Date: Mon, 9 Dec 2013 16:50:27 -0800
Reply-To: Rocket J Squirrel <camping.elliott@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Rocket J Squirrel <camping.elliott@GMAIL.COM>
Subject: Re: [OT] Efficiency of electric heaters?
In-Reply-To: <BAY404-EAS322E45963C61DC680E81B76A0D30@phx.gbl>
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Thanks, Dennis, for this overview!
And thanks to all for providing their thoughts on this subject. The
short-form summary, for those of you keeping score, is that 1500 Watts
is 1500 Watts no matter how the Watts is dissipated: into blown hot air,
into infrared radiation, or into a tank of mineral oil that re-radiates
the heat into the air -- they will all pump about 5,100 btu of heat into
the room per hour.
BUT some respondees did report preferences: infrared heats hung overhead
can be aimed at yer head or set in front to keep yer knees warm, and
that feels nice; and those who use oil-filled radiators seem to like the
comforting "glow" they provide.
But the Rocket J Squirrel Award For The Most Useful Bit O' Information
came from Mr. Marc Perdue who wisely pointed out that "[...] it doesn't
matter if you're right. She's right and that's all that matters, whether
you actually are or not."
Marc is, of course, absolutely correct. Happy wife, happy life.
--
Jack "Rocket j Squirrel" Elliott
1984 Westfalia, auto trans,
Bend, Ore.
On 12/09/2013 02:37 PM, Dennis Haynes wrote:
> 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.
>>>
>>>
>>
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