here's my problem-- homeowner has problem heating bottom floor,(two story home) has 50.000btu trane gas furnace. in the summer cools fine, but in the winter does'nt heat that well. homeower put plug in heater by R/A when regular heat was running --unit did fine-- here's my ? would putting a 70.000BTU 3 Ton in place of the 50.000BTU 3 Ton make up the difference needed to push the heat to satisfy the needed heat??