non-venting clothes dryers

Evidently there is a type called "electric condensing" which evidently uses heat to dry, and a water condenser to cool it back down and condense moisture. These cannot possibly be very efficient

The type I was familiar with is so called "heat pump" or "dehumidifier" type. You would have to find a specific model example, and the spec from the manufacturer should be able to tell the heat output

You will NOT find that in advertising on such sites as home depot, wally world, or lowes.