Just include that then!
"good evening, we got an e-mail asking us where we want our heat pumps, backyard or front. Either way, the thing is going to make noise and since I'm going to be living in between you two, perhaps we could coordinate the locations so that we don't end up complaining to each other about noise. Let me know if either of you has a very distinct preference, as I don't have any. Tink.
P.S. I hope you are more annoying than I am."