Every day people turn on the hot water faucet and let the cold water run until it gets hot. All of that cold water runs down the drain during the wait. An easy way to live “green” is to capture that cold water and use it to water your plants or freshen your pet's water bowl. This is a minor habitual change that will save you money and help to stretch the fresh water supply. However, there is another solution that will help you save all of that water, as well as give you more convenience.
Recirculating pumps are becoming much more common in remodels and new construction. Traditionally these units were found only on high end construction due to the added expense. However, they are gaining in popularity in arid climates, like the Southwest, due to water shortages and restrictions.
Water Efficiency
Recirculation systems provide significant benefits from a water efficiency standpoint. The main idea is that the hot water gets circulated through the entire hot side of the plumbing system. Consequently, hot water is essentially on demand. These pumps eliminate the need to run the water until it gets hot. This solution could definitely save you time and decrease your water bill.
Energy Efficiency
From an energy efficiency standpoint, the entire hot water system needs to be properly insulated to help with needless losses. A timer on the pump controller will also offset the losses when on-demand hot water is unnecessary (such as during off-hours).
Green Building
The US Green Building Council (USGBC) promotes water efficiency by granting extra points in their rating system if the hot water heater is within 20 feet of the line from the central manifold. This is a helpful strategy to reduce the waste of water, but not feasible with every floor plan. The USGBC also recognizes the importance of recirculation pumps in this section of their guidelines.
Tankless Water Heaters
Traditionally tankless water heaters would not work with recirculating pumps. If you wanted on-demand hot water with a tankless heater, you had to install individual units for each sink. Select manufacturers now offer models that work with recirculation systems. These specific units have a small tank inside that allows circulation of hot water without continuously running the burner.
