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WINDOWS: THE EYES OF A BUILDING

An Article by John Dreher, Manager of Danville’s Community Development Division

Article first published in The Commissioner, a newsletter from the Illinois Association of Historic Preservation Commissions

       Windows are among the least understood, most neglected, and unappreciated features in buildings today. In the past thirty years, more misinformation has been circulated about windows than probably any other building component. Valued until sixty years ago as sources of life-giving light and healthy ventilation, these “viewthrough” features of our homes and public buildings now are forced to compete unjustifiably with climate-control HVAC systems, laboratory-designed electronically balanced electric lighting systems, and many inflated myths about their liabilities.

What are they really for anyway?

      Anyone who has lived in an old house has probably noticed that the windows in homes built between 1840 and 1920 are rarely situated in the middle of a wall, and not often symmetrically

situated on the exterior either. In this period before effective electric light and air conditioning, windows were not placed to accommodate the location of furnishings. Windows were placed to effectively transfer light and air to, from, and through the building.

      In my own 1893 house, one window on the east wall of the dining room catches the low December morning sun, casts it through the irregularly placed pocket door to the front parlor, across that room and through French doors with sidelights, and into the library. That library, located on the northwest corner of the house and three rooms away from the December morning sun, lights up on Winter Solstice as if it had a southern exposure! The house has thirteen rooms, yet none that need artificial light in the daytime. These effectively placed and efficiently sized windows (seven feet tall) kept my wife and I comfortable most of last summer, and we used air conditioning on only 41 days in 2005. Change the size or placement of even one window or door and the economic and aesthetic advantages of this brilliant design could be destroyed.

      From the outside, windows are the “facial features” of a building. Shape, style, embellishment and placement tell the building’s story. Take care before you modify this arrangement, called fenestration, for it’s possible to spend a lot of money and simultaneously lose property value. Also, don’t forget that any window which captures sunlight during winter might be paying it’s own way as a passive solar receiver.

Windows and Energy Consumption

      Since roughly 1970, a long line of manufacturers, sellers and installers of new-fangled window stuff have combined rising energy unit-costs with laboratory data, added at least a spoonful of fear and a pinch of blarney to convince many people that “old window=bad window.” The granddaddy of all the exaggerated reasons to throw out your old windows for new ones is the double-pane or so-called “insulated glass.” Two panes of glass with a tiny space between them in place of the old single sheet of glass will yield an energy advantage of R-factor 1.

      R factor is a measurement of a material’s resistance to the transfer of heat. An R factor of 1 is roughly equivalent to that of a heavy piece of paper, hardly worth the thousands of dollars that changing windows can cost. In fact, a well-maintained 100-year-old wood window with a wood framed storm over it can often out-perform a new replacement window with double glass! If you then consider the tendency of double glass isolation seal between the panes to fail, and the higher cost of replacement in the event of breakage, then the upgrade to double glass loses it’s economic appeal.

      The very best way to compare the energy efficiency of windows is not by Rfactors anyway, which only rate the heat transfer resistance of a material; but rather by U-factors, which measure the efficiency by which heat and cold can pass through an entire component. When a window bears a U-rating, that rating reflects the effectiveness of the entire window unit overall. This is much better than simply knowing the efficiency of one of its materials. I cannot recommend the purchase of windows without a U-factor rating. Bear in mind, because U-factor measures the window’s ability to pass heat, the lower the U-rating, the better the window. There is no magic number, just compare between comparable products.

      If windows are not fitted well, and leak air around their parts, they will cost you more in energy expense than any consideration of the glass type, and that’s the same whether they are new or old. But, most old wood windows I encounter have been neglected. Built up paint, wear, and plain old Father-Time have made their previous tight fits into sloppy ones. With an investment of about one Saturday morning per window and minimal tools and skills, they can be re-fitted to operate smoothly and keep out the wind very effectively.

      Another grossly exaggerated excuse to landfill those old wood windows in favor of their new plastic grandbabies is the energy efficiency of the filled vinyl sash. On their best day, these molded replacements slightly outperform their wooden forbearers. I have encountered many disgruntled owners of new windows with broken locks, mounting pins, tilt-clips, lifts and balances on their less-than-ten-year old plastic windows. Unlike wood, which may be the most repairable substance ever known to man, when vinyl or aluminum manufactured parts break, you’d better pray the company is still in business. If not, you’re sunk. Bob Yapp, host of the PBS Series “About Your House,” says the reason they call them “replacement windows” is because once you start, you’ll never be finished ”replacing windows.”

Where does that expensive heat go anyway?

      It would be unfair to discuss windows and energy consumption without also pointing out an important feature about heat loss. It’s a fundamental law of physics that heat rises. This is called convection. It doesn’t travel sideways unless driven by the wind. The heat in your home travels

primarily upward to the ceiling by convection, and outward through the sides by either conduction, or wind through leaky windows and doors. Have any of you noticed that pets and children take three times as long to pass through a door at 25°F than at 75°F? This means that the same amount of insulation material is much more effective in your attic than in your sidewalls. Sidewalls conduct heat and cold, but the ceiling conducts it with convection shoving it along the path to oblivion. Think vertically. If you have only a finite amount of money to spend to reduce energy costs, consider bringing your attic insulation to R-38 or R-40 before throwing away your windows for new ones.

      If you really feel sorry for your utility company or are tired of all that dirty old money taking up drawer space around the house, install a skylight. Skylights are an excellent way to throw away money. As a bonus, you may also get a nice new source for “ice-damming” on your roof above the skylight. Ice dams are great because they only leak and ruin your ceilings during the

time of year when its darn near impossible to get onto the roof and repair them. They’re kind of like that old abscessed tooth that only goes off on Friday night after your dentist has gone away for the weekend.

Local Prices and Options

      If you have lead-based paint on the windows, (likely, if it was built before 1965) it is best to use a contractor trained in lead-safe practices. Despite idle-talk you may have heard, the health threats presented by deteriorated lead paint are real. An untrained workman can contaminate your whole house while conducting window work. For more about lead safety and windows contact me at Danville Community Development 217 431-2329.

      At the end of the article is a list, based loosely upon current prices, for a few common window replacements and solutions. Each scenario is based upon a 28” x 16” glass size double-hung window on the first floor: (Add approximately $200 per window for lead hazard reduction)

See A Field Guide to Lead Paint Safety:

www.hud.gov/offices/lead/training/LBPguide.pdf

Do not make the mistake of thinking that a price higher or lower than these listed here indicates a problem. Talk to your contractor or builder and discover why his/her price differs. Sometimes the high bid is the best bargain, and the low bid is no bargain at all. Most important, seek advice from someone with nothing to sell. Salespeople will often tell you that you need their products, and that may or may not be true.

About the Author:

      John Dreher is manager of the City of Danville’s Community Development Division, where he designs and facilitates grant-funded rehabilitation projects. He and his wife Barbara have restored the John Reynolds House, a local historic landmark. John is a former carpenter/joiner who recreates architectural details for historic buildings, including wood windows, and served eight years with the Office of the Illinois Attorney General where he investigated consumer complaints involving home improvement. He is also a licensed Illinois Lead Risk Assessor #L-8111, and

can be contacted at : jdher@cityofdanville.org.

THE IHPA BOOKS & VIDEO WEBSITE OFFERS THE FOLLOWING:

Windows: An Educational Video -- $10

Video offers advice on how to analyze windows' physical conditions and how to select appropriate preservation treatments such as renovation, lead safety, or replacement window design based on the Secretary of the Interior's Standards for Rehabilitation.

Lead Paint and Historic Buildings Training Manual -- $20

This training manual serves both as a curricula for classroom training about leadbased

paint and historic buildings or as a stand-alone training manual. Focusing on cost-effective and common-sense solutions, it dispels confusion about regulations and explains techniques on how to rehab and maintain historic buildings leadsafely.

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http://www.illinoishistory.gov/PS/store.htm

The Broadway Historic District Association is not responsible for and does not endorse any specific product on this page.