Every environment and application is different. For example, if the rodents are already nesting or if you have a very bad infestation problem, it may take a little longer. Some customers have had results in as little as an hour, and for others it took a little longer to clear their home of all rodents and unwanted pests. If units are on every floor, including basement, attic and garage, results will be faster. Once satisfactory results are achieved, we recommend that you leave the unit plugged in to maintain the results and to prevent the problem from occurring in the future.