Help with choosing a thermostat

[accht]

I currently have a 10-year old Honeywell thermostat. I'm happy with it, except that the maximum A/C setting is 90 degrees. Since it will go on every day when I'm not at home in the summer, I have to manually turn the system off before leaving the house, and frequently forget. I would like one that is either programmable to 99+ degrees, or can programmatically switch "off" during certain times of the day.

My second requirement is that I will run off batteries, and want a long battery life. Batteries in my current thermostat last for years, but my understanding is that the current models go through batteries much quicker because of "improved" LCD screens.

I've looked at Honeywell models RTH7500D and RTH6400D which fit the 99+ degree requirement but go through batteries quickly. Are there any thermostats out there at fit both needs? I'm only interested in brands that are reliable. Thanks for any replies.

[Paul Bee]

If you have a honeywell buy another honeywell, you won't be happy with anything else. I have a vision pro at my house and I love it. Buy the Honeywell that has the features you want. The good one isn't cheap and the cheap one isn't good.

[accht]

From experience, do you know of any Honeywell models that don't require frequent battery replacement?

[hmscool]

honeywell vision pro 8000. will have all u need and more. :couch:

[big sky hvac]

I currently have a 10-year old Honeywell thermostat. I'm happy with it, except that the maximum A/C setting is 90 degrees. Since it will go on every day when I'm not at home in the summer, I have to manually turn the system off before leaving the house, and frequently forget. I would like one that is either programmable to 99+ degrees, or can programmatically switch "off" during certain times of the day.

Am I reading this right, 90* & 99*??? If you're setting the thermostat that high, I can't even understand why you need an A/C?! What is your normal setpoint for when you are home....85*?? If you're shooting for anything under 80*, I bet that thing doesn't shut off from the time you get home until you go to work in the morning! I don't know that you really need a new thermostat, maybe an education on A/C. If you want a new thermostat, the Honeywell Vision Pro is an excellent choice. It can be hardwired(providing there are enough wires in the wall)with a battery back-up.

[tedkidd]

Where do you live?

[accht]

I live in California. I want it to be off during the day, when temps can get over 100. By the time I'm home in the late evening, the outside temp has usually cooled off to the high 80's. I turn the air on, and all's well. It cools the house to a comfortable temp within 30 minutes. The compressor kicks off within an hour, not the following day. Big_sky_hvac, you're saying I need an education in A/C because I choose not to have the house air conditioned all day when temps are at their highest and nobody's home?

[beenthere]

All of the Honeywells should get you a year plus from the batteries.

How long depends on how often they bring the system on and off. So no one can give you an exact 1, 2, 3 year answer.

[uniservice]

Sounds like you have a very good A/C system. Most systems that I see in Pac NW wouldn't be able to cool a house down like that. Most systems here would require having the A/C on during the heat of the day, to maintain a cooler temperature in the home than outside. Then when you return to the house, it would be cool and comfortable. A/Cs normally are sized to keep a home comfortable, but aren't great at lowering the temperature quickly after the space has become warm during the day. Usually they run for a very long period of time to dry and cool the air. That's why he said he was surprised that it didn't run half the evening trying to bring the temperature and the humidity down.

[bmathews]

Sounds like you have a very good A/C system. Most systems that I see in Pac NW wouldn't be able to cool a house down like that. Most systems here would require having the A/C on during the heat of the day, to maintain a cooler temperature in the home than outside. Then when you return to the house, it would be cool and comfortable. A/Cs normally are sized to keep a home comfortable, but aren't great at lowering the temperature quickly after the space has become warm during the day. Usually they run for a very long period of time to dry and cool the air. That's why he said he was surprised that it didn't run half the evening trying to bring the temperature and the humidity down.

It sounds to me like he has a oversized system. Mine is oversized by design and takes a long time to cool down if I let my house get out of control. (i.e. 90's inside) You can look around for a thermostat that suits your needs. Call a local a/c contractor. I will say that it isn't good for your house to get that hot. It ruins wood, paint and sheetrock over time when you let a house go to extremes. Whether it be hot or cold.

[heatairman]

honeywell vision pro 8000. will have all u need and more. :couch:

+1 nice thermostat really

[hmscool]

yes it is. only one i install on all jobs. longer battery life when common is wired in.:callpro:

[big sky hvac]

I turn the air on, and all's well. It cools the house to a comfortable temp within 30 minutes. The compressor kicks off within an hour, not the following day.

I'm calling BS on that!! Unless your setpoint is 79.5* & the indoor ambient is 80*, there would be a lot of humidity in the air and I can't see how it could cool it in 30 minutes. Generally as a rule, depending on outdoor & indoor ambient,(and other factors like humidity,etc.) it can take an hour to cool a house 1* - 2*. It's just beside me why you would allow it to get that warm. I agree with bmathews about that much heat not being good for the paint, drywall, wood, etc. Plus with that much heat & humidity, I wonder how much mold is in your home. It's like your house is taking a shower all day without a bath fan running. But to each their own, I still think the Honeywell Vision Pro is the best way to go. Call a pro out and have one installed.

[tedkidd]

Dry area of country, may not have much latent.

Hugely oversized unit. But hard to say what operational approach makes energy sense for that location. Might be good for grid to have ac off during day.

[classical]

To answer your question I do not think any thermostat has a cooling temp setting over 90 degrees. As others have stated if your system performs as say it is grossly oversized.

Oh and for what it is worth I would not put a Honeywell thermostat in a dog house White Rodgers is much better.

If your system performs as you say set the stat at 90 degrees and leave it at that it is much better for the house and furniture if you limit the temp extremes.

[accht]

Okay, thanks for the help. FWIW, much of California is a desert and periods of higher heat are accompanied by unusual dryness. I'll consider the suggestions to leave the AC on all day, but where I live the top-tier electric rate (which applies to most people) is $0.34 per kwh so leaving it on all day with nobody home becomes painful.

[Paul Bee]

Yeah

[beenthere]

Depending how long you've turning off the A/C when you go to work, and then on when you come back home.

I wouldn't worry about needing to leave it on during the day now, if it hasn't harmed your furniture so far.