Hey VaTom!

Ok so I'm intrigued...how does Passive annual heat storage work... I've not heard of it before?

How does the heat not dissipate over time into the earth's 50° temperature? The mass is somehow "charged" by the sun in the summer?

How's it work in your home?

Thanks,
Jameson

Hi Jameson,

Nice to see some interest. First, deep ground temperature is quite variable depending on where you are, not necessarily 50º. It takes about 2 years for the ground around a PAHS house to stabilize. When you get an equilibrium area at the extreme of your mass, it's a simple matter of dumping heat into the mass for later retreival. Designed correctly, your house will hover around 70º without your doing anything.

John Hait, the originator, learned from buried sensors that it takes about 6 months for heat to move through 20 feet of dry earth. Flywheel is a good comparison. Hait's particular genius was to put an insulating "umbrella" over the mass which both keeps it dry and and insulates it from climate extremes. His rule of thumb was to extend the umbrella 20 feet beyond the house perimeter.

I go a step further, by going directly to climate particulars and determining heat gain and loss of specific houses. I also now know that different geology around the house affects how fast the heat moves, and how large the umbrella should be. Obviously, different climates have different heating and cooling needs.

Hait's book "Passive Annual Heat Storage" was published in 1983. I happened onto a copy and decided it made sense. When we moved to Va and bought land, it was an easy choice. Since then I've learned a great deal about how and why it works. My house isn't particularly successful as we get a 13º annual swing, compared to Hait's 7º. I know why, I cheated a lot on his recommendations. Mostly, too much glazing and not enough ground contact.

Still, it's by far the most comfortable house we've ever lived in. The next one will be better. PAHS is both our heating and cooling system. Annual storage, pretty obvious when you think about it, eh?

I took his system and ignored his architecture. PAHS can look like about anything you don't mind paying for. I used commercial construction components for my place, cheap.
PAHS

Very Interesting Stuff! I will have to read up on this.

Thanks!
-Jameson

You're welcome.

Take a peek at my place. Below is a page put up as a surprise to me, never updated. My original intent was to use it as a future professional furniture shop. I keep getting sidetracked, haven't completed the next house.

A similar construction house nearby appraised substantially higher than it cost to build. That was a direct comparison to stick-built here. It is completely different inside, looked like a regular house (with finished ceilings). Neither place do we bother with any window coverings. Privacy isn't an issue, nor is the increased heat loss. It's owner now puts up with an 80 mile each way commute, won't give up the house. His previous one was a very nice SIPs post&beam. He much prefers PAHS.
Toms PAHS