I've been told that the Lennox Harmony Zone System is unique in the marketplace. My understanding is that it is the only system that seemlessly controls a variable speed blower using electromechanical dampers and a series of static pressure sensors to do so. If coupled with a modulating furnace apparently it can also control the amount of heat the system is calling for be it one zone or several. So the only thing that is missing from what appears to be an ideal system is the cooling side.
Certainly a two stage compressor with this system would make sense as would a two compressor unit like the Trane 21i if it is compatible. Ultimately an inverter based, variable speed AC unit would be the best solution using today's conventional offerings such as the Nordyne stuff from the likes of Amana and GE or possibly a inverter based heat pump like the Carrier system. Unfortuately these are expensive solutions and in the case of Nordyne max out at four tons plus there may be an incompatibility issue between brands.
In my case, the heat pump, which I am told is only slightly more expnsive than an equivalent AC unit, would not be used for heat as my natural gas costs are low relative to my electricity costs and that relationship is unlikely to change for the better. So I am not sure this makes sense from a cost perspective but I am certainly willing to consider it.
For general reference I own a 20 year old 3400 sq.ft., two story home (1st floor 1800ft. 2nd floor 1600ft.) in northern California. I would like three zones (two down and one up). My 20 year old, 5 ton York system is ducted for three zones, which I manually control at the air handler each season and my house is very comfortable year round. But I need to replace it soon.
So here are a few questions. Have I described the Harmony system correctly and is it indeed unique in the industry? I would like to have a zoned system (two or three) that has real world effeciency withouot spending a ton of money. So what is the least expensive plan for the AC component assuming that the Harmony system is the best option for zoning? If I don't need a fully modulating furnace how many stages of heat would be appropriate again assuming that I have to use the Harmony system?
I may be wrong but bypass circuits and dump zones just don't make sense to me so I would like a design that does not use these.
I beleive that a two system solution would be a great but expensive alternative. If I decided to go with two systems what tonnage/btu combinations would you recommend?
This is blue sky stuff but from a layman's perspective and with a reading knowledge only I can't help but wonder. Has anybody ever seen a system with two compressors and one coil or perhaps two stacked coils one for each compressor? Or is it possible to use two compressors and two coils with each coil in its respective air supply? What I am trying to get away from is two complete and separate systems in order to potentially keep the costs down.