Windows are so important for the well-being of homes’ inhabitants. They bring in natural light and fresh air, and they also help connect people to their broader environment, whether that is a busy city, a suburban neighborhood, or a rural setting.
However, residential windows are notorious for their energy inefficiency for two primary reasons: 1) they have very, very low insulation value… single pane windows are the worst, but even older double-pane windows are only slightly better; and 2) older windows are often leaky resulting in the loss of heated or (cooled) air… obviously, if you pay good money to heat (or cool) your air, the last thing you want is for it (and your dollars!) to leak to the outside.
The common solution is to buy replacement windows, but this approach comes with serious costs, both direct and indirect. Let’s look first at the direct cost: a solid window choice might be Andersen’s A400 series. This is a very good window–not top of the line, but it’s definitely a quality window that would serve as a good replacement unit. Pricing depends on the size, the options selected, and the dealer’s profit margin, but a fair, middle-of-the-road estimate for a typical window is $700. That’s not too bad until you calculate the installation costs. To install a new window properly, the technician needs to remove the window trim inside your home as well as on the exterior. Depending on what type of siding you have, this may be easier or harder. Once the trim is removed, the old window’s fasteners can be removed or cut to allow the window to be pulled out. The rough opening should be cleaned up, the framing sill needs to be sealed with costly flashing tape, and then the new window can be installed with caulk sealing and spray foam insulation before getting flashed around the perimeter. Finally, the exterior and interior trim can be reinstalled. Not surprisingly, the trim is often damaged during removal which necessitates replacement, and that then requires refinishing or painting to match the rest of the house. Let’s be conservative and say that the installation materials add $50, and the labor for the complete job (under the best scenario) is four hours at $30/hour which is a typical wage rate for carpenters, at least here in the northeast. Now we’re at $870, but that doesn’t include payroll costs, workers comp insurance, liability insurance, business overhead, a commission for the salesperson, and profit. Realistically, we’re probably talking about a total cost to the homeowner of $1500, give or take. If your house has, say, 15 windows, the cost will likely be well above $20,000!
Add to this figure the indirect, environmental costs associated with the manufacturing process for your new windows and the disposal of your old windows, and it becomes clear that new windows are not always the best choice for every circumstance.
Now let’s look at window inserts which are sometimes referred to as interior storm windows. They improve existing windows in three ways… 1) they seal any air leakage; 2), they create an insulating layer of air (air gap) between the window and the insert for improved R-value; and 3) they reduce noise transmission from the outside.
The cost of an insert for a typically-sized window is in the range of $300-$350, a fraction of the cost of replacement windows, and they will improve the performance of any window, old or new.