Last week, I was walking my dog in our old neighborhood, Bernal Heights. I had my camera with me, so I took the opportunity to do a little survey of residential windows within a 3 to 4 block area. I think about windows, probably more than I should, and I'm often asked about the pros and cons of different options, so I thought I'd lay them out here.
I’ve posted two groups of windows from my walk. The one above is a combination of old wood windows, replaced wood windows and replaced wood/clad windows. The one below is an assortment of replaced vinyl windows and aluminum windows that are in dire need of replacement. These photos can help define the aesthetic choices, but there is a lot more that goes into deciding on replacement windows besides looks alone. At the top of that list is cost, followed closely by energy efficiency and durability.
A common question among homeowners is what kind of windows should be used to replace old single panes? People are often aware of the need to install dual glazed windows, due to increased awareness and tax benefits for creating a more energy efficient home. They look to advertisements and showrooms to figure out the rest of the specifications for windows, but a real comparison of the options can seem daunting.
The two main options that homeowners consider in the Bay Area are Wood Windows and Vinyl Windows. Let’s look at how these line up with regard to cost, energy efficiency, durability and aesthetics.
Wood Windows: Wood windows were the standard in most homes built before the Second World War. They were built to last and easily repairable, which is why we still see most of the originals around today. Unfortunately, they’ve become the drafty windows that most of us complain about. Wood is a naturally insulating material, but the original single pane glazing tends to let heat escape. Once replaced with more efficient glazing, there is no reason the new wood windows can’t last for another 100 years.
The downside to wood windows is the need to maintain them, especially on the exterior of the building. A popular alternative is Wood/Clad Windows, in which aluminum profiles are applied to the exterior components to protect them from the elements without the need to refinish them. Wood and aluminum make a good team because the wood handles the thermal insulation aspect, while the extruded aluminum profile creates a clean form on the exterior. The aluminum's finish gives a strong resistance to fading and cracking. Aluminum profiles are available in a wide variety of colors. Though they will not replicate the look of wood, they do strike a close comparison to painted windows, since they are basically wood windows wrapped in color. (Note: These are NOT the rattling aluminum windows of the seventies.)
Vinyl Windows: These are the least expensive option, so they tend to be very popular. I’ll be honest, vinyl is not on my list of recommendations, and here is why:
1) The properties of vinyl change with temperature. Although all windows expand and contract with changes in the weather, vinyl expands more than twice as much as wood, and even more so in comparison to the glass it holds. As a result, the seal between the glass and vinyl framework breaks. This might not be an issue in more mild climates.
2) When parts break, the whole window must be replaced.
3) They cannot be painted, at least not successfully.
4) The details on most vinyl products result in a window that tends to flatten the façade. They are often installed so that the face of the window falls in line with the building’s face, creating no distinction or depth in the façade.
5) Muntin bars are not an option in the construction of these windows. First, muntin bars are those little frames around smaller panes of glass in divided light windows. Since a huge percentage of vinyl sales go to replacing divided lights in older homes, the manufacturers offer pseudo-divided lights. These are akin to a masking tape tic-tac-toe game between two panes of glass. They are everywhere.
6) As petroleum-based products that cannot be repaired, vinyl windows pack a hefty cost to our natural resources and landfills.
7) Vinyl windows actually aren’t allowed on street-facing facades in the City of San Francisco, but you wouldn’t know it by walking around. Check out the Planning Department’s Standards for Window Replacement here.
The aesthetic concerns that I’ve mentioned so far are not problematic just because they are unattractive. The conditions I’ve described run contrary to the very essence of a window as an opening within a façade. Historically, we’ve looked to windows to give our buildings character while providing a connection from the outside to the inside. Windows are celebrated in modern and traditional buildings alike. Whether with simple detailing or traditional ornamentation, they need to read as separate elements, with their own depth, set into the skin of the building. People who love their original divided lights need to recognize why they love them so much. My guess is that it has very little to do with the tic-tac-toe geometry and more to do with the way the sun catches each pane a little differently, the way the muntins can seem white in full light and a different color in the evening and the tiny streaks of light and shadow that surround each pane.
Cost can be the determining factor for most people. It’s important to remember that even among the low cost vinyl windows, you always get what you pay for. The price of a higher quality vinyl window is not so far from the range of a wood/clad option. When we take into consideration the other costs that I’ve mentioned, it makes a lot of sense to invest in wood or wood/clad windows, even if it means replacing them one façade at a time.
