Works with your hrv or air heating. The HomEvap is the most quiete and most energy efficient humidifier and cooler available. The HomEvap improves your comfort at home and provides a healthy indoor environment. No more complaints about stinging eyes, irritated noses and static shocks with the HomEvap. We have two HomEvaps on our HRV, one for cooling and one for humidification. Our daughter is asthmatic and the HomEvap reduces dust. So we have a healthie.