When you are in the market for a high quality unit heater at a reasonable price it is important to compare features to make sure the unit heater that you pick is truly the one you need. Always make sure you calculate the BTU required for your space with the exact measurement and specification so that you do not buy a unit that is too small or one the is too large. A unit that is too large will cost more and one that is too small will cost less but work much harder and cost you a lot more in the long run. Reznor makes both a UDAS and UDAP where the biggest difference is the fact the the UDAS models have separated combustion. One more thing I would like to draw your attention to is the Goodman Central Air Split Systems. You have to make three choices when buying one of these systems. The first being the size of you outdoor condensing unit for your cooling function, next you pick the appropriate furnace for your heating function, and lastly the evaporator coil that must match the BTU output of your condensing unit and the size of your furnace for a seamless uniform look. Anyone of our Customer Care members will be able to help you match the appropriate units to make your shopping experience a pure joy.