How many btus to heat 2000 SF?

The answer depends some on whether the 2000 square feet is all on one level, or divided into multiple levels. Typically 75,000 btu would be sufficient to heat 2000 square feet comfortably.

Call a pro that will do a heat calc for the home. The worst thing you could do is follow

a chart that goes by sq footage. Big mistake.

You have a heat calc done, this takes everything into account in the home.

Size of walls, 2x4 or 2x6, what insulation is in the home, Windows, everything that is important.

Call several Hvac contractors and ask them what software they use, and how much for the calc, this is the right way to get the right unit for your home.