Tankless Inline Hot Water Heaters Incompatible with Low Flow Fixtures

This post is a clarification on the development hot water heating devices and the lack of a unity of standards.

If you are thinking of getting an inline water heater, or " tankless" hot water heater, you had better do some serious research first. Do not just go in and tell your local plumber to install a unit without going through some serious calculations.

The first glitch I came across is that you need to run the water full out to activate the system. So if you have flow regulators installed on your taps and appliances you won't get any hot water. The specs on the tankless hot water heater call for a flow rate of around 1 gallon/ minute. So, to have your shower in the morning you have to turn the shower and sink on full hot and let them run until the unit turn on and the water feeds through your lines. ( Remember to do this before you run your dishwasher as well.)

During this warm up period, the tankless heater is burning 4 times the amount of gas as a regular heater. This may mean that you need to get a larger gas supply line put in. If you choose the electric version you may need to get a special high demand electric line. This means that you are using huge amounts of energy during these peak demand times.

A low flow shower head reduces the water flow to about 2 gallons per minute. The tankless water heater can only produce hot water (70F) at about 3 gpm. This means that you will most likely have your tap nearly on full hot. So remember this if there is anyone else wanting to use hot water at the same time. Notice that the ads for these units show a line up of people waiting to have a shower, NOT everyone having a shower at the same time.

So where is the saving coming from? Time. The tankless hot water heaters are supposed to have a 20 year lifespan. You would go through 3 standard tanks by that time. Also there is a saving on the energy used to heat the standard reservoir tank.

BUT! What if you just made a habit of turning the dial on your hot water tank to " vacation " when you head out the door each day? If you are really keen, you can even turn it down at night and then back up when you are making your breakfast. It only takes about 20 minutes for mine to reach full capacity. We have automatic thermostats, why not on our hot water heaters? They have them on commercial units.

In summary, if you have a steady demand for hot water, then a tankless hot water heater makes sense. This is for convenience more than ecology. The energy savings seem to be calculated during the resting periods since the inline hot water heaters use huge amounts of energy when in use. Standard tank heaters can be modified to be more economic and ecological.

So do your research and be sure to ask some hard questions when it comes time to change your hot water heater.