We have found that traditional window contractors used fiberglass insulation to air seal around the windows. Fiberglass insulation was designed to slow the rate of heat transfer and not to air seal. The appropriate seal around the windows should have been spray foam insulation around the windows.
Many people have found that after properly sealing their windows, the house was much warmer and they no longer felt the need to spend tens of thousands of dollars on replacements.
We can first inspect your windows using Thermal Imaging in order to determine the issue and then weigh the options on whether or not to replace vs repair.
The BLUE is cold air that is being pulled in around the windows with the Blower Door. The RED and YELLOW colors represent the warmer items in this shot. This a newly installed window. The installer did not properly seal this window. If it were properly installed it would not be showing blue around the outside of the trim area.