A properly designed & installed insulation method immediately reduces the need for the furnace to use more energy & results in significant savings.
You should have insulation in your walls, under your flooring, & in your attic.
You can even have insulation around your pipes. Insulation is required inside all newly manufactured moderate water heaters, too, but for a long time, water oil gas furnaces were known as one of the greatest wasters of energy – & currency! Those who wanted to save currency were encouraged to turn off their water oil gas furnaces when not home, & water furnace timers were sold all over the location, however now, though, water oil gas furnaces are not the big consumers of energy they once were. But you still need to have superb insulation, then pipes that lead to & from your water furnace should have insulation wrapped around them. Your attic should be insulated if it isn’t already, & if you do have insulation, you should check & make sure it is still in superb condition. The furnace creates a moderate environment, but heating rises, & if you don’t have superb insulation in your attic, you are going to waste that heated air the furnace made for you. Heating & cooling is often one of your greatest daily expenditures as a homeowner, & whatever you can do to decrease those costs is a superb idea. Not only are heating & cooling costs reduced, but you are also helping the environment & reducing your carbon footprint. If you are in the process of building a home, check with your builder to make sure you are able to use every opportunity to reduce your Heating & A/C use once you transfer in.