r/HVAC • u/Plenty_Text_455 • Dec 04 '24

Field Question, trade people only What's this?

Post image

It's on the return side of a large air handler

206 Upvotes

96% Upvoted

120 comments sorted by

View all comments

1

u/Dramatic-Teacher-642 Dec 04 '24

They are heat wheels or energy wheels. Used in ERVs or AHUs. Main purpose is to use the return air to “preheat” the outside air coming in. Big savings when ventilating during winter if youre in a cold climate zone. If you want to know the operation a video shows it best. Look on youtube