I have patio doors that open onto my (small) garden. When it's hot, I open the half of the door that slides, but usually leave the curtain across it to deter flies. I also have the back door open, with one of those fringe curtain things that's meant to keep flies out.

I also have a curtain which divides the living room from the hall, and I also draw that if the patio door is open during the day. Then, if a fly or two comes in, I'll open the curtain across the patio door so there's only one obvious way out for the fly and usually they fly right out again.

Once dusk falls I tend to keep the patio door closed, as I hate moths and daddy-long-legs (crane flies).

But, senyar, moths inside are Rudi's playthings.

The people who have those mongo houses eith multi-thousand dollar sliding doors don't open them except on perfect days.

Most people who own expensive beach homes never open the windows. Crazy

I live in an area that gets very buggy in the spring and summer. Some nearby friends of mine have recently begun having their yard treated (sprayed? I'm not sure of the mechanism) to keep pests away from their house (think mosquitoes and flies). I had dinner on their porch the other evening, and it was remarkably bug free. You have to reapply every few weeks, which is the downside, but it really is effective.