The 6 mil IRAC does retain a little more heat than 6 mil clear. But neither is a much better insulator than nothing. I've got two layers of the IR poly inflated and that's still very poor insulation. It probably cuts the heating bill in half compared to one layer of clear. But only delays temperature drop by about one hour at night. As the temperature falls in the evening the inside might be an hour later than outside at say reaching the freezing point. It still requires heat input to maintain anything above outside by morning. This is with a large greenhouse, 32x54x16ft. I also have a sunroom on the south side of the house. It provides a large amount of heat to the house by day. But at night it's the same as the greenhouse. So I move plants out at 9am and back inside at 5pm.

Thx all - Todd, not sure I understand the ramifications of your first sentence - sounds like you mean the low-e would not be effective as a single window on an enclosed porch - not worth the extra $$$? Due to how the porch was constructed, its quite OK as a porch but to make it into a sunroom or more integrated with the interior would require extensive work - the next person can do it if they want! It faces north too which means as a sun room, the total lack of sun in the winter would be a definite problem LOL!

It does seem very individual. Mosquitoes are a problem all summer in mid-South and especially at dusk. I previously had an open deck, so no overhead fan, and got driven in by bugs. Now have a screened porch which is elevated so not able to do a comparison re: height! But have some open deck down a few stairs and definitely more skeeters there. We eat on the porch a lot and another thing I wonder about is flies. Previously when having a meal out on an open deck we were constantly waving flies away & covering any food even if still serving. No such issues with screens. I do like that we have some unscreened deck because it is a different experience & when not buggy, I also like to sit out there.

A three season room, french doors to it? Call an architect. Footers, headers, permits, roof lines, and money. It isn't just "add a screened porch" . ..unless you use the one you have Otherwise? Buy a beautiful gazebo, and put it where it best suits the view. Enjoy in good weather with screens