What kind of Heating and Cooling system do I have?
Do not buy a smart thermostat without checking your system’s compatibility first.
You have to know which type of Heating Cooling System(HVAC) you have, Is your system compatible? Because your smart thermostat might not work with your heating and cooling system. Even worse you might fry your brand new smart thermostat or burn down your house in the process.
Typical HVAC systems that are compatible:
- Conventional forced air system
- Heat pump system
- Boiler system
HVAC systems that not compatible:
- Electric baseboard system
- Multivolt (Gas heating source furnace) Systems
Check out the graphics below to figure out which system you have.
Conventional forced air system
The most common heating and cooling system is conventional forced air system. If you have vents in your house that air blowout off, you have this type. All the smart thermostats in our list will work with this system unless it has more than 2 stages of cooling or heating. Check your current smart thermostat wires to make sure that you have up to 2-stages of forced air heating (W1, W2) and up to 2-stages of forced air cooling (Y1, Y2). If you have W3 or Y3 cables in there your system is 3 stages or more and it won’t be compatible with your new Wi-Fi smart thermostat.
Heat pump system
In a milder climate, people prefer to have heat pumps, for example, if you live in California or Florida, you might have a heat pump. It’s like an air conditioner, it should be located outside your house, providing heating and cooling. Check the wiring, just like conventional forced air systems, your new Wi-Fi smart thermostat will only support up to 2 stages. If you have a W3 orY3 you are out of luck. All the smart thermostats in our list will work with this system.
If you have a boiler system, also called radiant heating, you will have pipes under the floor or radiators. It warms your house by circulating water and steam through the pipes. This system will only have heating wiring. Check the wiring and make sure it’s only a 2 stage system. The wires should be W1 and/or W2. All the smart thermostats in our list will work with this system. Just make sure there isn’t more than 2 W wires connecting to your old thermostat.
Electric baseboard system
Electric baseboard systems are metal units on the floor. They are 110V-120V or 240V. This means it will fry your new smart thermostat if you try to replace your old one with a new wifi thermostat on the list. Because most of the new smart thermostats work with 24 volts. There should be a danger sign when you open the old thermostat and signs indicating the high voltage. There is a walk round by using a relay and transformer. By connecting your smart thermostat to a transformer and using a relay in between your smart thermostat and your system. But you should not attempt this on your own. We advise hiring a professional to do this type of work. You have been warned. If you have an Electric baseboard system your smart thermostat will not work.
Gas heating source furnace
Wall. Floor, fireplace furnace are usually a part of a gas heating source. These systems have a Multivolt system. They use a lot less electricity than wifi thermostats requires. These systems will not work with the new smart thermostats on the market because your new smart thermostat can not detect the wires.
Dual Systems and Multi Zoned Systems
On a Dual system, you might have the gas furnace and heat pump at the same time. The whole point of having a dual system is to cut the costs of heat pump’s inefficient heating. These systems will work with your new wifi smart thermostat. Installation and Setting up the smart thermostat is a bit harder than normal. You will have set up your thermostat correctly to a dual system. Most of the manufacturers will advise you to hire a professional to do the settings. A common problem about the setting process is how to set the fan option, which is default setting at “don’t activate”. You have to check if your gas furnace operates the fan independent of the smart thermostat. If it is, you should leave it off, if not you should leave it on.
Multi Zoned systems are used when you have a large house or have a system that heat and cool different zones in the house. You new wifi smart thermostats will support zoned systems. But they will not work for master and slave systems.
Which systems work with smart wifi thermostats
In conclusion, check what kind of system you have. If you have a Multivolt system or Electric baseboard system you can not install these smart thermostats. All the other systems that are low voltage are compatible with new smart wifi thermostats. If there is a danger sign or any indication that says 110V or more, and thick black wires with wire bolts, you should talk to an HVAC professional.
The following terminal designations are not supported.
- G2 G3
Otherwise, you are fine, go ahead and choose a thermostat and install it.
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What about systems with separate air conditioning and FHW, which is common in a lot of New England homes where air conditioning is added to an existing house.
Yes, smart thermostats will work with a system that has FHW (Forced Hot Water) and separate air conditioning. What kinda model do you currently own?
After reading the post, it looks like I have a conventional forced air system. I like in a condominium building and the heating cooling unit is located in the balcony.
I have called in Pepco to replace the thermostat and they told me that I cannot have WIFI enabled thermostat as, my system does not have a C-Wire (only 4 wires instead of 5) and can only install battery operated thermostat.
Can I substitute G-wire for C-wire and have a WIFI enabled thermostat? Please help.
What kind of system do you have? Did you check https://www.zareview.com/thermostat-installation/
and https://www.zareview.com/thermostat-wires/ ?
Which thermostat do you want to install to your system?
If there are no C wires coming from the system, you have the following options.
Option 1) You can run a C wire from your system to your thermostat. Get 18/7 thermostat wire and run it from your system to your thermostat. This involves finding your control panel and figuring out the C wire terminal there and run the copper wire along the other cables to the thermostat.
What if you don’t want to run a wire from your HVAC to your thermostat? Are there any alternatives?
Option 2)You can get an adaptor. Simply purchase a LockState Connect LS-24VAC 24 Vac Adaptor for LS-90i, and plug it into the closest socket. Use that as a C wire. It has a 20-foot cord and this will solve your C wire problem.
Option 3)You can use a Venstar ACC0410 Add-A-Wire Accessory, which turns 4 wires into 5 wires. You simply plug in your 4 wires into terminals on Venstar and connect the wires to your thermostat. But this will only work if you only have 4 wires. Check out the video below for installation instructions.
Option 4)There is another quick method that I do not recommend. You can connect the G wire to your C wire terminal. Since G wire controls your fan, you will not be able to manually turn on your G wire. But your fan will still work for your heating and cooling when needed. It’s automatically turned on and off by your system as explained above.
I rather do the job right and be able to manually turn on my fan when I need it.
Most of the thermostat companies have a video showing how to install their thermostats.
I live in Pennsylvania, where my home has the original radiant hot water (baseboard) system, powered by an oil burning furnace set up, with a separate central air/heat pump located outside (with separate ceiling ductwork/register vents). The way this was set up is that, if “Heat” is selected, and the outside temperature is 40F or higher, the heat pump kicks on, blowing warm air from the ceiling air register vents. If the outside temperature is 39F or lower, the oil-burning furnace kicks on, and heats the home via the radiant hot water baseboards.
Will the Smart WiFi stats work, and if so, all of them? Or should I lean toward any specific type/brand that would handle my scenario above?
Thanks so much for any help/advice.
I live on the 13th floor of a condo in NJ. My hvac unit is a whalen series vi-a vertical stack with both heating and cooling via a switch on the wiring box. The thermostat was upgraded from the stock model to a round honeywell t87f. It looks like they rewired the line voltage to 2 durakool mercury relays and 1 2terminal 24v transformer (pri: com 208v 240v blk red org) that is using the 240v setup? with one red wire going up to tstat and 1 black going to both of the relays at the coils. 1 of the relays seems to be separated for the fan as it is wired to the separate fan switch on the wiring box. Up on the tstat box there are 3 wires, red for power, yellow and green with a white jumper between w and y. I bought an ecobee4 and cant figure out how to provide a cwire. Talked to support and they said its not compatible. I am leaning towards the option of connecting to an nearby outlet, but there is a jbox within the units cavity that I could potentially hard wire to? Or Could i add a wire from the transformer terminal where the red is connected and feed straght to the tstat?
I have pictures if it helps.