Stainless vs. Copper Chiller

I want to use an immersion chiller as a HERMS. Sit it in the HLT for keeping mash at temps (possibly) and use to chill wort at the end of the boil (sit the IC in an ice bath within the HLT and pump the wort thru it and back to the BK). Since I will be running the wort thru the chiller itself, wouldn't stainless be better?

Something like this?

which has a better heat conductivity? i think its the copper but i have no proof.

Either will work fine. The stainless steel chillers tend to be made out of much thinner material than copper and they will transmit heat faster than you can flow water through them.

I've seen several posts about this in the past with arguments for and against stainless with the real world test showing no meaningful difference between the materials given the same length and OD size of tubing.

Forgetting price, I'd opt for SS every time. Easier to keep clean.

Copper hasn't failed me once, 50 ft chiller chills in 10 mins so no complaints. Copper transmits heat and cold better.

They both transmit heat very quickly. It's true that copper transmits heat faster than an equal thickness of steel, but the stainless tubing is thinner walled so you can't actually make that comparison.

Whichever is faster, though, doesn't matter in practice: both exchange heat fast enough that it's your water flow rate (as opposed to any minimal insulation from the tube walls) that governs the heat transfer.

Some people think there's a benefit to including copper in the pre-fermentation brew system. Stainless is cheaper and easier to clean. Opinions vary on which is prettier.

Use whichever you like.

Thanks all. Thats what I was thinking on the stainless; easier to clean, cleaner overall as far as wort going thru it goes.

As fa as using it as a HERMS, what are your thoughts? I will be pumping ice water from the bottom of the HLT (which the IC will sit in) back to the top to recirculate the water over they coils. The wort wort will pass from the BK thru one side of the IC, out the other and back to the top of the BK. My thinking is it will chill the wort and be easier to clean out then my Therminator.