Reznor V3 Series Model UDAP high efficiency greenhouse heaters are excellent for greenhouse heating applications. These gas-fired unit heaters are power vented in order to eliminate heat losses up the flue pipe. Power vented models have a higher initial cost than similar "gravity" vented models, but will save tons money on fuel costs. UDAP heaters are designed for 82-83% thermal efficiency. All Reznor V3 series heaters are CSA Design Certified, and have a refreshing appearance with a glossy white cabinet finish.