Not really a repair, but our electric water heater is 17 years old,
but working OK. We are a family of three, but I think we use a lot
more hot water than an average family of three (some of us take long
baths). Our electric company will give us $250 for replacing it with
a heat pump water heater. Can you give me an estimate of the
reduction of electricity use if we do change?

"Judson McCranie" wrote in message
...
Not really a repair, but our electric water heater is 17 years old,
but working OK. We are a family of three, but I think we use a lot
more hot water than an average family of three (some of us take long
baths). Our electric company will give us $250 for replacing it with
a heat pump water heater. Can you give me an estimate of the
reduction of electricity use if we do change?

can't your electric company do this?

On Fri, 20 Jun 2014 22:24:37 -0700, "Pico Rico"
wrote:

can't your electric company do this?

I could do it if I knew approximately how much electricity my old one
is using, but I don't.

On Sat, 21 Jun 2014 01:08:33 -0400, Judson McCranie
wrote in


Not really a repair, but our electric water heater is 17 years old,
but working OK. We are a family of three, but I think we use a lot
more hot water than an average family of three (some of us take long
baths). Our electric company will give us $250 for replacing it with
a heat pump water heater. Can you give me an estimate of the
reduction of electricity use if we do change?

If you use a lot of hot water you are going to hate the HP heater. It
has a long recovery time and reverts to resistance heating when there
is a large HW demand. I estimate less than 5% reduction in
electricity use, but that is just a guess.
--
I kill-file all messages posted through Google Groups.

On 06/21/2014 01:00 AM, VinnyB wrote:
On Sat, 21 Jun 2014 01:08:33 -0400, Judson McCranie
wrote in


Not really a repair, but our electric water heater is 17 years old,
but working OK. We are a family of three, but I think we use a lot
more hot water than an average family of three (some of us take long
baths). Our electric company will give us $250 for replacing it with
a heat pump water heater. Can you give me an estimate of the
reduction of electricity use if we do change?

If you use a lot of hot water you are going to hate the HP heater. It
has a long recovery time and reverts to resistance heating when there
is a large HW demand. I estimate less than 5% reduction in
electricity use, but that is just a guess.



Additionally, your locale is important.


Viz: In the Chicago area it would be pretty useless in the Winter.

In Phoenix it would make sense.

On Sat, 21 Jun 2014 05:10:21 -0500, philo* wrote
in

On 06/21/2014 01:00 AM, VinnyB wrote:
On Sat, 21 Jun 2014 01:08:33 -0400, Judson McCranie
wrote in


Not really a repair, but our electric water heater is 17 years old,
but working OK. We are a family of three, but I think we use a lot
more hot water than an average family of three (some of us take long
baths). Our electric company will give us $250 for replacing it with
a heat pump water heater. Can you give me an estimate of the
reduction of electricity use if we do change?

If you use a lot of hot water you are going to hate the HP heater. It
has a long recovery time and reverts to resistance heating when there
is a large HW demand. I estimate less than 5% reduction in
electricity use, but that is just a guess.

Additionally, your locale is important.
Viz: In the Chicago area it would be pretty useless in the Winter.
In Phoenix it would make sense.

+1. I forgot about that.

BTW, the OP mentions $250 the utility will "give". Is that a rebate
or credit against your electric bill? Or are the giving you the WH
free plus a $250 credit?

Bottom line for me is that if they gave me the HPWH free plus a $250
credit, I still wouldn't take it.
--
I kill-file all messages posted through Google Groups.

On Fri, 20 Jun 2014 22:24:37 -0700, "Pico Rico"
wrote:

can't your electric company do this?

"Judson McCranie" wrote in message
...

I could do it if I knew approximately how much electricity my old one
is using, but I don't.

Agreed, 17-y.o. appliances are not labelled to indicate consumption.
But there now are many conservation organizations (some governmental,
some voluntary) that ought to be able to tell you how much energy
your old heater uses (per 100 gallons to 40 deg. C.): and there are
even cheap meters you can interconnect between one appliance
and the main supply.
--
Don Phillipson
Carlsbad Springs
(Ottawa, Canada)

On Saturday, June 21, 2014 8:41:22 AM UTC-4, VinnyB wrote:
On Sat, 21 Jun 2014 05:10:21 -0500, philo� wrote

in



On 06/21/2014 01:00 AM, VinnyB wrote:

On Sat, 21 Jun 2014 01:08:33 -0400, Judson McCranie

wrote in





Not really a repair, but our electric water heater is 17 years old,

but working OK. We are a family of three, but I think we use a lot

more hot water than an average family of three (some of us take long

baths). Our electric company will give us $250 for replacing it with

a heat pump water heater. Can you give me an estimate of the

reduction of electricity use if we do change?



If you use a lot of hot water you are going to hate the HP heater. It

has a long recovery time and reverts to resistance heating when there

is a large HW demand. I estimate less than 5% reduction in

electricity use, but that is just a guess.



Additionally, your locale is important.

Viz: In the Chicago area it would be pretty useless in the Winter.

In Phoenix it would make sense.



+1. I forgot about that.



BTW, the OP mentions $250 the utility will "give". Is that a rebate

or credit against your electric bill? Or are the giving you the WH

free plus a $250 credit?



Bottom line for me is that if they gave me the HPWH free plus a $250

credit, I still wouldn't take it.

--

I kill-file all messages posted through Google Groups.

I'm sure there must be resources, articles, etc on the internet
that discuss the advantages/disadvantages of a heat pump approach.
I agree with the poster that said climate is going to make a big
difference too. What works in Miami isn't going to work as well in
MN. Given the increased cost of the more complex system, I'd be
skeptical about the payback too. If they were a great idea, you'd
see them a lot. I haven't seen one here in NJ.

Also, I assume nat gas isn't available, but if it was, it would be
my first choice.

On Saturday, June 21, 2014 10:32:31 AM UTC-4, Don Phillipson wrote:
On Fri, 20 Jun 2014 22:24:37 -0700, "Pico Rico"

wrote:



can't your electric company do this?



"Judson McCranie" wrote in message

...



I could do it if I knew approximately how much electricity my old one

is using, but I don't.



Agreed, 17-y.o. appliances are not labelled to indicate consumption.

But there now are many conservation organizations (some governmental,

some voluntary) that ought to be able to tell you how much energy

your old heater uses (per 100 gallons to 40 deg. C.): and there are

even cheap meters you can interconnect between one appliance

and the main supply.

--

Don Phillipson

Carlsbad Springs

(Ottawa, Canada)

What cheap meter do you use to record the energy used by a
50 gal WH over say a week?

Judson McCranie wrote:
Not really a repair, but our electric water heater is 17 years old,
but working OK. We are a family of three, but I think we use a lot
more hot water than an average family of three (some of us take long
baths). Our electric company will give us $250 for replacing it with
a heat pump water heater. Can you give me an estimate of the
reduction of electricity use if we do change?

Don't forget that if the WH is in a heated area, it is going to make the area
cooler. If the area is heated with electricity, the total electricity used will
be higher, or your gas or oil heat will use more fuel.

They must need a condensate pump on these thing too.

On Sat, 21 Jun 2014 01:40:36 -0400, Judson McCranie
wrote:

On Fri, 20 Jun 2014 22:24:37 -0700, "Pico Rico"
wrote:

can't your electric company do this?

I could do it if I knew approximately how much electricity my old one
is using, but I don't.
Your old one uses exactly 1 btu to heat 1 lb of water 1 degree F.
Being electric you can consider it to be 100% efficient. Figure 3.4
BTU per watt. Figure 7.48 US gallons per cu ft/ and 62.6 lb per cu ft.


IF you have a 40 gallon heater and inlet temperature is 45 Deg F and
thermostat is set at 140F, you are heating 5.34 cu ft of water by 95
F degrees, so you are using 5.34X95x62.6=31757 BTUs to heat the tank -
aprox .935KwH of power if you take an hour to heat the water.

That's a rough calculation of the amount of electricity required to
heat a tank of water.

Now I know someon's going to shoot holes through my calculations -
that's a cast-in-stone and gold plated foregon conclusion.

What is important is the efficiency of the heat pump - or it's
conversion factor - there is also another name for it that I can't
remember - but basically how many watts of heat it puts out for every
watt of electricity consumed. IF it is 140% efficient, you save 40%
of the cost of heating your water. If it is 110% you save 10%. Then
you need to figure out how long that heat-pump water heater needs to
run between breakdowns in order for it to pay for itself in
electricity cost savings. I hope you are under 50.

On Saturday, June 21, 2014 8:07:46 PM UTC-4, wrote:
On Sat, 21 Jun 2014 01:40:36 -0400, Judson McCranie

wrote:



On Fri, 20 Jun 2014 22:24:37 -0700, "Pico Rico"

wrote:



can't your electric company do this?



I could do it if I knew approximately how much electricity my old one

is using, but I don't.

Your old one uses exactly 1 btu to heat 1 lb of water 1 degree F.

Being electric you can consider it to be 100% efficient. Figure 3.4

BTU per watt. Figure 7.48 US gallons per cu ft/ and 62.6 lb per cu ft.





IF you have a 40 gallon heater and inlet temperature is 45 Deg F and

thermostat is set at 140F, you are heating 5.34 cu ft of water by 95

F degrees, so you are using 5.34X95x62.6=31757 BTUs to heat the tank -

aprox .935KwH of power if you take an hour to heat the water.



..935Kwh is .935kwh whether it takes an hour or 24 hours.
And that would be a 935 watt heater running for an
hour, which a quick reality check says isn't going to heat
40 gallons by 95 degrees. You just got the decimal point wrong,
it's about 10x that.




That's a rough calculation of the amount of electricity required to

heat a tank of water.



Now I know someon's going to shoot holes through my calculations -

that's a cast-in-stone and gold plated foregon conclusion.



Glad to oblige, but your process was correct, just a math mistake.



What is important is the efficiency of the heat pump - or it's

conversion factor - there is also another name for it that I can't

remember - but basically how many watts of heat it puts out for every

watt of electricity consumed.

COP

IF it is 140% efficient, you save 40%

of the cost of heating your water. If it is 110% you save 10%. Then

you need to figure out how long that heat-pump water heater needs to

run between breakdowns in order for it to pay for itself in

electricity cost savings. I hope you are under 50.

Looks like the COP for a WH is around 2+.

http://www.greenbuildingadvisor.com/...aters-come-age

I'm actually surprised, I would have thought it would be at least 3.

So, bottom line you'd be heating for about 1/2 the cost. That assumes
that the other side of the heat pump is somewhere like an unheated basement,
where it doesn't matter if it cools it off or not.

Lowes has them for as little as $1000. Seems like it could have a
reasonable payback period, depending of course on how much you use it,
the electric rates. If they give you some big govt/utility rebate,
it might make it very attractive.

philo* posted for all of us...

And I know how to SNIP


On 06/21/2014 01:00 AM, VinnyB wrote:
On Sat, 21 Jun 2014 01:08:33 -0400, Judson McCranie
wrote in


Not really a repair, but our electric water heater is 17 years old,
but working OK. We are a family of three, but I think we use a lot
more hot water than an average family of three (some of us take long
baths). Our electric company will give us $250 for replacing it with
a heat pump water heater. Can you give me an estimate of the
reduction of electricity use if we do change?

If you use a lot of hot water you are going to hate the HP heater. It
has a long recovery time and reverts to resistance heating when there
is a large HW demand. I estimate less than 5% reduction in
electricity use, but that is just a guess.



Additionally, your locale is important.


Viz: In the Chicago area it would be pretty useless in the Winter.

In Phoenix it would make sense.

I believe the heat pump is mounted directly on top of the heater and uses
surrounding air. No outside parts.

--
Tekkie

Seems to me I heard that GE now makes those water heaters. There must be a reasonable demand for them or GE wouldn't be in the marketplace.

On 06/23/2014 07:26 PM, Tekkie® wrote:



Additionally, your locale is important.


Viz: In the Chicago area it would be pretty useless in the Winter.

In Phoenix it would make sense.

I believe the heat pump is mounted directly on top of the heater and uses
surrounding air. No outside parts.




I believe you are right.

Still...I would think they'd function better in Arizona where they are
usually installed in a hot garage...than in a Northern location where
they'd be in a cool basement.