The Jon has linked to above are ace, those bambi ones run from essentially a fridge motor so they're as noisey as a fridge, ideal for in the house.
They do a budget range too if you look for their sellers on line, I don't know what area you're in but the first six on that link are perfect for your needs !
You could look in some of these links
http://www.aircomps.co.uk/category/p.../bambi-budget/
http://www.airsupplies.co.uk/air-com...get-range.html