Should Windows Be Installed From The Inside or Outside?

One of the questions I'm asked by home owners shopping for Replacement Windows is should they be installed from the inside of the home or the outside. The truth is that in most cases it really doesn't make a difference.  There are companies that prefer to install from the outside and use this in their presentation as a selling point insisting that it is a better way.

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Many factors will determine what makes the most sense.  When you install a replacement window from the out side you have to cut out the exterior blind stop trim that the storm window is attached to. This is not a piece that comes off very easily and will need to be replaced or trimmed with aluminum to make the window look good when finished. It may be less disruption inside the home by installing it from the out side but by leaving the out side stop in tact and installing from the inside creates a better seal from air infiltration.

There is an interior trim stop that is removed when doing the installation fro the inside of the home and a better seal of  caulking can be placed under this stop to block the outside air. Many companies do not caulk this way and instead caulk after the trim goes on. It's very important to caulk inside and out before installing the trim stop to create a proper moisture barrier and eliminate any potential for drafts.

Sometimes due to the type of windows and interior trim there is no other choice but to install the windows from the outside of the home. If properly caulked and trimmed this is not a problem and the window installation will be air tight and the windows will perform as intended.