Off Grid Home Forums Technical Discussion tankless water heaters Re: tankless water heaters


There are many within the green building and energy efficient movement that are somewhat opposed to tankless water heaters. They are certainly the right choice for many situations especially for off-grid people who already have propane infrastructure.

However, many feel tankless are not the greenest choice for most situations. At least two very good studies (by Consumer Reports and University of MN) find that its not cost-effective to switch from existing tank water heater to tankless.

People who are using solar to pre-heat should be aware of the problems associated with using tankless.

Other general problems with tankless: Most dont work with low flow fixtures, Cold water sandwiches, lose supply during power outages, dependence on a non-renewable resource, a possible increase in overall energy use due to endless supply.

Yes, tankless eliminate standby losses but if they arent the newest,cutting edge models, then their pilot lights burn just as much energy as the standby losses of a tank. There are new electric tanks available that are very efficient, simple and easy to maintain, easy to add insulation too, work great with solar, and can be fueled with renewable electricity. The new Rheem Marathons fit this description while being affordable and dont have Anode rods to maintain.

All this being said, LP tankless makes the most sense for off-grid with propane infrastructure. Just be sure to get one with electronic ignition, efficient condensing technology, and of course be aware of the effects of occupant behavior.