After replacing his old gas water heater with a new, pilotless, gas water heater that is rated as highly efficient, Jimmy' s gas bills increased. Each of the following, if true, contributes to an explanation of the increase mentioned above EXCEPT: ['After having done his laundry at a laundromat, Jimmy bought and started using a gas dryer when he replaced his water heater.', "Shortly after the new water heater was installed, Jimmy's uncle came to live with him, doubling the size of the household.", "The new water heater uses a smaller percentage of the gas used by Jimmy's household than did the old one.", "Jimmy's utility company raised the rates for gas consumption following installation of the new water heater."]