energy efficient windows

Windows: Replace or Refurbish?

Windows are an important part of your home’s appearance, both inside and out. Many people I meet proudly tell me that they’ve recently installed replacement windows to increase their home’s comfort and energy efficiency. But is this (likely huge) investment in new windows worth it? There are a number of issues to weigh before proceeding down this costly path.

Issues to Consider

  • Why do you want to change the windows?
    • Aesthetics: the windows are not a style you like or want
    • You feel drafts from the windows and want to be more comfortable and save energy
    • The windows no longer function properly
    • The windows may be only single-glazed (one layer of glass) and affect comfort
    • You are doing another home maintenance project that affects certain windows so you want to take the opportunity to replace old windows or skylights (see our recent re-roofing blog)
    • It’s noisy outside and you want to improve your sound barrier.
  • Will you be living in your home long enough to get a return on your investment even if replacement windows will increase the value of your home?
    • Consider all of the elements of cost: the windows, installation costs, window hardware, painting the windows if needed, as well as the possible paint and repair of surrounding areas both inside and outside as a result of removing old windows and installing new
    • Measure the cost against projected energy savings (provided by manufacturers)
    • Estimate the likely percentage increase in your home’s value if you install new windows (ask your realtor). These numbers will enable you to calculate the years to “payback”.  If payback exceeds the time you expect to live in your home, consider holding off.

Food for Thought

If you want to change the aesthetics of your windows, replacement may be the only path. In a moment I’ll highlight some issues to consider when buying new windows. If you are thinking of replacing your windows for one of the other reasons mentioned, consider this:

  • It’s drafty: Many window drafts will be reduced if you install high performance insulation in the attic/roof and basement (see our getting-ready-for-winter blog). “What? I was talking about new windows, not my attic.”  Because of thermodynamics, 25% of the air entering your home comes in the basement then, since hot air rises, is carried up and out of your home through the roof.  Replacement air pours in through hundreds of small openings, including around windows. So if you install high-performance insulation to stop air from coming in the basement and going out the top (like wearing a hat in winter), you should solve a big part of your draft problem.
  • Your windows no longer function properly: This is a common problem with old wood windows, especially those with weights.  It’s worth getting a quote for a high quality repair, even if the window has to be taken apart.  Repairs may cost a couple of hundred per window while replacement may cost several hundred–and that’s before factoring in related costs like painting and repair of adjoining areas.
  • Single glazing: Windows that have only one layer of glass conduct a lot of heat to the outside in winter and allow a lot of heat to travel in during the summer.  If you like the existing windows, before ripping them out, consider various types of storm windows and energy panels. It may be a much more economical investment and achieve most of your comfort and energy efficiency goals.
  • You’re doing other home maintenance work that affects the windows: For example, for me, it made no sense to keep 20 year old double-glazed skylights when I was replacing the surrounding roof, so I took the opportunity to install new, triple-glazed skylights. Similarly, it might be worth it to replace an old window if you’re repairing siding or doing some other nearby maintenance project.
  • Exterior noise: Is there is a new exposure to street noise, a nearby airport or noisy neighbors? This is a tougher decision regarding window replacement.  Although some types of new windows can provide meaningful noise abatement, replacement really must be considered in the context of what percentage of the building envelope is represented by the windows, as well as what other steps have been taken to abate noise. Noise-proof windows won’t help if the walls and roof are not sound resistant also.

Buying New Windows

There is a wide range of available products made of different materials and at different costs.  Be realistic about your willingness to maintain beautiful wood-framed windows, although some homeowners address that issue by purchasing aluminum-clad wood windows. The cost of your final choice will affect the payback period mentioned above.

Before you get too hung up on sales pitches regarding triple glazing and U-values, it’s worth noting that the best high-performing windows sold in this country have R-values of 4 or 5. So if you are building or renovating a house with R-20 to R-30 walls and then poke a bunch of holes in those walls for R-4 windows, you are clearly degrading the overall energy performance of those walls, regardless of whether the window is rated R-3 (U-0.3) or R-5 (U-0.2). This seemingly small spread in U-value can have a big impact on cost without generating much savings. From an energy efficiency point of view, we should live in houses with no windows!

Perhaps more important when installing new windows is proper insulation of the window frame with high-performance insulation before trimming, as well as the style of window, e.g., casement versus double hung, fixed versus operable and so on.

energy efficient window
A “high performance” window installation

Green Home Consulting consults on new window considerations and choices when it becomes part of the design team for a new build or residential renovation. We look forward to hearing from you  914-967-2956


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