Re: [VAL] water heater - tankless

["Tom" <thomm@xxxxxxxxxxxxxxx>]

Gerald,

I'll answer you in brackets below:


> Tom, don't count on that new tankless water heater saving as much energy
> as the vendor claims. Those claims are based on the poorest of
> insulation on the tank type water heater and neglect the fact that the
> heat from the heater that leaks goes to heat the house in the winter, so
> that "wasted" heat will have to be replaced by the furnace to keep the
> house at the same temperature. And neglect the fact that your A. O.
> Smith held water hot for days without energy input.

My old A. O. Smith water heater had the best of insulation properties when 
it was built back in 1989, the outside never felt warm to the touch at all, 
no matter how could it was in the laundry room where it is installed.  My 
laundry room has floor vents for heat and a/c, the water heater never added 
or subtracted from my ambient air temperature -- and I never had one of 
those water heater jackets on it either.  I know it stayed warm for days 
(the water inside) due to the times when the power went out for days due to 
the ice storms we sometimes get.  It was and is a very well insulated water 
heater and I'd still recommend that brand today.

I think it's interesting that Consumer Reports *no longer reports about 
water heaters* because they say that they are all about "equal" in operation 
today -- electric consumption for heating so much water to such and such a 
temperature over a set amount of time.  Things do get better with age. ;)

> A major flaw in the tankless heaters, whether electric or gas is that
> they take their energy in a large lump, larger than the peak consumption
> of the tank type heater. This peak consumption can increase the size
> needed for the pole transformer and if many consumers used the tankless
> heaters, the size of the power plant required to feed the electric
> utility. And that raises the cost of that energy. Today most utilities
> work to smooth out peaks and one classical function of the storage hot
> water heater has been to heat at night with way off peak energy and then
> disable the water heater by a time clock or remote control device during
> times of peak power consumption. At times storage hot water heaters and
> in some places were given a special rate when fulfilling that peak
> reduction mode. The tankless water heater does just the opposite to the
> utility.

Granted, the tankless type has several parts that consume electricity as 
needed to heat the water in the beginning AND to keep heating the water 
until you tell it to stop by turning off the faucet.  However, the tankless 
types are not always "on" or "ready" as most of them are set to run 24/7/365 
days per year.  Most of those "little gray boxes" are hardly used today from 
what I've seen and Lowe's had the oldest models marked down from about $30 
to just $12 the other night when I was at their store.  So much for people 
buying the boxes to save energy.

My household consists of just two people and our animals.  Our animals don't 
require daily hot water like we do. ;)  With my old water heater setting on 
"go" all the time except for when we leave town is expensive, even if the 
insulation is the best around that tank.  I DO expect to save money on my 
power bill.  I WILL post the first complete month "difference" between the 
times when I had the new tankless type and when I had the old tank type.

We don't use much electricity around our home and our bills reflect it.  In 
the winter my electric bill might run $85.00 and in the heat of the summer 
it might run 'high' if it's $150.00 which is only for a few months per year. 
Most of the time during nice weather we have our windows open and the fans 
on.  The fact that our house is built from 2x6's rather than 2x4's is one of 
the main reasons for my lower than my neighbor electric bills.

I like the fact that when I need hot water it comes on, when I don't, it 
shuts off.  Also, with the hard water we have I will NO longer have problems 
in a water heater with mineral buildup which is another plus -- for me.

> And in the RV situation where the propane comes from just a pair of 30
> or 40 pound tanks, its quite possible for the peak gas demand of the
> tankless heater to be greater than the ambient heat will vaporize LP in
> the tanks, so that the tankless heater may start out good, but soon fail
> to keep up with the water flow leaving the shower getting cold. In some
> applications (like vehicles running on propane and farm corn dryers)
> liquid propane is run to a vaporizer to be able to get gas at a rapid
> enough rate without having to carry several hundred pounds of propane
> tanks. I know my standby generator running just 5 KW needs a minimum of
> a pair of 100 pound tanks to get enough gas to run in the winter. It
> doesn't have a vaporizer.
>
> Gerald J.

I believe that the propane type of tankless water heater will give you as 
much hot water as you desire until you run out of gas. ;)  I know that my 
Airstream hot water heater coming on and off to keep the tank to temperature 
IS a waste of propane.  These new tankless heaters vary the amount of gas to 
regulate the amount of flame to heat the water to a certain degree which you 
are fully able to set yourself.  The flame adjusting to the need will save 
propane I believe.

Tom

PS:  Joann, I think you WILL have all the hot water you can handle and then 
some without compromising the longevity of your system.  Your mileage may 
vary. ;)