Recession Heating - Is New Dyson Hot The Answer?

DecentLivingWage

Thank you all so much, that was really helpful , with the recession getting worse I've decided that many peoples days of heating the whole house are numbered - so I now have my little fan heater to take over when the one hour boost goes off! I better just clarify that I'm talking about sitting rooms at the moment!

steve-L

DecentLivingWage wrote: »

Thank you all so much, that was really helpful , with the recession getting worse I've decided that many peoples days of heating the whole house are numbered - so I now have my little fan heater to take over when the one hour boost goes off! I better just clarify that I'm talking about sitting rooms at the moment!

Being serious you probably want to heat most of the other rooms to 14-15 degrees or so.....

But here a little fan heater can really help (I'm not suggesting spending £300 on a Dyson)..... but most often I find I can heat the bedroom to 14-15 degrees (by experimenting with the thermostat on the radiator) and have the lounge a comfy 19 or 20.... for the evening.... then 5 mins before bed stick on the fan heater to take the edge off.... and in the morning it comes on automatically on a timer plug just for 5 mins....

I have a kid (and his mother) at home so I actually have the heating come on mornings as well but if I didn't I'd not bother as I'd be dressed, coffee and off to work... so no point even having it heat the whole house ....

If you only heat to 14-15 degrees except one room you'll find the heating bill much lower. Kitchens heat themselves when being used....

I often stick a fan heater in the shower/loo (not while I'm in it) for 5 mins to heat it up (and then remove before using the shower for obvious safety reasons) as opposed to have the radiator on.

oldskoo1

they do make good hoovers!

err vacuums

Cardew

steve-L wrote: »

It's been said on here before but it doesn't make it true.
It may be close to 100% and certainly closer than a gas heater where a certain percent is going up your flue but they cannot be 100% ....

THE BASIC PHYSICS
1) Some of the electricity in the heating coil goes into magnetism not heat.
SLIGHTLY NON BASIC PHYSICS
2) A heating element is not A perfect black body.
I just deleted the rest as it strikes me anyone with a post grad in physics wouldn't make the statement and anyone without one has a lot of catching up and maths to learn before it can be explained.....

Try Wikipedia http://en.wikipedia.org/wiki/Black_body
A electric heating element is NOT a perfect black body.

However much more important ... a fan heater has a fan.... this takes up some energy... not much of a 2kW heater but more than 0%

(why do you think pubs use halogen heaters outside? its because they are more efficient)

.

Whilst I have enjoyed your posts and obvious knowledge of the energy industry; as was pointed out in the other thread(by graham) where you made that statement - you are quite mistaken in your theory of what constitutes 'basic physics.'

Without going into it too deeply, you need to understand the First Law of Thermodynamics, which in the simplest of explanations states that 'energy cannot be created or destroyed'

Your example of a 2kW fan heater where the fan uses some power is correct, but what you appear not to understand is whatever power is taken to run the fan is converted to heat. Thus if the fan uses 5watts or 100watts the heat output is still 2kW

Put qty 20 non-heating fans each drawing 100watts in a room and their total of 2kW will manifest itself as heat.

The relatively small amount of electricity used to turn the fan is converted to additional heat, so that efficiency is not a problem: all heaters, including fan heaters, without external ventilation are 100% efficient, meaning that all energy input goes into the room as heat.

Put qty 4 x 500watt floodlights in a room and they will produce the same 2kW heat. Similarly any magnetism will be converted to heat.

Also halogen heaters are not more 'efficient' as you state. They may be more effective in that they 'beam' heat toward an object. An analogy might be that a 40watt desk reading lamp might be more effective in illuminating a book being read, than a 100watt ceiling lamp.

So the bottom line is whatever type of electrical heater is used they are 100% efficient in converting electricity to heat.

I am not sure why you introduced the concept of a 'black body'. That essentially deals with the ability to emit energy at different frequencies.

grahamc2003

steve-L wrote: »

It's been said on here before but it doesn't make it true.
It may be close to 100% and certainly closer than a gas heater where a certain percent is going up your flue but they cannot be 100% ....

THE BASIC PHYSICS
1) Some of the electricity in the heating coil goes into magnetism not heat.
SLIGHTLY NON BASIC PHYSICS
2) A heating element is not A perfect black body.
I just deleted the rest as it strikes me anyone with a post grad in physics wouldn't make the statement and anyone without one has a lot of catching up and maths to learn before it can be explained.....

Try Wikipedia http://en.wikipedia.org/wiki/Black_body
A electric heating element is NOT a perfect black body.

However much more important ... a fan heater has a fan.... this takes up some energy... not much of a 2kW heater but more than 0%

The use of the heater means efficiency is not a simple conversion of electricity into heat anyway....
It matters HOW its used.....
Do you keep your central heating at 15 and then want to top up to 20 in a room if you arrive home early? Do you have a home office you heat sometimes or want to heat the loo ?

No point using a low power convection heater or storage heater in the loo because by the time its heated up (assuming normal bowel movements) you already flushed and left.... the convection heater will then continue to heat the empty room..... although you could drag it out with you into the living room (I suppose while it cools down?) Whereas the fan heater will have heated the room more quickly (using more kWh) but have heated the room at least while you were reading the MSE forum on your iPad/Laptop on the loo.

Fan heaters and halogen heaters are more directional than convection so you can heat you without having to equalise the whole room.... or if its not even a room (why do you think pubs use halogen heaters outside? its because they are more efficient, they cool very quickly when they are switched off..... but just try the effect of sitting in a garden 3' away from a convection heater....? Almost all of the heat will be lost...

(bolded bit) - ... but anyone with a post grad degree in physics definitely would not say anything else you said in your post. Neither would anyone with a bachelors Physics degree, and neither anyone with A level physics.

I went into great detail a few days ago when you said the same thing, and you didn't reply to my correction of your views.

You're (still) arguing against well known laws of thermodynamics which have been accepted for hundreds of years - they aren't really posters opinions, they are scientific laws.

I've no idea what black body radiators have to do with this discussion. A electric bar fire will emit some radiation and will heat some air by conduction which will then set up convection currents. The light emitted is simply radiation in the visible spectrum. Add up all the components of heat and you get exactly the amount of electricity used. Your fan heater will put some energy into accelerating some air, but when the air slows due to the air's viscosity, the kinetic energy in the air will be converted into heat. Again, add up all the components and you get .... well if it doesn't add up to 100%, then we're either creating or destroying energy.

Mind you, if I'd spent £300 on a strange shaped fan heater which substantially heats in exactly the same way as a £10 fan heater I'd probably convince myself it was doing something special (as opposed to simply looking special).

rogerblack

steve-L wrote: »

THE BASIC PHYSICS
1) Some of the electricity in the heating coil goes into magnetism not heat.
SLIGHTLY NON BASIC PHYSICS
2) A heating element is not A perfect black body.

A heater has a dimension of about 1m. 50Hz AC has a wavelength of approximately 6000km.

In order to be an efficient radiator of EM you would need the heater to be at least 300km long or so.
At 1m, it will be utterly undetectable in the 'far field'.
Not even nanowatts (one trillionth of the input power) will be radiated.

equitable

For me - rogerblack has it !

Max Planck [and the big-bang theory] gone mad in this thread, its too deep for me lads 'n lasses, for me if it absorbs all and reflects none of the radiant energy falling on it what's this heating a home debate about ?

At room temperature radiators painted white or black or red or whatever would glow, but the black would glow in the infrared so you wouldn't be able to see it anyway would you ?

Wywth

As I understand the advert for this product, James Dyson is not attempting to re-write the laws of thermodynamics. I would have hoped that posters here would recognised how clever this guy is - he's got more than a GCSE in science!

This new heater is not about producing more heat from an given amount of input energy (from what are almost 100% efficient heaters anyway) but about using the heat produced in a more efficient manner. Essentially, as I understand it, you do not have to heat the ceiling and air above you so much before you heat yourself.

Whether one can justify a £300 price tag is down to your own cost-benefit analysis, but I remember when many people used to baulk at paying £250 for a [STRIKE]hoover[/STRIKE] vacuum cleaner when Hoover were selling their own for just £50 ... and nowadays every [STRIKE]dyson[/STRIKE] vacuum cleaner manufacturer is trying to copy his original technology (which they all originally refused to even consider for their own products)

penrhyn

Miele do not produce Dyson clones and make better vacuum cleaners in the process. Replaced my messy Dyson with Miele and much prefer it.

Wywth

For anyone interested, a quick google indicates these heaters can cost less than £240 each (including delivery), and not the £300 being banded about earlier in this thread.

http://www.purewell.co.uk/dyson-hot-am04-fan-heater-ironblue-p-2324.html

I haven't done a thorough search so maybe you can find an even cheaper source?