OK due to some problems that are too long to go into at this time we are going to have several window replaced on our 2 year old home in the Santa Cruz California area. We are just above the typical summer fog zone at about 350ft elevation. Even though we are in a very temperate coastal climate our home is in a warmer micro-climate, and is shielded from the prevailing NW cooling winds. We have clerestory windows that we leave open from about May 1 thru Oct 1, that keep us cool enough that we haven't put in an air conditioner yet...

With that in mind we are going over a few options for some replacement windows.

We have about 45 windows in our home - and several are huge windows (96" x 72") with no overhangs and little, if any, shading.

Our upstairs is a very open floor plan with our Kitchen, dining, family room and living spaces all in one continuous space. We previously selected LoE-366 glass for the upstairs SE, S, & SW facing windows. This seems like it has been a good choice for us due to the heat gain we still get upstairs most days.

Now that we are forced to do some window replacements in other areas including some of our downstairs bedrooms, I am thinking that when those windows are replaced I would switch the glass in those areas from LoE-272 to LoE-366.

We only heat the home NOV-FEB and use in-slab radiant heat downstairs, with radiant baseboards upstairs. Our downstairs heat is really only on after dark & very early in the morning - before the sun would ever heat those bedrooms - by the time any solar gain could be used in those rooms we are upstairs for the day. If I leave the window blinds open in those rooms they will overheat on sunny days year round. We have good insulated cellular shades that we leave closed most of the time in the bedrooms. I would love to reduce that amount of heat gain downstairs, that now seems to be bothersome, open the blinds more, and lose less radiant heat in the winter at night. We have tons of large windows so VT is not a concern - besides the blinds are closed most of the time now anyway! We are very happy with the LoE-366 windows in our upstairs.

Since we do have so many large windows in our upstairs living space, on cold, cloudy days we really need the heat on all day long. However, on sunny days we open our windows most months.

Should I look at just using LoE-366 for all of our replacements ? These would be 1 facing WNW & 1 NE facing upstairs, plus 1 WNW, 4 SE, & 1 SW in our bedrooms.

Sorry for the long post - I have read tons of other responses and posts on this site, and received help here in the past - thanks in advance!