We love to give existing houses facelifts! Saving what you can of an existing home is perhaps the most 'green' thing we can do as architects and builders.
I drive around and see the potential in every small and tired house. We can't help it! Perhaps it is like a hairdresser instantly giving a client a make-over in their mind as they walk in the door. We see the many possibilities of composing beauty out of almost any house and we love doing it ~ it is one of the funnest parts of our job.
AND there is a great added benefit! If your house is in need of a curb appeal 'facelift' it probably means new windows or new siding or both...maybe a new entry porch and maybe a small addition are also on the agenda. All of these things offer the PERFECT opportunity for what is called a 'Deep Energy Retrofit'. Usually this entails re-insulating, caulking around construction gaps and windows and doors etc. All of which is amazingly easy to do once the siding is off the house! And new windows will greatly enhance your energy efficiency if your existng windows are 'of a certain age'...
SO what better time to make your house really energy efficient than when you are doing a 'face lift'?
Then you can do the HVAC system and maybe add a PV or Geothermal system.... We always tell our clients: the place to start is the building envelope. If the building envlope is super insulated and well sealed, then the size of your HVAC gets to be much smaller. Don't update your HVAC until you have addressed the leaky building envelope.
Listen to your mother : )