Honeywell RTH6450D1009 Programmable Thermostat Reviews

I have compiled the most useful user reviews about the Honeywell RTH6450D1009 Thermostat from internet. Here you are :

Watch out for “Smart Response Setting”, February 11, 2011 (4 star)

85 of 89 people found the following review helpful

I had to replace an older cheaper Honeywell that decided it didn’t know what time of day it was.

I decided to go with this more expensive model– but I had reservations after having read some reviews and comments elsewhere where some people complained that the furnace was always on, or they were burning more oil or gas than before. . .

I found the reason–

It’s called ‘Smart Response Technology’

It’s ‘ON’ by default if you do the quick DIY install.

To turn it ‘OFF’ you have to download the FULL MANUAL from the Honeywell site to see how to get into the ADVANCED Settings of the device. The pamphlet you get in the package is just your BASIC setup.

I bought the programmable Honeywell to control my oil usage and keep the furnace from heating the house in the dead of the night when everyone is in bed. And I would set the Program to turn the Furnace ON and reset the Temp back to 70 degrees at 7 AM. In short– The Furnace turns ON at 7 o’clock and in time, (20 minutes or so) the house gets warm.

What SMART RESPONSE does is uses an algorithm to attempt to get the house to the Programmed Temp BEFORE the Programmed Time. The result is the Furnace will turn ON an hour or more BEFORE the time you set to raise the temperature until it hits 70 degrees EXACTLY at 7 AM.

Okay– it’s a nice, cute helpsy idea that I’m sure a Honeywell Programmer/Engineer is rightly proud of. Problem is, the Furnace is BURNING OIL when I don’t WANT IT TO.

I didn’t notice what the Thermostat was doing until late one night I was watching a movie real late– when I heard the Furnace go ON and STAY ON at 4:30 in the morning. And I was like: “WTF?” When I went to look at the Thermostat, it displayed: ‘In Recovery Mode’

That was the Smart Response circuit attempting to ease the night-time temp back up to 70 degrees in time for 7 AM. Except that meant the thing was BURNING MY OIL AT 4 IN THE MORNING!! If I hadn’t been awake, I would never have noticed this.

So disable “Smart Response”. That way the Furnace only comes on when YOU program it to.

Thermostat powered by battery only; can’t use system power, January 17, 2011 (3 star)

58 of 60 people found the following review helpful

This is a nicely designed unit, and the instructions are easy to understand and follow. However, the product description is missing an important fact in that this particular model cannot accept a power feed from the system, and therefore REQUIRES the batteries to function. If your home doesn’t have a system power feed, this functionality is of course irrelevant; however for those of us with this feature, other thermostats are probably a better buy.

As of January 2011, the following Honeywell and LUX products on have the ability to accept system power:
Honeywell RTH7500D Conventional 7-Day Programmable Thermostat
Honeywell RTH7600D Touchscreen 7-Day Programmable Thermostat
Lux Products TX1500E-010 Smart Temp Programmable Thermostat
Lux Products TX9000TS-004 Touch Screen 7 Day Programmable Thermostat


Large display and easy to set up, September 12, 2010 (5 star)

23 of 24 people found the following review helpful

I needed to replace my fifteen year old thermostat for one which was easier to adjust and change settings if needed. I chose Honeywell as they have always gave great life and service. I am using this on a steam heat system only, so I needed to connect only two wires. I did leave the jumper in as directed in the manual. I did power off my heating equipment (very important) we don’t want surprises. This thermostat has a large display which can be back-lit simply by quickly pressing one of the control buttons. I only needed to program morning and night settings, you simply skip over the times you don’t want to program. When in operation it displays both set temperature and room temperature. I would have to say it is accurate within +/- 1 degree as I compared it with three other thermometers. I installed the batteries before I attached it to the wall base and did all setting and programming ahead of time. The batteries are easy to replace when needed as they fit in a flip out holder from the side, no need to remove any covers or remove the thermostat from it’s base.


Avoids temperature overshoot, November 14, 2010 (5 star)

12 of 12 people found the following review helpful

I replaced my RTH230B with the RTH6450D.
I have a forced air fuel oil furnace.
The old thermostat would turn on the burner and not turn it off
untill the air temperature rose one degree.
The problem is the burner heats the heat exchanger in the
furnace and the blower runs until it cools.
It would overshoot the desired temperature by 5 degrees.

This thermostat turns on the burner and turns it off even before
the blower starts. When the blower DOES start it blows over
a cooler heat exchanger. When the blower shuts off the
temperature is at the set temperature.

No temperature overshoot must mean I’m saving money.

PS: Backlit display (Push the left button twice to illuminate
the display without changing settings)
PS:4 programmable events each for Weekdays, Saturday and Sunday.
PS: Easy install… my setup needed only two wires.


auto change function would not work, February 21, 2012 (5 star)

14 of 15 people found the following review helpful

The first RTH6450 thermostat delivered to my home would not let me enter the “auto” system mode. It would only switch from “off” to “heat” or to “cool”. The programming menu skipped over this function (#12, auto change) during programming of the unit. The thermostat, although marked everywhere as an RTH6450, behaved like an RTH6350. It only showed weekdays and weekends in programming (Along with the “auto” function not working, it also didn’t separate Sat and Sun like it was supposed to, per the package and the instructions).
After consulting Honeywell phone support and trying several things, I was told my unit was defective and to send it back to where I bought it.
The auto change feature is the main reason I purchased the RTH6450 instead of the RTH6350. Living in Tucson, AZ it’s nice to have this feature in the spring and fall as you may need heat overnite and AC during the afternoon.
Update 2/23/12: I received the replacement unit from Amazon today and it works as advertised. I have weekdays, Sat and Sun to program and the auto function also was there when programming the unit. It would seem that the 1st unit that I received was mis-marked at Honeywell.
I have sent the defective unit back to Amazon using their return paperwork and mailing label that I did online. So…I’m not crazy…the thing was defective, whew.
FYI-I did all the programming of this 2nd unit, including the scheduling, while sitting in a comfy chair. All of the functions and schedules can be set once you put in the 2 AA batteries. Then after I was done, I plugged/pushed it onto the wall mount plate which I had already screwed to the wall and hooked up the wires.
Hope this helps.


A Great Buy! Easy Set Up. Not sure about the negative reviews…, December 3, 2010 (5 star)

8 of 8 people found the following review helpful

I purchased this unit skeptically because of the negative reviews regarding installation. I have zero experience with thermostats or anything heating/cooling related. I installed this unit in 15 minutes with a Phillips screwdriver and a mini-Flathead screwdriver. It is so unbelievably simple to install I don’t know how a person could mess it up. Label your existing wires based on where they are hooked to the current thermostat and reconnect them to the new unit. Very simple, very easy to accomplish. If you can physically turn a screwdriver, you can install this unit.

The programmable feature is why I bought the unit. The menus are extremely intuitive and easy to navigate. The light on the unit is very handy as I hate turning on the hall light every time I want to adjust the temperature. I love not having to remember to turn the heat up or down every time I go to work, get home, go to bed, wake up in the morning. It’s a great feature.

All in all, well worth the money. It’s simple to install, program, and use. I’ll have one of these no matter where I live from now on.


Technical details are wrong, December 29, 2010 (3 star)

7 of 7 people found the following review helpful

Technical details section said this unit has a filter change reminder. I couldn’t find this feature during programming. I contacted Honeywell and they informed me this unit does not have this function. I am returning this unit for one that has this feature. Very easy to install and program. Accurate temperature control.


Extremely Easy Installation Process, September 12, 2013 (5 star)

6 of 6 people found the following review helpful

My AC System: Single stage Heat/Cool heatpump with Aux Heat: Lennox CB26UH-024-R-230-1;
OLD t-stat: Honeywell TH5220D1029 non programmable)

Actions that i performed:
1. Put 2 AA Batteries in NEW t-stat (Honeywell RTH6450 5-1-1 programmable)
2. Set Date/Time on NEW t-stat
3. Turn OFF the AC/Heat on OLD t-stat (on the wall)
4. Shut down circuit breakers (panel) to completely cut power to the AC/Heat-Pump unit.
5. Remove OLD t-stat’s face-plate (gently pull away from the back-plate)
6. Take a pic from cell-phone camera to get the existent wire connections
7. Unscrew the connection-slot screws from the OLD t-stat & gently remove the wires from each slot.
8. Remove back-plate of OLD t-stat from the wall
9. Place/screw the back-plate of NEW t-stat in the wall
10.Attach wires to the NEW t-stat (refer Install Guide for connections)
11. Place the face-plate of the NEW t-stat (gently press onto the back-plate)
12. Turn on the circuit breakers (panel) to resume power to the AC/Heat-Pump unit.
13. Leave the AC/HEAT on NEW t-stat in OFF position (it will be turned ON in step#16 below)
14. Set AC/Heat-Pump Functions on the NEW t-stat (refer Install Guide for all functions)
15. Set Schedule and temperatures on the NEW t-stat (refer Operating Manual)
16. Turn ON the AC/HEAT on NEW t-stat or use “AUTO”
17. The system will show a flashing “cool” or “heat” sign for 5 minutes before the compressor starts
(This is a normal safety margin for the compressors; IOW: Don’t Panic.)

Read the Install Guide – 15 mins (
Read the Operating Manual – 10 mins (
Step 10: 5 min or less (if you have read the Install Guide)
Step 14: 5 min or less (if you have read the Install Guide)
Step 15: 10 min or less (if you have read the operating instructions)

– You do NOT have to be an electrical/HVAC engineer to install this – even Honeywell claims it as a DIY install – which it ACTUALLY is – no, I don’t work for Honeywell :=)
– Replace batteries once a year or when “Change battery” appears on t-stat (heck, we change oil in our cars more frequently than that)
– For all those claiming “I ain’t needing no eff’ing manual to install this”:
Do yourself a favor: put down the beer can, leave your machismo aside (wash your face if it helps) & RTFM.
These 25 min or so that you will spend reading the manual could save you upto $140.00
(that’s the quote i got from a local AC repair company to just come & install this – not including the price of t-stat)
– If you are programming your new t-stat (step#14) BEFORE turning on the breaker (Step#12) your settings may be wiped out when the breaker is turned ON, so you may need to re-program it.
– Remember to turn OFF the SMART Response (during step #14) – countless folks/reviews have mentioned it being a nuisance
– Remember to set BOTH the “Cool” and “Heat” temperatures separately (during Step#15) – if you have not chosen “AUTO CHANGEOVER” Function (during Step#14)
– Perform the installation during daytime so if you run into issues, you can call Honeywell Support 1-800-468-1502 for wiring assistance
(They are actually quite knowledgeable & helpful if you are patient/tolerant enough to understand their accent – They do speak politely & slowly for “US” customers)

All my fears of replacing t-stats have been laid to complete rest. It was a very simple & straightforward process.
With just a bit of due diligence, I started saving money even before i installed the thing (because i did not have to pay the AC repair company); since I have 2 t-stats that needed this upgrade, the actual savings have doubled.

Amazon product delivery was quick, as always; priced better than local HD stores – I could not ask for a better experience.
I hope this review helps quash any fears that folks like me have, before i started this project. Thanks all & God bless.


very well designed, easy to install, January 31, 2011 (5 star)

6 of 6 people found the following review helpful

After using a White Rogers 1F78 model, this Honeywell is everything the WR isn’t. The instructions are incredibly well written. The setup was a breeze (although my furnace was a very simple, standard setup). The buttons are easy to push (unlike the White Rogers), and the display is completely logical and well labeled!

There is the dilemma of how to turn on the backlight without changing a setting. Because the buttons are nicely responsive, almost any push will activate the button (as you would normally desire). I have found that a quick tap of the UP or DOWN buttons triggers the backlight but does not change the temperature setting.

It does make a fairly loud click when the thermostat clicks on or off, but it’s hardly a problem (the White Rogers was virtually silent). I like (and indeed, insisted on) the ability to see both the current air temperature and the programmed temperature. The clock display is small, but that’s fine because I don’t need to see the clock except to make sure it’s on time.

The White Rogers was plagued with inability to handle static discharges (it would completely reset the unit, argh!). I haven’t tried shocking the Honeywell.

The battery pack is easy to remove, and there is a slot that holds a handy reference card. Honeywell products are well thought out! Refreshing!


from – Great product, October 27, 2010 (5 stars)

17 of 18 people found the following review helpful

“This is a great thermostat for your home. Installation was easy and programming was fairly easy. It already comes pre-programmed with the “wake” “leave” “return” and “sleep” times and temps. I programmed my own settings and didn’t take long to catch on. Battery pack allows you to program while on your couch then snap on to the wall faceplate when done. Very easy to override the temp setting. Seems quite accurate. Only suggestion I have is to make sure you have a very small regular screw driver available to tighten down the wiring to the wall faceplate”

Easy to install,
Lots of features


You can find more reviews on Amazon’s site, if you click this link.

If you think you need a cheap, simple and powerful thermostat, I believe this one is for you. This doesn’t have any ‘fancy’ features like wifi – touch screen – learning functionality etc., however it does the required job properly. Considering the low price tag, this is one of the best ones from the budget point of view. You can buy it from Amazon’s site by using this link : Honeywell RTH6450D1009 5-1-1-Day Programmable Thermostat.