4x4x6.5 feet. I running the euro hood from htg with the 6inch duct fan. It's amazing in the tent how mucheasier it is to keep the heat down than even in a big room i found. Its made to get that heat out. I use passiv eintake, winters coming, otherwise i need more fans. I also use a big metal house fan int their that i found is ten times better thana plastic tbletop one.