Residential furnaces come in various sizes, furnaces needs to be correctly sized to provide efficient heating and cooling. A furnace sized too small will not deliver, or it can strain to deliver enough heating to your home, while an oversized furnace will waster energy and money. Both can lead to excessive breakdowns and premature failure.

Our field is filled with people who should know better, but who persist in using “rules of thumb” when it comes to selecting a furnace size. Sometimes they will base it only the square footage of a home, or when replacing a unit will simply select the same size as the old one.

Common sense tells us that bigger homes probably will require larger furnaces, but a lot more goes into selecting the proper size for any given amount of space. Proper size should be based on energy-loss calculations that take into account window area, the amount of insulation and other factors. This evaluation needs to be done room by room.

Energy-loss calculations need to be done when replacing a furnace. One simple reason is that the old equipment might have been improperly sized, which might well be the reason it broke down. Even if the old furnace was right for the job, replacing older unites with high-efficiency models often enables you to downsize to a unit that can do more with less and save you energy and money in the process.

Also, with any furnace installation or replacement, it’s important for the technician to check the ductwork to make sure it is appropriately sized and not plagued by leakage. Your furnace is the heart of your home’s HVAC system, while the ductwork is its arteries. You know what happen to your heart if your arteries get clogged or get diseased.

No doubt you’ve heard the old adage “you get what you pay for.” People who shop for the cheapest price when selecting an HVAC company will most likely end up with someone who cuts corners. One way to cut corners is to sue a “rule of thumb” instead of energy-loss calculation when selecting or replacing a furnace.