Electric Heaters
 

Morning All. I have a 2m X 6m UPVC conservatory with warmup under tile heating. Although this warms the floor well and takes the cold edge out of the room it isn't warm enough to keep the conservatory doors open into the house so it isn't getting much use during the winter. I would like to use a free standing heater on a timer so I can set it up to run at the same time as the central heating so the room is still part of the house (if you know what I mean). So I really would like to know which type of heater would be the cheapest to run. I have been leaning toward oil filled but I may be wrong am I ?

Electric Heaters
 

It happens that Alec formulated :
Morning All. I have a 2m X 6m UPVC conservatory with warmup under tile
heating. Although this warms the floor well and takes the cold edge out
of the room it isn't warm enough to keep the conservatory doors open
into the house so it isn't getting much use during the winter. I would
like to use a free standing heater on a timer so I can set it up to run
at the same time as the central heating so the room is still part of
the house (if you know what I mean). So I really would like to know
which type of heater would be the cheapest to run. I have been leaning
toward oil filled but I may be wrong am I ?

A 3Kw oil filled heater, or a 3kw fan heater, or a 3kw radiant heater
will all cost exactly the same amount to run.

--

Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

Electric Heaters
 

"Harry Bloomfield" wrote in message
...
It happens that Alec formulated :
Morning All. I have a 2m X 6m UPVC conservatory with warmup under tile
heating. Although this warms the floor well and takes the cold edge out
of the room it isn't warm enough to keep the conservatory doors open
into the house so it isn't getting much use during the winter. I would
like to use a free standing heater on a timer so I can set it up to run
at the same time as the central heating so the room is still part of
the house (if you know what I mean). So I really would like to know
which type of heater would be the cheapest to run. I have been leaning
toward oil filled but I may be wrong am I ?

A 3Kw oil filled heater, or a 3kw fan heater, or a 3kw radiant heater will
all cost exactly the same amount to run.

If they are energised for the same length of time

Electric Heaters
 

powerstation wrote:
"Harry Bloomfield" wrote in message
...
It happens that Alec formulated :

Morning All. I have a 2m X 6m UPVC conservatory with warmup under tile
heating. Although this warms the floor well and takes the cold edge out
of the room it isn't warm enough to keep the conservatory doors open
into the house so it isn't getting much use during the winter. I would
like to use a free standing heater on a timer so I can set it up to run
at the same time as the central heating so the room is still part of
the house (if you know what I mean). So I really would like to know
which type of heater would be the cheapest to run. I have been leaning
toward oil filled but I may be wrong am I ?

A 3Kw oil filled heater, or a 3kw fan heater, or a 3kw radiant heater will
all cost exactly the same amount to run.

If they are energised for the same length of time

But the oil heater will need to be on for longer to bring the room up
to a given temp, and will then give out that stored heat after switch
off. Oil filled heaters are also the largest and highest purchase cost
option.

If youve got space outside, an area of silvered mylar film on a frame
could get a lot of sunlight in there, and is a cheap but not that
pretty way of solar heating to extend your season.

If your conservatory is single glazed, secondary glazing could enable
you to not need the extra heating. Roller blinds loaded with plastic
film are a low cost tidy way to do this. Mylar is longer lived than
polythene.


NT

Electric Heaters
 

A 3Kw oil filled heater, or a 3kw fan heater, or a 3kw radiant heater
will
all cost exactly the same amount to run.

If they are energised for the same length of time

But the oil heater will need to be on for longer to bring the room up
to a given temp, and will then give out that stored heat after switch
off. Oil filled heaters are also the largest and highest purchase cost
option.

My point exactly, the 3kw is the input rating, not the output.

Electric Heaters
 

powerstation wrote:

A 3Kw oil filled heater, or a 3kw fan heater, or a 3kw radiant heater
will
all cost exactly the same amount to run.

If they are energised for the same length of time

But the oil heater will need to be on for longer to bring the room up
to a given temp, and will then give out that stored heat after switch
off. Oil filled heaters are also the largest and highest purchase cost
option.

My point exactly, the 3kw is the input rating, not the output.

Yup. Theyre also the bulkiest. I think their advantage is theyre safe
around kids, more so than fan heaters which can be blocked, or old
radiant heaters that can be poked. And theyre silent, but so are
convectors and (real) radiators.


NT

Electric Heaters
 

I have a 3kw oil heater made by Delonghi with a timer and an instant heat
button. I've had it for 2 years and have been pleased with it. It kicks out
a lot of heat and is fairly quick to heat up a medium size kitchen. I've
never had to have it on it's maximum setting even in the coldest of winters
and the timer is handy.
Mel.

wrote in message
oups.com...
powerstation wrote:

A 3Kw oil filled heater, or a 3kw fan heater, or a 3kw radiant
heater
will
all cost exactly the same amount to run.

If they are energised for the same length of time

But the oil heater will need to be on for longer to bring the room up
to a given temp, and will then give out that stored heat after switch
off. Oil filled heaters are also the largest and highest purchase cost
option.

My point exactly, the 3kw is the input rating, not the output.

Yup. Theyre also the bulkiest. I think their advantage is theyre safe
around kids, more so than fan heaters which can be blocked, or old
radiant heaters that can be poked. And theyre silent, but so are
convectors and (real) radiators.


NT

Electric Heaters
 

In article ,
powerstation wrote:
But the oil heater will need to be on for longer to bring the room up
to a given temp, and will then give out that stored heat after switch
off. Oil filled heaters are also the largest and highest purchase cost
option.

My point exactly, the 3kw is the input rating, not the output.

They're near enough the same thing with electric heaters.

--
*There are 3 kinds of people: those who can count & those who can't.

Dave Plowman London SW
To e-mail, change noise into sound.

Electric Heaters
 

Alec wrote:
Morning All. I have a 2m X 6m UPVC conservatory with warmup under tile
heating. Although this warms the floor well and takes the cold edge out
of the room it isn't warm enough to keep the conservatory doors open
into the house so it isn't getting much use during the winter. I would
like to use a free standing heater on a timer so I can set it up to run
at the same time as the central heating so the room is still part of
the house (if you know what I mean). So I really would like to know
which type of heater would be the cheapest to run. I have been leaning
toward oil filled but I may be wrong am I ?


--
Alec

With electric heater the energy output is exactly the same as the
energy input.

If you feed, say, 3kW in as electricity you will get exactly 3kW out in
some form of energy. Unlike oil, gas etc. there is no "wasted fuel"
going up a flue.

So, the only question is what sort of energy comes out?

Those I can think of a

1) Heat - this is good as it's what you want (and it's generally what
electricity is happiest turning into) you can assume that anything you
can't otherwise account for ends up in heat.

2) Light - Most electric heaters give out a little light, if only in
the "on" indicator. The indicator uses so little that you can ignore
that. Most give out very little light for the element (have you ever
tried to see by the light from a 2 or 3-bar fire?). Halogen heaters
give off a reasonable amount, but this probably accounts for well under
5W. Also that light doesn't stay as light, when it is absorbed by
surfaces in the room it gets converted to heat, so the only light that
is actually wasted by a heater is the amount thag escapes through
windows (quite a lot in a conservatory!)

3) Sound - a very tiny amount of energy is converted into sound, and
this can really be ignored.

4) Movement - This could be in the form of some sort of rotation of the
heater head (I've seen this on some halogen units) or movement of air
by a fan heater. But again, this energy doesn't just "vanish", it gets
converted into heat eventually (basically friction losses).

So, 3kW electricity in gives as close to 3kW heat out that there is no
point comparing.

Electric Heaters
 

In article .com,
"Sadly" writes:

With electric heater the energy output is exactly the same as the
energy input.

If you feed, say, 3kW in as electricity you will get exactly 3kW out in
some form of energy. Unlike oil, gas etc. there is no "wasted fuel"
going up a flue.

Well there is, but it happens at the power station before
the energy is delivered to you. You get under 40% of the
energy, and some ~60% goes out the top of the chinmey and
cooling towers.

--
Andrew Gabriel

Thanks for all the replies. The room is double glazed with a single skin dwarf wall. I will probably stick with an oil filled rad if it's no more or less than anything else to run.

Electric Heaters
 

On 10 Dec 2005 05:48:11 -0800, wrote:

powerstation wrote:

A 3Kw oil filled heater, or a 3kw fan heater, or a 3kw radiant heater
will
all cost exactly the same amount to run.

If they are energised for the same length of time

But the oil heater will need to be on for longer to bring the room up
to a given temp, and will then give out that stored heat after switch
off. Oil filled heaters are also the largest and highest purchase cost
option.

My point exactly, the 3kw is the input rating, not the output.

Yup. Theyre also the bulkiest. I think their advantage is theyre safe
around kids, more so than fan heaters which can be blocked, or old
radiant heaters that can be poked. And theyre silent, but so are
convectors and (real) radiators.

I am gobsmacked. If you put 3kW into a heater, apart from a few microwatts
of electrical radiation, 3KW is what you get out..


NT

Electric Heaters
 

On 10 Dec 2005 08:54:02 -0800, Sadly wrote:

Alec wrote:
Morning All. I have a 2m X 6m UPVC conservatory with warmup under tile
heating. Although this warms the floor well and takes the cold edge out
of the room it isn't warm enough to keep the conservatory doors open
into the house so it isn't getting much use during the winter. I would
like to use a free standing heater on a timer so I can set it up to run
at the same time as the central heating so the room is still part of
the house (if you know what I mean). So I really would like to know
which type of heater would be the cheapest to run. I have been leaning
toward oil filled but I may be wrong am I ?


--
Alec

With electric heater the energy output is exactly the same as the
energy input.

If you feed, say, 3kW in as electricity you will get exactly 3kW out in
some form of energy. Unlike oil, gas etc. there is no "wasted fuel"
going up a flue.

So, the only question is what sort of energy comes out?

Those I can think of a

1) Heat - this is good as it's what you want (and it's generally what
electricity is happiest turning into) you can assume that anything you
can't otherwise account for ends up in heat.

2) Light - Most electric heaters give out a little light, if only in
the "on" indicator. The indicator uses so little that you can ignore
that. Most give out very little light for the element (have you ever
tried to see by the light from a 2 or 3-bar fire?). Halogen heaters
give off a reasonable amount, but this probably accounts for well under
5W. Also that light doesn't stay as light, when it is absorbed by
surfaces in the room it gets converted to heat, so the only light that
is actually wasted by a heater is the amount thag escapes through
windows (quite a lot in a conservatory!)

3) Sound - a very tiny amount of energy is converted into sound, and
this can really be ignored.

4) Movement - This could be in the form of some sort of rotation of the
heater head (I've seen this on some halogen units) or movement of air
by a fan heater. But again, this energy doesn't just "vanish", it gets
converted into heat eventually (basically friction losses).

So, 3kW electricity in gives as close to 3kW heat out that there is no
point comparing.

You forgot te EM field radiated by the elements. Get your tinfoil hat on
now!

Probably at least as powerful as living 500 meters from an overhead power
line :-) :-)

Electric Heaters
 

Am constantly amazed by the nonsense, here and on other news groups, about
whether one type of electric heater is more 'efficient' than another!
As several posters have said if several different heaters each consume say 3
kilowatts and you switch on/plug in any one of those heaters, so that it
runs continuously for one hour, it will use (and cost you) 3 kilowatt hours
(or 3 units) of electricity.
Whether the heater turns that electricity into heat immediately and quickly
with radiant heat coils that are and 'feel' warm or takes a longer time to
slowly heat up a finned tank of oil that then slowly warms the air in a
living area is a matter of convenience, the features of the heater etc.
The various features of a heater such as a circulating fan or small
indicator light use so little electricity that all 3 kilowatt heaters can be
considered equal.
The 'effectiveness' of different types of heater may be another matter. We
use permanently wired with individual room/area thermostats, electric
baseboard heaters mounted often on the inside of the exterior insulated wall
of each room under a window. So they are self circulating air convection
heaters; no fans.
But in say our garage, we may for short term heat while working on a vehicle
in winter, use a 3.5 Kw heater with a fan to direct the warm -area to here
we are working on the vehicle etc.

Electric Heaters
 

Terry wrote:
Am constantly amazed by the nonsense, here and on other news groups, about
whether one type of electric heater is more 'efficient' than another!
As several posters have said if several different heaters each consume say 3
kilowatts and you switch on/plug in any one of those heaters, so that it
runs continuously for one hour, it will use (and cost you) 3 kilowatt hours
(or 3 units) of electricity.

Energy out vs energy in gives you 100% with radiant, convection, and
fan.

Energy out vs energy in gives you around 300% with a heat pump. If the
OP will se significant use of the heating, this would be a far better
bet.

IRL though, total energy out / total energy in isnt the relevant figure
of merit. What is more to the point is energy out when its wanted /
energy in, and in this respect oil filled rads are the worst
performers. They will also take longer to heat the room with the same
power rating. Both because of thermal storage.


NT

Electric Heaters
 

So I really would like to know which type of heater would be the
cheapest to run. I have been leaning toward oil filled but I may
be wrong am I ?

Electric heaters are effectively 100% efficient at point of use. Therefore,
all electric heaters, provided they are thermostatically controlled will
cost the same amount to run. A 2kW will cost the same as a 3kW, provided it
is able to maintain the desired temperature. A fan heater will cost the same
as a convector.

Personally, I quite convectors. These often have a boost fan if needed.
However, they're usually plenty effective enough without it. They are much
cheaper than oil filled rads and warm up much more quickly.

Oil filled rads look good and are safer, as they shouldn't cause a fire if
some muppet drapes wet clothes across them to dry.

Christian.

Electric Heaters
 

Christian McArdle wrote:

Electric heaters are effectively 100% efficient at point of use.

A common myth... OK the efficiency is close to 100%, but power lost due
to voltage drop in the wiring is often higher than people realise. The
wiring regs allow up to 4% voltage drop, so /in extremis/ 4% of the
energy you pay for may go to waste. It all depends on whether the heat
from the cable can be counted as "useful."

Example - take a 3 kW immersion heater fed via 20 m of 2.5 mm^2 cable.
Assume Uo = 240 V, to reflect reality rather than nominal values. The
resistance of the heater element will be 240^2/3000 = 19.2 ohms, and the
loop resistance of the cable is about 0.3 ohm. The same current flows
through both, so the fraction 0.3/19.2 of the metered power heats the
cable - IOW the efficiency of heating the water is 98.5% not 100%, and
about 45 watts is wasted heating the cable.

--
Andy

Electric Heaters
 

In article ,
Andy Wade wrote:
Example - take a 3 kW immersion heater fed via 20 m of 2.5 mm^2 cable.

I'd say that is unusually long. Have you been taking lessons from dribble?

--
*Microsoft broke Volkswagen's record: They only made 21.4 million bugs.

Dave Plowman London SW
To e-mail, change noise into sound.

Electric Heaters
 

Electric heaters are effectively 100% efficient at point of use.

A common myth... OK the efficiency is close to 100%, but power lost due
to voltage drop in the wiring is often higher than people realise.

The voltage drop in the wiring is not "at point of use", which is why I was
careful to state as such when mentioning 100% efficiency.

Christian.

Electric Heaters
 

Example - take a 3 kW immersion heater fed via 20 m of 2.5 mm^2 cable.

I'd say that is unusually long. Have you been taking lessons from dribble?

I doubt it is excessively long in many installations. Remember that it often
has to take a circuitous route, and perhaps go up a storey or two. Indeed, a
quick estimate on the length of my immersion heater cable is 18m.

Christian.

Electric Heaters
 

Christian McArdle wrote:

The voltage drop in the wiring is not "at point of use", which is why I was
careful to state as such when mentioning 100% efficiency.

OK - fair point, so long as it's understood that the "point of use" is
not the same as the "point of metering."

--
Andy

Electric Heaters
 

The message
from "Christian McArdle" contains
these words:

Example - take a 3 kW immersion heater fed via 20 m of 2.5 mm^2 cable.

I'd say that is unusually long. Have you been taking lessons from dribble?

I doubt it is excessively long in many installations. Remember that it often
has to take a circuitous route, and perhaps go up a storey or two. Indeed, a
quick estimate on the length of my immersion heater cable is 18m.

Ouch. Mine is no more than 22 feet at the most (plus the length of the flex).

--
Roger Chapman

Electric Heaters
 

In article ,
Christian McArdle wrote:
Example - take a 3 kW immersion heater fed via 20 m of 2.5 mm^2 cable.

I'd say that is unusually long. Have you been taking lessons from
dribble?

I doubt it is excessively long in many installations. Remember that it
often has to take a circuitous route, and perhaps go up a storey or two.
Indeed, a quick estimate on the length of my immersion heater cable is
18m.

I make mine 4 metres.

--
*Procrastinate now

Dave Plowman London SW
To e-mail, change noise into sound.