What size furnace for 3400 square foot house?

To determine the appropriate furnace size for a 3,400 square foot house, you typically need to consider factors like insulation, climate, and layout. A general rule of thumb is to allocate about 30 to 60 BTUs (British Thermal Units) per square foot, depending on the climate. For a well-insulated home in a moderate climate, a furnace with a capacity of around 100,000 to 150,000 BTUs would likely be suitable. However, it's best to consult with a heating professional for an accurate assessment tailored to your specific circumstances.