Translation:There is lots of furniture in his room.
The "is" doesn't have to do with "lots", it has to do with "furniture". "Furniture" is singular/collective noun. "There are lots of things" or "there are a lot of things". "There is a lot of light" or "there is lots of light".
I'm Australian and I would definitely say "There is lots of furniture in his room".
olimo Hi I don't know how long ago you asked this but I just came across it and looked up the answer. It's in this site: http://www.englisch-hilfen.de/en/grammar/lot_of.htm. Simply stated it says: "It is not the phrase a lot of or lots of which determines singular or plural, but the subject of the sentence (here water and computers).
A lot of water is wasted. Lots of water is wasted.
singular A lot of computers are needed at schools. Lots of computers are needed at schools. plural