Self-contained air-cooled through-the-wall units are the most economical and easiest to install—no licensed HVAC/R technician required. The evaporator side blows cold air into the cellar while the condenser side absorbs warmth from the cellar and exhausts it into the adjacent room. Self-contained units tend to be noisier than either ducted or split units. There are models for wall thicknesses ranging from 2X4 framing up to 20” thick insulated concrete or block; room-to-room indoor models as well as interior-to-exterior models. If warm-side conditions permit, cellars as small as 150 cu. ft and up to 2000 cu. ft. will accept a through-the-wall unit.