What Size Furnace Do I Need? | Furnace BTU Sizing Guide 2025

  Choosing the right furnace size for your home in Murrieta or Temecula, CA is one of the most important steps toward keeping your home warm and energy-efficient during the colder months. At Hutchinson Heating and Air Conditioning LLC , we help homeowners make informed decisions about furnace sizing, installation, and system performance. Why Furnace Size Matters An oversized furnace can overheat your space quickly and shut off before completing a proper heating cycle, which leads to uneven heating and increased wear and tear. On the other hand, an undersized furnace will struggle to maintain temperature, run constantly, and consume more energy over time. Getting the right size means better comfort, lower energy bills, and longer equipment life. Understanding Furnace BTUs Furnace capacity is measured in BTUs (British Thermal Units), which refers to how much heat a furnace can produce in one hour. The correct BTU level depends on several home-specific factors, including: Total squar...