Atwood Hydro Flame Corp 32690 Furnace Medium 35,000 Btu 12V Tubular design residential style heat exchanger maximizes air distribution. More even air flow through the heat exchanger reduces hot and cold spots. Reduced air turbulence for a noticeably quieter operation. Increased cubic feet per minute of airflow exchanges air 10% faster, which heats the coach quicker. Weight savings affords less gas consumption and additional carrying capacity.