I am looking at alternatives for an efficient yet semi-reasonably priced HVAC system for a SIP home (in a hot humid climate).  It appears there are several ways to go and I would like to hear of others experiences with this.  I would expect to put in an ERV for ventilation.  One of my main concerns is humidity control (with good/great efficiency & comfort).

1.  Geothermal - appears to have the best efficiency but pricy for the expected savings if the building envelope is very efficient.  I have to drill a well anyway though so it may not be as bad if I sink the ground loops when drilling the well for drinking water.  Central Florida however may not be as efficient with our warmer groundwater temps.

2. High efficiency standard ducted system.  The IQ Drive at 23 SEER appears to be at the top of the heap as far as efficiency.  It appears the inverter technology allows for additional humidity control and efficiency at less than peak loads.

3. Mini Split systems.  This way the ventilation system with smaller ducts would be completely separate from the HVAC system.  The multiple indoot units appear to offer automatic zoning.  Mitsubishi Mr. Slim series appear to be a rather efficient one at ~ 16 SEER (also with inverter technology for variable run rates). 

4. High Velocity Systems.  I've heard about these using smaller ducts and being a good option for a tight envelope structure.  I know very little else about them including manufacturers,efficiencies etc.

I don't know much except from what I've been reading on here. I had someone suggest a high velocity system for our house and after phoning around to some of the distributers they told me they are at a premium. They said to expect to pay a lot more (about $4000) than a regular A/C system and no matter what I would get a lot more noise. Too bad, it seemed like a great idea considering we don't have many walls to run ducts.

 Once again, I'm no expert it's just what I've found.

Sean

Torben;

Geothermal ......... hard to find anyone do a system in Florida

High Efficiency .... we use Hi-efficiency variable speed air handlers, take humidity at start up and wind down without compressor running...........have had good experience with these systems

Mini-splits, OK if you don't mind the wall units

High Velocity System ...High cost, good for retro fitting old buildings


ERV's not necessary in my opinion, I have one in my home now, but will not in the next one.
a simple 4" duct to return air plenum with damper is best and cecommended by the FSEC

Mini Splits
The Mitsubishi City Multi has a model that can be ducted if you object to looking at the unit.
Bob I

Chris, do you have any brand names or model numbers you could recommend for the high efficiency variable speed air handlers?

Jelly;

I prefer the Trane XLi series

I am just finishing a new SIP build and we decided to go with 6.5" SIP walls with spray foam on the roof deck, non vented atic. For 3044 living we have two units a 3 and 2.5 ton units and an ERU. Bedrooms on one and living on the other. We are going with Lenox units and two units to get the high SER values ~ 20. It is still a work in progress but I'm hoping for <$100 per month for utilities. We'll see!