Water heaters of yesterday are rapidly becoming extinct as new, high-tech, high efficiency water heaters take over the marketplace. In this article we look at conventional water heater systems and the associated pros and cons.
The first water heater we will consider is the old standby, the gas fired conventional storage type water heater. Storage type water heaters are the most simple, and most conventional style. These are the tank type water heaters that we are used to seeing all across America in traditional homes.
They work by storing water in an insulated tank and heating the incoming cold water to a comfortable hot temperature and then storing that heated water for future demand. The positive side to these heaters is a relatively low installation cost and if sized correctly, they can produce a large amount of hot water flow to multiple fixtures simultaneously. The downside is that the stored hot water has high standby heat loss percentage due to the large amount of stored energy in the tank. A gas water heater combusts gas in the gas burner located underneath the storage tank and heat the water directly by flame and indirectly by hot combustion gases traveling up teh flue baffle. Here is a photo of a high efficiency energy star rated storage type, power-vent gas water heater.
Electric storage water heaters have heating elements that heat the water using electrical resistance. These water heater heaters remain popular due to their cheap cost, and very easy installation. However, their efficiency as far as environmental footprint, and financial costs of operation are among the worst! A traditional electric water heater may be cheap, but it will cost you a bundle in utility bills and these are not very green at all! There ar some more energy efficient models available with energy star ratings, and to the right is a picture of one manufactured by Rheem.
The energy factor (EF) of a water heater is based on recovery efficiency (the amount of hot water produced per unit of fuel consumed), standby losses (percentage of heat los per hour), and cycling losses. The higher the energy factor, the higher the efficiency of the heater. As discussed above conventional storage type water heaters tend to have a lower EF due to lower recovery efficiency and higher standby losses associate with storing energy. So, now in the next article, we will move on to more efficient water heating technologies with higher energy factors.