It is as important to understand the space you're heating as it is to know the unit you are heating with. Examine your home and rooms. Remember that south-facing rooms may overheat during the day and call for extra heat in the evening. Bedrooms may be closed off or out of use during the day, but create high demand at night. While zoning will answer many of these issues, two-stage or multi-stage furnaces are the ideal solution since they can deliver high, medium or low levels of heat depending on demand, without creating excess. When designing heat zones or controlling heat through registers, excess heat must always be taken into consideration. If it is not dumped into an excess heat zone, such as a spare room, workshop, basement or garage, the heat can back up into the furnace, causing damage.
Whether you intend to install insulation yourself or hire a contractor, make sure that you know the guaranteed minimum R-value you are looking for. Have any contractor state that installed R-value as part of the bid. Also, prepare for the project by assessing what needs to be done to reduce air infiltration before installation. Include the cost of these added components and labor in your cost calculations. Keep in mind, too, that a tight home requires ventilation, so you may need to take another look at your bathroom and whole house ventilation strategies. Armed with all of this information, select the insulation that meets your energy efficiency, budgetary, and installation requirements. The end result will be a job well done, with energy and cost savings to tally long into the future.