GBA Logo horizontal Facebook LinkedIn Email Pinterest Twitter Instagram YouTube Icon Navigation Search Icon Main Search Icon Video Play Icon Plus Icon Minus Icon Picture icon Hamburger Icon Close Icon Sorted

Community and Q&A

Summer vs. Winter Solar-Heat Gain and Window Treatments

aunsafe2015 | Posted in General Questions on

Climate zone 4a.  In the summer, I typically keep my plantation shutters arranged so that direct sunlight does not come into my house, especially in unoccupied rooms.  I’ve noticed that it actually does help to reduce the temperatures in those rooms on sunny days.

In the winter, I usually arrange the shutters so that direct sunlight does come into my house to help heat it up a little bit.

My question is:  In winter at night and on cloudy days with no sunlight, will closing the plantation shutters provide any meaningful benefit in terms of keeping the cold out (or keeping the heat in)?  Letting the sunlight in on sunny days does appear to provide some noticeable heat benefit.  Just curious if I should be going around opening my shutters every morning and closing them every evening, or if I can just leave the shutters open 24/7 in the winter.

Thanks for any input.

GBA Prime

Join the leading community of building science experts

Become a GBA Prime member and get instant access to the latest developments in green building, research, and reports from the field.


  1. GBA Editor
    Kiley Jacques | | #1

    Hi Aun,

    This article will be of interest to you—it takes a deep dive into passive-solar heating principles: A Quantitative Look at Solar Heat Gain.

  2. Expert Member
    BILL WICHERS | | #2

    Closing your shutters in the winter will help at night, but probably not enough to make any real difference, and likely not enough to even make a measurable difference. With the shutters closed, you will have slightly less air movement over the exterior surface of the window which will slightly reduce the thermal losses, but only by a little bit.

    The reason the shutters help so much in the summer with heat gain is that they actually BLOCK sunlight from entering. That sunlight IS energy, so the shutters are actually blocking energy from entering your home before it can warm things up inside. In the winter, that same sunlight can actually help you by warming up the interior a little.

    My recommendation would be to leave the shutters open in the winter. The shutters hurt you during the day, by reducing solar gain that would otherwise provide some additional free warmth for you home, and at night their benefit is too small to be meaningful so it's not worth the effort of opening and closing them each day.

    If you want to save energy in the winter, see if you can put in a storm window, or try exterior window film. The air gap created between the window glass and the film adds an additional insulating layer similar to the way multi-pane windows do, and provide a real benefit. Note that that window film is typically a one-season product though, and only adds a little insulating value, less than you'd get going from a double to a triple pane window, for example.


    1. aunsafe2015 | | #4

      Thanks, Bill. This is what I was thinking, and also what I was hoping to hear.

      Thanks to the other posters for the responses as well. Very helpful.

  3. onslow | | #3

    Aun Safe,

    When I lived in Chicago area, nominal CZ5, I tried the double honeycomb shades on my very poor quality double pane windows. The room was more comfortable and I did save heat in the winter overnight, but at the expense of massive condensation collecting on the frame edges. Your shutters likely allow enough airflow that this doesn't occur, so don't get sold on new shades for heat savings.

    Removing the warm room air from easy contact with the windows led to the glass surface cooling below the dew point. Mopping up the windows every morning was annoying, so mostly the shades got used in the summer to keep the house a bit cooler. The inner side of the shades had a slight aluminum-like coating, which did help bounce the heat energy back some.

    In the new house I made sure to go with triple pane and only have privacy shades on a few windows now. I chose a very low SHGC and gave up on the idea of winter sun gain. For best sun heat reduction in the summer, shading the window from outside will gain you more than shades on the inside. The sun will be warming your shutters, which then will act like little radiators to the room. Still some benefit to using them just better to keep the energy from getting to the window first.

    The old awnings seen on many homes in Chicago were ugly but effective. Deciduous trees are a more tasteful method, but come with those pesky leaves every fall. It is a kind of pick your poison choice.

Log in or create an account to post an answer.


Recent Questions and Replies

  • |
  • |
  • |
  • |