I'm specifying 10 ton w2w system for a large home with 130k design heat load (radiant floor). One equipment option would have two 5 ton heat pumps connected to a single load loop. I'm considering DSH for one of the heat pumps with 50 gal buffer supporting natural gas primary water heater. It makes no sense to add DSH to both heat pumps, but in this configuration, I won't be able to sequence (alternate) the heat pumps, which is standard practice when I have two systems supporting a single load loop. The thing about sequencing is that the benefits cannot be calculated. It's a risk mitigation play to avoid dominant use of one system. Does anyone think I should lose the DSH in order to keep the sequencing? Also, in general, does a DSH have better payback with a closed loop vs an open loop system?