For a furnace, it would be nice to be able to enter in the stage 1 and stage 2 BTUs/hr and have the interface calculate the therm usage. Then you could also enter in a general utility rate and then get the runtime cost. Maybe a similar idea could be applied to heat pumps. Then some really interesting aggregate stats could be done across the community.
This is a similar request to this: Energy usage data from Emporia Energy circuit-level monitors - #2 by ramsaymike but it would rely on the user to input the data.