Tankless vs Tanks
Tankless, instantaneous, on-demand hot water has never been more popular. And why shouldn’t it be? Energy efficiency is reported to be in the 80-85% range (95-99% for the condensing units), tankless heaters only heat the water when you turn a tap on, they’re almost silent running, and CO2 emissions are reduced by 900-1000 pounds per year per average household installation! Maybe it's time to replace your water heater?
HOW DOES IT WORK?
Probably the main thing to realize is that a tankless system is just that – tankless. No water storage tank at all. With a tankless system, when you turn on a hot water tap, here’s what happens: Opening the faucet allows water to flow inside pipe and through the tankless unit right to your faucet. A flow sensor within the tankless system detects this flow usually within a split second and turns on the flame, instantly heating the water to your desired temperature setting of 125-130 deg and the water flows out your faucet hot.
Tankless heaters have no time to gradually heat the water, it needs to heat the water fast, efficiently and now! This is why a typical gas tankless heater runs at a whopping 199,000 BTU. Thankfully, it only fires on demand, but when the demand is there it FIRES! If you have an 15 minute long shower, its firing for an 15 minutes long. A typical hot water tank relies on its storage (usually 40 to 50 gallons) and an extended recovery time (40 to 60 minute range).
30% of most home energy is consumed heating water and tankless water heaters are more efficient at heating water than traditional storage tank-type water heaters. Most tankless units are energy efficient within the unit themselves. I mentioned before that typical tankless units run at 80-85% efficiency and the higher end condensing units upwards to 99% energy efficiency rating. What may surprise you is some natural gas hot water tanks have energy efficiency ratings as high as 67%. Modern hot water heaters are much more efficient than they used to be.
COLD WATER SANDWICH
People investigating tankless systems or who’ve spoken with someone who owns this sort of system will invariably come across the term “cold water sandwich”. What does this mean? With a tankless system, let say your spouse just had a shower so the water lines between the shower and the tankless heater are all hot. Now its your turn for a shower, so you jump in and turn the water on. Immediately, there is hot water coming because the lines are all full of hot water, and you’re in there happily singing at the top of your lungs. But remember, some less expensive tankless systems aren’t truly “instantaneous” – and I love this part - so while the flow sensor is waiting for a ½ gallon of cold water to go through before it decides to come to life and start heating, you’ve got a ½ gallon of cold water barreling down the line toward you while your singing in the shower. “IEee!” Cold water sandwich! Kind of like putting a bucket of cold water above a partly open door.
JUST A MATTER OF TIME
A quality tankless is the smart choice, they quiet, small in size saving space, and will pay for itself in a few years and, last an average of 25-30 years depending on usage and water conditions, pre filters of various kinds are available to maintain your tankless longevity, the state of California now requires all new homes with gas have tankless water heaters installed, soon other states will follow and the traditional tank water heater we have come to know will phase out. Only a matter of time all homes in America will be tankless and in Asia and Europe only tankless have been used for over 50-years.