The energy savings and economic benefits of various low-E window types are given for Florida residences. The results are based on detailed annual hourly whole house simulations. Tinted and clear glass and window coverings were also simulated. The results indicate annual space conditioning cost savings in Orlando, Florida, of:

Clear low-E windows relative to clear double glass from $.03/ft² ($.35/m²) to .29/ft² ($3.14/m²)

Tinted low-E windows relative to tinted double glass from $.10/ft² ($1.08/m²) to $.23/ft² ($2.48/m²)

Based on the results, maximum initial incremental costs compared to clear double glass to obtain a 10% return on investment over a 20 year life were calculated for the low-E clear windows. The analysis indicates initial incremental costs no greater than $.47/ft² ($5.06/m²) to $3.54/ft² ($38.10/m²) would be required to meet the economic goal in Orlando.

Noneconomic benefits are also discussed. An analysis for a summer design day shows the peak hour mean radiant temperature in a small room with one entire wall of west-facing glass can be reduced by 3-10 F (1.7-5.5°C) with different low emissivity glass types.

Units: Dual