In the process of buying a new house. Currently, at my house, I have a Trane system that is variable speed. I really like that it runs at a low speed nearly all the time. It really is more comfortable when there is airflow, even if the air temperature is not as low. I keep my thermostat set to 74 - 76 most of the time (In Florida). My girlfriends apartment can feel very warm even if the air is set to 70, and it's made worse by the fact she has no ceiling fans. I find my house more comfortable, despite the warmer air temps.
But... and this is a big one. The thermostat freaking sucks big time. I have been able to sorta automate it with a community app/driver and using temp/humidity sensors around the house, but it's still not great. And with a variable speed system you are locked into their proprietary thermostat. If I were to use something else, my system would lose the variable speed bit.
The house we are buying has 2 AC systems. Someone, miraculously, one of them is the original system when the house was built in 1985. I don't understand how it has survived 40 years in the Florida sun and humidity, but it somehow has. But this is going to be literally the first thing we replaced when we buy the house. The other AC system feels brand new by contrast, but it's a 2008. We'll probably wait a few years and replace it as well so that the two keep a little distance in age.
All of the equipment I'll be taking with me is zwave, mostly 700 series, with a mix of a couple 500 and 800 series. I know they make zwave thermostats, but I don't know how well any of them work. So I could go with a 2 stage system and a basic thermostat that I can automate through Hubitat. But I really like my current variable speed system. Are there any on the market now that the thermostats are not as locked down?
How are the "big name" players in this field? I think that would mostly be Nest and Ecobee, but it's not a topic I have kept up with over the years.
There are some variable speed systems that work fine with a conventional thermostat (like an ecobee or any z-wave/zigbee thermostat). Daikin and Bosch are two that come to mind. There may be others.
If I was getting a variable speed system, I'd get a Bosch and use an ecobee. With a C-8 Pro, you can control an ecobee locally, while retaining the capacity to use the ecobee app if necessary.
I like my Daikin much better than the Fujitsu Haylcon units. With the optional Wifi module, Hubitat can control the Daikin directly, with no cloud access and HVAC settings done through the traditional IR remote control are reflected in Hubitat, which is a great convenience and very easy for guests etc to control without Hubitat access.
When I had my HVAC replaced one thing I told the contractor is that I don't want factory lock in with a vendors thermostat and wanted to continue to use my ecobee and the room sensors. He said that would limit my unit choices since 90+ percent efficiency units are the ones with factory mandated thermostats. We chose the traditional Carrier with the regular controller board and a fan that only has one speed for cooling and another setting for heating and it's controlled via jump on the board.
I have a high efficiency Rheem furnace/AC combo that I installed in 2020. The installer recommended the Nest thermostat, but since I already had an Ecobee 3, I elected to reuse it. The installer had to reverse a couple of contact wires, but the thermostat works fine. All of the fancy electronics related to the variable speed fan and soft start are on the control board. The thermostat just controlls the temperature setpoint and mode.
If the existing units still work and haven't shown a massive amount of extensive service needs, I'd be inclined to run until failure. At the very least, live with the units and see what you do and don't like with the current setup.
New/different houses have a way of finding any spare money and time you have inadvertently left in plain site - don't kick start the process by throwing $10-25k at something you can limp along for years.
Well, it's a 40 year old AC system and the sellers just let us know it stopped working yesterday. So... now we're dealing with that. We already negotiated the purchase price lower with the anticipation of replacing the system pretty much immediately anyway, but I was hoping it could at least wait a couple of months to let us move in and give me time to research.
Do you mind sharing what model air handler and compressor you have? Everything I've been able to find indicates that you need the Goodman GTST connected thermostat, but that the Daikin One Plus thermostat will work too since a Goodman is just a re-branded Daikin.
Don't know about your condenser, but the GMVC96 furnace is a 2-stage furnace.
The furnace control can modulate the blower speed. So any thermostat that does 2 stages will work fine - it's just on/off for each stage, and the control board handles the blower.
I don't know if the Honeywell, or any other conventional thermostat, will work with a fully modulating Goodman furnace. Like this one:
Want to add - @waterboysh; personally, I would get a 2-stage furnace over a fully modulating furnace. There is less that can go wrong, and the difference is comfort is not that much. And then you can use it with any conventional thermostat that works with Hubitat.
