I do have a customer with the same problem who has constructed a "stand-off" wall on part of his house - he claims it works.  He says he still sees some, but he sees more on his stand-off wall than he does on the house.  The wall was constructed in 1995 so he does have a little history.  For the past few years my men have reported that the boxelder bug population (around his house) seems smaller since its construction.  Part of the cycle. You have to understand, this guy is a doctor, probably has scads of money that you and I don't have, and had this idea to solve his problem.  This is how it works - or is supposed to work.  I saw it under construction, and then finished, except for painting. He also asked me not to take any pictures, so I can only give you a verbal description. The "stand-off" wall consists of a lattice wall that stands off from the house wall about 8 inches, is built in sections, and each of the sections are removable, with each section hanging on wooden and steel stanchions secured to the main wall.  With the sections removed, the stanchions are designed and arranged so they can also be used to support scaffolding for painting and caulking.  The sections of lattice are very light in weight, built in a tight lattice. Not much light comes through the lattice, and it is painted a much darker color than his light-colored house.  He had his lattice custom made by a carpenter, but commercial lattice you can buy at Home Depot would do just as well and probably cost a whole lot less.  Double the lattice so you can't see through it. It doesn't look bad at all.  In fact, unless you look closely, it looks like it's part of the house. It's only on one side of his very large wood-sided house, the small back end, and the wall doesn't cover all areas.  He says he studied the bugs for a couple of years, and had the wall erected in those problem areas.  One of his relatives is an architect and sketched out a couple of quick drawings which were then used by the carpenter. The carpenter made his own changes, the doctor made some too, but the end result (on his rustic-looking home) looks okay to me.  I don't really know how effective it actually is. The idea, of course, is to give the bugs a resting spot that doesn't lead directly to the main structure or living quarters.  I can see that, in theory, it might work to some degree, but I think you would also have to do "everything else" too.  The good doctor DOES have his two (very beautiful) trees sprayed each year, and says that he also caulks every year.  He says he used to spray the latticework wall with a soap solution, but it marred the paint surface, so he says he doesn't spray it anymore, and doesn't really notice a difference inside the house.  He also claims a noticeable reduction on his air conditioning bill, he didn't mention a saving on his heating bill. In a conversation with him in late 2004, he claimed that, for the past couple of years the tree has had a minimum of bugs.  We have had colder weather here, the past few years and the trees have been sprayed religiously.