For what it's worth we are heating with 90F water. We have three 250' tubes in our kitchen, dining, pantry, laundry/mud room. Typically there are 2 tubes in a 16 OC truss opening, but some have three tubes and we are using the light weight fins. I can walk on the tile above and tell you if I am standing on a two or three tube truss. When it starts to get cold I turn on just one of the three tubes, then two and finally all three and it holds the house to about 15-20F

If I had to guess I would say each additional tube adds 50%. So if I am getting 10k btu with one I would guess 15k with two and maybe 20k with all three. I am guessing from how much time the heat pump runs and how much electricity we use as I turn them on.

Hi Brock,

Thanks for your reply, good to hear that you have my future setup, radiant staple up on a heat pump. 

That is good information re the increased heat from #2 and #3. 

For my info, can I ask you a few questions about your system?

1.  What are the approx. dimensions of the plates you're using? 

2.  Do your remember the source of plates?

3.  Are you using 1/2" pex?

4.   Finally, on the heat pump question, is 90 deg the hottest you ever run - and did you try or consider a warmer temp?

Thanks for the good info!

Jeff

Our system is goofy, basically I am using a water to water geo-comfort 4 ton to heat our 16,000 gallon indoor pool up to 90F. The heat pump runs about 10F hotter than the pool water, so it runs about 100F out of the geo.

I circulate 90F water from the pool through 1/2 oxygen barrier pex around the house and only run the geothermal heat pump "off peak" or at cheap electricity rate bringing the pool back up to 90F, it usually drops by about 1/2 of a degree during on peak times.

The plates are 4 feet by 5 inches wide. We got them from Menards, a local (upper Midwest) Home Depot type store. They didn’t have any manufacture stamp on them or anything noting who made them or from where.

Brock,
That makes perfect sense, nice to get the low cost geo heat working for both pool and house. The more I talk to people about this I'm pretty confident I can improve the heat output significantly by adding the second tube and fully plating it. Thanks for your input!
Jeff