TH3110D1008 Pro Non-Programmable Digital Thermostat

This is an outstanding product, perfect for an installation in a simple HVAC system where detailed programming is not required. It is extremely easy to install, even for an unsophisticated person. Only tools required are a small drill and a screwdriver. Optional is a level. On iPhone, there is a built in "level" on the Compass App. The only critical thing is to record the wiring with respect to the terminals on the original installation, and to reproduce those on this product's terminals. Important: Use the terminal designation, and NOT the wire color which may vary depending on the installation. If your original installation has a "C" wire, this thermostat will not require batteries, although they can be installed for backup in the event of a power outage which is really not important because if that occurs, there will be no line voltage to operate the fan motor of the furnace so that you do not want to ignite your furnace's burners. If your installation does not have a 24 volt line(C), you will need batteries. The unit comes in two parts which click together. The back part, or the face plate is the one you install on your wall with the hardware provided, and onto which you affix the designated wiring. After this is completed, you just "click on" the front part of the unit which receives its power from juxtaposed contacts on the faceplate. It's that simple. The display on the unit is easily viewable in large numbers, which consists of both the ambient temperature, and the preset temperature which is adjusted with two buttons(up and down) on the right side. The illumination is not permanently lit, mainly to conserve battery power, but can be turned on by merely pushing briefly on either the up or down buttons. It is an LCD display on a bright yellowish-green background and quite attractive. I've had my unit for about 6 months and it has been very reliable, and accurately heats or cools exactly to preset temperature. If your usage pattern consists of adhoc, by hand, quick adjustment of temperature when in the house, day/night, and away, and don't need a more complicated, programmed method of usage, this is the unit for you. It is a waste of money to buy the more expensive versions that allow the more advanced usage patterns. Honeywell is a tried and true company in the field of HVAC thermostats, and this item will not disappoint. No conflict of interest with this company! BOTTOM LINE: UNQUALIFIED BUY for the appropriate user.

This is for the TH3110D1008. It is a one heat stage, one cooling stage non-programmable thermostat. It has the capability of operating a heat pump, but if you have backup or emergency heat, it will not work properly for that. I have never seen a heat pump without backup/emergency heat, so I do not recommend this unit for heat pumps. I have installed this model on all my rental houses, most of them originally had programmable thermostats, and all of which have one stage cooling and one stage of electric heat as they are in SE Florida and as we only need to run the heat for a few days a year it makes no economic sense to install more elaborate heating equipment in this part of the country. It has completely cut out the problems and questions my tenants were having regarding programmable thermostats. I also like this model because it can be powered from the air handler instead of from batteries. I wire these with the C wire, which eliminates the need to use batteries. This also eliminates complaints from my tenants when the batteries die on the thermostat and they do not know what to do. Most people that rent are not handy and do not want to fool with any house problems, no matter how minor. If you have a one stage cooling system with electric or gas/oil forced air heat, here is what you need to wire: Red wire (24 VAC) from air handler to the R terminal Blue (usually, could be another color) wire (common) from air handler to the C terminal Yellow wire (cooling) from air handler to the Y terminal Green wire (fan control) from air handler to the G terminal White wire (heat) from air handler to the W terminal Except for the common wire, the colors above are very common, although your colors may vary. The point is, to wire the R, C, Y, G, and W terminals on the thermostat to the corresponding functions on your air handler. All the thermostat does is connect 24 VAC from the R terminal to the Y terminal when it calls for cooling, 24 VAC to the G terminal when the thermostat is to operate the indoor fan, and 24 VAC to the W terminal when the thermostat calls for heating. It is really that simple. If you have electric heat, the thermostat will turn on the fan when it calls for heat. If you have gas or oil forced air heat, the furnace will very likely have a thermostat that will turn on the fan after the gas/oil flame has heated up the heat exchanger, and once the thermostat heat setting is satisfied, that furnace based thermostat will turn off the fan once the heat exchanger cools down. However, even when you have the thermostat set for gas/oil heat, the thermostat WILL CONTROL THE FAN when it is cooling mode if it is properly configured. A common problem with gas/oil furnaces is the failure of this thermostat, so if you have fan control problems with gas or oil forced air furnaces, you need to check the fan control thermostat in the furnace before blaming this thermostat. Also, depending on the type of heating system you have, besides the electric or gas/oil slide switch on the back of the thermostat, there are a few other settings that you should configure for optimal satisfactory operation. It is easy to do, and the included directions explain what you must do, and this is done by the raise/lower buttons on the front of the thermostat that are normally used to raise and lower the temperature. (Don't confuse this configuration programming with the functions of a programmable thermostat.) If you are replacing a thermostat that uses batteries, and want to power your new thermostat from the air handler, please note that it is possible (likely) that the blue wire (if you have one, and the common wire is usually blue but could be another color) is not hooked up to your present thermostat, and it is not hooked up at the air handler as well. If you want to avoid using batteries, in that event you will need to open up the air handler and connect the blue wire to the common connection in the air handler. The common connection is connected to the grounded metal frame of the cabinet in every air handler I have ever worked on. If you only have 4 wires from your air handler to where the thermostat is installed (because that is all that a battery operated (or older mechanical) thermostat needs to control heating, cooling, and fan), then you will need to run a new wire from the air handler or furnace to the thermostat, install an add-a-wire accessory to trick the system into thinking there is a 5th wire, or just resign yourself to use batteries. Here is a link to the add-a-wire accessory. https://www.amazon.com/Venstar-ACC0410-Wire-Accessory-Thermostats/dp/B01IF3QXMC/ref=sr_1_fkmr1_1?ie=UTF8&qid=1519606131&sr=8-1-fkmr1&keywords=diode+for+thermostat+5th+wire#customerReviews The point is to not even install the batteries, since when the power to the air handler is off, the thermostat is useless anyway; why bother with them. The thermostat functions very well. It maintains the temperature to 1 degree of your set point (assuming your heating and cooling equipment has the proper capacity to maintain the set temperature). It will remember the heat and cooling set points -- i.e. when you set the heat set point, and switch to cooling, when you switch back to heating it will remember the previously set heating set point, and it remembers the settings after a power outage. The display is back lit and simultaneously displays the set point and current temperature, and it seems to be well made. I have installed 11 of these with no failures and no problems.

I ordered this thermostat to replace an older Honeywell RTH1100B model that worked great for years but got damaged by corroded batteries and is now discontinued (why these thermostats do not have an option to run on the 24 VAC system power is beyond me). Since both the old and new thermostats were made by Honeywell, it was easy to install as the wiring hookup was identical. After installation, I noted that the temperature reported by the new thermostat seemed a bit low but I figured it was due to having been in the Amazon delivery van for several hours. I set the temperature to the desired room temperature and the heat immediately came on. I went on to do other things and forgot about it. About an hour or so later, I was feeling quite warm and noticed the heat was still on. I went to check the thermostat and it was still reading a low temperature! The heat was running continuously for over an hour. I immediately shut it off and checked the room temperature. A standalone digital thermometer said 68 while the thermostat said 57. Not good. I put the thermostat in standby and figured I would wait a few hours and see if anything changed. The next morning, the new thermostat now read 52 and the room temperature was 60. Something was definitely wrong. I initiated an exchange with Amazon and a replacement arrived two days later. I installed the new one and it immediately read the same temperature as the digital thermometer so I was happy. I have been using the replacement for four days now and it is working as expected. The backlight is very helpful in low light situations and having both the room temperature and set temperature displayed side-by-side is helpful too. And as luck would have it, the mounting hole locations were identical to the previous thermostat so it was a simple mounting job. As long as you get a properly functioning unit, it should work very well. If not, Amazon's exchange procedure is painless and I was able to get the issue rectified pretty quickly (it was possible to manually activate the heat on the defective unit so I was not freezing waiting for the replacement). I gave the thermostat five stars because the replacement is working very well. I figure the defective unit was a "one off" and not indicative of the overall quality.

Now that I've used this through all seasons, I feel I should pass on my opinions (updated further down). First, I'm happy with this. The backlight is good, as my unit mounts in a dim hallway. Controls are fairly straight-forward, and the digits are big enough to read without glasses. But I recently discovered a mild issue, which took some figuring out. When I installed this in the summer, I set the internal switch (on the back of the unit) to "gas/oil," since I have a gas furnace. But then my central a/c wouldn't come on. I came back here, read some questions and answers, and realized I needed to set that switch to "electric." Then my a/c ran fine. Come fall, I noticed that when the furnace came on, the fan started blowing right away, which would be COLD air for the first couple minutes. That's not how it worked before, or how any gas/oil furnace I ever used worked. It still WORKED, but I was bothered by the discrepancy. Recently, I remembered that "gas/oil-electric" switch, and set it to "gas/oil." NOW my furnace works normally, the burner heating the firebox before the fan starts up. Which means that I'll have to remember to change this switch about twice a year. That's why I'm only giving it 4 stars (updated to 5). If the couple minutes of cold air don't bother you (or you have an electric furnace, I suppose), this won't be a problem. But my previous digital thermostat didn't have this issue (or the switch), and I've ALWAYS had either gas or oil heat. I guess I just consider it clumsy, and don't see why this couldn't be done better. <UPDATE>: With advice from a comment, I found this has parameters that can be set to resolve my issue. The manual is available in PDF format from Honeywell. It's still acts a little different (my central A/C continues to run for a bit after the temperatures "makes") but that's not a problem, just something that makes me go, "Huh."

No frills and performs exactly two functions (heat on and off)...just what I wanted. The build quality is okay. Feels like cheap plastic and depending on how often you need to replace the unit's batteries, I can easily see the casing cracking (or breaking) at the hinges. Don't expect more for what you are paying here - sub $30 thermostat. The display is easy to read with a backlight screen. The information displayed includes the actual temperature (the larger number displayed) and the desired temperature (smaller number displayed in the upper right hand corner). I'm not an electrician, but the unit was easy to install (thank you YouTube for the numerous tutorial videos). For as many people who want the newest and greatest technology and functionality, there are still those who want nothing more than a simple on/off thermostat. This is that simple option. This item is a definite go.

I have been using this thermostat for 4 days and so far I am pleased. It does seem to help my PTAC unit keep my room temperature reasonably stable -- certainly more stable than the bulb/capillary thermostat that was installed previously and which was just two feet away from the unit. I was surprised to see that the temperature readout on the Honeywell thermostat was much higher than what I was sensing (e.g., 78 degrees in what felt like a 73 degree room), but then I found the following information on Honeywell's website, so this perhaps explains the reason for the discrepancy: "Honeywell digital thermostats are designed to display the room temperature in a way similar to how people sense temperature. This means the thermostat takes into account not just the ambient air temperature but also the radiant temperature of objects in the room (i.e., wall and furniture). Room thermometers often only read ambient air temperature so they will not match the thermostat reading. Also, Honeywell thermostats do round in the display to the nearest whole number (half number in Celsius) and to the temperature setting. For example, if you have the thermostat set to 72 degrees the system will turn on and off but the inside reading on the thermostat never changes from 72. The actual temperature did fall to 71 or up to 73 and that is what turned on the heating or cooling but the thermostat display will stay at 72 to avoid jumping up and down constantly." Commenting on the noise from the relay in the Honeywell thermostat, which others have noticed: it is definitely an audible click whenever the thermostat relay kicks open or closed. This is unavoidable with a mechanical relay (in this case, the Omron G6SK-2F-H). A solid state relay would probably not have been feasible for this kind of thermostat because the thermostat is designed to switch 24 volts AC at a few amperes (as is standard). I'm not sure if an SSR can switch such high voltage and amperage, but if it can, then I would say it was a poor design choice on Honeywell's part because an SSR is completely silent. The clicking noise on the Honeywell thermostat is, of course, not an issue if your thermostat is located in a hallway. But if it's in your bedroom, you will definitely hear it. It's just a question of how much it bothers you, how light a sleeper you are, etc. Others have noted the long battery life. I think this is due to the fact that the display is a low power consumption LCD with a backlight LED that turns on only when a button is depressed. Moreover, the Omron relay is of the "latching" variety, so once it flips either open or closed, no more energy needs to be expended to keep it in that position. The coil on a non-latching relay would have had to be continually powered to keep it in the "closed" position. So this was a good (probably standard) design choice. Since I keep my thermostat in my bedroom, if I could find a silent thermostat (one with an SSR), I would probably switch to it only to avoid the click sound. But I don't know if any such thermostat exists and it seems unlikely that one could determine that without buying it and opening the darned thing up. In the meantime, I'm pleased with this unit and recommend it, especially for its ease of operation and installation, and apparent ability to maintain a stable room temperature.

First, yes this will work on an RV. The batteries (Duracell, not cheap ones) can either be used as backup power or as primary power. It was literally out of the box and mounted running my two wire 12v suburban heater system on a 1985 Beaver motor home in less than 5 min. Just put 12vdc hot (usually red wire) on post 'R', then furnace wire (usually white) on post 'W' (heat relay). Some think that because it is a 24vac unit that it won't work. But it is a simple single contact relay that basically connects the wire on 'R' to the wire on 'W' turning the furnace on. This unit is also capable of dual transformer operation. So for those motor homes that control both AC and heat from the wall you can use this also. Just pull the jumper between 'R' and 'RC' then use the individual input powers, with post 'RC' to post 'Y' for AC and as prior stated for heat. The main difference between a motor home and house is that you will have to use the batteries as your primary power. Without the batteries, it won't run a motor home furnace unless you own one of the modern ones with a house type system. Most of those use inverters to convert the 12vdc house battery into 115vac then they use a step down transformer to get you the 24vac needed. In that case your good with using the batteries as backup for power loss. If you get spunky and want to make it work without batteries as primary you could by teeing off the 12vdc input for the furnace and add a resistor in line to drop the voltage to 3vdc then attach to the positive side of the battery case where the batteries go and attaché the negative side to a ground wire that you would probably have to run yourself. Can't use post 'C' as it isn't ground, merely the return for the 24vac transformer input which you won't have in a standard older 12vdc system. As for a house this unit will only be good for a heat pump system without emergency heat capability or as two individual units (AC compressor, separate heat unit) If you want the former you need model TH3210D. It has an AUX post for heat and an 'E' post for emergency heat. The units will run with or without batteries on a 24VAC system. This unit was shipped to my house on Halloween night and some little bugger stole it out of my mail box, opened it and left me the packing material. I emailed Amazon and in one hour had a response saying that the replacement was on its way. It arrived in two days. I am Amazon prime and order a good bit, so don't know if that has any weight but they have my business for sure. That is how you take care of customers. Thanks Amazon.

This thermostat is great not so much for what it does do, but for what it doesn't do. No fighting to override programs. Simple, straightforward setting of heat or cool temp. No annoying blinking display like my old LuxPro. It always shows both the current temp and the set point. It will remember your set points if you go back and forth between heat and cool. (Unlike my old LuxPro, it does not run the AC compressor briefly for no reason when switching to cooling mode and the temp is below the set point.) The backlight only goes on when you change the set point (first press lights it up, subsequent presses change the temp). Backlight shuts off after a few moments, leaving you in peace. If you have a C wire or can run one, it will run off the hvac power and it doesn't need a battery (yes, it will remember the settings if there is a power failure). And there is no crying wolf about low battery. Otherwise, if you don't have C wired, it can run off batteries. Installation is straightforward, just copy which color wire goes to which letter terminal on your old thermostat and double check at hvac. Remember, the color is not what matters, what matters is that the letter on the thermostat is connected to the same letter on the hvac. The are only very minor negatives. The thermostat snaps onto the base plate. I would prefer if you could release it without prying it off. Also, I wish that the manufacturers would standardize on mounting plate hole spacing, so that you don't have to do drywall repair every time you install a new thermostat.