OK, I have been living in my home (my first home) for 9 years. I still have the original non-digital thermostat control that came with my heatpump. My heatpump is still doing OK but I have read several places that a modern after-market programmable thermostat will do a better job. I don't want to waste my money though. I'm assuming they are easy to hook up - just a couple control wires, right? Are the $50 - $60 units I see at Home Depot worth installing?