I think the EPA adopted the B415 standards of Canada for furnace's which uses cordwood. A majority of central heaters on the market right now have firebox sizes from 6 to 8+ cuft. which make it almost impossible to pass. I think as newer technology is worked into design, firebox sizes will decrease and heat output will increase with the burning of the smoke. I'm excited to see furnace's move in this direction. Yes they will become more expensive but the benefits are worth it.