Does RES check take thermal mass into account?
RES check does not perform load calculations; it computes an overall UA (u-factor x area) of the envelope components. In most locations, the code allows walls having a heat capacity greater than or equal to 6 Btu/ft² °F to have a higher Uo factor than low-mass wood- or metal-frame walls (see Tables 502.1.2a-502.1.2c of the MEC; Tables 502.1.1(1)-502.1.1(3) of the 1998 IECC; and Tables 502.2.1.1.2(1)-502.2.1.1.2(3) of the 2000 and 2003 IECC). Masonry or concrete walls weighing at least 30 lb/ft² and solid-wood walls weighing at least 20 lb/ft² are eligible for this credit (the area to be considered is the exterior surface area of the mass wall). In the software, eligible mass wall components receive this credit as an increase in the code building UA (the mass wall required Uo factor is greater than the low-mass wall required Uo factor). Brick veneers or log walls constructed of logs less than 7 in. thick currently do not receive this credit. The Uo factor for all mass walls except log w
