Oil radiator v electric heater 24 October 2021 at 10:12AM in LPG, heating oil, solid & other fuels 11 replies 683 views

jumpingjack75

Hi all. My daughter & I have taken over a fairly small gift shop. Its a shop frontage in a Victorian house with a cellar underneath. Over the last couple of days, with the dip in temperature, we realise we will need to have some sort of portable heater over the winter. Ideally it will need to be on a timer. We are on a tight budget so don't want our electric bill to rocket. We have very little space so can't really have anything too big. Does anyone have any experience with the oil radiators. Are they efficient & keep a good heat throughout the day or would an electric fan heater be a better option? Thank you in advance

lohr500

Someone else may come along and contradict me, but for a given kW rating, I don't think it will make much difference.
Both convert electricity to heat at the same efficiency. The fan motor in a fan heater will use a small amount of extra electricity though, reducing the overall efficiency. 

The difference is that an oil filled electric radiator will take longer to heat up than a fan heater, but once up to temperature it will radiate heat for a period of time before the thermostat kicks in to heat it back up to temperature again.

Oil filled radiators tend to give off a more "gentle" heat. As the name indicates they radiate heat. Fan heaters are more direct and instantaneous.

The problem with a shop is that if the front door keeps being open and closed an oil filled radiator may struggle to quickly bring the room back up to temperature. It may be worth investigating over door electric heaters as an option. 

danrv

jumpingjack75 said:

We are on a tight budget so don't want our electric bill to rocket. 

If there’s no other heating in the shop, it may do.
I quite like convector type electric radiators. Quicker to heat than oil filled.
Whichever type, they’ll all give the same heat relative to their power rating, but in a different way. Keeping the heat in is the main thing.
I have a few £20 convectors from Toolstation and they have 24hr timers. 

Verdigris

Radiant heating focused on the area where the worker mostly is would be most efficient. They will feel wam even if the air temperature is relatively low.

Reed_Richards

lohr500 said:

The fan motor in a fan heater will use a small amount of extra electricity though, reducing the overall efficiency. 

That's not true unless the fan blows the air out the door.  In an enclosed room the air currents created by the fan will dissipate into an increase of the Brownian motion of the air molecules in the room, making the air slightly warmer.  So you still get 100% efficiency converting electricity into heat.  

masonic

Reed_Richards said:

lohr500 said:

The fan motor in a fan heater will use a small amount of extra electricity though, reducing the overall efficiency. 

That's not true unless the fan blows the air out the door.  In an enclosed room the air currents created by the fan will dissipate into an increase of the Brownian motion of the air molecules in the room, making the air slightly warmer.  So you still get 100% efficiency converting electricity into heat.  

While the argument presented sounds logical, I'm having a hard time believing that a 50 W desk fan throws 50 W of heat into the room via kinetic energy imparted on air molecules. Suggests if I got 20 of them in a room they'd be as effective at warming it up as a 1 kW convection heater. I suppose the same is true of playing loud music?

QrizB

masonic said:

Reed_Richards said:

lohr500 said:

The fan motor in a fan heater will use a small amount of extra electricity though, reducing the overall efficiency. 

That's not true unless the fan blows the air out the door.  In an enclosed room the air currents created by the fan will dissipate into an increase of the Brownian motion of the air molecules in the room, making the air slightly warmer.  So you still get 100% efficiency converting electricity into heat.  

While the argument presented sounds logical, I'm having a hard time believing that a 50 W desk fan throws 50 W of heat into the room via kinetic energy imparted on air molecules. Suggests if I got 20 of them in a room they'd be as effective at warming it up as a 1 kW convection heater.

Yes, they would. The energy has to go somewhere.

masonic said:

I suppose the same is true of playing loud music?

Yes again, although in this case the waste heat from the amplifiers will be a contributor too. (I recall working on PA in the distant past and having to leave the amp racks powered up for 15 minutes after the end of the gig to let the cooling fans do their work.)

Cardew

masonic said:

Reed_Richards said:

lohr500 said:

The fan motor in a fan heater will use a small amount of extra electricity though, reducing the overall efficiency. 

That's not true unless the fan blows the air out the door.  In an enclosed room the air currents created by the fan will dissipate into an increase of the Brownian motion of the air molecules in the room, making the air slightly warmer.  So you still get 100% efficiency converting electricity into heat.  

While the argument presented sounds logical, I'm having a hard time believing that a 50 W desk fan throws 50 W of heat into the room via kinetic energy imparted on air molecules. Suggests if I got 20 of them in a room they'd be as effective at warming it up as a 1 kW convection heater. I suppose the same is true of playing loud music?

Not only is Reed Richards correct, but a certain Albert Einstein would have agreed with him.

He  - Einstein - not Reed Richards - proved that you cannot destroy energy. 

masonic

Thanks all, as I said, it seemed logical, but was something I'd never considered before.

lohr500

Reed_Richards said:

lohr500 said:

The fan motor in a fan heater will use a small amount of extra electricity though, reducing the overall efficiency. 

That's not true unless the fan blows the air out the door.  In an enclosed room the air currents created by the fan will dissipate into an increase of the Brownian motion of the air molecules in the room, making the air slightly warmer.  So you still get 100% efficiency converting electricity into heat.  

I stand corrected. 

Verdigris

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