We are starting a build and trying to figure out if it's worth heating/cooling an unfinished basement. The two main floors will have a unit each. Main floor a Lennox 20 seer variable speed unit with dual fuel. The home will have open cell foam on the outside envelope and rafters, be tested for HERS rating with a reasonable # of air exchanges an hour. I know that a Manual J is being planned, unsure about a Manual D or S. Air handler in basement and in "conditioned" attic. House will be located in Deep South.

The basement is about 2400 sq/ft. 500 will be heated/cooled. The remainder is being called "conditioned space" in the sense that it's inside the building envelope. The builder plans to put a full time humidity sensing/de humidifier in the unfinished area. The basement has a number of windows that are west facing with many windows shaded by a deck. 3 sides of the basement will likely be below grade.

The actual cost to heat/cool the area is TBD as we are very early in the build. Heating is of less importance to us as we have an electric fireplace + space heaters to cut the cold. I'm more worried about the basement being too hot/stale. Mainly will be used by kids as a play area. Any thoughts and/or need more information to comment?