322]

a house still needs to get aired out during winter time , so anything that prevents the window from opening I would not do/suggest .

[@racerx1326]

Please make video on how to replace these windows

[@Ang.0910]

If they’re original old wood windows: don’t!!! There is more valuable and will last longer than anything made today just get storm windows salvage them if possible or do the DIY things in the video.

[@duncan359]

but the old windows will last longer if you reglaze and keep them sealed

[@cya177]

Disappointed - Wanted to see plexiglass being installed on the outside without framing - instead of using plastic. I personally find using plastic over my outdoor windows has been much more energy efficient than plastic over inside windows. However, the plastic breaks down over time so am wanting to do plexiglass as well as a nicer looking curb appeal versus my plastic. I can’t afford new windows and sashes so trying to keep them from rotting further. It’s been very helpful both in winter and summer. I grew up in a era when putting plastic over outside of windows in winter was a common thing. It’s not a thing now days but they aren’t paying my utility bills so I don’t really care what others think and I’m not in a HOA, though I try to install it as tight and neat as possible so it’s not a even bigger eye sore. Thus again why I want to switch to plexiglass but need it to cover my entire window sashes and wood frame are and looking for ideas on best way to do this. A bit more complicated than sticky tape and a staple gun.

[@DaveWesely]

Fiberglass insulation to stop drafts?!! NOPE. Air goes right through fiberglass, it only acts as an air filter. Use the foaming sealant. Except it's expensive and messy. Better yet buy closed cell foam sealer/backer. It comes in different diameters to match gap size. Then apply cheap latex painter's caulk to the gap between the window and stud (both sides) and squeeze the backer tube into the caulk. The caulk helps the tube slide into place and seals the edges. It's cheaper and not as messy. Many home builders have skimped on sealing window and door perimeters. If you can remove and reinstall window/door trim, this is by far the most effective insulation you can get.

[@tammyschilling5362]

People can rag on old wooden windows all they want, but they are at least reparable. Modern windows are basically disposable and only last 6-10 years on average before the seals fail and you have to replace the darn thing.

[@peehandshihtzu]

I have a way of sealing those old wood frames, get them wet. :)

[@akoznasovajusername]

In some cases, by doing all that, you could also cause a condensation issue in your house.

[@CertifiedMailSignatureRequired]

if you've got single pane like a lot of us, we already have condensate on the interior glass leading to drips onto the wood frame/below - aka, ya - we know. this would only help that.

[@BritonWells]

Or like me, screw the window shut and caulk it inside and out! Some homes have far too many operable windows that are never used

[@abunchahooey]

Exactly! If we open windows here in spring or fall, we use the exact same ones that create a cross breeze throughout the house. It’s 4 windows. I told my husband we should seal all the other ones because most of them leak a bit.

[@bbtank3000]

He speaks almost exactly like his father.

[@Ang.0910]

Do NOT change out your old wood windows!! New windows will never last as long for only a minimal R value upgrade! Those original windows are better than anything made today! Salvage storm windows or use the cheap options here.

[@arpitamuchhal2713]

Sad to see disrespect of old wood windows. There are many of us spending more per window than replacing them to restore. Old windows with storms are extremely efficient. And they are made of wood that will last couple hundred years if maintained. I am in the process of restoring over 100 year old windows. They will last another 100 years!

[@elizabethvillalobos4504]

Next time remember you’re speaking to average consumers

[@zeroskater720]

Ummm he said A hole ……. 0:37

[@kronk358]

Not being rich enough to have 35 windows helps

[@komaboi19]

"My wallet ain't that big", says the dude who is a millionaire. 🤣🤣

[@s1dest3p]

Kevin's wallet is actually that big...

[@scottthomas5819]

Comments get points! Comment comment comment...

[@billsherman6129]

There are goals with any window system (or door, or building envelope): #1 is to keep water out. #2 is to reduce air exchange (which will also prevent moisture exchange). #3 (lastly) is insulation. Fiberglass batting does NOTHING to prevent air or water intrusion/exfiltration. The team should have done a better job in this video but it wasn't horrible.

[@justjason7662]

🤔 middle of summer in Texas and researching how to weatherize windows for some ideas for an older home with crap windows. All video suggestions are yankees trying to hide from their freakish winters. Meanwhile, I’m still trying to figure out what this “winter” thing is during our mild fall months of November-February with 50-80 degree temperature ranges. In the middle of second summer we’re ranging from 105-120 degree days and these guys are talking about opening their windows when they get out of “winter”?! We open our windows and actually give our AC a break in “winter” which may I remind you is just second Fall for us except for the two weeks in February where something catastrophic happens that no one in Texas understands and everything starts turning to ice. As terrifying as it is, it only lasts two weeks, and none of us know how to drive during that time, so we just shut the entire state down…. Literally… the entire state… Most accurate representation of Texas seasons I can surmise: Spring = March-April First summer = May-June Summer= July-August Pre-Fall = September (this depends on El Niño or El Niña year if you’re from up north… don’t ask… just know September can vary wildly) Fall = November - February (2nd week) Winter = February (3rd and 4th weeks) Then sudden temperature change from winter’s 20s-30s back to Spring’s 70s-90s. Sometimes a 65-69 if we’re having a mild spring. (See El Niño/El Niña year) If you start to understand all that, then you have to learn our drought patterns that usually last 5-10 year spans of reduced rainfall and higher average temperatures across all 6 seasons. Except if we’re in a drought we technically lose pre-fall and just extend summer by another month to include September. Oh yeah, and then there’s the random weather change that can happen any time of year and produce any kind of weather pattern for anywhere from 1 day up to 2 weeks. 60 degree day in summer. Ice in spring. Hot muggy thunderstorms in fall or pre-fall. 90 degree day in our 2 weeks of winter. 🤷🏻‍♂️ basically just take everything I explained and understand at any time of the year for an unknown number of days the weather will be completely wrong and flip you the middle finger 🖕🏻 just to screw with you. 🤔 should I explain the tornados too??? 🤷🏻‍♂️ meh, we’ll leave some surprises! 🤣

[@CertifiedMailSignatureRequired]

sounds like a wonderful place to avoid.

[@jameskozlowski4139]

Its February you are a few months late.

[@darylfitz4189]

What entails being a “master” carpenter…. ? “can you come over and fix my drywall, mr handymanguy…..?l Sure, that’ll be $78.74. But I am a master and my charge is $778.746 If you can’t afford it we’ll all laugh at you like the high-faluten jackasses we are.

[@rupe53]

I always laughed at those saran wrap storm windows, which might be fine if you are stuck in some drafty apartment for a few years. The flip side here is the best you can do price wise is maybe $5 a window. If you replace it each year then you might as well buy storm windows after 20 years... and that's just cost out of pocket, without labor.

[@riverraisin1]

Saran wrap is easier to store in the summer.

[@DanBurgaud]

R value, U value... All these just to confuse the customer, to make the product look better. next time, someone will come with another category called CI value - which refers to "consumer idiocy"; the higher the number, the higher the chance the customer will be fooled into buying it...

[@StoneE4]

Maybe the _"consumer idiocy"_ is coming from consumers who are confused by simple scales of insulation and thermal transmittance values.

[@brandonmathiassweet3284]

I couldn't agree more. U-Factor is to make newer windows seem better then they actually are.

[@StoneE4]

@@brandonmathiassweet3284 _"U-Factor is to make newer windows seem better then[sic] they actually are."_ U values are a measurement of thermal transmittance. It's not like the window industry invented the concept in order to sell windows. You may as well be saying, "Length measurements are to make lumber seem longer _'then'_ it actually is."

[@brandonmathiassweet3284]

@@StoneE4 Yes, I understand what U values are. Perhaps the use of U values as the industry standard where r-value is the norm may add to a bit of a misunderstanding of a window's thermal performance. And perhaps those selling the windows capitalize on this misunderstanding.

[@StoneE4]

​@@brandonmathiassweet3284 If you understood what U values are you never would have said the following... _"U-Factor is to make newer windows seem better then[sic] they actually are."_ Hopefully you've remedied your ignorance.

[@badgerfactory]

too much talking...literally just 10 sec of video showing anything

[@DanBurgaud]

4:30 get your kid's playdough... same result...

[@babbott6902]

This video was a waste of time. All talking but no substance until the very end. If I wanted to know about storm windows or the cost of getting new windows, that's what I'd search for. Wow

[@vladislavovich100]

Instead of these storm windows just make double glass window with a gap between glass sheets approximately 2-3 inches or more.

[@cercumflexcircumflex]

Dude in the grey long sleeve is skeeted out of his mind lmao talking at 2x speed