[RickM]

Jim, I assume the ATS has the "exercise" feature as well...? If not you may want to negotiate for a unit that does. As mentioned it may be used once a week during the season or not for twenty years. Think about the car you depend on sitting for twenty years and then you go to start it.....yikes. Just reiterating that it's a nice feature to have.

Regarding engine speed. Most of the units I've dealt with were 1300-1700 rpm. However, they are also more on the commercial side. Still on the affordable side. The housings that come with the higher rpm models are better than in the past so noise is less an issue.

BTW, Catepillar makes home back-up units nowadays as well. Come to think of it an electrician friend is tight with the distributor. If you want to compare specs and prices for a group buy just PM me and I'll forward on.

PS: In colder climates don't forget to include the heater/furnace/boiler circuit....brrr. Ice storms are a common cause of outages.