Honeywell TH6110D1021 FocusPro Programmable Digital ...

• Large backlit display with soft-touch button interface
• Precise temperature control of +/-1-degreesF with auto change from heat to cool.
• Energy Star Rated 5-2 programming with 4 programmable periods per day
• Programming for weekdays, plus weekends.
• Compatible with heating and cooling systems*

Honeywell thermostats:
It is a fine programmable thermostat. However, the thermostat depends solely on the batteries it comes with; It is unable to receive power from the heating/cooling system's 24V transformer, unless the existing system has 5 wires rather than the standard 4 wires. So, if batteries run out without the owner noticing it, and the house is left vacant for a length of time in the middle of winter, a crisis may result.

Great 'stat but be careful where you buy:
Honeywell TH6110D1021 FocusPro 6000 5-1-1 large display prog digital thermostat heating cooling I replaced my c. 1995 Honeywell mercury switch with this model and can only praise it for its functionality, appearance, ease-of-use, and easy change out. Indeed, the I used the same screws used for my other 'stat and the wiring was a snap. I believe that mine is powered by the furnace's 24v transformer with a battery back-up. Operation and programming are simple, and intuitive programming is a snap. I particularly like the ability to fine tune 4 periods/day with separate times and temperatures. A small gripe is that I don't know where to put the supplied reference card although I don't really need it. One caveat is that several vendors sell the same unit. I would search using the exact model # in order to find all of the vendors available. Since Amazon does not sell this one itself, it pays to check each vendor's return policy, which can vary greatly. Some charge a high restocking fee and some appear to discourage returns. I ordered mine from Apex Controls which was a "sponsored link". It cost $50 as opposed to ~$65 on the major vendors. They sent mine in 2 days in perfect condition, plus they appear to have a fair return policy. I also didn't like to adaptive option since it assumes that it always starts from the same temperature, which is not our case. I just programmed it to switch on 15' prior to when we needed it. Honeywell also sells a unit that is identical except for a smaller screen. The big screen model is useful if you wear glasses and need to see the readout. I have read complaints about some models that make a loud click. This one clicks but it is inaudible more than 2-3 feet away, unless your house is completely silent.

Great product and price!:
I did quite a bit of research on programable thermostats to replace the "dumb" thermostats in our (NEW CONSTRUCTION!) home. One of them controls a heat pump and I wanted a thermostat intelligent enough to ramp up to the set-point without using resistance heat. This one had about the best price on the Web and works great. I bought a similar looking thermostat to control a gas furnace/AC. The instruction card insert is very handy (particularly for my husband who is less skilled in this regard).

Good, but not perfect.:
I like this thermostat, but it's not the perfect one for warmer climates like here in Florida. Reason? One, you cannot set it for automatic switching between cooling and heating unless the heating temp. is at least three degrees above the cooling temp. We like to have the overnight heating temp. two degrees BELOW the daytime cooling temp., and in the winter, when it's cool at night and hot during the day, it must switch to heat mode at least three deg. HIGHER than where you have set the cooling temperature during the day. Bummer. The thermostat does keep the temp. at a very narrow one degree or less difference, but 77 degrees when cooling feels colder than 77 degrees when heating. (humidity) Therefore, I must switch from cooling during the day to heating at night, and change the temperature setting each time (it automatically sets the three degrees difference even when on HOLD). If you live in a colder climate though, it would work very well.

Consumer Reports Correctly Rated This Excellent!:
I consult Consumer Reports on any major purchase and electronics. They have a strong track record with me. I bought this thermostat after reading their report. It performs flawlessly. As other reviews said, there is a 3 degree "dead zone" between heat and cool if you use the "Auto Changeover" setting (which I use). It does not impact my comfort at all. If you prefer the manual change over from heat to cool, the 3 degree does not apply. Highly recommend this item.