How to keep flies out of the house?

Best way is to secure all doors and windows and make sure screens fit properly. Keep your yard as tidy as possible and do not leave any pet food outside.

Hi Evelyn,

Sorry to hear you have flies galore, they are a health hazard to say the least. The only way to do this is to not open doors and windows, use screens or a/c whenever possible. You are doing everything right, but the animal waste is the big draw, no way around it.

Of course flyswatters work well, but that is after the fact they are already in.

Have you considered a system of double screen doors opening in opposite directions? Or a hanging a curtain of thick plastic strips at your doorway. Make sure your screens are in good repair.

Best to you.

Hi Evelyn! I'm not sure about foolproof. Have you considered involving an exterminator?

This is a bit different, but have you ever gone through a grocery store door and been hit with a blast of air? My suggestion is that you find and install rectangular fans outside, above your doorways, but pointing down about 60°. They would need to be fairly strong, which wouldn't be very cheap, but it would be a one-time purchase. Leave it running during the day or just when you tend to use the door. If it is mechanical, it could be put on a timer. This way, going in or out, flies will find it harder to enter.

Flies also tend to avoid basil and vinegar. Try planting large pots of basil near your doorway. Using Abel Baker's fan suggestion should intensify the effect. Wash patio door tracks and kitchen painted walls and laminate countertops with full strength distilled vinegar.