Date:         Mon, 9 Dec 2013 17:37:25 -0500
Reply-To:     Dennis Haynes <d23haynes57@HOTMAIL.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Dennis Haynes <d23haynes57@HOTMAIL.COM>
Subject:      Re: [OT] Efficiency of electric heaters?
In-Reply-To:  <CAJ-pOoYZTKh0z28-rkxV6-AAaTBnUH0cmLCaO8ZMeFnNmGSZmQ@mail.gmail.com>
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Depending where you live electric heat can be extremely expensive or
reasonable. Here on Long Island we pay close to $0.20/kwhr. However, with
oil near $4.00/gallon it may not be a bargain. One kwh of electric heat
produces ~3,412 Btu/hr. of heat.  100,000 Btu/hr. requires 29.31 kw/hr. If
you are paying $0.10/Kwh that 100,000 btu/hr. only costs $2.91. A gallon of
fuel oil is ~138k/btu.  So you would need .7246 gallon to produce 100,000
btu. Now consider that even if you were to get 85% efficiency you really
need .853 gallons. At $4.00/gallon that same heat in oil really costs $3.40.
Add the cost of the pumps, blowers, controls, equipment investment and
maintenance oil heat may not be a bargain. To compare natural gas heat look
at your bill. Likely you are looking at some cubic feet or therms number.
Both equate to about 100,00 btu. Gas is usually more efficient especially
with modern equipment so maybe use 90% as your efficiency factor. Buying a
new home you want gas heat. As for propane that gives about 96,000
btu/gallon. Also use 90% for your efficiency and do the math from there.

The trick of using portable electric heaters for most is the ability to keep
the whole house cooler and just heat the room(s) that need a bit extra or
only when they are occupied. As for which ones work best it does come down
to preference and intended use.

Dennis

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Dick Wong
Sent: Monday, December 9, 2013 1:01 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: [OT] Efficiency of electric heaters?

Yes, 1500W in an electric heater is 1500W.  The units is sitting inside the
room, so all the heat that is generated, whether it is blown out with the
fan, radiated into the room, heated by an inefficient fan motor or is coming
off of the overheated power cord ;-), still contributes to the room.
 If your room is drafty, poorly insulated or has a very high ceiling, the
air that is heated is short lived or floats away.  The fan units primarily
heat the air.  The radiant units primarily heat the objects (people).  The
radiator (oil) style devices do a combination of both (and can be slow to
get going).

You may feel warmer (or at least the one or two body parts) when you are in
front of the radiant heater, but as soon as you move away, it's gone.
 Since the fan units heat the air, the whole room feels warmer, but it takes
longer to heat all of that air.  A radiant heater gives you localized
heating, i.e., hot spots.

That's my story and I'm sticking to it. :-)

Stay warm in Oregon.  It's cold here in the mid-section of California too.

-Dick-
87 Vanagon Syncro (Blaze)


On Mon, Dec 9, 2013 at 9:34 AM, Larry Alofs <lalofs@gmail.com> wrote:

> The electrical energy 'consumed" by the fan also ends up as heat.
>
>
>
> On Mon, Dec 9, 2013 at 12:31 PM, Jeff Palmer <jpalmer@mymts.net> wrote:
>
> > I would say this is on topic.  Lots of us use electric heaters to
> > supplement.  Much cheaper than Propex :) My two cents from a guy
> > living in -30 weather:
> > Electricity is 100% efficient (or close) regardless of the fixture,
> > but
> it
> > may or may not be price competitive with less efficient heaters that
> > use different fuel.  I think?
> > I prefer radiant heat - much more comfortable and stable.  And
> > quiet.  I would think the nasty fan on some electric heaters must
> > consume extra
> power
> > too.  Love my oil filled unit.
> > Jeff
> > > Date: Mon, 9 Dec 2013 07:59:19 -0800
> > > From: camping.elliott@GMAIL.COM
> > > Subject: [OT] Efficiency of electric heaters?
> > > To: vanagon@GERRY.VANAGON.COM
> > >
> > > Hi all,
> > >
> > > (This is not Vanagon-related but I don't know another pool of
> > > engineers and scientists to write to, so I'm writing here for
> > > help.)
> > >
> > > It's pretty cold here in Bend, Oregon, and the house that her son
> > > is renting is colder than he'd like. It's an older house, built
> > > cheaply, and only has electric baseboard heaters -- no gas, no
fireplace.
> > >
> > > Mrs Elliott has been looking at electric heaters and asks whether
> > > some put out more heat than others. "1500 Watts is 1500 Watts,
> > > same BTUs" I
> > sez.
> > >
> > > I sez, "It doesn't matter whether the heating elements are fifteen
> > > one-hundred Watt light bulbs, or whether the heating elements are
> > > put
> in
> > > an oil bath; it doesn't matter whether they write the words `infrared'
> > > or `quartz' on the enclosure: you'll put the same heat into the room.
> > > All heaters are alike in terms of heat output.
> > >
> > > "Sure, an infrared heater can be `aimed' directly at your body,
> > > which
> is
> > > real nice; and others have blowers that can direct the heated air
> > > and stir the air to keep the colder air from pooling on the floor,
> > > but in terms of how warm the overall air in the room eventually
> > > gets, all 1500 Watt heaters are the same."
> > >
> > > That's what I sez. But she knows I'm a bit of an idiot sometimes
> > > and is tempted by expensive 1500 Watt heaters, thinking there must
> > > be a reason why they promote this quartz or that oil-filled
> > > feature. She points out that when you turn off an oil-filled
> > > heater, it still radiates heat for quite some time afterwards; I
> > > point out that the slow cooling is
> matched
> > > by slower warming.
> > >
> > > Can the engineers and scientists in the room comment on this
> > > matter? So that This Marriage Can Be Saved? If I'm wrong, I'm wrong.
> > >
> > > (Probably don't want to clutter up the list with this, please
> > > email to me directly.)
> > >
> > > --
> > > Jack "Rocket j Squirrel" Elliott
> > > 1984 Westfalia, auto trans,
> > > Bend, Ore.
> >
> >
>