Home & Garden Columns

If there is a phrase found in a real estate listing that fills me with even more horror than “updated kitchen,” it has to be “new dual-pane windows.” Dual-pane windows are probably one of the biggest scams ever foisted off on an unsuspecting American public. The lies and half-truths promulgated by window replacement companies should be right up there with other famous lies like “The dog ate my homework” and “Only one glass of wine with dinner, officer…” 

Most houses built before the 1960s, with a few exceptions, had wooden windows, built with close-grained old-growth wood. Wooden windows, if maintained, can last hundreds of years. Many buildings on the East Coast that date to the 17th or 18th centuries still have their original windows, and in Europe, buildings older than that retain their historic sash windows. 

Wood windows are the most vulnerable of historic building elements—millions are being dumped in landfills every year. And that is an absolute travesty. The multi-billion dollar window replacement industry would like you to believe that single-glazed wooden windows are drafty, not energy efficient, don’t work well, and require constant maintenance. Almost every week the newspaper is filled with ads for replacement windows, with headlines like, “Are your windows costing you money?” or, “Whole house window replacement—only $2995!”  

PG&E will give you a rebate for ripping out your original windows to put in dual-pane replacements. Often the local building code demands insulating windows in new construction or remodeling. Go back and consider the phrase “multi-billion dollar”—with that much money at stake, do you think these companies have your best interests at heart? They Are Lying, and when they aren’t lying outright, they are conveniently failing to mention numerous pertinent facts. Here’s a list from one internet replacement window site about when or why you should consider window replacement: 

“Don’t bother to fix a window that has cracked glass, rotted or otherwise damaged wood, locks that don’t work, missing putty, or poorly fitting sashes. 

“ Homeowners with windows over twenty five years old should consider replacing them … A home is an ideal candidate for a window replacement if its windows are sealed or painted shut or the sash cords are broken…” 

Okay, I’m gasping with disbelief here, but let’s take these one at a time: 

1. Cracked glass. On a single glazed window, cracked glass can be replaced using items readily available at the local hardware store, costing maybe $25, tops, if you do it yourself. If you pay a glazier, maybe $100—still cheaper than a new window. If the glass in a double glazed sash cracks, you have to buy a whole new glazing unit (assuming the company is still in business) which will cost $100 or more, and then pay a glazier to install it, because it’s not a do-it-yourself thing. 

2. Rotted wood. This most likely place for this is the joints of the bottom sash. If not far gone it can be dug out and the hole filled with wood putty or even Bondo. If farther gone, it can be repaired with epoxy consolidants. This is also true of rot in the frame. If it’s so far gone that the bottom rail falls off when you raise the window, there are several companies in town that can make you a new custom sash- average cost, maybe $150, depending on size. (Look in the Yellow Pages under “Windows, Wooden” for companies.) 

3. Locks that don’t work. Are these people kidding? Buy a new lock at the hardware store. Cost? About $3. 

4. Missing putty. A quart can of Dap 33 window glazing: about $6.50. 

5. Poorly fitting sash. Many reasons for this, but if it’s not structural, then weatherstripping works wonders. 

6. Windows sealed or painted shut, or broken sash cords. Easily fixed with a few simple tools and some labor, or if you don’t want to do it yourself, Wooden Window (893-1157, www.woodenwindow.com) will be happy to do it for you. If you want to do it yourself, I highly recommend the book Working Windows by Terence Meany ($14.95 at your local bookstore). 

Those who’ve been around since the Sixties may remember the bumper sticker “Eschew Obfuscation.” When window replacement companies aren’t lying outright, you better believe they are obfuscating.  

Obfuscation #1. Replacement windows will significantly reduce heating /cooling costs. 

Okay, this is math, so take notes… there will be a quiz! 

Only 20 percent of the heating loss (or cooling gain) in a building is through the windows. The other 80% is lost through roofs, walls, floors, and chimneys, with most of it going out the roof. And most of the cold air is sucked in through the floor from the basement or crawl space. Reducing the heat loss through the windows by 50 percent (double-glazing) will only result in a 10 percent reduction in the overall heat loss. So let’s say you pop for the $2995 window special.  

That’s only ten windows—the smallest bungalow I ever owned had 20 windows. Misleading the public about actual costs is one of the sleazy tactics employed. So you’re really going to have to spend more like $5,990 for twenty windows. (or about $32,000 for aluminum-clad wood.) Let’s also say that your utility bill averages $200 a month. A 10 percent reduction on the heating bill amounts to $20 a month or $240 a year. At that rate it would take about 25 years to recoup the $5990 investment (Payback on the more expensive windows would take 133 years.) 

But wait, according to the Environmental Protection Agency, 40 percent of the average household energy bill goes to heating and cooling. So at $200 per month, only $80 goes to heating and cooling. Saving 10 percent on that would only be $8 a month, putting the payback time at 62 years for the vinyl or 333 years for the aluminum-clad. For the same amount of money (or less!) that replacement windows would cost, you could insulate the attic and the walls and install a damper on the chimney and get an 80% reduction in heat loss.  

Or you could spend that money on storm windows. A recent study conducted at the Oak Ridge National Laboratory using actual wooden windows (removed from a house that was being demolished) showed that the addition of storm windows reduced air leakage by a considerable amount. They used a double-hung window with loose sashes, no weatherstripping, gaps between the sashes and frame, missing caulk, cracked glass, and dry rot in the frame. The second window was a dual-pane double hung window with loose sashes and no weatherstripping. For storm windows, they used non-thermally broken aluminum storms with operable sashes and no weatherstripping. 

Interestingly enough, the addition of storm windows to both windows reduced the energy flow of the single glazed window substantially more than the dual-pane window. Using a measurement which took into account both air infiltration and conduction through the glass, without storm windows, and with a wind speed of 7 m.p.h., the single glazed window lost about 565 BTU’s per hour, while the dual-glazed window lost 644. With the storms added, the single-glazed window lost 131 BTU’s per hour, while the dual-pane window lost 256.  

Then they removed the storm and weatherized the first window, which involved squaring up the frame so the sashes fit more tightly, replacing rot in the frame, re-glazing the panes, caulking cracks in the frame, installing a sweep at the bottom of the lower sash, and installing a new window lock to improve closure- then ran the tests again. At 7 m.p.h., heat loss for the weatherized single glazed window was 256 BTU’s, compared with 131 for the unweatherized window with a storm. By comparison, the dual-pane window WITH A STORM also had a heat loss of 256. They didn’t compare weatherstripping PLUS a storm window, but clearly, a storm window gives you more bang for the buck (about a 75% reduction in heat transmission) and weatherizing alone gives the same reduction as a double-glazed window.  

Obfuscation # 2. Maintenance-free exterior- no painting or staining required.  

No painting or staining POSSIBLE, in the case of vinyl. What if you get tired of the color? And you know how funky that cheap resin outdoor furniture looks after a couple of years? That’s what the vinyl or vinyl-clad window will look like. And you know how plastic has static electricity that attracts dirt? As for aluminum, even an anodized coating doesn’t last that long, at which point you have to paint it. If it’s not anodized, then it corrodes and turns white. And what if you get tired of the color? 

Obfuscation # 3. Extremely durable and long-lasting.  

I guess that depends on your idea of what constitutes long-lasting. A vinyl window has a life expectancy of approximately 20 years, aluminum about 10 to 20 years, a new wood window from 20 to 50 years. An original wood window that is consistently maintained and kept painted can last as long as 200 years, if not more. Part of the reason that an old wood window lasts longer than a new one is that old windows are made of old-growth timber, which grew very slowly and is extremely close-grained and dense, whereas new wood windows are made from second-growth wood, much of it from fast-growing trees harvested from tree farms, where the growth rings are much further apart. The softer sapwood resulting from fast growth is far less durable. 

But here’s the thing they’re really hiding: the average lifespan of a double-glazing unit is TEN YEARS OR LESS. The seal around the glazing can fail within ten years, causing the glass panes to fog. And the plastic and neoprene seals used to hold the panes in new windows degrade in ultraviolet light. Imagine trying to find a replacement gasket after the window company has gone out of business. 

Obfuscation # 4. Insulates against noise. 

Sure, till you open it. Actually, a single-glazed window has an STC (Sound Transmission Class) rating between 20 and 27, depending on how thick the glass is and how airtight the window is. In a dual-pane window, the STC rating is governed somewhat by the distance between the two panes- the larger the distance, the better the rating. (This suggests a storm window might be better than double-glazing, being further away.) 

For each doubling of the airspace between the panes, the STC increases by about 3. If the panes are close together, the rating may actually be lower than for a single pane, because the airspace acts like a spring and transfers vibration from one pane to the other. Triple glazing provides the same noise reduction as double glazing, unless the spacing between panes is quite large. On average, dual-pane windows have an STC rating of 28-35. A single layer of _” laminated glass (which has a layer of plastic in the middle) has an STC rating of 33, which suggests that it might be better to replace the glass in a single-glazed window with laminated glass if noise is an issue, instead of wasting the money on new windows. 

In addition to all the reasons above, the fact is that double-pane windows just do not look the same as single-pane windows. The necessary spacer between the panes is hard to disguise, so even if you pay extra for “true divided lights,” the spacer makes the muntins too thick (muntins are the pieces of wood that divide the panes of a multi-light window). 

Nor will the new windows have the wavy antique glass that gives old windows their charm. So save yourself some money, save the architectural character of your house, and don’t send your perfectly good windows to the landfill. Whenever I see a real estate ad that says “new dual-pane windows” I always think, “ Yeah, architectural integrity destroyed”- wouldn’t you rather the ad for your house read “original charm maintained?” 

Jane Powell is the author of six books, including Bungalow Details: Interior, all available at www.bungalowkitchens.com. She can be reached at hsedressng@aol.com.