Laura Mackall and Robert Manley did not set out to build a passive house when they embarked upon the renovation of their 1860s townhouse in Carroll Gardens. The building required a near gut renovation, so when they inquired for bids, Laura on a whim included a contractor with experience in passive construction. Surprisingly, the bids came back with a relatively small difference in cost. They decided to take the plunge.Laura’s father, Louis Mackall, a Connecticut-based…