Thank you. I forgot about the fan on the forced air. We do have someone look in weekly but i continue to look for technology to reduce possible issues. This one does have an extreme temp alert. Anyone else have any experience with these thermostats?

You don't say what brand/model of thermostat is of consideration. One of the HVAC units at work was replaced last year and the contractor included an Emerson Sensi WiFi-capable thermostat. WiFi doesn't have to be enabled but the WiFi app (via iPhone/iPad or Android or Sensi's web site) is the only way to program a temperature schedule and access a few extra settings (such as auto heat/cool switching and security lockout of the buttons on the thermostat). It does have a battery to maintain programming during a power failure but of course there's no way a little AA battery can power the blower and/or compressors and/or heat strips. I thought the WiFi angle was more a gimmick than a useful feature (notwithstanding the requirement to use it for programming a schedule) but it has proven to be convenient. The only glitch thus far is that it has lost the WiFi connection to the office network on a handful of occasions, which prevents remote/app access but it still runs the heating or cooling. Haven't been able to figure why that happens but it always recovers the WiFi connection within a few hours.

Thanks. I am looking at the

Honeywell Wi-Fi Smart Thermostat RTH9580WF

This thermostat has no replaceable battery. But I would think it has a built in battery in order to keep the clock current in the event of a power outage.

You would need to install a back up generator with an automatic transfer switch if you want to power the furnace while you are away during a power outage.

Thanks Mike. We dont have many or long lasting outages and we do cut off water to the house so i guess we are ok even if. I just wqsnt sure if the battery was a meaningful consideration for us. Appears not which is probably why they dont have one. I think settings are saved on a hard drive.

Ivy,

I am quite confident the thermostat has no hard drive. There may be a non-volatile RAM which would keep all settings data, but that would be expensive. But you would still have the problem of losing the clock if power is removed if there was no battery.

Hmmm.

this is what it says (not sure where i got the hard drive idea, i have been looking at a lot of thermostats)

"This highly rated app is backed by Honeywell's reliable network, for dependable access and peace of mind. Available for iOS and Android devices."

but, if we are out of town, there is an outage and when it comes back the router is not working, will it know the set temp?

The thermostat will remember the temperature setting and schedules. If the router is down, then you won't be able to communicate with the thermostat via the internet.

How do it remember with no hard drive and no wifi connection and no electricity and no battery?

i just read a q&a on amazon that said they had trouble keeping a connection and tech sup told them it had to be within 25 ft of router. Not sure now. (We are not within 25 ft).

Did you ever wonder how laptop and desktop computers keep accurate time even after they been unplugged or their battery dies? The clock is powered by a small nicad battery on the motherboard. This is what I think is inside the thermostat. The battery powers a small amount of memory which also holds all the programmable settings.

The WiFi range of the thermostat may be limited since it has a very small antenna. Put your cell phone if the area of the thermostat and look at the WiFi signal strength. If it is strong then you should be OK.

I will do that. Thanks.

Two out of three lines on the little wifi symbol on both iphone 5 and ipad air2.

how good or bad is that?

Is there a stat which connects to internet with cell service like my security system?

Not sure if it will work with your furnace but look up AirPatrol Nordic on amazon

Thanks