My experience (which may not be typical) is that market value is, at least at the moment, negatively impacted by over-emphasising the low energy usage of a house.
When we had our house valued a couple of years ago, the valuer knocked 5% of the value because, in his words, it was an eco house and that made it of limited marketability. Given this, and the relatively high cost of Passivhaus certification (at least £2k, probably more when you add in the premium that every supplier is going to chuck on for providing the additional information) then I don't think it makes sense, unless you really want to proudly display the plastic plaque you get from the PHI.
Far better, in my view, to design the house to meet the same sort of performance level, and then keep the energy bills. That way, when you come to sell (if you ever do) you can just make copies of the bills to show any prospective buyer the running cost. I'm inclined to think that the low energy classification systems, be they AECB, SAP or Passivhaus, just aren't on the radar for most buyers, and some may well be put off by what they see as odd or complex features, like well-sealed windows, MVHR, minimal heating system provision etc. Far better, I think, to just have a note on the sales particulars that says "this house costs £XX to run every year, and the vendor can provide bills as evidence".