GBA Logo horizontal Facebook LinkedIn Email Pinterest Twitter Instagram YouTube Icon Navigation Search Icon Main Search Icon Video Play Icon Plus Icon Minus Icon Picture icon Hamburger Icon Close Icon Sorted

Community and Q&A

GBA Prime

Join the leading community of building science experts

Become a GBA Prime member and get instant access to the latest developments in green building, research, and reports from the field.


  1. jackofalltrades777 | | #1

    I found it interesting that double pane American made windows would be illegal to install in most parts of Europe (Germany). Due to being so inefficient and because they leak so much air (sliders, single/double hung).

    US is like 20 years behind to parts of Europe when it comes to energy efficient windows.

    1. Expert Member
      BILL WICHERS | | #2

      It depends on the manufacturer. Not all "American made" windows are so inefficient, but it's true that most of the mass market products aren't up in the high efficiency range. A lot of this is that most use a single seal, while a typical euro (or even Canadian) window uses a double perimeter seal. Some of the other differences are in the design, with the typical euro window using a thicker frame than is common in American designs. This is an aesthetic difference.

      There have been better models (in terms of energy efficiency) coming out, but it's been slow. Right now, if you want a top performing window in the US, some of the best options are from Canadian manufacturers. There are US manufacturers that focuse on energy efficiency (Alpen is probably the best known), and you see some of the smaller manufacturers discussed on GBA periodically. Most of the smaller manufacturers tend to serve their relatively local regions and aren't nationally known.


Log in or create an account to post an answer.


Recent Questions and Replies

  • |
  • |
  • |
  • |