Bathrooms offer several opportunities to make energy saving improvements.
Select low-flow showerheads, faucets and toilets.
Replace normal incandescent light bulbs with energy efficient fluorescents.
Add wall, ceiling and duct insulation if you will be opening walls.
Seal air leaks around doors, windows, electrical outlets.
Upgrade existing windows by adding storm windows, caulking and weather stripping, and adding window treatment or coverings.
Replace old windows with new, energy efficient windows. www.energysavers.gov/your_home/windows_doors_skylights/index.cfm/mytopic=13340