Issue with Powerwall thermal programming

[wwhitney]

Those look great; do you know if they are code compliant in California?

For what purpose and what code? For crawlspace ventilation, it's not immediately clear to me:

CRC R408

From a performance point of view, the question is whether the closed vents in cold weather would allow an excess build-up of ground-source moisture. If you have a vapor retarder on your crawlspace soil, that would be less of a factor, although still non-zero.

Better than temperature control would be a vent that opens and closes based on relative humidity, although that would have to be powered. The best controller would probably use outdoor temperature and dew point vs crawlspace temperature and dew point to maintain the crawl space RH below 60% while maintaining the temperature as close to 70F as possible.

I favor an R408.3 unvented crawlspace.

Cheers, Wayne

 

[charlesj]

One thing to remember about insulation is that it just slows down heat energy transfer, doesn't keep it in or out.

ps, am surprised the thermo is set to 40deg, not closer to 50 on the low end.

 

[BGbreeder]

For what purpose and what code? For crawlspace ventilation, it's not immediately clear to me:

CRC R408

From a performance point of view, the question is whether the closed vents in cold weather would allow an excess build-up of ground-source moisture. If you have a vapor retarder on your crawlspace soil, that would be less of a factor, although still non-zero.

Better than temperature control would be a vent that opens and closes based on relative humidity, although that would have to be powered. The best controller would probably use outdoor temperature and dew point vs crawlspace temperature and dew point to maintain the crawl space RH below 60% while maintaining the temperature as close to 70F as possible.

I favor an R408.3 unvented crawlspace.

Cheers, Wayne

That was the section that I was wondering about.

I think for fire risk abatement we will head down the R408.3 crawl space path, although to my mind it is really a vented or conditioned crawl space. I just want the outside openings gone(Fire risk, rodents, etc.), though there needs to be some venting for the propane water heater.

For the original poster's use, I think that they would be great. One top and bottom?

All the best,

BG

 

[wwhitney]

I think for fire risk abatement we will head down the R408.3 crawl space path

There are also intumescent vents that close up when they get to hot, and have baffles to prevent the passage of embers.

For the original poster's use, I think that they would be great. One top and bottom?

The side walls of the enclosure are very close to the Powerwalls' intake and exhaust vents, so I think side vents lined up with the Powerwalls' vents are necessary. Maybe top and bottom in addition.

Cheers, Wayne