Had the new high efficiency gas furnace installed 3 days ago. Just have a question about the new furnace smell. I expected a smell when the furnace was first fired up and for a day or two after, but how long should this smell normally last. It has been running consistently off and on since installed (much longer run times than old furnace and more even heat). I noticed this morning that the burning smell is very strong to the point that it is irritating me. For some reason I assumed it would go away after the first few cycles. Is this normal, and how long will this smell typically last? New furnace is much smaller than the old. Old was 100K btu 78% and new one is 60K, 96%+.