The truth at last

On Mar 13, 11:29 am, "rb608" wrote:
On Mar 13, 1:44 pm, Scott Seidman wrote:

Of course,
while all this analysis is going on, you don't stop turning off the lights
in empty rooms.

As a result, my heating system needs to consume less energy, in fact
that exact same amount of energy, to heat that room (so long as the
room temp is below the thermostat setting, and ignoring the light
energy leaving through windows).

So is energy wasted? No. I'm not suggesting that light bulbs are an
efficient heat source, but BTU and KwH are measurements of the same
thing, regardless of the source or form. To be sure, there are the
relative overall efficiencies of oil, gas, or electric heat to be
considered, but an electric light bulb left on in an electrically-
heated house is a wash as far as I can see in terms of energy
conservation. Am I missing something?

Lightbulbs are inefficient heating elements. Your furnace (assuming
you
have a reasonably efficient furnace) will heat your house using a
lot less energy than the light bulb would.

Plus if the room is already hot, you'll expend more energy on
fans or air conditioning to compensate for the light bulb.

Turning off the lights is still a tiny amount of energy in the grand
scheme of things
- Ken

On Mar 13, 3:02 pm, " wrote:
Lightbulbs are inefficient heating elements.

For homes, yes; though they work quite well for incubating poultry.

Your furnace (assuming you
have a reasonably efficient furnace) will heat your house using a
lot less energy than the light bulb would.

Says you, but why? IF you wanted to heat your house with light bulbs,
why would that use more energy than a heat pump? Are the laws of
conservation of energy or heat transfer different for light bulbs vs
an oil burner? If both bring the same amount of energy into the
house, and both convert that energy into heat; how are you suggesting
it's possible that one provides more heat than the other? I'm not
saying that the light bulb contributes significant heat from a comfort
standpoint, but every KwH the bulb consumes is one KwH the furnace
doesn't need to provide. Where's the waste?

(And again, I'm ignoring the relative efficiencies of providing that
incoming power through fossil fuel or electricity.)

Plus if the room is already hot, you'll expend more energy on
fans or air conditioning to compensate for the light bulb.

I agree, that's why I added the assumption that the room was not
already hot.

Turning off the lights is still a tiny amount of energy in the grand
scheme of things

I agree, but 1 KwH is still 3413 Btu.

Joe F.

On Mar 13, 12:43 pm, "rb608" wrote:
On Mar 13, 3:02 pm, " wrote:

Lightbulbs are inefficient heating elements.

For homes, yes; though they work quite well for incubating poultry.

Your furnace (assuming you
have a reasonably efficient furnace) will heat your house using a
lot less energy than the light bulb would.

Says you, but why? IF you wanted to heat your house with light bulbs,
why would that use more energy than a heat pump? Are the laws of
conservation of energy or heat transfer different for light bulbs vs
an oil burner? If both bring the same amount of energy into the
house, and both convert that energy into heat; how are you suggesting
it's possible that one provides more heat than the other? I'm not
saying that the light bulb contributes significant heat from a comfort
standpoint, but every KwH the bulb consumes is one KwH the furnace
doesn't need to provide. Where's the waste?

You are missing the efficiency. I high efficiency furnace consumes
1000kWh of energy and turns it into 970kWh of heat. A light bulb
consumes 1000kWh of energy into 200kWh of heat (I'm making up #s).
There is always energy lost in the conversion. A light bulb gives
off a lot of it's energy as light.
- Ken

" wrote in message
You are missing the efficiency. I high efficiency furnace consumes
1000kWh of energy and turns it into 970kWh of heat. A light bulb
consumes 1000kWh of energy into 200kWh of heat (I'm making up #s).
There is always energy lost in the conversion. A light bulb gives
off a lot of it's energy as light.

I agree; but where does that light energy go? It's my contention the light
is absorbed by the furnishings & surfaces & becomes heat. That kinda
illustrates the rationale behind my question. Because that light-heat
conversion isn't obvious, it only appears wasteful; but in reality, all of
the energy entering the house has to go somewhere; it doesn't "evaporate"
with no effect. Energy enters the house via the power lines. It leaves
through heat loss through the exterior surfaces. Energy in = energy out.
Light, fossil fuels, electricity; doesn't matter. Energy is energy. Leaving
a light bulb burning is just another energy input. Anything coming in that
route has to reduce the energy demand from other sources by an equivalent
amount. Yeah, it seems wasteful; but I can't justify that with the physics.

Joe F.

"rb608" wrote in news:1173814996.907721.300450@
8g2000cwh.googlegroups.com:

IF you wanted to heat your house with light bulbs,
why would that use more energy than a heat pump?


What if you really wanted to cool your house??
--
Scott
Reverse name to reply

"Scott Seidman" wrote in message
. 1.4...
"rb608" wrote in news:1173814996.907721.300450@
8g2000cwh.googlegroups.com:

IF you wanted to heat your house with light bulbs,
why would that use more energy than a heat pump?


What if you really wanted to cool your house??

Light bulbs would be a bad choice.

Wolfgang

"Wolfgang" wrote in
:


"Scott Seidman" wrote in message
. 1.4...
"rb608" wrote in
news:1173814996.907721.300450@ 8g2000cwh.googlegroups.com:

IF you wanted to heat your house with light bulbs,
why would that use more energy than a heat pump?


What if you really wanted to cool your house??

Light bulbs would be a bad choice.

Wolfgang




I'm amazed that the remarkable culinary capabilities of the easy bake oven
have not entered into this subthread.


--
Scott
Reverse name to reply

"Scott Seidman" wrote in message
I'm amazed that the remarkable culinary capabilities of the easy bake oven
have not entered into this subthread.

Well, that omission has been remedied now. Tx. :-)

Joe F.

On Mar 13, 2:56 pm, Scott Seidman wrote:
"Wolfgang" wrote :







"Scott Seidman" wrote in message
.1.4...
"rb608" wrote in
news:1173814996.907721.300450@ 8g2000cwh.googlegroups.com:

IF you wanted to heat your house with light bulbs,
why would that use more energy than a heat pump?

What if you really wanted to cool your house??

Light bulbs would be a bad choice.

Wolfgang

I'm amazed that the remarkable culinary capabilities of the easy bake oven
have not entered into this subthread.

Well, I'm no physicist, but while kennie's analysis of energy lost as
light from a light bulb is theoretically correct (sorta.....see Joe's
comment about what happens to the light), I suspect that his numbers,
which he admits to having made up, are a gross distortion of the
truth. Incandescent bulbs are HOT!

Besides, the neglible heat loss is more than made up for by
metabolizing the cookies that come out of the overn.

Wolfgang

"Wolfgang" wrote in message
Besides, the neglible heat loss is more than made up for by
metabolizing the cookies that come out of the overn.

You betcha. That's why I don't bother with that low-calorie stuff at home,
I gotta keep the family warm. :-)

Joe F.