First thanks to the people who responded to my previous question about slinky burial depth and bedrock. Someone asked about the length of my slinky trenches and pipes. It brings up a good question, one of which I've been trying to resolve by talking with a number of vendors/designers. So far I've spoken with 4 different designers and each has had a different take on why my loop configuration should be. First the known constraints: I've purchased a 4 ton ClimateMaster Tranquility 27. With a bit of creative routing my property will support either 4 100' long trenches, each about 5.5 -7' deep -or- single massive trench 80' long, 40' wide and 5.5-7' deep . The the soil is a mixture of sand and clay and for most of the year is saturated at depths below 3-4 feet. Designer 1 said I should stay away from Slinky's altogether - Not an option given the layout of my property. Designer 2 suggested 4 1000' slinky loops of 1 1/4 " pipe in 100' trenches. Designer 3 said that both the 1000's loops and the 1 1/4" pipe were serious overkill, and therefore recommended 4 800' slinky loops with 3/4" pipe in 80' trenches. Designer 4 said I should do 8 500' loops of 3/4" pipe all brought back into the basement to an manifold to avoid having to thermally fuse pipes in the ground. So, 4 experts and 4 different design recommendations. I certainly value all the information they've provided me, but at this point I'm a bit perplexed as to how to choose between the various design recommendations. -David

I have designed and installed 20 or so slinky systems. Option #3 is the one I would go with. I have a slinky loop in my own house and I know how well it works.

Option #2 - 1.25 pipe in a slinky is not practical.

Option #4 - With 8 - 500' loops of 3/4" pipe, the flow through each pipe is too slow which gives a low Reynolds Number. This affects the heat transfer of the loop.