Inspecting Old, Double-Hung Windows

Smart Inspector Science

July 8, 2022

If you believe all the marketing hype, we should replace our windows ASAP, and the new windows will pay for themselves in a few years. Yeah, right. Let’s take an honest look at a typical type of older window you may encounter.

Old, Double-Hung Windows

Back in the early 1900s, wood, double-hung windows were the most common design installed in homes. Many local cabinet shops built windows like the one shown in Illustration D042. This window has two operable sashes that slide up and down, providing the option of upper sash or lower sash ventilation. The design has attractive “lights,” or small units of glass. It was designed to shed water to the outside with an angled sill and drip.

Illustration D042. Parts of a Window — Double-Hung

Because the wood sash is heavy, this design uses a pulley and rope system with a cast iron weight for counterbalance (Illustration D043). The size of the weight required a non-insulated space at the side. Eventually the cord would fail, but it could be replaced through an access door hidden behind the lower sash on the window jamb.

Illustration D043. Double-Hung Window — Sash Cords

A Good, Real-Life Example

Photo 1 shows old double-hung windows in the unfinished attic of a home built in the 1920s. Note the double sash, latch, ropes, broken ropes, and weights. Normally, some of these details would be hidden behind plaster. There is also an operable metal storm window. Photo 2 provides a closer view of the cast iron weights and ropes.

Photo 1. Double-Hung Attic Windows
Photo 2. Sash Cords, Weights

In cold climates, double-hung windows were fitted with wood storms, as shown in Illustration D086. When properly maintained, these windows were quite efficient, although they required maintenance of paint or varnish and switching/storing individual storms and screens according to the season.

Illustration D086. Double-Hung Window — Section

When to Replace Windows

Windows should be replaced because of issues like rot resulting from poor maintenance. Sometimes it makes sense to replace an abused window when the cost of restoration approaches the cost of replacement. Even replacing a sash cord can be expensive; often, all of the sash and jamb components are covered with many coats of paint. Broken sash cords can be a safety issue you should note in your report.

Why to Keep Old Windows

Some wood windows must be maintained because of the historic value of the home. They’re a beautiful component of an old home, never to be matched by vinyl replacement windows. And then, of course, there are the potential issues with cheap and poorly installed new windows.

Energy Aspects

Are modern replacements more efficient? Sure, the glass is often thermally insulated, and the area around the window jambs can be filled with insulation for even greater efficiency. But this minor gain doesn’t justify replacing a well-maintained window. Replacement windows will not pay for themselves in a few years, as often advertised. Take a good look at a detailed energy evaluation of a typical home—window replacement is always very low on the payback list.

The Takeaway

Don’t tell your customers that replacement windows are always a good idea. Keep in mind that energy savings by itself is never a reason to replace old windows.

To learn more, attend Tom’s technical presentations at educational sessions for ASHI chapters and local groups. Tom can also provide his knowledge for your educational event.

The opinions expressed in this article are those of the author only and do not necessarily reflect the opinions or views of ASHI. The information contained in the article is general and readers should always independently verify for accuracy, completeness and reliability.

How to Operate Your Home is a proud ASHI Affiliate member.


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