When you’re considering replacing your existing heating system, it can be difficult to determine what you need. Aside from efficiency levels and heating capacity, furnaces come in different types with regard to how the gas valve and blower motor operates. Knowing your options and understanding the difference between furnace types will help you in making your decision. Before speaking to an HVAC specialist to determine the best fit for your home, you should understand the differences between single-stage, two-stage and variable-speed furnaces.