A furnace and air conditioner is only as good as the company that installs it. Make sure that who ever is installing it is putting the right size unit in. The only problems we have had with JANITROLS are units the have been installed improperly. Don't assume that because you have a 100,000 BTU furnace now that you have to replace it with a 100,00 btu unit. The company should be do a heating and cooling load for the house to be sure you are getting the right size you need.