Hot Water Without Wasting Cold – Metlund D’Mand Pump
Have you ever waited for the water to get hot at your faucet and thought about how much water you’re wasting? I have a Gas Tankless Water Heater at my house but it’s located on the opposite side of the house from my Master. If I turn on the faucet in my Master Bath it takes around 1 minute and 15 seconds for the water to get hot. The current government standard flow for a faucet is 2.2 gallons per minute, so my routine to get hot water to my sink wastes 2.75 gallons every time I use hot water!
The usual solution for this problem is to install a circulation pump at your water heater. These pumps are pretty common to see in larger custom homes (>2500sf). They are set to circulate the hot water based on a timer system for the morning (maybe 5AM-9AM) and evening hot water use (6-10PM). The problem with these pumps is that you are going to waste a ton of energy continuously pumping hot water through your air conditioned house. They basically create a boiler/radiator system inside your walls for 8 hours every day! Plus, if you have a tankless water heater hooked to a continuous circulation pump you likely will cut the life expectancy of that fancy tankless in half or a third. My Rinnai tankless unit has a warranty period of 60 months or only 12 months if it’s used with a (Continuous) Circulation Pump.
Here is a better solution for getting hot water to your bathrooms that are a long way from your hot water source. Metlund D’Mand Instant Hot Water Pumps. I call these a “smart” version of a circulation pump because they have a temperature sensor that tells the pump that the water at the fixure is hot and it shuts off the pump. The warranty period on my Tankless is not affected by installing this type of pump.
I shot this video last week at a project we completed with Austin Architects Rick & Cindy Black about the Metlund system we used. -Matt Risinger Principal of Risinger Homes in Austin, TX