This depends on the size of your house. In order to achieve full home coverage, you want to ensure you have enough Vilos throughout your home. If your home is 1,500 square feet or less, one Vilo will be enough to cover your home. If your home is larger than 1,500 square feet, we recommend the 3 pack, this can cover up to 4,500 square feet. If your home is larger than 4,500 square feet, you can purchase additional single packs until you have enough to cover your desired space.