HEAT PUMP EFFICIENCY

I have a thought about increasing efficiency in my heat pump during the winter months in upstate PA. I am thinking of fabricating a shroud to go around the outdoor unit, made of insulated sheet metal. Ducting the shroud to the lower level of my home. My home is a split level. The idea is to use the outdoor fan to pull indoor air across the outdoor coil in heat mode. I could mix some outdoor air with the indoor air to create 40 to 45 degree temp across the coil. The heat that would be removed from the house would be recycled back in through the heat pump. I figure this would eliminate the electric auxillary from calling and eliminate the defrost cycle. I could use a contoller with an actuating damper and rtd to maintain a constant air temp acoss the outdoor coil when the temp outsiide is below freezing. Does this sound like a reasonable plan? Is there anything I need to consider or anything I am missing? Thanks for any input.