Paul spake thus:

On Mon, 02 Oct 2006 11:11:44 -0400, John_B wrote:
Like the OP, I would like to see some hard data comparisons between
the two types of water heaters, from a reasonably unbiased source,
like Consumer Reports.

==========================================
Tank Water Heaters
Pro: Hot water is always available when needed
Con: Heats water, even when it is not needed

On-Demand Water Heaters
Pro: Does not heat water when it is not needed
Con: May take some time to get the water hot

On-demand heaters use a big blast of flame to get the water hot, as
opposed to the on-going smaller flame of the tank water heater.

WHICH ONE IS MORE EFFICIENT ON AN ONGOING-BASIS?
==========================================

That is the question.

By the way, let me amend your list of pros and cons a little bit. After
this weekend's repair job, I can testify that demand heaters do indeed
heat water *on demand* as their name implies; it takes very little time
to get hot water out of the tap.

Another consideration because of the higher gas volume:

On-demand water heaters:
Con: may require more extensive/expensive venting than conventional heaters


And another one:
Con: Requires periodic maintenance (including possible parts replacement)

(as opposed to a tank heater which only needs to be drained periodically)


--
Save the Planet
Kill Yourself

- motto of the Church of Euthanasia (http://www.churchofeuthanasia.org/)