What thermostat mdl was replaced? Call dealer back. If the labor was on their dime, then the price is high. You see this basic prog thermostat on the Internet for around $50. A fair price would be around $100 since he is stocking this on his truck. And BTW, not an upper end pricey model.

iMO

Thanks. After posting this I did call the HVAC company. They will take it back. I asked if I could please get TWO new thermostats without all the bells and whistles instead of this one. Oh, yes, but each would cost $165. They only carry White/Rogers.

I don't think so! Online I see what look like perfectly acceptable thermostats for about $60 each. I arranged to call the company to come get this thing once I have our handyman install new ones. Now...what are good Plain Jane thermostats? I'll start a new post.

The thermostat you almost bought can be found on line for $39.25 plus shipping. Here is one of many suppliers: White Rogers Thermostat. You don't have to spend $60.

Almost all thermostats control heating and cooling are programmable. They are all electronic since the mechanical type used mercury switches.

You should rethink the the annual contract. It seems the HVAC company is going to charge a price which covers their labor costs. You could buy the thermostat and have them install it but I would think there would be excuse why they can't do that.

Mike -- Thank you for that link. I see my "$175" model for $66 + shipping.

One of our neighbors swears there is an 'address tax' for our area. He's right.

I'm also wondering if I should just let our East thermostat keep on keeping on until it fails -- or is its circuit board likely to fail soon too?

I think I'll buy two simple thermostats and keep one on hand.

Thermostats usually last a long time. I had a Honeywell mechanical thermostat in my house that failed when it was about 22 years old. One of the plastic gears wore out. Circuit boards are fairly reliably. An electrical storm is probably the most likely cause of failure.

No reason to replace a thermostat that you like and is working. But if you want peace of mind and want the thermostats to be the same, then replacing both if fine. As you can see they are not very expensive and easy to replace.

I thought I'd provided all the necessary information but I failed to note that our systems are two-stage. Each one has its own thermostat.

I don't understand the difference. The thermostat just calls for the system to go 'on' and then 'off' once the set temp is reached, right? In summer, we usually go from 75F days to 68F at night.

Sorry to be slow 'getting' this.

I can only locate one furnace manual: Carrier 58TUA and 58TMA. The cover illustration is of a "WeatherMaker 8000 two-speed".

Ye gods! I'm just reading the manual for the thermostat that is going back. It says it is "Blue Single 1/1 Stage" and "Single Stage or Heat Pump". Maybe that's why, although it is programmed to lower to 68 at 6 p.m., it starts down at 5 p.m. -- until I jab the 'up' button.

You have a 2-stage furnace, you have to determine if you also have a 2-stage AC condenser. Get the model numbers from the condensers and we can try to determine whether they are single or dual stage.

The thermostat the HVAC contractor was trying to sell to you is not going to work well with a 2-stage furnace. He may have done this because your current thermostat is also a single stage type.

A 2-stage furnace has a low and high speed. When the furnace first turns on it starts in the low stage. If the thermostat can't be satisfied after a period of time, it goes to high stage. Most of the time the low stage is adequate to maintain a set temperature. The high stage is needed when coming out of a set back period, or on very cold winter nights.

A 2-stage thermostat will control the staging of the furnace. The thermostat figures out which stage to use based on how close the programmed temperature is to the room temperature.

But if the thermostat is a single stage type, then the furnace decides which stage to use. The furnace as no idea what the house temperate is and what it should be. So what happens is the furnace always starts in the low stage, and then after a few minutes (3-5 in most cases) it will shift to high stage and stay there until the thermostat is satisfied. This is a really poor way to use a 2-stage furnace. You get little benefit of having 2-stages of heating.

You can still get the cheap plain Jane thermostat and continue using the furnace the way you always have, or buy a better thermostat and make better use of the furnace. I don't think you are going to find any mechanical 2-stage thermostats. Also you need an additional wire from the thermostat to the furnace. There is a good chance the wire is already there and not connected. If it is not, then there is going to be an additional expense to run the wire. In addition a switch may have to changed on the furnace control board.

It would have been nice if the tech had explained this to you and let you make some of these decisions.

Mike -- Thank you for explaining this so well. How frustrating to know that the original HVAC guy not only failed to set up adequate ducting for our north-facing rooms, but failed to hook up two-stage thermostats. After we paid thousands more to buy two-stage systems! (Our contractor did pay to add a small boiler and hot water tubing under the north rooms.)

This all goes back to our contractor who was always cutting corners hiring the subs. We had never built before, so we can keep having these happy moments of 'discovery' since 2001.

The Carrier manual for the A/C says Split System Air conditioners. The condensers say 38CKC. One is Model #4101E12684. One is Model #3301E11441.

It appears that I must hire *some* HVAC person or electrician to install two proper, 2-stage thermostats. I'm reluctant to call our current HVAC company after this mistake, yet we have paid him to service our system through this winter. Someone has to see to connecting ALL the correct wires to let the system run as intended.

Many thanks!

The Carrier 38CKC is a single stage AC condenser. The other numbers you posted are serial numbers.

Builders are known for spending as little as possible when it comes to HVAC. This is not surprising. You need to find an HVAC contractor you can trust. Paying for annual maintenance is expensive and as you can see has its problems.

Why did the builder add a boiler? The two furnaces are not cable of keeping the house warm in the winter?

Great. We have two-stage furnaces and single stage condensers. Can I still get some two-stage use for the heating? Should I still look for two-stage thermostats?

There is inadequate ducting to heat north rooms. Our build was the HVAC man's first job, as we only learned when the problems cropped up. He also had to move both the thermostats. We actually enjoy the warm floors -- but I'm happy to have the ducting delivering humidified air in winter.

Our current HVAC company had been recommended by two neighbors. It has a top BBB rating. All I can do now is 'pick one' out of the dozens advertising in our area.

Thanks for your patience with this.

I would recommend getting a 2-stage thermostat so you can make better use of the furnace. The thermostat can work with single stage AC.

No excuse why the original HVAC contractor could not uniformly heat and cool your house with two systems. If you like the current set up then continue using it.

Hopefully I have given you enough guidance so you can ask the right questions and make some informed decisions.

Good luck.

Thanks, Mike. That's the last puzzle piece in place: A two-stage thermostat can work with a two-stage furnace and a one-stage condenser. Now I just need someone to install two two-stage thermostats and hook them up properly to both furnaces and condensers.

I was afraid you were going to say I had to buy new condensers -- and who knows what would mesh with 14-year-old furnaces!

I'll start a new thread asking for recommended two-stage thermostats.