Tankless water heaters are seen as a green option that will save you money, but this may not be the case.
Over the course of the past two years, I have noticed homeowners adding more green features to their homes. I feel that the drive behind this trend is a desire to save money. Our energy bills continue to rise, and it is a natural response to find ways to reduce our costs. Moreover, going green is fashionable. Many of these green products are so new that we are not sure of the downsides or the problems we may face. A recent conversation reminded me of a report about how a tankless water heater may not save you money. Since I could not find the report, I thought I would share my discoveries here.
The main fault which seems to occur with adding green features and not obtaining the cost savings we expect seems to lie in our own perceptions. When we consider a device to be energy saving, we perceive that it can be used more, because it is not using as much energy. I wish that I had the study to reference, but my memory recalls that these researchers discovered that the average shower with a tank water heater is ten minutes. Because we feel we are using less energy, a shower with a tankless heater is averaging around twelve minutes. Those two extra minutes per person per shower is enough to wipe out any savings that you would have obtained.
Another misapprehension that we have is instantly hot water. People believe that water coming from their hot water faucet should be immediately hot. Whether the water is coming from a tank or tankless unit, it has to travel through pipes to the faucet. If the water sits in those pipes, it will cool down. Insulating pipes and pre-heating the water with a solar heater are aids, but the real solution is a recirculating hot water system. Otherwise, you have to give a chance for the hot water to reach your faucet, just like the tank version.
The one criticism for which I do not really have an argument against is the costs associated with the installation and maintenance of a tankless unit. These appliances have not been around long enough to know all of the true costs, but here is the criticism: the initial installation cost is great in comparison to a tank water heater; like any unit, it will need maintenance or repair at some time in its life; and the repair and maintenance costs can be so high that they would wipe out any savings achieved by using less energy, so total cost would be much more than a tank heater when adding everything together. This can be a reasonable argument; however a question does hang over it. What is the cost to repair and maintain the unit? It is likely that we could assume a ten year life span on the components. I base this on my experience with HVAC burner compartments (tank water heaters suffer from mineral build up in the tanks, before experiencing problems with the burner). I have not met anyone who needed to repair a tankless water heater, so I have no idea what the cost would be, but it may wipe out the money saved on energy.
When searching for an online version of the report about these units not saving you in energy costs, I found that the feedback on tankless water heaters has been mainly positive. That is great, but it does not help the consumer make an informed decision. I did find a forum, which brought up many concerns and compliments for tankless water heaters, and I think it is worth looking over, if you want to get a picture of the pros and cons of this appliance. Take the time to read it here.