Retrofit windows are an adjustment to existing windows to improve the windows energy-saving ability. Retrofit window solutions can include adjustments such as storm windows, interior window panels, and interior thermal blinds. To replace a window will cost you much more than having a window retrofitted as the price is much lower to have a retrofit instead of replacing your windows.
Exterior Storm Windows
The most popular reason for installing exterior storm windows is to save energy and money.
You need to be aware when buying and installing storm windows that they are not poor-quality or poorly installed as they could permit air leakage.
You should never rely totally on storm windows alone to fix bad windows. More than anything, relying on storm windows alone to fix bad windows is never a solution. Storm windows are an addition to a home's windows but they will never offer the weathertight nature of true windows.
Interior Window Panels
Interior storm windows, also known as invisible storm windows, are installed parallel to your existing window and improve the thermal and air leakage responsibilities of the window.
Interior storm windows are also popular for being solid acrylic and semi-permanent. Interior storm windows are attached by magnetic strips or compression gaskets and can remain in place for as long as the homeowner desires.
Interior cellular blinds are made of lightweight fabric and open and close easily. When the blind is fully extended a thermal shield between the cold window and the warm interior is activated.
Some cellular blinds are installed at the top of the window frame. Quilted window blinds are equally effective and are made of a thick, quilted fabric that rolls up and down.
One downside of using thermal blinds as your retrofit window solution is that they are not transparent. They can only be used at night or, if you wish, during the day but they do not allow natural light into the house.