Vyana replaces the air in a room instead of cleaning the same air again. It comes as a pair of units. One brings outdoor air in. The other pushes indoor air out. Both fit in a window or through an outside wall, with no contractor. Each unit measures indoor CO2, PM2.5, PM10, VOC, temperature and humidity. Over Wi-Fi it also gets local outdoor air quality and the weather forecast. It compares the two and exchanges air only when the outdoor air is better or will be better. The pair moves up to 270 CFM through a washable MERV 7 filter, at under 45 dB. The front lid is also the door. Four small motors close it when outdoor air is worse, so the house stays sealed. Because the system runs when the outdoor temperature is already comfortable, it lowers heating and cooling costs instead of raising them. $625 per pair.