Originally Posted by Riviera
I'm pretty familiar with commercial HVAC systems, and my explanation would probably go beyond the level of detail warranted for this forum, but here are some tidbits:
What I "don't " like:
1. My system is a Mitsubishi "M" series system, that allows for up to 5 zones per compressor. In theory, this gives you lots of individual control in each room. However, each outdoor compressor really needs to be in either heating, or cooling, at any given time. That sounds fine, bust most people don't understand that nuance, so my guests (and spouse) are continually trying to change the system over to one mode or another. This creates issues with the system controllers, and we invariably get system errors. Ultimately, I had to resort to making one t-stat the master t-stat for setting heating or cooling mode. If I had it to do over, I would have spent the $ for a commercial grade system (called "VRF"), that would have allowed for simultaneous heating and cooling in different zones.
2. A heat pump system is slow to react to different setpoints. Most people are accustomed to turning up a t-stat, and getting a quick heating result. That doesn't happen with heat pumps.
3. My system is complex. Most techs (including the one who installed it), get lost in a sea of system complexity, software settings, and troubleshooting. I had to resort to reading the manuals myself, in order to get the system software to do some of what it needed to do for my setup to work properly.
4. There is a ton of refrigerant piping to serve this type of system. When you get a refrigerant leak, you are on a treasure hunt.
What I like:
1. The concealed air handlers that we installed (with proper duct sizing) are incredibly quiet.
2. I have 10 zones. Let's face it, most people have one zone. So, aside from family training issues, we are getting a higher degree of occupant comfort.
3. The exterior compressors are quiet. If I had installed several conventional AC compressors, I would have had to listen to them when using our outdoor spaces.
I have no idea if I might be saving money. My wife complains that the electric bills are high, so I have to explain that we don't get a big bill for fossil fuels. These days, given the energy efficiency of most new homes, I am not convinced that the theoretical savings between one system or another, are really worth the debate. On paper, you can make any system look good.
Sorry you asked?
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