Instant hot water systems are gaining popularity in homes across the country. The basic idea of an instant hot water system is to keep hot water lines hot all the time, so that you don’t have to wait for the cool water to run out of the line before the hot water flows. This is accomplished by installing a small pump on the hot water line of the house. The pump has a built in thermostat, and when the water in the line drops below a certain temperature (usually 85 degrees) the pump turns on and pumps the cooler water from the hot water line into the cold water line. When the hot water reaches the pump, the thermostat turns the pump off.
There are several benefits to using an instant hot water system. The obvious benefit is that you don’t have to wait for water to warm up before you wash your hands, take a shower, etc. In large houses, where the water heater can be very far from the master bathroom it can take quite some time before the water is warm enough to use. Water conservation is another benefit, since you would usually be pouring water down the drain while you wait for the water from the faucet to warm up. Since the water is pumped into the cold side of the tap rather than into the sewer, the instant hot water pump can substantially reduce water usage.
There are some energy costs involved in keeping hot water at your fingertips at all times, although the savings on water use generally outweighs these costs. The pump itself uses a small amount of electricity, but the larger factor is that your hot water heater will have to run a little more than usual to keep the water in the pipes hot. In order to limit this operational cost, many of the pumps that are used come with built in timers. The timer allows you to schedule the hours of the day you would like to have hot water instantly available, as well as the times when it is not necessary. This way you can have your hot water ready to go when you take your morning shower, but you aren’t wasting energy in the middle of the night when everyone is asleep anyway. Insulating the hot water lines throughout the house will also reduce energy costs (whether you have instant hot water or not), but this isn’t a very practical option for retrofitting existing homes.
There are several different styles of hot water recirculation systems available, but there is one that is by far the easiest for homeowners to install in an existing home. By installing the recirculation pump under the sink that is farthest from the hot water heater, you can eliminate much of the plumbing that would be involved in other systems. The Auto-Circ Pump made by Laing is a good example of this style of hot water pump. Installation of under-sink pumps can be done by just about any level of do-it-yourself homeowner.
Installation is as simple as turning off the water, disconnecting the hot and cold water lines from under the sink, attaching these lines to the pump, and then adding a second set of water lines from the pump up to the faucet. After the water lines are installed and the water is turned back on, the pump is plugged into a gfi outlet and the timer is set to the desired times for the pump to run. The whole process takes less than half an hour and requires few or no tools!
Once the pump is installed and running, all of the faucets between the water heater and the pump will be supplied with instant hot water. Some very large houses may need to have more than one pump in order to effectively provide instant hot water (there are also larger pumps that are made to handle a longer plumbing run).