SIP Heating and Cooling

[Captn]

Has anyone found a less expensive option for SIP home heating and cooling?

[StressMan79]

I don't know what you mean. a SIP home is not a magical thing where the laws of physics do not apply. Heating/cooling options are the same AFAIK. There are some altermative ways, say swamp cooling, solar driven heat pump, etc, but I don't know of any SIP specific designs that fix any of the problems--carnot efficiency and no free energy (other than solar)

-Peter

[Captn]

The biggest problem with a SIP home is not cooling, it's humidity ... a conventional air conditioner will short cycle and not only run up your electric bill, but it will not remove the humidity from the air in the house leaving you prime for mildew.
Heating is not nearly the same problem in that a conventional gas will fire and kick off, but the fan will run until the plenum is cooled .... yes, solar and wood are options, but you need outside air for combustion.

High Velocity makes a solution, however it is very expensive ... I wondered if anyone had approached the problem here as yet.

[rreidnauer]

That would be a sizing problem, not a construction problem. HVAC needs to be appropriately sized to a home's energy losses.

[Captn]

I totally agree ... sizing is important, but you run into special problems when you get above R30, or so I've been told.

[donjuedo]

Has anyone found a less expensive option for SIP home heating and cooling?
A SIP home has good R value and blocks water vapor from going through walls. Other technologies accomplish these two features and need no special heating or cooling as a result.
As long as the AC is not over-sized and short cycling, the humidity in a SIP home will condense normally. The on cycle is primarily governed by the amount of air to be cooled (and the AC unit size), and the off cycle is governed by the rate the insulation permits heat to re-enter the home.
Basically, if you get your AC sized for your home's square footage (and regional zone), I don't think you need do anything special/expensive.

Peter L.

[Captn]

A normal home in the houston area requires about a ton of cooling per 500 sq ft. This is assuming R19 celing and R13 wall insulation according to my HVAC guy. If you reduce heat loss by going above R30 I would think that requirement would be reduced and you would need a smaller unit. The question is then what would the tonnage per sq ft need to be?

[donjuedo]

I don't know that number.
When you get away from the rough rules of thumb, you need details about the overall load of your home, like window area and single/double/triple pane + low-e coatings, roof type and color, shade or lack of it, and so on. Can your HVAC guy do that kind of evaluation? I wish I could, because it makes so much sense. Hopefully, someone can chime in with those kinds of details on how to properly size a system.

Peter L.