We’ve been conditioned to believe that size matters. It’s a simple idea that makes sense. Sometimes, though, it’s a dangerous way to approach a subject – and the mechanical equipment in your home is an excellent example of this. As many of us will be firing up our furnace for the first time in many months, let’s use this example. We’ll stick to gas in our example.
Gas furnace capacity is measured in British Thermal Units, or BTUs. It’s very reasonable to presume that a bigger furnace will be a better furnace since more BTUs means more heating capacity. Reasonable, but incorrect. While it’s true that an 80K BTU furnace can heat a space faster than a smaller 60K one, it can short cycle– it turns off quickly because the house has reached the desired temperature. This is hard on the equipment. Imagine it like starting and stopping your car frequently versus a nice highway cruise.
Gas furnaces also have a variety of staging configurations. A single stage furnace is the least efficient; it will always use 100% of its capacity and thus the most fuel. A dual-stage furnace will start by using less gas to meet the heat demand, and only if it doesn’t reach it after a specified time will it move to full capacity. For even more efficiency and savings, variable stage or modulating furnaces are also available.
To make sure your home stays warm in the colder months, and you don’t overspend on fuel, it’s very important that you have the right size furnace for your home. So, how do you know if your equipment is the right size? A professional can perform an analysis called a heat loss and gain calculation. It considers factors like the size of your home, the construction materials and their insulative properties, etc. This process often reveals that the equipment in a home is too big or too small, which means it’s not working as efficiently or as effectively as possible. The next time you’re considering changing your home’s mechanical equipment insist that your contractor perform this process – it could save you a nice chunk of change!
