| We all do it. Run water down the drain while | | | | existing home. |
| waiting for hot water. Who is going to jump into | | | | There is another class of hot water circulating |
| the shower when the water is freezing cold! Well | | | | systems that do not require a return line. These |
| no one. Is there a way to avoid running all of that | | | | systems use the cold water line as the return line. |
| water down the drain? | | | | The cold water line always connects to the inlet |
| Yes. A hot water circulating system will eliminate | | | | of the water heater, so it will always work. There |
| the need to run that water down the drain. There | | | | are a number of approaches being used for these |
| are several types of hot water circulating | | | | cold water return type hot water circulating |
| systems available, and they are fairly easy to | | | | systems. |
| understand. | | | | In some instances, for instance, where the water |
| The first type of system is the full-time circulating | | | | heater is lower than the rest of the system like in |
| system. In this type of system the hot water | | | | homes with a basement, a gravity type system |
| outlet of the water heater connects to a pipe | | | | can be used. Since hot water is less dense than |
| that runs past each fixture in the home, and then | | | | cold water, the hot water rises up from the |
| back to the water heater. A small pump circulates | | | | water heater to the fixtures and the cooled off |
| the hot water through the pipe, thus there is | | | | hot water goes down the cold water return line |
| always hot water near every fixture. Instant hot | | | | back to the heater. A connection is required |
| water! | | | | between the hot and cold water lines, and a valve |
| But there is a price to pay! This is an expensive | | | | that responds to temperatures is installed |
| system to operate, since the pump consumes | | | | between them. Without a valve, the hot and cold |
| some energy and is running constantly; you have | | | | water would always mix when you used either |
| to pay for that energy. But far greater is the | | | | one. |
| expense of heating the water. Heating water is | | | | Some systems use a pump connected between |
| very expensive, and so when you pump it | | | | the hot and cold water lines with a built in valve, |
| through a long pipe, and the pipe is losing heat | | | | and as with the full time systems, some are |
| energy to the atmosphere around it, you end up | | | | operated via a timer, some are temperature |
| spending a lot of money to heat the hot water | | | | controlled, and some use both methods. |
| piping and its immediate surroundings. | | | | Another type of system is known as a “hot |
| You can place the pump on a timer, so that | | | | water demand system”. With the demand |
| during periods that people don’t normally use | | | | type system, the user must push a button or |
| hot water, the pump is turned off. That helps, but | | | | utilize some other signal to start the pump, and |
| it is still very expensive. Some systems also | | | | then when hot water reaches the fixture, the |
| control the pump by monitoring the temperature | | | | pump shuts off. |
| of the water. The pump turns off when it | | | | The demand system is the lowest cost in terms |
| reaches a set point, and then back on when the | | | | of operating costs since it does not cause any |
| water drops to the lower set point. This reduces | | | | more heat loss than if you just used the hot |
| the energy consumption by the pump, but does | | | | water fixture without the system. It only pumps |
| little to reduce the far larger energy losses of the | | | | when you “demand” hot water. Typically |
| heat loss from the system. | | | | such systems use only $1 to $2 per year in |
| Another problem with these systems is that they | | | | electricity for running the pump. |
| require a dedicated return line from the furthest | | | | You obtain your hot water more quickly than if |
| fixture back to the water heater to function. This | | | | you ran the faucet full blast, and you don’t |
| is an expensive option when building a home, and | | | | wastefully run water down the drain. You’re |
| a far more expensive option to add on to an | | | | happy and the environment is happy! |