Insulating windows vs. passive solar

[Villanelle]

I live in Germany where it is often gray and overcast in the winter, and where we are far enough north that the winter sun is short-lived and not-especially direct. It also gets pretty cold in the winter.

Thankfully our rental house has really great double-paned windows.  It also has roladens (metal shades that close so completely they block out all light). 

I an torn between opening the roladens and letting in the sun, no matter how meager, and closing them as an extra layer of insulation.  One extra piece of info that may be relevant is that when they are closed I have to turn on a light in whichever room I'm using during the day, but when they are closed, I don't.

Thoughts?  (Some windows are on the mostly-northern facing side of the house and some on the mostly-southern side, if that makes a difference.)

[Posthumane]

I would tend towards keeping them open on somewhat sunny days. At my latitude (about 51 degrees north) even the few hours of sunlight we get in the wintertime makes a significant difference in how often the furnace comes on. On overcast days it probably doesn't make much difference, though I find that natural light keeps me in a better mood than having electric lights on at home so that would again tip it towards keeping them open for me. The roladens, if they are what I'm thinking of, are mostly for protection from intruders and the like, and I don't think they do very much for extra insulation.

[sunshine]

I would personally let the sun in. Have you considered the cheap  insulating kits that go on the inside of the window? The light still shines through and the view is crystal clear. I seriously need the sun with our sub zero and blah winters! We have very heavy insulated drapes that get closed at night for extra heat retention.

[Rural]

You won't get much sun and through the north facing windows. Why not compromise and open the ones on the south?

[Abe]

I think the insulation from the roladens will be minor compared to the heat gained from the sun. Also, not having the sun can contribute to poor mood (now called seasonal affective disorder) and vitamin D deficiency (still called the same thing).  Consider buying polycarbonate (or acrylic, but has less infrared transmission) sheets and cut to the size of your window, inset them into the window with a 2cm gap and glue into place. It will add some insulation to your window due to the air gap and allow most of the heat through.

[Villanelle]

I think the insulation from the roladens will be minor compared to the heat gained from the sun. Also, not having the sun can contribute to poor mood (now called seasonal affective disorder) and vitamin D deficiency (still called the same thing).  Consider buying polycarbonate (or acrylic, but has less infrared transmission) sheets and cut to the size of your window, inset them into the window with a 2cm gap and glue into place. It will add some insulation to your window due to the air gap and allow most of the heat through.

I don't want to glue anything, as this is a rental, and the way the window are, I am not sure how this would work.  The are basically flush with the walls (and swing open like doors, rather than sliding open like American windows) so there is no recess into which I could put anything.  Also, any thing with much expense at all wouldn't have much of a pay off as we will only be here one, or maybe two more winters. 

You won't get much sun and through the north facing windows. Why not compromise and open the ones on the south?

This is what I'm doing now.  I just wasn't sure if there was a better plan.

[Gerard]

I have a similar situation (only latitude 47, but maritime climate means lots of cloud). I find the passive solar advantages are the greatest in the spring and fall, especially April, when there's longer days and more sunshine, but it's still cold enough that you benefit from the extra sun energy. As a diagnostic: try sitting in the sun when it does come through the window (or lie in a square of sunlight on the carpet, like a cat!). If you're feeling warmer after five minutes or so, then the gain is probably worth it.
wrt the plastic insulation, many brands now come with two-sided tape, not glue, and the residual adhesive washes off pretty easily once the warm weather arrives. I put it on my north/west facing windows.
[edited to add: And whichever way you go, wash the windows more often. I'm always amazed how much light is getting stopped by dirt!]

[StarswirlTheMustached]

You won't get solar gain on the north side, so keep those babies shut tight. Leave south open during daylight hours, natch. East in the morning, and west at night. If you can't see the sun (or wouldn't be able to, if it weren't cloudy), you won't get anything heat-wise, from that window.
Just curious: do you know the R-value of your roladens? (also, I thought that was a beef dish.)

[Villanelle]

No idea of the R value.  Though insulation isn't their (primary?) purpose, surely the do at least a bit of good.  If they don't let light through, then they aren't letting much air through.  While the material isn't exactly prime insulation, they are an extra layer between the cold outside air and my slightly heated indoor air, so they must help at least a bit. 

And it should gave two "L"s.  RoLLadens.  Sorry. 

[turboseize]

You won't get solar gain on the north side, so keep those babies shut tight. Leave south open during daylight hours, natch. East in the morning, and west at night. If you can't see the sun (or wouldn't be able to, if it weren't cloudy), you won't get anything heat-wise, from that window.
Just curious: do you know the R-value of your roladens? (also, I thought that was a beef dish.)

That would be "Roulade". And the thing at the windows is "Rolladen". ;-)


Besides protecting (a little bit) from burglars, they have the very same use as the original Fensterladen: keep the sun out and protect the window glas. They also offer a little bit of insulation.
And I fully agree with you: close them when it's dark, open when you want daylight.

[eyePod]

Hah!  This hits close to home.  We rent an apartment which has HUGE windows (ceiling to floor) in our living room which is sunken about 3 feet compared to the kitchen area.  On top of the windows being there, they face north.  The sliding doors have terrible seals and need to be replaced.  Since this is an apartment, I say too bad!  Our method, although not very attractive looks-wise, definitely gets the job done.

It's detailed here(http://www.builditsolar.com/Projects/Conservation/bubblewrap.htm), but basically, we duct tape strips of bubble wrap at all the seams and then use bubble wrap on all the windows to add an extra layer of insulation.  i swear these windows are just a single sheet of glass.  They are ice freaking cold to the touch.  This allows us to really use less heat in the winter. When it's on, it's set to 68, and I lower it even more at night and turn it off when no ones home.  We do have a space heater for the little ones room which is unbelievably powerful!  We get a HUGE roll of bubble wrap (about $75 shipped to our house) from Uline and then I use the rest of the material for packing eBay shipments.  This comes out of our utilities budget but definitely pays back itself within about 1.5 months.

Only negative is that since we end up duct taping a lot, we don't get to re-use it.  This isn't that big of an issue because I can use it for shipping and we are short on space in general.