Why you DONT want to buy a variable speed Furnace.
Buying a Variable speed ( this is different from a multispeed Furnace ) mean that the you have to buy a Thermostat from the Manufacturer for about $500. In addition, you are *forever* bound to this specific thermostat. Manufacturers cite that this gives greater efficiency, but this has to be proven ( Since they dont actualy say that a 96% efficient multispeed furnace is less efficient than a 96% variable speed furnace ).
Whats wrong with the Manufacturers Thermostat? Well for starters , it costs $500. For another Furnace manufacturers are just starting to arrive in the 90s technology and are discovering touchscreens and schedules beyond basic schedule programming. And they are not doing this willingly, they are infact being dragged into this screaming by the new entrants such as Google, Ecobee etc.
The life a Furnace is expected to be around 15-20 years. In the old days , when you retired the furnace you changed the thermostat. Those were the days of bimetal and mercury thermostats. Electronics has changed all that and a thermostat can add new features your old thermostat didnt have. Infact the entire market for third party thermostat was born because the furnace manufacturers have fallen behind and are stagnant and arrogant. Have they changed? Not at all!
Why is it locked into the manufacturers thermostat. because the Variable speed furnace communicates with the thermostat , with a protocol (method) which only that specific manufactuere uses. Well, in fact a single manufacturer might use several different protocols which are not compatible across their product lines. Also During that life of 15 -20 years, the manufacturer will upgrade the protocol, but it still means you cant get a newer thermostat from even the same manufacturer.
What about if you want to keep the same thermostat? with a network connected ( WiFi) thermostat this is also not really an option. Since with New Security Vunerabilities in your network being discovered here and there. Its absolutely imperative that those be patched. Do you think any manufacturer will maintain their equipment for 15 years. ( will your cell phone manufacturer main the code for 15 years ? ). It guarenteed this will not happen. Already the first generation( released about 5 years ago) of Manufacturer thermostats are Not being maintained actively. ( and yet those products are still being sold ! )
What about new features that are yet to come. Yes you will forever have to forego them.
Sure if you have, complicated setup with multiple zones you have to buy the manufacturer thermostat, But I'm willing to bet that in the next 3 years most third party thermostats will also pass the stagnant manufacturers in this aspect.
When will this change? When Google or Apple buys a Furnace manufacturer and brings a uniform standard to the Furnace communication.
p.s: A Similar analogy would be, Would you prefer a smart TV or would you prefer to have an external media player/ media box?
Pay it forward.