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Green Building Blog

Should Your Old Wood Windows Be Saved?

We weigh the options with cost, complexity, efficiency, and preservation in mind

Image Credit: left, Tom O’Brien; center, Michael Pekovich; right, Daniel S. Morrison

Old wood windows are as charming as they are maddening. While they offer appealing craftsmanship and an authentic sense of home, they typically leak like a sieve. With rising fuel costs, an unstable economy, and a catatonic housing market, it’s simply becoming more and more difficult to look at those old units with pride.

If you live in a historic district, you may not have the option of installing replacement windows. If you live elsewhere, however, you may be tempted to ditch the whole preservationist mentality and hop on the vinyl replacement train in hopes of reaping all the green rewards and cash savings of a modern home. Don’t—not without carefully considering your options first.

By assessing your existing wood windows and making the right upgrades, you might be able to restore them to rival the performance of a standard replacement—at a fraction of the cost.

Consider the potential of your existing windows

You might make a window-replacement contractor’s head spin if you tell him that you’re going to repair rather than replace an old, drafty wood window. After all, thanks to progress in building technology, tight windows with astonishingly high insulating values — Serious Windows, for example — are now available. But not every advanced building solution or product makes sense for everyone. For many, repair work is a desirable alternative to replacement.

In a collaborative effort, the Vermont Energy Investment Corporation, the University of Vermont’s Department of Civil and Environmental Engineering, and the U.S. Army Cold Regions Research and Engineering Laboratory set out to test the value in wood-window repair. In their 1996 paper, “Testing the Energy Performance of Wood Windows in Cold Climates,” they assessed the performance gains accrued through various wood-window upgrades, including the…

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10 Comments

  1. Apollo S | | #1

    Lead paint - not as easy
    I think problem #7 isn't getting full pragmatic light. These old windows often have way too many layers of lead paint. Stripping that paint is really hard and expensive job, if proper precautions are taken. Reality is, way too many contractors and homeowners just don't take those precautions. Seen my share of those using heat guns or blowtorches (both a no-no).

    8-16 hours per window to properly remove lead, replace the glass, and mitigate issues caused by decades of use - it was cheaper to buy more efficient replacement windows and get modern mechanism. Keeping old windows is over-rated, unless you ones are in pristine condition.

  2. Lloyd Alter | | #2

    Excellent article
    The joke in the heritage field is that replacement windows are called that because every 15 years you have to replace them again. Even if that is not quite true except for the cheapest vinyl, every study going shows that the payback on replacing old windows with new ones takes forever. However people in the field tell me that the main reason people change isn't energy, it's maintenance.

    The article also doesn't address the option of acrylic inserts. I just outfitted my house with a new design of insert (can I say a trade name, here, Indow?) and they change everything in terms of draft and comfort and I have the thermographic photos to prove it. There is no reason to change windows when they can be fixed and this new tech exists.

  3. David Argilla | | #3

    Lloyd
    for the inserts, do you ever get problems with fogging on the inner surface of the glass window (between the insert and the window?)
    Thanks

  4. Norm Farwell | | #4

    Lead remediation in old windows is a huge economic opportunity
    An article in Mother Jones in 2013 made a surprising argument: lead in gasoline fueled the crime wave of the 60-90's, and lead in old windows is still doing terrible damage to those who can least afford it. Estimates suggests that a national program window replacement would payback 10-1 in avoided costs. A couple of highlights from the article (http://www.motherjones.com/environment/2013/01/lead-crime-link-gasoline)

    "Neurological research is demonstrating that lead's effects are even more appalling, more permanent, and appear at far lower levels than we ever thought.... The EPA now says flatly that there is 'no demonstrated safe concentration of lead in blood.'

    ...Lead paint chips flaking off of walls are one obvious source of lead exposure, but an even bigger one, says Rick Nevin, are old windows. Their friction surfaces generate lots of dust as they're opened and closed... Nevin estimates that there are perhaps 16 million pre-1960 houses with lead-painted windows, and replacing them all would cost something like $10 billion per year over 20 years.

    Soil cleanup in the hardest-hit urban neighborhoods is tougher to get a handle on, with estimates ranging from $2 to $36 per square foot. A rough extrapolation from Mielke's estimate to clean up New Orleans suggests that a nationwide program might cost another $10 billion per year.

    So in round numbers that's about $20 billion per year for two decades. But the benefits would be huge. Let's just take a look at the two biggest ones. By Mielke and Zahran's estimates, if we adopted the soil standard of a country like Norway (roughly 100 ppm or less), it would bring about $30 billion in annual returns from the cognitive benefits alone (higher IQs, and the resulting higher lifetime earnings). Cleaning up old windows might double this. And violent crime reduction would be an even bigger benefit. Estimates here are even more difficult, but Mark Kleiman suggests that a 10 percent drop in crime—a goal that seems reasonable if we get serious about cleaning up the last of our lead problem—could produce benefits as high as $150 billion per year.

    Put this all together and the benefits of lead cleanup could be in the neighborhood of $200 billion per year. In other words, an annual investment of $20 billion for 20 years could produce returns of 10-to-1 every single year for decades to come. Those are returns that Wall Street hedge funds can only dream of."

  5. MKCF | | #5

    This article is a few years old I see, but I'll comment here anyway. I'm a cabinetmaker/millworker by trade, and I have made many windows and doors over the years. I'm currently in the process of putting my newly repaired old windows back into their jambs. I'll share my insights here for anyone interested.
    Lead paint: I used steam to soften and remove this, and a lot of elbow grease while wearing protective gear. But if I was going to do it again, I would have the sash dipped in lye. Yes this can definitely interfere with adhesion of future paint, varnish, etc. but taking the time to neutralize the alkalinity in wood joints strikes me as much easier than removing old lead paint the slow way, and less dangerous in terms of exposure.
    Old Putty: Steam is the way my friend. There are several youtube videos on it. I built a steam box out of rigid builder's foam and a camping stove for heat, works great. The putty comes right out and so does the glass.
    Beauty: Why do we live in old houses? If you have wavy glass, you are lucky. Some of the windows in my old house are new and made with double-glazing. I made them. I did everything I could to match the old windows, but there is no comparison in terms of beauty. I also made brand new single-pane windows, but they are not as beautiful as the originals. Even new wavy glass is not the same as the old stuff. Beauty is hard to come by, and worth preserving.
    Economics: Restoring a house full of windows is an enormous undertaking. If you do the work yourself, it is not expensive. Probably cheaper though if you pay someone else for restoration instead of purchasing and installing high-quality replacement windows. It depends on how far gone the originals are. Either way it's an expensive proposition.
    Indows: You kind of don't need to restore your old windows if you put these things in (theoretically and depending on their condition obviously). But a leaky outer window and a tight inner window is an ideal configuration in terms of allowing the system to breathe outwardly. Keeps lead dust out of your house too, at least in theory. I think they are brilliant.

    1. GBA Editor
      Brian Pontolilo | | #6

      Hey MKCF (would be great to know your name).

      Thanks for sharing your experience.

      The steam box does work really well. And as you note, it is super important to be careful when removing lead paint. Protective gear is a must as is working over a well-tarped area to catch the paint chips.

      1. MKCF | | #7

        Before I began the stripping process I made the decision not to have the windows dipped, as I heard there could be future adhesion problems and also the possibility that the lye would damage the wood in other ways (possibly darken it). I have since come to the conclusion that it would have been the best option. There are few "dip shops" still in operation in Connecticut these days, the one I found was on Cape Cod. Old sash are easy to disassemble, but I'm pretty sure that a good soak in vinegar water overnight would allow the acid to penetrate into the sockets of the mortises and neutralize the lye.

        There is another, very safe method of paint stripping which is to simply leave the sash outside for several years until the paint falls off. You have to catch them before rot sets in. Not a very practical solution but a safe and easy one if you have the luxury of time.

        In my experience, it is very difficult to distort or warp very old heart pine such as one finds in old woodwork. I would perhaps attempt a more serious steam and/or water bath method in the future as a much cleaner and chemical-free approach. More water, more heat, longer soak. If I once again find myself faced with the un-enviable task of stripping a lot of lead paint. The infrared heater works, but it is tedium defined.

        I would also like to touch on the subject of replacement paint. I have no faith in modern paint. Lead was outlawed in '78 I believe- and I don't think any of the billions of gallons of paint that have been applied since then has survived outdoors to this day. Instead, it peels and cracks and gums up and falls off.
        I went with tung oil and pigment. It's dead flat and you have to like the look. Repeated applications of oil bring up the sheen however. It ought to never peel since it is a penetrating oil and not a film forming finish. Maintenance involves a quick rub with Scotch-Brite and re-application of oil, one a year or as desired. I'll let you know in 30 years how it performed.
        Similar to the Allback paint system, but I tested their linseed oil and mold grew in it. Tung oil should be an improvement. I added some zinc as a good measure.

        -Mike Christie-Fogg
        http://www.foggfauxbois.com

  6. Jud Aley | | #8

    We restore any where from 25 to 100 single pane wood windows per year, right now the guys are working on a window project in New Haven. Below is right off of our web site on the "Frequently Asked Questions page.

    Replacing or Restoring Old Wood Windows Frequently Asked Questions

    Q: What is the cost of window restoration?
    A: There are two different levels of window restoration that R.J. Aley can provide, Mechanical Restoration and Full Glass Out Restoration. Please note that the more panes of glass per window the more labor intensive the work and the more costly the restoration will be. If there are fewer panes of glass the restoration takes less labor and will be less costly. Below are some typical window restoration costs.
    Mechanical Restoration of a 100-year-old double-hung wood window that is 30” wide by 52” high with 6 panes of glass on the upper sash and 6 panes of glass on the lower sash can cost from $400-$600 per window. This estimate includes the following:
    • Making both sashes operational so they open and close easily
    • Adding Spring Bronze weather stripping if none exists
    • Removing only loose and peeling paint, or paint that interferes with the smooth opening and closing of the upper and lower sash.
    • Replacing any missing or broken sash chains or ropes
    • Replacing any broken or badly cracked glass and missing glazing putty
    • Adjusting the window so the center meeting rails match and the sash lock functions as it should.
    • Install a Harvey brand True Channel triple track storm window.
    • Painting the window after a mechanical restoration would add additional costs.
    Full glass Out Restoration can cost as much or often more than replacement windows. In general, a full glass out restoration of a 100-year-old double-hung wood window that is 30” wide by 52” high with 6 panes of glass in the upper sash and 6 panes of glass in the lower sash can cost $1000-$1,400 per window. This price includes all of the following:
    • Safely remove the window sash from their frames using EPA mandate Lead Paint Work Standards
    • Steam strip lead-based paint from the two window sashes
    • Remove all existing glazing putty and replacing it with new putty.
    • Make minor repairs to the sash.
    • Prime all sides of the sash with oil based primer
    • Replacing any broken or cracked glass
    • Installing new spring bronze weather stripping.
    • Install new brass weight chains.
    • Install new brass sash locks.
    • Install a Harvey brand True Channel triple track storm window.
    • Painting the window after restoration would add additional costs.
    • Note: In most cases we can proved historically correct reproductions of your existing antique window sash for the same cost or slightly less than a full glass out restoration.

    Q: I want to save money on my home’s energy bills. Is replacing my windows the first thing I should do?
    A: Absolutely not. Your first step should be to schedule a Whole House Energy Audit completed by a Building Performance Institute certified professional. R.J. Aley provides this service, which among other things, identifies where your home is leaking air. In our experience most of the air loss is not through the walls or windows. It is likely that most of your home’s heat loss is through your attic due to inadequate insulation. Another possible cause of high heating bills may be an outdated furnace or boiler that is not operating efficiently. Only after you have increased your attic insulation, sealed your home’s air leaks, and updated or tuned up your boiler or furnace, should you consider restoring or replacing your doors and windows. Bear in mind that if you choose to restore or replace your doors or windows, it is likely you will never recoup your investment.

    Q: I want to live more sustainably and use less energy. Doesn’t it make sense to replace my windows?
    A: The “greenest” windows are the ones that already exist in your house. If you replace your original wood windows they will go into a landfill. By restoring your windows you’re not adding to the waste stream, and they will have very few, if any, petroleum-based products in them. Vinyl replacement windows are made from oil, as are the jamb liners on high-quality wood replacement windows. If we want to reduce our dependence on foreign oil, we need to reduce demand for it in all its forms—including vinyl windows. In addition, the manufacturing process, and emissions from transporting the windows, all add to global warming.

    Q: Are replacement windows more energy efficient than wood windows?
    A: If installed incorrectly, cheap vinyl replacement windows will leak more air than the original wood windows with aluminum, or wood storm windows. This leads to higher heating bills than if you had left the original wood windows in place. Restored wood windows with modern weather stripping and a good quality aluminum triple track, or wood storm window, are almost as energy efficient as high-quality replacement windows if installed correctly. A new double pane replacement window may have a rating of R-5 at the glass if installed correctly, whereas a restored wood window with an exterior storm window may have an R-Value of 3.75

    Q: Why is it so important that old wood windows have exterior storm windows? How long do they last?
    A: A restored single pane wood window must have some kind of exterior storm window to come close to the performance of a properly installed high-quality replacement window. The air space between the window and the storm window creates the insulating factor; therefore, exterior storm windows are a necessity. Further If you don’t install an exterior storm window then in 2-5 years the freeze/thaw cycle, rain, snow, and sun will degrade the putty and paint of your newly restored windows dramatically shortening their useful life span.

    Q: Which type of storm windows are the best?
    A: Over the years we have tried many different types of storm windows. We have found that fixed sash wood storm windows are the most energy efficient because they have fewer cracks and gaps for air to leak through or around. Furthermore, they can be ordered with double pane glass to increase the insulation factor. However, these windows can be expensive and are labor intensive. The storms will need to be removed in summer and replaced by screens, and in autumn the screens need to be replaced by the storms. If you don’t want to make this kind of a commitment, this is not the right window for you.

    Q: I don’t want to deal with the hassle of installing and uninstalling exterior storms and screens twice a year. Can I install interior storm windows instead?
    A: We strongly discourage the use of any type of interior storm window on antique windows. Over the years we have been asked many times to repair rotted antique wood windows that are 75 to 100 years old or more. The windows functioned perfectly and never suffered any rot problems until interior storms were installed. The space between the interior storm and the original wood window traps household humidity, which results in condensation and moisture build up on the wood window, which leads to rot. For more information on this problem contact our office.

    Q: Is there a storm window brand you recommend?
    A: Harvey Brand Tru-Channel Storm windows are economical and convenient. This triple-track white aluminum storm window has a built-in screen, and also has one of the lowest air leakage rates of any triple track storm window.

    Q: If I replace all my windows, won’t I save more on energy costs and recoup my investment?
    A: Not necessarily. If you replace or restore all the wood windows it typically reduces a home’s energy use a minimal amount. Let’s say your investment in your windows saves you $400 per year (this is higher than average, and the amount saved could be as low as $50.00). If you spend $10,000 on 10 high-quality wood replacement windows, or the restoration of 10 original wood windows, it will take you 25 years to see a return on your investment ($10,000 ÷ $400 = 25). Unfortunately, after 25 years, your gas-filled replacement windows will most likely be leaking and will need to be replaced again, so you never actually save any money. In contrast, 25 years after your wood windows have been restored they should last another 25 years, as long as you maintain them by painting as needed, and keeping the storm windows closed in winter.

    © 2013 – R.J. Aley Building Contractor LLC – All Rights Reserved

    1. MKCF | | #9

      Howdy R.J.
      The reason new paint on old window fails in 3-5 years is that modern paint sucks. Lead paint works. It's also deadly poison and no one should use it anymore.
      Call me cynical, but it strikes me that if new paint lasted for 30 years the paint companies wouldn't sell as much paint.
      Have you ever tried linseed oil paint? My tung oil paint is an experiment I confess. There are a lot of boats in my area and there are two main camps in brightwork restoration: oil, and varnish. Oddly enough, long-oil varnish seems to be the preferred type, and yes, it's mostly oil. The oil people just use oil. No one puts water-based varnish on boats, at least no one I know.
      Have you seen the Allback website? An entirely different approach to painting windows, but a time-tested one. I see the only flaw as their choice of oil, linseed being edible and therefore appealing to mildew. Borates might be a good additive to a tung-oil based paint.
      My objection to triple-track is that they are so ugly, and also their air-sealing properties are pretty bad. They are difficult to fit properly with no gaps, one must rely on caulk which eventually fails. Depending on the beauty of the original windows they are still probably an improvement over replacement windows because at least one can appreciate the beauty from indoors, but outside original fenestration is seriously obscured by triple track.

      In my experience, condensation is caused when warm, moist air contacts a cold surface. Theoretically, if the interior storm window is perfectly sealed, warm moist air will remain in the building envelope. If you have a poorly sealed storm window (air infiltration), the wood sash IS going to be colder than the inside air of the house, and you WILL get condensation. Case in point: I have a cottage with ugly vinyl windows with interior grilles between the panes of their IG units. On cold mornings, the glass directly over the grilles has condensation on it, because the plastic is conducting heat from the inside of my house to the exterior. The condensation forms in a grid. On very cold mornings, water condenses over the entire surface.
      I think probably the best solution is to have exterior AND interior storms, and the entire system should dry to the exterior.
      Thoughts...?

  7. HaakonC | | #10

    Many green sites have long touted keeping old windows when possible. On this site for instance, there is "What Should I Do With My Old Windows?", By Martin Holladay, July 25, 2014; "Low-e Storm Windows Are Big Energy Savers" By Scott Gibson, October 18, 2015; "Save Energy With Storm Windows", By Mike Guertin, April 20, 2015, and the present article. Now, 6 years later than these articles, there is less talk of saving old windows, but that what we have opted to do.

    We have been in our 120-year-old house in Eastern Massachusetts about 35 years. A couple of old double-hung windows had already been replaced with vertical single-pane sliders when we moved in; we replaced a handful and a half more with insulated double-pane wooden frame ones made by a local builder, but have not been very happy with them. So last fall we found a great window person to fix up the old windows--he weather-stripped all sides, replaced many of the sash cords and parting beads, and fixed up some of the sills and other surfaces. We have a painter doing some reglazing where it is needed.

    The next phase is replacing the 32 (external) storm windows, including the basement windows which are the only ones which never had storms. Some of the storms are themselves very old and badly need to be replaced. Others are only 10-15 years old, but we have decided to replace them too, for two reasons. The low-e glass now available should be a significant improvement, and the triple-tracks with the screen have been driving us crazy. Every time you want to open a window, you have to mess with the screens, open or close the lower sash, and then mess with the screen again. We want to replace them with double track. We seldom want to open the top sash. We don't expect even this to pay for itself--the low-e might pay for itself in 40-50 years for the storms that don't absolutely need to be replaced--but hopefully should make our home a little more comfortable.

    However, what I thought would be easy is turning out to be difficult--deciding on which units to buy. In the last couple of years, AERC and EnergyStar have finally come out with ratings for storm windows. Among the external storms, only Larson and Quanta have been rated. We have ruled out Quanta, as their ratings don't seem to be appreciably better than the Larsons, and we haven't found anyone to install them in our area. The Larsons seem pretty good from the ratings. All the 2-track Larsons show Emissivity 0.15 and Solar Transmittance 0.69 on the EnergyStar site; Their top-of-the-line double-hung L203E has AERC 1.2 Air Leakage Rating 0.7, and (from the AERC site) U-Factor .26, SHGC .41, and VT .47 . ProVia, the other major player, doesn't have a rating. I can't find out whether this is because it is a pain to apply for it, they haven't gotten around to it, or because they wouldn't or didn't pass. Or maybe it's because, unlike Larson, ProVia makes replacement windows, where they probably make a bigger profit. I did talk to customer support at both ProVia and Larson. I couldn't get out of Larson what glass they use, but I was able to glean that ProVia uses 1/8" Energy Advantage glass, which is a trademark of Pilkington, and the Pilkington site shows a VT 84, U-Factor .5 Summer, .66 Winter, SHGC .77 for this product. But I don't know if these ratings can be compared, since the Pilkington ratings are just for the glass and the Larson figures are for the whole system (even though it just has a single pane). If they can be compared, the highter VT for the ProVia is probably good--I've heard that above 40 is generlly okay, but Larson mentioned a slight rainbow effect in certain light. The higher SHGC might be good as well. We live in EnergyStar zone 1, which is dominated by heating costs (even more so for us, since we have photovoltaics which will hopefully pay for most of our AC). This figure for SHGC is higher than what I have seen recommended though. The one possibly worrisome thing though is the U-Factor, which is twice as high as Larson, although again I don't know if these can be compared directly.

    The other, maybe deciding issue is that Larson doesn't seem to be so available in our area. Their site says that Lowe's is the only dealer, although Home Depot also shows them on their website. But Lowe's has a big problem with accessibility. I have phoned them 8 times at different times of day, and was never able to talk to a person--I just got hangups. I was able to chat with a bot, which said that the nearest store that has one model of the Larsons (not the one I want) is over an hour away. Home Depot doesn't answer either, but I went to their (closer) store and they said they don't have them in stock. I was able to locate an installer who installs both brands, who said that he thinks there isn't much differene between them. However, he also says that he thinks that low-e is just a gimmick, since it wears off easily (not true, from what I have read. The pyrolytic coatings used for single-pane, and increasingly for outer panes of integrated window systems, are sturdy) The two local, recommended storm installers both say that they only install ProVia, because they think it is a superior product.

    So this ia all pretty confusing. This is a substantial expense, even if it is a fraction of the expense of replacement windows (or maybe not, including the repair of the primaries).We may well go with the ProVia, since it seems like the most viable option, but it would be good to know that it is at least comparable if not better. I'm sure we aren't the only people in a comparable situation, although I am aware we are going against the trend of replacing everything.

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