His problem is WELL BEYOND anything that an OAK would gain. The few posts above you tell the true problem > HEAT SINK. Floor, walls, ceiling, interior walls, doorways, windows, drafts, NO INSULATION anywhere. He says the one steam radiator heated the room better but if he has his boiler running then ALL THE REST of the radiators in the house are pumping btu's into adjacent rooms (at a huge cost, probably).Didn't I see somewhere on here that there is a single pipe which accommodates both exhaust venting and OAK, with one line running inside the other and the exhaust prewarming the combustion air for greater efficiency? IIRC, this might be a solution for you.
If he wants to save money, his only solution is a BIG coal stoker. (broken link removed to http://www.leisurelinestoves.com/files/77994427.pdf)
(broken link removed to http://keystoker.com/products.php#cfb)
He needs to get his money back and invest in something that WILL WORK! You all are just leading him down the path of no return, literally.