Woke up to the heater on (sigh). It was 67 inside, nice and cool. Heater turned off. Went to Home Depot last night and bought reflectix, which is essentially aluminum paper bubble wrap. Didn’t pay attention to the R-values as there are many rules on the instruction sheet.
So I took down one of the pieces of cardboard I had wedged into the skylights down, and this stuff was just the right width to be shoved up into the skylight. it says it wants 1/2 inch space, but I figure the double pane on the skylight supports that. Also, there was a lip around the top of the skylight box, so I just cut a length and used my yard stick to push the edges up into the lip, with some hanging down inside. I can see little pokes of light, but much less than the cardboard allowed, plus this reflective value should be much greater.
I’m leaving the other skylight cardboarded and will see if I can find a way to determine height of day temperature effectiveness. I don’t have a infrared thermometer yet, but I’ll work something out.
I got a 25ft roll so maybe a couple of sheets to lie inside the blinds might help on the sunny side while I am here, just move it from window to window as needed and let the blinds hold it up. Hmm…. Renting makes one try and find solutions on the cheap that are not terribly awful looking.