[Greenbuilding] cost to run appliance--math help

[Nick Pyner]

Funny you should ask..... I think you should agree with your wife but maybe
wind down the thermostat to about 140 or so. 190 has to be really stretching
the friendship. We have a 750w 1 gallon and about thirty years ago I wound
back the thermostat from 180 and had a clock parallel with the element to
test it. The on-time was significantly reduced.

Our heater has recently been controlled by a timer through its exclusive kWh
meter. It was off during peak period and overnight. It was consuming about
1.3 kWh a day. In the last few days I have bypassed the timer. The on-time
has hardly changed. Yesterday it was 1.5 kWh.  The trouble is that the water
usage is in the peak tariff period and so one can be sure that is when the
power to recover is being consumed, so it is costing about five times as
much and the timer will be put back into commission.

Even with everything against you, your heater is unlikely to cost more than
20c/day. Not so bad with the cheap electricity you have, even if it's more
than the other appliances.

Nick Pyner

Dee Why   NSW

-----Original Message-----
From: greenbuilding-bounces at lists.bioenergylists.org
[mailto:greenbuilding-bounces at lists.bioenergylists.org]On Behalf Of
Benjamin Pratt
Sent: Tuesday, 22 November 2011 2:39 AM
To: Green Building
Subject: [Greenbuilding] cost to run appliance--math help


My house came with a small "Instant hot water dispenser" to keep 1/2
gallon of water at 190 degrees f. I've had it unplugged since day one
because i thought it was wasteful expensive to run. My wife wants to
use it this winter and asked me how much it would cost us. Good
question. Can anyone give me an estimate on how much it costs to
run--versus a kettle or a microwave? The math is difficult for me, and
i have no idea how often it would run. I suppose i could put it on a
timer to turn it off at night...

It is 115v 6.5A 750w, and has 1/2" or so expanded foam insulation but
not complete on all sides.
Our energy cost is about $0.09 kWh
thanks!!!!

Ben



On Sun, Nov 20, 2011 at 1:01 PM, Gordon Howell -- Howell-Mayhew
Engineering <ghowell at hme.ca> wrote:
> Hello Gennaro:
>
> I can appreciate your comments about the green building list being about
> green building.  My read of it was that Nick was responding to the
incorrect
> use of "kilowatts" to refer to energy -- and I agree with Nick and the
> strength of his comments re the misuse of kilowatts.  I am on a similar
rant
> against this misuse -- even with electric utilities and electricity
> regulators (imagine!).
>
> Frank Tettemer should have said "kilowatt-hours".  I am amazed at how many
> people mix up the terms "kilowatts" (of power) and "kilowatt-hours" (of
> energy) ... we don't mix up "kilometres per hour" (of speed) and
> "kilometres" (of distance) (or "miles per hour" and "miles") so why do we
> mix up energy and power?  ("power" is not electricity in the slightest...
> electricity is electric charges)
>
> Power (watts, W), speed (kilometres per hour, km/h), electric current
> (amperes, A) and frequency (hertz, Hz) are respectively merely rates of
> change in energy (joules, J), distance (kilometres, km), electric charge
> (coloumbs, C) and states (cycles of anything), but people seem to be
> commoditising power as if it is something that is bought and sold.  This
is
> getting a lot of people really confused, unfortunately, when it is instead
a
> very simple concept.
>
> The only reason why there is any issue with this is because the Sumerians
> developed the sexagecimal system over 4000 years ago
> <http://en.wikipedia.org/wiki/Sexagesimal> that gave us 60 minutes per
> hour... (thanks guys)
>
> I welcome anyones comments.
>
> +Gordon Howell, P.Eng.
> Edmonton
>
>
>
>
>> Date: Fri, 18 Nov 2011 17:57:24 -0500
>> From: Gennaro Brooks-Church - Eco Brooklyn <info at ecobrooklyn.com>
>> To: Green Building <greenbuilding at lists.bioenergylists.org>
>> Subject: Re: [Greenbuilding] Fwd: energy savings myths
>>
>> This list is about green building. not just energy. learn the
distinction.
>> its about time you did.
>>
>> Gennaro Brooks-Church
>> 347-244-3016
>>
>> On Nov 18, 2011 5:43 PM, "nick pine" <nick at early.com> wrote:
>>
>> > Gennaro Brooks-Church - Eco Brooklyn <info at ecobrooklyn.com> wrote:
>> >
>> >  After building a Passive House in NY I learned it only needed
>> > insulation
>> >> to code - R18. What made it or broke it was how well the 6mil plastic
>> >> air
>> >> barrier was sealed. Just a one inch hole in the plastic rendered the
>> >> house
>> >> unable to heat with the tiny mini-splits. Seal the hole and you can
>> >> heat
>> >> the house with a hair drier.
>> >
>> > Absolute bull****! Hogwash! Rubbish! Nitwit! Try using actual numbers!
>> >
>> > Frank Tettemer <frank at livingsol.com> wrote:
>> >
>> > Even having been experimenting and physically working on these
questions
>> > for over fourty years, it has taken most of a generation of time to cut
>> > our household's daily energy consumption to two armloads of firewood,
>> > about a dollar's worth of propane, and two to four kilowatts of
>> > electricity per day.
>> >
>> > More absolute bull****... Kilowatts are power, not energy. This list is
>> > about energy. Learn the difference between power and energy!
>> >
>> > Nick
>
>
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--


b e n j a m i n p r a t t

professor art+design
the university of wisconsin stout

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