those critters are almost impossible sometimes!
#1: put any and all fruit in the fridge. dont leave food sitting on plates, or even in the garbage at this point because that encourages them. put food in an old ice cream bucket, and dump it (including the bucket if you want) when your trash is going to be picked up.
#2 clean all your surfaces. doesnt have to be with bleach or anything, just whatever you normally use.
#3 stop letting these flies ruin your day. cook at home; you'll save a ton of money.
#4 your heating bill wont go through the roof, i was VERY doubtful about that whole "turn your heat down when you are gone to save money" thing. but we've been trying it and it actually works. so even if you completely wipe out the whole house with cold, you can be assured its going to cost you no more to warm it back up than it normally would to keep it heated up.
#5 you dont have to go to that extreme to get rid of them
heres what you can do
-get a glass, plastic cup, container, whatever you want.
-fill it less than half full with apple cider vinegar.
-put saran wrap tightly over the top, and poke some holes in the top
-leave it sitting where the flies seem to 'congregate'. it might take a while, but they will crawl in there, and not be able to get back out. take extreme caution to not open it in the house, or bump it and loosen the saran wrap. you can take it outdoors and dump it if you want.
these things can come from the most innocent sources, but one thing is for sure that they are hard to get rid of. they also feed on just about anything, but they are not harmful to humans or pets. even if you eat them, as gross as that sounds, they wont hurt you. just like i said, put your fruit and stuff in the fridge for now, dont leave food sitting out AT ALL, and keep the surfaces clean. my mom says that a certain grocery store has them bad so she wont buy her produce from there. but really, anything you can keep in the fridge will help you prevent them.
anyway, good luck, i hope this idea works, and stop going overboard, its not like they are lice or anything ;P