ᐅ Energy Demand: Snow on Skylights & Shutters with Triple Glazing in Winter

I have two questions for the experts regarding the following situations, as I have found differing opinions:

• If snow accumulates on a roof window (double-glazed), does it affect the room’s energy demand?
• When the outdoor temperature is low (below 0°C (32°F)), does it make a difference to the room’s energy demand whether the roller shutters of a large floor-to-ceiling window (triple-glazed) are fully closed or left slightly open?

Merry Christmas to everyone!

stromneuling schrieb:

1. Does snow on a roof window (double-glazed) affect the room’s energy demand?

2. When the outside temperature is low (below 0°C (32°F)), does it make a difference for the room’s energy demand if the shutters on a large floor-to-ceiling window (triple-glazed) are fully closed or left tilted open?

Interesting – but in real life totally insignificant and not measurable – topic.

Regarding 1: Snow acts as an additional insulation layer, so it provides better insulation at night. However, during the day it blocks sunlight, which increases heating demand.

Regarding 2: Yes, it makes a difference. Fully closed shutters insulate better.

BUT: None of this is something a) you will feel or b) see reflected in heating consumption.

Thanks for the explanation, then I don’t need to put much effort into any automation anyway :-)

nordanney schrieb:

1. Snow acts as an additional insulating layer. It provides better insulation at night. But at the same time, no sunlight enters during the day. This leads to increased heating demand during the day.

I think that is only partly true. Snow does insulate against outside air but essentially maintains a temperature close to 0°C (32°F) at the window itself. So, if it is 10°C (50°F) outside (even at night), the snow surface stays at around 0°C (32°F) — this is always the case because otherwise it would melt while the rest remains cooled. Snow therefore acts as a strong temperature sink for anything above 0°C (32°F). Below 0°C (32°F), snow functions as insulation.

GeraldG schrieb:

Snow acts as a strong temperature sink for anything above 0°C (32°F). Below 0°C (32°F), snow serves as insulation.

Yes, but since snow is no longer an issue at an outdoor temperature of 10°C (50°F) (heat loss from the interior through double glazing also accelerates snow melting), you shouldn’t get hung up on every “but” ;-)
Otherwise, you’ll end up writing a dissertation.

nordanney schrieb:

Exciting – but totally unimportant in real life, something that can’t really be measured – topic.

So unimportant. Especially when you want to see the Christmas lights hanging outside from indoors 😉