I am not sure of the significance, other than the obvious, but if you look, you will soon find hearts everywhere.
Sometimes you will find them in the most unexpected places, like the door below, long forgotten.
The heart on this bright door is tiny & not easy to spot, but to me, the brilliant red color says it all.
In this detail, you can see the tiny hidden heart along with other striking hard wear.
On this door one finds a heart, & other medieval elements, on one side & on the other, a modern intercom system, as well as, a "No Pub" ( publicity ) sign. I love the little window just above the door.
The "hand" door knockers, which you also see many of, came later. You will often see an assortment of different locks, handles, & pulls on one door, each added at different historical junctures.
The door below boasts an up side down heart along with other interesting decorative additions.
It is hard not to be drawn to a door that invites you in with a heart. I am completely charmed by this medieval practice.