After 30 minutes you start to lose cannabinoids so leaving it for 3-4 hours would mean a lot of the cannabinoids are vaporized, hence the crazy smell in your house. Try decarboxylation for 25-35 minutes and wrap the Cannabis in foil. That way all your cannabinoids vapors stay in the foil and you don't vaporize the good stuff through heating for too long. That method almost doesn't smell at all and creates the deathly potent Edibles we desire. Finally add lecithin to your Edibles to increase absorption and removal of cannabinoids from the plant. Here is the data: