Repair, Don't Replace, Old Wood Windows
Is it my imagination or is almost all the discussion on this forum about replacement windows? I manage a remodeling company in the mid-west. We repair and/or replace windows as needed without prejudice either way. If a window can be repaired and that's what the customer wants, we repair it. If the customer wants it replaced, we replace it. It seems to me, however, that we are frequently asked to replace windows that don't need to be replaced, and we think replacing windows is a frequently bad economic and environmental choice. I know there are a lot of people on this forum that make their living replacing windows, and what I am about to say will probably drive them nuts. But it is a discussion that ought to be had, so here it is.
You may be unlucky and have old aluminum or steel windows on your old house, or even replacement vinyl windows from the 1970's or 80's. Most likely these cannot be repaired, and must be replaced. But if you are lucky enough to own a house with old wood double hung windows, you often have the choice to repair OR replace.
Most wood double-hung heritage windows can be restored and upgraded to rival the performance of a standard replacement window, and usually at a fraction of the cost. And there are other important advantages of repairing rather than replacing. You not only save on your own heating a cooling costs, which reduces waste and your carbon footprint on the planet, you also save the resources and energy cost required to manufacture new windows which considering what new windows are made out of, is not an inconsiderable savings. You also preserve, not just wonderful old-time workmanship, but the superb old growth wood from which your windows were made. We can't build windows like that any more. It's not that our craftsmen do not have the skill and experience. Any of our master carpenters or cabinetmakers could build a traditional window. But we can't get that dense, heavy old growth wood, and the new wood is ... well, we're pretty sure it's wood, but it's just not very good window wood.
Are Replacement Windows a Good Investment?
Before 1996, primarily as a consequence of the pervasive and unceasing marketing of replacement windows after the energy "crisis" of the 1970's (when gasoline prices jumped to an astounding $.80/gal. oh, for the good ol' days), it was nearly universally thought that replacement windows were vastly superior energy performers. But then the State of Vermont and the U.S. Army joined together to actually test the performance of restored heritage wood windows.
They repaired and restored 150 windows all over Vermont, then tested them against replacement windows in similar situations. What they discovered was an eye-opener. They found that the energy savings difference between restored old windows and new replacement windows amounted to just a few dollars a year. When a storm window was added to a restored window, the window/storm window combination actually outperformed many of the new thermal windows. These findings have been well supported by subsequent studies.
Keith Haberern, a professional engineer, in an analysis of New Jersey homes found that the annual energy savings of a modern replacement window over an old window in good condition is 626,000 Btu. How this translates into dollars depends on the cost of energy in your area. There are 1020 Btu, on average, in a cubic foot of natural gas, so the average saving to a natural gas customer is 614 cubic feet of natural gas per window. In most of my state, Nebraska, a cubic foot of natural gas sells for 1.2 (as of 2007). The energy cost savings, then, is a $7.37 per window per year.
At this rate, if you have 20 windows in your old house, your total annual savings would be about $147.40. The cost of a good quality thermal replacement window, installed, is about $500. You can pay a great deal more for a replacement window, but you will not find a quality window for much less. So, your window replacement cost will be around $10,000.
To pay for your replacement windows out of your energy cost savings would take a whopping 68 years. Odds are pretty good you won't live that long. But if you did, consider this: The life expectancy of a modern replacement window is only 15-40 years. So by the end of the 68 year payback period you will have replaced your replacement windows at least once, maybe twice. The net result, then, is that you will never actually recover your initial cost of replacement windows from energy savings alone.
Other studies have found even worse results. Researcher and energy consultant Michael Blasnik looked at actual energy bills of houses in upstate New York before and after replacement windows were installed and found the actual average annual savings per household was just $40.00 not per window but per house. Based on these findings, he concluded that it would take 250 years for the cost of the replacement windows to be repaid from energy cost savings alone.
Obviously there are reasons other than economic reasons to buy replacement windows. New window sashes tilt out for easy cleaning, they have several lock positions so the window can be opened slightly and still be secure (although old windows can be modified to do this). Old windows don't have these nice features. Or your old windows may have deteriorated to the point where they really can't be fixed although this is very unlikely. But if it is your intent to reduce your cost of heating and cooling to pay for your windows out of energy cost savings, think again. It won't happen.
While many replacement window manufacturers still claim reductions in household energy use of up to 35% after installing their replacement windows, most admit that these projections are based on hypothetical computer models, not actual field testing. When these claims have been field tested, little or no actual savings have been found. I have yet to find any window manufacturer's claims of energy performance to be backed up by actual field testing. If you know of one, please let me know.
Where an old window is restored and equipped with a good storm window, the old window system has been repeatedly shown to outperform the standard thermal replacement window. And it costs much less to restore an old wood window than it does to replace it with even an average thermal window.
Windows Built to be Repaired
Old wood windows were made to last for many generations. They were built to be repaired. The old-time craftsmen knew that their windows would last a good long time, but not forever. So they built windows that could be easily fixed when something finally did give way. Modern windows are not built that way. Most have a expected lifespan of less than 40 years, and other than replacing the glass, cannot easily be repaired. Frames are single integrated structures, as are sashes. In fact, in some modern windows, frames and sashes are completely integrated so literally noting can be repaired except some very incidental parts. But an old window is at least a dozen individual parts put together with joinery that can be undone It can be taken apart and any of the parts replaced individually without replacing the entire sash, or, worse, the entire window.
It can also be fully weatherstripped and insulated. We use a system that insulates sash weight pockets to between R-18 and R-22 probably better insulation than is in your walls. Using the right, long-lasting, materials, weatherstripping is actually fairly easy. Any competent window man (or woman) can do it in about an hour.
It can be a lot of work. But professionally restoring your old window is about half the price of replacing it with a new thermal window -- typically between $200 and $300 -- and wastes nothing. Old growth hardwood is saved from the landfill, and a lot of good old-time craftsmanship is preserved. If you can do it yourself, still more savings -- figure about $100 for materials.
Of course it is not yet as energy efficient as a new window. For that we are going to have to add a storm window. A good quality white aluminum storm window installed is about $80 in this area, and I doubt it is much more elsewhere. An upscale wood combination storm window from a company like SpenserWorks will cost a bit more (caveat: we have no connection to Spenserworks whatsoever).
If you already have storm widows, then you are just that much ahead, But assuming you don't, your cost to repair your old wood windows and add a good storm window is about $325.00 vs. $500 and more to replace them. This is a savings of $5,500.00 in a 20-window house. For your investment you get a window that should be good for another 100 years, while a replacement window is doing very well to last 40 years. Your window performance is just as good if not slightly better and you saved 45% of the cost of installing replacement windows.
I not alone in my opinion that repairing old wood windows is often a better choice than replacing them. The href='http://www.preservationnation.org/issues/weatherization/windows/additional-resources/nthp_windows_repair_replace.pdf'>National Trust for Historic Preservation has this to day:
Many window replacement manufacturers claim greater savings than actually occur. Since windows account for at most 25% of heat loss, the payback and time to recoup your investment in terms of energy savings could take between 40 and as much as 200 years, based on various studies. A study from Vermont show the saving gained from replacement windows as opposed to a restored wooden window with a storm is only $.60. The added problem is most replacement windows will not last as long as 40 years, much less over a hundred years. And some are being replaced only after 10 year of service."
Anyway, that's my view. Opposing argument is certainly welcome, but please, if you quote studies or statistics, back it up with a reference. Here are my references:
"Replacement Windows and Furnaces in the Heartland; Indiana's Energy Conservation Financial Assistance Program"
](http://www.scribd.com/doc/20481724/Replacement-Windows-and-Furnaces-in-the-Heartland-Hill-1990) Center for Energy Research, Ball State University, Indiana, 1990. (Replacing windows without any other energy improvement results in an annual savings in energy costs of 1.4% per year.)
"What Replacement Windows Cant Replace: The Real Cost of Removing Historic Windows" Journal of Preservation Technology, 2005. (Replacement windows do not provide enough energy savings to justify the embodied energy cost of the new windows or the loss of authenticity.)
Testing the Energy Performance of Wood Windows in Cold Climates A Report to The State of Vermont Division for Historic Preservation, Agency of Commerce and Community Development" University of Vermont, Vermont Energy Investment Corporation, U.S. Army Cold Regions Research and Engineering Laboratory. (The energy savings between replacement windows and restored wood windows based on a multi-year Vermont study was found to be insignificant.)