This paper presents simulated performance of
insulation/radiant barrier systems under different
Texas climates. A transient heat and mass transfer
model which predicts thermal performance of
residential attics (Medina, 1992) was coupled
with an "economic" subroutine. Simple payback
periods were estimated which were based on current
insulation and radiant barrier (RB) prices (materials
and installation), and current and forecast electric
rates. It was found that when the analyses were
based solely on reductions of ceiling heat loads
during the summer time, a combination of R-11 with
RB was more effective than upgrading the insulation
level to R-19. Similarly, adding a radiant barrier to
an existing insulation level of R-19 proved more
effective than upgrading to R-30. When heat gains
to the cold air traveling inside A/C ducts (\which are
usually installed in attic spaces) were considered, all
insulation/radiant barrier combinations showed
faster payback periods than insulation upgrades,
During the winter time, insulation upgrades proved
to be more effective than insulation/radiant barrier
combinations. The simple payback analyses
presented herein include both summer and winter
simulations
