The Tankless Hot Water Myth
The Tankless Myth
We have heard this SO many times that I have to try and explain why its completely just a misunderstanding.
Here is a version of the myth “because the water is heated instantly at the unit you will always have to wait for hot water at your tap” or “you have to run the water for a minute or so to get the hot water so its not really instantly hot”.
For some reason many people seem to think that these tankless systems are able to provide hot water at the tap instantly. We have even heard people claim that tankless hot water heaters are not environmentally friendly because you have to run the water for a period of time before the hot arrives.
From this image you can you can see the flow that water takes from a tankless to a tap. The black bar represents insulation, when no one is using hot water the insulation works to keep the existing water in the pipe hot. Over time this water does get cold, by morning the pipe will contain nothing but room temperature water. When you turn the hot water tap on it has to push all the cold water out of the tap, once its gone then you can get the warm water.
From this image you can see that hot water needs to take the exact same route that hot water from the tankless must take. Therefor it has to push out all the cold water currently contained in the hot water pipe before the user will get hot water and thus there is really no difference between the two systems. Well one is much more economical and energy efficient then the other.
No one keeps there car running all night so that it hot in the morning why keep water in your house hot 24 hours/day? Tankless water heaters solve this problem, and there is practically no noticeable difference between the systems, well that’s not true there is a numerical one on your gas or electric bill.
February 9, 2013
I think the misunderstanding comes from people confusing the tiny electric-based water heaters that fit under the sink in a kitchen. These are intended as hot water for tea or other hot drinks, or enough to fill a small pot.
These are quite instant, but will not provide hot water for a shower, bath, etc.