I'm replacing my 30-year old Geothermal system with a new one. I have four quotes, all of them telling me the house duct-work, etc. was designed well and efficient. One issue is the house is over 4,000 sq ft and the current system has only one zone, which will be fixed to two zones with the new system.
Three of the HVAC guys tell me I should do a 2 stage system - save energy, etc. The fourth is suggesting a single stage for a few reasons: He has replaced a lot more compressors on two stage units than single stage units (even saying his mfg rep says the same thing), the zones will still have over 2,000 sq ft each, the house is brown, open to sun with a lot of windows, etc. so the system will still need to crank 100% most of the time when it's on anyway. It's also less expensive - though not by much so that's not an issue. My issue is that the guy suggesting the single stage has been helping with my current system for years - I trust him, etc. He says he's taken everything about my house into account and would suggest the single stage. That said, he's OK to install the two-stage if that's what I want.
Thoughts from anyone in the business?