On Tuesday, May 26, 2015 at 9:14:59 AM UTC-4, Pat wrote:
On Tue, 26 May 2015 06:09:58 -0700 (PDT), trader_4
wrote:

On Monday, May 25, 2015 at 6:37:09 PM UTC-4, bob haller wrote:
Has anyone ever seen a heat / AC thermost where you set the temperature you want for heat or cool, and the thermosts automatically switches between heat and cool depening oon outdoor temperature?

I have some elderly friends who are having a tough time....

I think the ultimate solution will be assisted living but they are fighting that.

The Honeywell VisionPro will do that. It's an option on the
install menu. You should check the manual for the particular
model to make sure it includes it, not sure if they all do.

Personally, I wouldn't want it as it's likely it's going to
use more energy. I don't want mine kicking on to cool if it's set
to 74 and it happens to go to 77 during a spring day.

I actually like it when mine does that. It reminds me to change the
filter and clean the compressor coils for the season. (I do change
the settings between winter and summer, though.

If anything, having it change by itself would seem to me to
be less likely to remind you to do cleaning than if you change
it from Heat to AC manually.


I lower the heat
setting during the colling season and raise the cool setting in the
heating season so the system doesn't often do both in the same day).

But if the thermostat is making it's own call on when to switch
there is no heating season, no cooling season. It switches on it's own.
And if you do what you just said, with auto switchover, it gets
worse. Let's say you have manual changeover. So, it's spring
and you have it set to 77, AC mode, it's a mild day and it's 72 right now
in the house. It won't go on. If you have it set for auto changeover,
it will go on and fire up the furnace to get it to 77.