Our house was built in 2003 and still has the original furnace. The Google compatibility test stated we were good to go. I pre-ordered the Nest and received it 2 days after it launched. I was so excited to get rid of our ancient thermostat. I installed it the same day! The Google Home app was really easy to use and walks you step by step through the install. I ran into an issue when I saw that our old thermostat wasn’t using a C (common) wire. There were three wires that weren’t hooked up. I went to the garage and opened up the furnace so I could look at the electrical panel. The same 3 wires were not hooked up to anything in there. I hooked one of the unused wires to the C wire on both ends (Nest & furnace). Boom! The C wire was recognized and we had constant power going to the Nest. Overall I love the look, the Home Screen displays the date, time, indoor/outdoor temperature and humidity. It’s easy to use with my Alexa Dot and does everything that we needed. We’re happy with it and would recommend it. Tip: check with your gas/electric provider they may have a rebate for buying a smart thermostat. We got $75 back!