After 1-1/2 years I can report on the success of exterior window film for reflecting much of the suns energy before it passes into the window. The problem with interior reflective film is that the sun energy passes through the glass twice. This heats up the glass and much of this heat is transmitted into your home. Heavy curtains will stop the sunlight after it passes into your home. They will heat up and most of this heat will transfer into the rest of your home. The exterior film reflects much of the sunlight before it enters the glass. The product I purchased and installed is: BDF EXS15 Exterior Window Film Privacy and Sun Control Silver 15, Dark - 24in X 50ft This is for people who have already purchased and installed windows for their home and did not get the low-e coating and renters who want a quick low cost solution to a window they do not own. Maybe you can figure out a way to buy the same quality from China and save costs. I purchased from the US to improve the chances that I was getting a quality product for exterior use. If it was interior I would not be worried about the quality. There are a number of YouTube videos that show the tricks on how to install window film.
Sorry. I do not have any left over. Maybe it can be purchased in shorter lengths. Or you can find someone here on DI who will split an order with you. I imagine there will be people who only want to do one window. If you cannot find someone to split an order with and you cannot get smaller quantities from China, then you can try using the interior film on the exterior of the window. The window shop across the national highway from CityMall has the interior film and it can be purchased in small quantities. I would try using this film on the outside of the window with an expectation that it will maybe last three years. Cleaning the window before application is critical. Every little microscopic spec will show a small bubble in the film after it is installed. Here are the steps for cleaning. 1) Scrub it twice with soap and copious amounts of water. 2) Use a razor scraper to scrape off the microscopic specs that are stuck to the window. This is included in some of the kits. You will not be able to see these specs but you can feel them as you scrape the entire window. 3) Wash window again. I found that on a used window I was not able to get the perimeter edges around the rubber completely clean. I think the dirt leaked out from under the rubber while doing the install.
But they will reduce the sun's rays entering the house. Nothing will be 100%. Found this (first one I came across so perhaps better articles are available): https://ultimatewindowtinting.com/how-tinted-windows-can-help-reduce-heat
Maybe you installed a poor quality or installed on the interior? The heat reduction from mine is easily noticeable. I still draw the curtains in the morning and late afternoon when the sun is low and shining directly through the window. Without the curtains the direct sun causes glare on the computer monitor. The exterior film greatly reduces the heat admitted. It has been proven that the higher quality films block up to 79% of the solar heat, reduce glare up to 83%, block 99% of UV rays and reduce heat loss in winter by up to 30% (low E films). If reflective glass was not installed during initial construction, window films offer a cost-effective solution for the existing windows to look and perform as well or better than reflective glazing. Window films have often reduced the HVAC load on buildings to the point where expensive upgrades to equipment were unnecessary. https://www.conveniencegroup.com/myths-about-window-film
They might reduce the heat but the curtains feel warm to touch. Skipjacks film covering seems a better option.
