According to the DOE, unit heaters account for almost 18 percent of commercial space heating energy use, specifically in commercial and industrial areas like warehouses, loading docks and production areas.
The DOE’s Better Buildings Alliance commissioned a study to compare Cambridge Engineering’s SA-Series high discharge temperature heating and ventilation (HTHV) direct-fired gas heaters against standard unit heaters.
The study, “Field Demonstration of High-Efficiency Gas Heaters,” analyzed the HTHV heater, which uses 100 percent outside air, under normal use conditions at a warehouse outside of St. Louis, Mo. The field study was conducted in a 41,667-sq-foot facility and made direct comparison between four new Cambridge SA-250 HTHV direct gas-fired heaters and six existing gravity-vent unit heaters.
The DOE report demonstrated that Cambridge SA-Series HTHV ultra-high efficiency gas heaters provided a 20 percent natural gas savings compared to a conventional gas heater. In addition, by bringing in 100 percent outside air, the technology could also satisfy minimum ventilation requirements for high-performance buildings.
The report concludes that savings are achieved with Cambridge SA-Series HTHV heaters in thermal efficiency (>90% compared to 78%-82% with unit heaters), seasonal efficiency (90% compared to 63-80% with unit heaters), and reduced temperature stratification between the floor and ceiling. By installing Cambridge equipment, the warehouse achieved an estimated cost savings of $965 for an average heating season.