Heat exchangers -- metal fins and attachments that help channel heat into and out of the air in your home -- are a common part of air conditioner and heating systems. Air exchangers use heat exchangers, but they are not tied to a specific heating or cooling task. Instead, they are designed to improve a home's insulation quality and help save money.
You do not need an air exchanger. They do not provide primary heating or cooling functions like an air conditioner or heat pump does. They do not have the same health benefits that humidifiers or air filters do either. However, they do allow you to create a source of fresh air in your home without losing heating. If you want a consistent source of fresh air but do not want to open a window or crack a door to get it, an air exchanger may be the solution.
Air exchangers are primarily used in order to save heat. They open to outside air, but as the inside air flows out to be replaced, they use a system to draw the heat away and give it to the incoming outdoor air. The air itself is renewed, but the heat remains in the house. The most effective versions are those that mimic heat pumps with refrigerant systems.
Air exchangers are very useful for altering humidity as well. This works well if you do not want to invest in a dehumidifier but still have a tightly sealed house that makes it difficult for moisture to escape. The air exchanger allows water vapor and condensation to escape into the outdoor air while bringing in dryer air. This helps create a greater equilibrium between indoor and outdoor humidity levels.
Air exchangers are effective at saving money in place of other methods to get fresh air. Good air exchangers can save up to 80 percent of the heat in the air, according to North Dakota State University, which means you do not need to spend the energy to replace this heat using furnaces or heaters. As a result, your heating bills are lower. The only time air exchanger efficiency can struggle is when the air outside is very cold or very humid.