My builder installed a fresh air timer on my furnace, a 24-hour pin timer with 15-minute increments. When it's on, it runs the fan and opens the fresh air damper. The resulting air that comes from the registers is cold (it's cold outside) but not as cold as the outside air, which leads me to believe it's mixing the outside air with recirculated air from inside.
We ran it on always-on mode for a while to help with the carpet and paint fumes, but it's cold enough outside now that the constant cold air is bothersome. How often/how long/at what times should I run it during different times of the year? The settings the builder left on the timer were clearly the result of someone just haphazardly poking a few groups of pins so it ran a few hour-long intervals every day.
I've poked around on the web a bit but there's an amazing amount of jargon and conflicting advice out there.