Restoration work will soon finish on his latest acquisition, a 150-year-old estate in Zalanpatak village that has 37 acres and a five-bedroom house. The Prince will let it out as a guesthouse when he's not there, as he does with another Transylvanian property he owns.
Heritage: The Prince owns two properties in Transylvania, home to his ancestors
So just what is the appeal of this central Romanian region, best known for Dracula's castle, fairytale Saxon villages, deep forests and the haunting Carpathian mountains?
'It's extremely beautiful and considered by many to be the standout region of Romania,' says Edward Russell, who runs sales website homesinromania.co.uk.
'Transylvania has forests, lakes, cities, good access and of course everyone has heard of it. The speculators who thought they could make a quick buck a few years ago have gone and the interest from Britons is now modest but steady,' he says.
David Cox, of estate agency Property Frontiers and an expert on international property investment, says Romania remains an emerging country, but 'has a strong ownership-centred culture, meaning the property market is well-suited to capital growth in the long term'.
He believes Transylvania has two tempting spots for adventurous British buyers. One is Cluj-Napoca in the region's centre. With Romania's largest university, it has a high proportion of foreign students who form a large community of renters.
The airport has opened a new terminal and Nokia has one of its largest telecommunications centres here. Brasov, in southern Transylvania, is another major academic centre and transport hub.
'Property here consists of new apartments in the somewhat sprawling industrialised areas and contemporary and older- style family homes,' says Cox.
Royal appointment: The Prince is a fan
Transylvania is one of the most affluent parts of Romania, yet property values remain low compared to other eastern European locations. The country entered the EU in 2007, just as many western countries were hitting recession. Consequently there was no surge in overseas buyers to push up house prices.