Estimating size has always been tricky, because it depends on the insulation value of the boat, climate, and how quick you want the boat to cool down. It also depends on window covers and awnings and how much window space you have. Houses, on the other hand, tend to have similar insulation values, and the rate at which they cool is not important because people leave the AC on all summer.
A salty Kiwi named Ross Norgrove once said that the most important tool for the owner of a wooden yawl adorned with a bowsprit is a sharp ax. To some degree, his witty comment holds true for contemporary sailors contemplating a mini-bowsprit.