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Glass coating/film to reduce solar gain. Anyone have experience?

  • 11-02-2022 12:36pm
    Registered Users Posts: 1,815 ✭✭✭ WesternZulu

    I live in a new build where the kitchen/living room is south facing and has large windows and a large slider meaning that there is direct sunlight coming into the room throughout the day. In hindsight I was very naive as this is a massive problem for solar gain, it didn't even cross my mind before we moved in but it became very evident afterwards.

    The windows are great for views and really add to the room but the solar gain is something else, even during winder time if the sun is out and shining in then the room gets uncomfortably warm. In summer it obviously worsens and in the evening the slider gets direct sunlight from the west and acts like a huge radiator it becomes so warm even after sunset. During winter the room could be nearly 25C degrees on a sunny day, last year during summer it got up to 32C! I dread days now that are sunny for this reason; the room becomes a furnace!

    I have been looking into solutions over the past few months in the hope of someway easing the solar gain. Besides putting up an expensive external sun blockers that would do little to block direct sunlight when the sun is low I am at a bit of a loss of what to do.

    I recently heard about window films that may help and was wondering if anyone has any experience of them in a residential property? How effective are they and if they drastically change the appearance of the glass from the inside/outside?

    Something along these lines:


  • Registered Users Posts: 502 ✭✭✭ mike_2009

    I put a 3M film on all my windows for security reasons - adds a laminate to make it a bit trickier to break. I put in polycarbonate secondary glazing and this has helped a bit with solar gain, not much with noise though.

    Back to your question - first check with the window / glazing manufacturer to ensure any window film is not going to void your warranty. Next, do they work - absolutely. They can darken the room however and there are different grades. They may be prohibited with laminated glass, you may need toughened glass so find out what you have.

    Also Brise Soleil or External window blinds worth checking out (check planning though).

    I'll PM you some links to discussions elsewhere about this topic you should read.

  • Registered Users Posts: 502 ✭✭✭ mike_2009

    Your profile is private so browse to and search for "window film" WITH the quotes and the threads to read are:

    Window Film

    Window Film further info

    Windows Film Latest

  • Registered Users Posts: 1,815 ✭✭✭ WesternZulu

    Thanks a million Mike for all the info and for sending on the external links - I will look into those. Great to hear from someone who has got them. According to one company I called the films have become extremely common in new builds in recent years because of what he called 'The Dermot Bannon Effect".

    It's reassuring to hear that they are effective, my only concern is that they might impact the view when looking out the windows. Then again it's probably something I'm willing to compromise on if they make the room more comfortable to live in. No point if you have a nice view if you resent spending time in the room because of the heat.

  • Registered Users Posts: 502 ✭✭✭ mike_2009

    They may darken the window slightly but you could ask for a sample and test it - should be removable (get a small square if possible). Glazing can deal with this issue but you have to specify them carefully and not many suppliers offer this, plus the film is a good fallback if you buy a house and inherit the issue.