Google this and one gets many variations of the same theme. Most, if not all, are referring to upright bikes not recumbents in their calculations. My question is: Even though we do not use all the different muscles that an upright rider can, aren't we still using virtually the same amount of energy to get from point a to point b?
If you have an aerodynamic model of recumbent and ride on flat ground, you can use significantly fewer Calories. OTOH, a heavy recumbent in hills might burn more. A HRM might give you a good idea, but even that is only a calculation.
Well, I should have searched the forums before asking the question because it has been hashed over ad nauseum. Online calculators are wildly inaccurate and exist only to make riding seem quantifiable. Obviously, if one can get out every day and exercise for an hour or two or three and gradually build up speed and endurance they will feel better and be healthier. And if you take in fewer calories than you need, good things can happen.