Replace a water heater: what to get.

[Gordon]

I may have to replace my water heater. It is a electric
tank model. It sits next to a gas furnace, so it could
be replaced with a gas model. It could also be replaced
with a tankless, on demand type.
I could also go solar as well, since I have a pretty
easy run from the roof, through an interior wall down
into the garage.

So my choices are pretty wide open:
Gas vs Electric.
Tank vs On demand.
Solar or not. (NB, solar is probably not compatible
with a tankless heater).

Any thoughts or suggestions?

 

[Bob F]

I may have to replace my water heater. It is a electric
tank model. It sits next to a gas furnace, so it could
be replaced with a gas model. It could also be replaced
with a tankless, on demand type.
I could also go solar as well, since I have a pretty
easy run from the roof, through an interior wall down
into the garage.

So my choices are pretty wide open:
Gas vs Electric.
Tank vs On demand.
Solar or not. (NB, solar is probably not compatible
with a tankless heater).

Any thoughts or suggestions?

Where I live, gas probably costs 1/2 of electric.

Is it easy to add another legal exhaust vent?

 

[vaughn]

Where I live, gas probably costs 1/2 of electric.

Is it easy to add another legal exhaust vent?

Yep...what Bob said.

I would never install an electric hot water heater if gas were a practical
alternative.

Also, gas hot water heaters usually give you quicker recovery. Talk to your
local gas company before you buy. They may have a special deal for you.

Vaughn

 

[Gordon]

Where I live, gas probably costs 1/2 of electric.

Is it easy to add another legal exhaust vent?

Easy enough.

Would you suggest tank or instant water heater?

 

[tim]

Where I live, gas probably costs 1/2 of electric.

Is it easy to add another legal exhaust vent?

Another option is the new 'heat pump' electric water heater. It
uses a heat pump mounted on the unit to pull heat from the
surrounding area to heat the water, with the standard resistance
elements to kick in if faster recovery is needed. Claims (that
seem to be pretty well substantiated) are for up to 50% savings in
operating costs. The units cost about double what a regular heater
costs, but with those savings the pay-back seems to be about four
or five years. Seems to be worth looking into.

 

[(PeteCresswell)]

Per Gordon:

Would you suggest tank or instant water heater?

I'd be interested in the answer to that question too.

Lotta years ago, all my German relatives had instant water
heaters: one at each sink.

Now they all have central heaters and I'd like to know why.

 

[vaughn]

I haven't seen the German roll-up shutters here either:
http://www.rolladen.com/

Here in south Florida, Rolladen shutters are the gold $tandard. They are so
expensive that you only see them on mansions and government buildings. I would
love to have them on my second floor windows because they can be operated from
inside the house.

Getting back to the original post, I don't think that tankless heaters have
achieved much market penetration in the US, though they seem to be more popular
in countries where energy is more expensive. Most of what they save is from
pipe losses, because they can be installed near the point of use. If you
install one centrally for the whole house, you still are left with those same
losses! If you install one for the kitchen, laundry and one in each bath, you
will pay much more than the cost of a central unit, plus you now need to run
circuits or gas plumbing to each location, plus your cost of maintenance will
skyrocket. They certainly make no sense in my house.

Vaughn

 

[(PeteCresswell)]

Per Jim Wilkins:

I haven't seen the German roll-up shutters here either:
http://www.rolladen.com/

Those things are *great* if you need to sleep during the day.

We'd roll in there jet-lagged at about 8 in the morning, crank
down the rolladen, close the door, and it would be quiet and
totally dark in the bedroom.

The German homes I've been in - those of mechanics at my late
father-in-laws truck repair shop and other skilled-but-manual
workers - were generally on the quality level of the
multi-million dollar homes I see here near Philadelphia in the
USA.

 

[Bob F]

Easy enough.

Would you suggest tank or instant water heater?

I chose a tank, as it is compatible with the recirc pumps I use to heat the hot
tub and get instant hot water at the taps.

 

[Neon John]

I've had a paloma tankless that has been running for nearly 20 years with
no problems. It's small and the newer ones are much better by now I've
heard. It's great you never run out of hot water as long as you have
fuel.

Same here. 20+ years on a Paloma. Other than a regulator diaphragm
that is excessively corroded by chlorinated water, I can't imagine
mine getting much better.

I occasionally want to take one of those long hot soaking showers that
would drain a tank heater. No problem with the Paloma.

When I use my pressure washer I hook it up to the hot water tap.
Voila! A hot water washer that will run hot as long as I want it to.

The Paloma is (AFAK), is the only tankless heater that both modulates
the heat to maintain temperature at varying flows AND does not need
electricity to operate.

As that saying goes, "They'd pry my Paloma from my cold dead hands".


John

 

[danny burstein]

The Paloma is (AFAK), is the only tankless heater that both modulates
the heat to maintain temperature at varying flows AND does not need
electricity to operate.

how does it ignite the gas? Standing pilot, or...

... or a piezo sparker that gets moved by water presssure?

(that would be nifty)

 

[Gordon]

The old paloma has a pilot light


Some of the small ones have batteries like:
http://www.sportsmansguide.com/net/cb/cb.aspx?a=667361

and some Bosch models can run without power:

http://www.boschhotwater.com/BoschHotWatercomHome/GasProducts/BoschMod el1
600H/FeaturesandSpecs/tabid/1024/Default.aspx

My neighbor has an older version of that one that's been running for 10
or so years.

I'd never get a tanked water heater myself.. the tankless kick ass

-Zachary

OP here:
Thanks for the info. Tankless would have another advantage around here;
No tank to fall over in an earthquake. If they aren't much more
expensive than a tank model, and they can run durring a power
failure, then I see no reason to not have one.

 

[(PeteCresswell)]

Per Gordon:

Would you suggest tank or instant water heater?

I know nothing, but my son-in-law-the-engineer said something
about all tank-type hot water heaters (emphasis on *all*) will
eventually have the tank corrode though and have tb replaced.

Dunno from instant heaters - i.e. maybe there is an analogous
point of failure there too.

Maybe somebody who knows something can comment.

 

[vaughn]

If they aren't much more
expensive than a tank model,

Unless things have changed since the last time I checked, they are considerably
more expensive than the tank models. Also, just for discussion, there are the
new high-efficiency electric "hybrid" heat pump models if you insist on paying
more money.

Vaughn

 

[vaughn]

Per Gordon:

I know nothing, but my son-in-law-the-engineer said something
about all tank-type hot water heaters (emphasis on *all*) will
eventually have the tank corrode though and have tb replaced.

That is true. It is also a good reason to buy a heater with a longer
warranty...because those are the ones with the thicker tanks.

Dunno from instant heaters - i.e. maybe there is an analogous
point of failure there too.

Most home appliances are designed around a life expectancy. In the absence of
better information, figure ten years for major appliiances. Nothing improves
with age (except wine & women). ;-)

Vaughn

 

[Bob F]

OP here:
Thanks for the info. Tankless would have another advantage around
here; No tank to fall over in an earthquake. If they aren't much more
expensive than a tank model, and they can run durring a power
failure, then I see no reason to not have one.

They are substantially more expensive. For a gas one, your gas piping may be a
limiting factor also. They need a LOT of gas.

 

[Bob F]

That is true. It is also a good reason to buy a heater with a longer
warranty...because those are the ones with the thicker tanks.

I don't think it's thicker tanks, it's more anodes, the way I've heard it. It
you periodically replace the anode, you should be able to keep a tank heater
going a long time.

They have problems with hard water, requiring extra maintainance to last their
best. They are generally copper, so don't rust like tanks.

 

[danny burstein]

[regarding tankless water heaters]

They are substantially more expensive. For a gas one, your gas piping may be a
limiting factor also. They need a LOT of gas.

hmmmmmm... let's say four gallons/minute getting raised
from 60F to 110F, or fifty degrees. [a]

That's about 35 pounds, times fifty -->> 1,750 BTUs/minute.

Expanding that out we get to 105,000 BTU/hr.

A gas furnace rated at 100,000 BTU is easily fed
by a 3/4 inch pipe (inside the house).

So it shouldn't be an issue.

[a] federal specs mandate a maximum of 2.5 gal/minute

http://www.energysavers.gov/your_home/water_heating/index.cfm/mytopic=13050


..

 

[daestrom]

I don't think it's thicker tanks, it's more anodes, the way I've heard it. It
you periodically replace the anode, you should be able to keep a tank heater
going a long time.


They have problems with hard water, requiring extra maintainance to last their
best. They are generally copper, so don't rust like tanks.

That's been my experience. Had a heater tank last fifteen years before
I sold the place. Some can be hard to install without a lot of overhead
clearance, but they make replacements that come in sections that you can
screw together as you lower it into the tank.

daestrom

 

[daestrom]

Easy enough.

Would you suggest tank or instant water heater?

What's the real goal?

If you want to take a really long shower without running out of water,
consider a regenerative heat-exchanger on the drain. This recovers a
lot of the heat wasted in the drain water (hot water heating costs
literally 'going down the drain').

I've had this unit for about ten years now and it recovers over half of
the energy used to heat the water. Makes running out of hot water
virtually impossible (I have a tank heater but it has a high recovery
rate and combined with this preheating the incoming water, I've never
had a shower turn cold on me).

http://gfxtechnology.com/contents.html#selection

I have the S4-60 model, but I bought it from a distributor for about
$275 instead of the 'factory direct' price (but that was 10 years ago...)


If, on the other hand, you have some other goal, what is it? Tank-less
can go for days/weeks with no standby losses (except a pilot light if so
equipped). But the up-front costs are higher.

daestrom