Let’s say you are doing at least 5,000 pounds per day (250-room hotel), you will use 15,000 gallons of water each day. If you heat 70% of that, you will heat about 10,500 gallons of water each day. If your tap water temperature is roughly 60-degrees and you want your wash water temperature to be 160-degrees, then you will heat 10,500 gallons of water by 100-degrees. Heating 10,500 gallons of water will take an enormous amount of energy. An 18-wheeler tanker truck will not quite hold 9,000 gallons. That’s a lot of water to heat every day.
Heat energy is sometimes expressed in units called Btu’s or British Thermal Units. This standard unit of measure is defined as the energy required to heat one pound of water, by one degree. Water weighs 8.3452641 pounds per gallon. 10,500 gallons of water weighs 87,625 pounds. Heating that by 100-degrees will take approximately 8,762,527 Btu’s. That is an enormous amount of energy and that’s not counting any inefficiency in the boiler – and that’s only for ONE day and your typical laundry operates 365 days a year!
The energy used to heat the water usually comes from Natural Gas or electricity. Natural Gas is a Carbon-based fossil fuel that produces Greenhouse Gases (GHG’s) when burned. Electricity used will most probably be produced by coal which is also a Carbon-based fossil fuel that produces GHG’s when burned.
Natural Gas volume is usually stated in cubic feet (cf). One cubic foot of Natural Gas will produce about 1,030 Btu’s when burned. Each thousand cubic feet (MCF) of Natural Gas (1,000 ft3) burned releases about 120.593 pounds of carbon into the atmosphere.