The size of the furnace you need depends on various factors including the square footage of your home, the climate in your area, the insulation levels of your home, and the design and layout of your house. Professionals use a calculation called Manual J Load Calculation to determine the right size of furnace your home needs. This calculation takes into account all of these factors to determine how much heating your home requires to maintain a comfortable temperature. It’s essential to get the sizing right; a furnace that is too small may not heat your home adequately, while a too-large furnace can lead to inefficiency and increased costs. Consult with a professional HVAC contractor to ensure the correct size is selected for your home.