yup.. it was actually really nice when I'd go visit them during the summer. It would be pretty much the same temp. all summer long.

check your pm, i doubt it needs to be replaced and 16,000 is insane

what did you end up choosing?

I have a forced air system and the downstairs is cold while the upstairs is baking is this just dirty ducts?

You can save alot of money by just bleeding the system once in a while.

Check around the water heater, and look for a valve. If you pull it, you should hear water comming out. Attach a hose to the end of it, and drain it out.
Turn off the heater power, and the Water main. Bleed both the heater and Boiler. DO THIS AT LEAST once a year, or every season.

Or just bleed it from the heater until you see clean water flowing out only. Sometimes you have to bled it for a little bit before the dirt comes out.