Most RV's can be helped by adding a dynamat type product for additional insulation. The problem is getting it applied onto the area you need it on. Lifting a doghouse and adding to the underside is relatively easy, getting it attached to the underside of the floorboards is another issue. Lifting the carpet and applying would be a help, but not as much as getting the insulation on the exterior and reducing the heat from getting into the cabin to begin with. As BGMAC indicated, your make and model will help get more specific answers to your question.