Just moved to The Villages in Florida.
Small house built in 1990 has steel door, screen door, single pane
windows in aluminum frames. Am looking for sites or info on the payback
period for different ways to improve efficiency. House has new A/C -
Heat pump from Trane. No way to get to attic to improve insulation up
there. There are aluminum awnings over most windows.
Some possible ideas I am considering (in no particular order):
Storm door with full glass.
New front door of wood.
Double pane windows - would be vinyl clad.
Film on existing windows.
Storm windows with full glass.
Combination of some of the above.

Yes I am going to Google but there are so many choices.
Would prefer replies from folks with experience or training or URLs to
good sites.

TIA

Lou