Do not get me wrong, tankless water heaters are the greatest thing since sliced bread! There is alot of misinformation or marketing tactics that mislead the end user of the tankless. I am here to share some of the aspects of the tankless water heater that you need to know prior to purchasing one.
1. Know the incoming water temperature at your home. The importance of this is because the tankless unit can only raise the temperature of water a certain degree with the water flowing. General rule of thumb is the colder the incoming temperature the amount of hot water produced is significantly reduced. Example: Tankless company advertises 9 gallons per minute of 120 degree water. They base that figure on an incoming water temperature of around 70 degrees F. If your incoming water temperature is, lets say, 50 degrees...it drops that gallons per minute down to around 4.5 gallons per minute. If you are discussing a tankless purchase with a plumber or box store, just ask them for a "Maximum Flow Curve". That will give you an exact figure of what hot water production you will be getting.
2. There is a little bit of a life style change involved with a tankless water heater to remain efficient on gas usage. Unless you live in the southern states where incoming water temperature is high, you are going to be restricted on how many fixtures you can run hot water through at the same time. For example, you would not be able to run a dishwasher, shower, and washing machine at the same time. Where I live in northern Washington state, my tankless will give me enough hot water for two showers at the same time but nobody better wash there hands during the shower or the flow goes down and the water gets a little CHILLY!
3. Expect that your first few gas bills may not go down and actually might rise a little. You have never had an endless amount of hot water before and it takes some getting used to. In our experience at Sullivan Plumbing, we have found that when a customer figures out that they can relax in a shower, not having to worry about running out, the showers tend to run a bit longer. (Especially for the teenagers) The energy savings calculated by the manufacturers is based on if the tankless is used the same amount as a conventional tank type unit. A tankless gets alot of its conservation from no standing pilot. This means if your running it, your cooking around 190,000 BTU of fuel compared to 50,000 BTU from a standard hot water tank.
4. Ask your supplier how readily available are repair parts for the unit you are looking at. Coming from experience, some tankless manufacturers can be a nightmare to get parts. I really do not want to bash any company here, just ask your local water heater warranty agent. Sullivan Plumbing is a warranty agent for just about every tankless and conventional tank manufacturer and there are night/ day manufacturers when it comes to warranty and parts.
If you found this post helpful or if you have a subject you would like covered, just let me know!
Thanks,
Don
