Isekai Tensei Ojisan wa Shizuka ni Kurashitai is a Manga/Manhwa/Manhua in english language, Adventure series, english chapters have been translated and you can read them here. You are reading chapters on www.mgeko.nl fastest updating comic site. The Summary is

After having several setbacks in real life because of his loner nature and holing up in his house, Toudesuke Saionji, a middle-aged man, throws himself into his inventions. Until, one day, he causes an explosion during one of his experiments and ends up reincarnating into another world. Now that Toudesuke has yet to find some way to go back to his old world, will he keep to himself along with Satalia, a vampire girl who adores him, and lead a quiet life where he dedicates his time to his inventions...?!