MATSS is a 2-dimensional finite element program for simulating transient heat transfer in typical wall envelopes. It is capable of modeling the R-value of wall systems under steady-state conditions and the yearly energy usage of a wall system in a given climate zone. It is able to quantify the potential energy savings of a wall system due to the thermal mass benefit of masonry.

Documentation on the usage of the software along with some of the calculations employed are included with the program. The documentation also includes instructions on how to perform simulations of user-defined custom wall geometries for additional flexibility.