Can 1 24v transformer support 2 smart thermostats.

Question

I replaced my old thermostat with a lyric. My doorbell transformed was unused and 16 V. I replaced that with a 24 and wired it directly to my lyric. Everything works great.

If I do an additional thermostat in a different zone can I just add more wire to that existing transformer? Will multiple devices on the 24v cause issues?

Thanks

Answer 1

I have run multiple thermostats and even a 24v damper off a single transformer. Most thermostats are very low draw but to make sure look up the power requirements for each and add them together. Now compare that to the transformer wattage/ amperage. If less is needed from the 2 stats than the transformers rated output you are good to go. If the same or more than the transformers output you can get a larger single or another smaller transformer (usually cheaper) and have 1 for each stat.

Answer 2

Ratings matter. Every transformer has a VA rating. Every thermostat has a VA rating.

You know which transformer you bought, and the VA rating is important enough to be usually part of the name of the product.

You can compare the VA rating of the transformer to the VA draw of everything connected to the transformer.