If you have subterranean termites then the orange oil will kill termites on or in the wood. However, subterranean termites come from, as the name indicates, the sub terra or underground. As a result, a pesticide will have to be used that has a residual soil life. If you have drywood termites, then I may be hesitant to use orange oil only. Again, it may kill the ones it contacts, but you may need to use another method in order to surely rid your home. I have heard of people that use a tenting method that doesn't use any pesticide at all, but instead uses a heater to heat the inside temperature of the house to around maybe 120 to 130 for 24 hours or so. This prolonged heat will kill them. It certainly wouldn't hurt to ask around to see if that is an option if you are concerned about pesticides.