Good point. I think you may be right. I would have thought 40,000 would be enough for the bay area. But here's an online rough estimator that says for 2,000 sq ft, you need 58,0000 OUTPUT btu. Assuming
95% eff, he'd need 61,000 btus.Of course, this is just a rough estimate calculator, but I'd trust it more than the shyster he's dealing with. Given the more temperate climate, I'd also go with a two stage if possible so that it can fire on low most days.