I have a hoover windtunnel

which way does the filter go back in on wind tunnel white side towards sweeper or facing out to see white thru grill

Hi, You don't say which model windtunnel you have but most are the same. The canister is in two sections with a Hoover emblem to the right of the handle. this is the side the filter goes on. The bracket slides out and holds the round filter, the round filter snaps into the bracket so that the end of the filter with the opening goes down to fit the hole in the bottom of the canister. When putting the canister back in the vacuum be sure the top goes back flat on the canister and the locking lever is open all the way. You have to slide the canister back in level and then it will drop down into position you can't tilt it. now you can lock it. Good Luck!