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A metric prefix is a unit prefix that precedes a basic unit of measure to indicate a multiple or submultiple of the unit. All metric prefixes used today are decadic.Each prefix has a unique symbol that is prepended to any unit symbol.
Direct electric resistance tank water heaters are not included in the Energy Star program; however, the Energy Star program does include electric heat pump units with energy factors of 200% or higher. Tankless gas water heaters (as of 2015) must have an energy factor of 90% or higher for Energy Star qualification.
Condensing boilers are water heaters typically used for heating systems that are fueled by gas or oil. When operated in the correct circumstances, a heating system can achieve high efficiency (greater than 90% on the higher heating value) by condensing water vapour found in the exhaust gases in a heat exchanger to preheat the circulating water.
Most water heaters are either 40 gallons or 50 gallons, but can go as low as 10 gallons or as high as 120 gallons for commercial use. Price differences between capacity tiers range from $50 to ...
Early hot water systems were used in Ancient Rome for heating the Thermæ. [13] Another early hot water system was developed in Russia for central heating of the Summer Palace (1710–1714) of Peter the Great in Saint Petersburg. Slightly later, in 1716, came the first use of water in Sweden to distribute heating in buildings.
A young boy in Zimbabwe was rescued from a “lion-infested” national park after going missing for five days.. Tinotenda Pudu, 7, went missing from his village in the northwest of the country on ...
Kate Middleton’s return to greeting the public on Christmas Day was a poignant moment, not just for her, but for the many who had been eagerly awaiting her comeback after a difficult year.