Laars’ Mighty Stack Volume Water Heaters are fit for apartments, restaurants, hotels, laundries, schools, businesses and large homes. Its contractor-friendly design combines the Mighty Therm 2 boiler with an 80-gallon storage tank resulting in 199, 300 and 399 MBH sizes fueled by natural or propane gas. With less than 10 ppm NOx emissions, the sealed-combustion Mighty Stack offers 83% thermal efficiency and meets low lead requirements. Key assets include its small footprint, a removable upper boiler section for easy handling, common venting and up to 50 feet of Category I or III venting. It can also be installed inside or outside.