ACIQ Heat pump: Should i connect 24V or HA,HB with thermostat?
My house is a single-story home of almost 3,000 sq. ft. in Southern California. The current system has a Goodman 5-ton condenser, a Goodman furnace, and an Aspen coil.
I’m currently getting quotes to replace the entire system, remove the gas furnace completely, and switch to a heat-pump-only system. I’m specifically looking at newer systems with slim condensers, such as the ACIQ Extreme+ or AC Pro Z Series.
As I understand it, if I install one of these new systems, I have two options for connecting it to thermostat. First option is connect to my existing Ecobee thermostat. The first option is to use a standard 24V connection, but in that configuration, the condenser would essentially operate in only two stages: low speed and high speed.
The 2nd option is to get a thermostat specifically designed for ACIQ or AC Pro and use the two-wire HA/HB connection. This would allow the condenser and air handler to communicate with each other, enabling the system to operate at multiple speed levels. More importantly, the system could run long cycles at very low speed even after the desired temperature has been reached, helping maintain a more stable indoor temperature compared with a traditional central AC system.
By “traditional,” I mean that once the desired cooling temperature is reached, the AC shuts completely off. Then, when the indoor temperature rises again, the AC turns back on.
My main concern is whether anyone here has experience with these newer heat-pump systems and has actually compared the two operating methods: using a standard 24V connection versus using HA/HB communication.
If you have, which setup did you find more energy-efficient in terms of your actual electricity bill?