Crawl spaces get very hot in the summer which makes it harder on your air conditioner! If you don’t have enough insulation this can really hurt your bills! Power Gable fans can cool the space lots and your air conditioner won’t have to work as hard! Also they have a humidity setting and the crawls also can get a very high humidity levels! I have seen it rain in them sometimes. That causes lots of problems. Rotting of joists rafters decking Etc. it can make the sheetrock moist and cause the textures to come off! It can cause mold to grow then it can get into your living space and thats really bad. You can check out my mold page to see how bad it can be. We can install turbines and power turbines on houses where gable fans won’t work!