It's just a marketing gimmick - good installation/service practices and energy efficiency upgrades can save far more energy than some dinky solar panels produce, at a fraction of the cost.
General public's attitude towards our energy predicament:"I reject the reality of finite resource depletion and substitute it with my own; energy is infinite, we just need an alternative storage medium to run the cars on. The economy can grow indefinitely - we just need to "green" everything! Technology is energy! Peak what?"
It all depends on your electric rate. In my area, electricity is too cheap for a payback over the panel life. Your area may be different. They can provide nearly all of the power required for the heat pump or AC, but if you have a power failure the inverters shut down.
There is a 30% federal tax credit with no cap for the solar part of the job. There may be state tax credits as well.
Wouldn't it be better to put a stand alone PV system on the house, rather than something tied to the HVAC system? If the HVAC system needs to be replaced, would you need to retrofit the PV panels to work stand alone, or are they already set up that way, just marketed by Lennox as part of their system?
I have a customer that had 3kw of solar panels on his house. 3 ton heat pump. It's central Texas weather. Keeps his house 78 during summertime. He said it lowered his electric bill $50 a month if that puts your savings in perspective.