Oil filled rad or convection heater

textbook

Which is cheaper?  And how many fins on an oil rad for a lounge 4 metres x 5metres?

lohr500

Cheaper to buy, or run?

Both will cost the same to run, but if used regularly any plug in heater is an expensive form of heating.

Convection heater likely to be a little cheaper to buy as they are a simpler design. Do a Google search to get some ideas of prices.

Hard to say what sized output you need for a 4 x 5 meter room. It depends on how well insulated the property is, height of room, frequency of opening and closing doors to adjacent rooms, etc, etc.

Go for a larger 2.5kW or 3kW model with variable heat settings. Then you can adjust the power consumption to suit your needs. Almost all convection and oil filled radiators will also have a thermostat to allow you to set the room temperature.A larger model is also more flexible should you want to move it to a larger room at any point.

EssexHebridean

What’s the context for this? Is it just to top up heat where there is also a primary form of heating installed? If so, what is that primary form of heating? 

FlorayG

For running costs an oil filled will be marginally cheaper to run because it still gives off heat after it's switched off - however, it also takes a while to heat up in the first place so that saving is very tiny; depends on how warm the room is when you switch it on and switch it off
Depends on do you want instant heat (convection heater) or room heating (oil filled)

vacheron

All electric convection air heaters are bound by the same laws of physics.

To heat 1KG of air by 1 degree C, you require around 1000 Joules of energy. Electrical power is measured in Watts (1 Joule per second) and total power consumption in Watt Hours.

Therefore if you have a sealed room, heating that room by, say 10 degrees, would require a certain number of Joules and therefore Watt Hours, the only difference is the way different types of heaters "feel" when heating a room, and the speed at which they can achieve it.

If you want the room to heat quickly, go for more KW, and therefore (probably) more fins. If you can tell us how quickly you would like the room to heat up, (in say degrees per hour), and the height of the room (as we need to know the volume of air to be heated) we can give a reasonably precise figure.

Reed_Richards

Provided they both have a thermostat that switches them off when the room reaches a set temperature then the running costs will be very similar.  If they draw the same amount of power then the oil-filled radiator will take a bit longer and a bit more electricity to get the room up to a particular set temperature because it has to heat its own oil as well as the room.  But when it is switched off the hot oil in the radiator will slow the rate at which the room cools down again.

DullGreyGuy

FlorayG said:

For running costs an oil filled will be marginally cheaper to run because it still gives off heat after it's switched off - however, it also takes a while to heat up in the first place so that saving is very tiny; depends on how warm the room is when you switch it on and switch it off
Depends on do you want instant heat (convection heater) or room heating (oil filled)

In principle it will cost the same because the convection heater heats up faster so is turned off earlier and the oil radiator needs to run longer to heat the room to the same temp so consumes more electricity but this is offset by the fact the oil is a thermal mass so gives out its heat longer so in the sealed room scenario both would cost the same. 

In practice it can be a little different, only going to be in the room a short time? You won't benefit from the slower discharge of heat so its cost more to heat and you waste the residual. A few hours at the end of the day in the lounge... as it closes in on bedtime you may need to turn the convection heater back on but you may just move closer to the oil filled to use the last of its residual warmth rather than putting it back on and so be cheaper. 

All electric heating is close to 100% efficient and claims that one form is cheaper than another (when warming the whole room) is snake oil. Gas heating is much more efficient than it used to be but its the massive difference in energy cost that drives the issue

FreeBear

lohr500 said: Hard to say what sized output you need for a 4 x 5 meter room. It depends on how well insulated the property is, height of room, frequency of opening and closing doors to adjacent rooms, etc, etc.

Over on another thread, a poster is currently running an experiment using a 2kW electric heater in a similar sized room. Early data suggests a 1°C rise in around 30 minutes.

Scot_39

The power will determine space long term max temps.  The type maybe initial room temp rise - but if you want true instant gratification an even cheaper fan heater might be better still for space heating- and a radiating heater better for heat the person.

So taking one brand at Argos and room space for radiator types

One brand Dimplex says their 1.5kW radiator type 18m2
Their 2kW radiator type 25m2  (oil filled ,or non oil filled rapid heat)
But another brands 2kW oil filled says 20m2.

Other stores and other brands available.

Cost wise - they overlap - but 2 kW convection start say £30, 2kW full sized radiators - from c£50 - maybe a bit less in sales as some on offer at national chains like curry's and argos sites (where those quotes for room sizes came from).

So e brands do 2.5kW radiators - fan heaters can still be 3kW, many now 2kW (3kW long term a lot of load for a 13A domestic plug and socket - so a lot backed off max powers). 

Having had the cheap c£30 convection plain box at parents house.  It did kick out a lot of heat and probably less thermostat cycling initially.  It was very light so very movable - when cold -  but always worried too light in case accidently knocked etc.  And wouldn't want to leave one unattended.

It also gathered dust if not covered so stank as it burned off wire hesting element at base  on initial use. 

Same with a fan heater - wouldn't leave unattended.

I went for an oil filled radiator.  2.1 kW full sized 9 fin if count end one. It does take a couple of minutes to warm - but it's really not that sluggish - but they do tend to reach temp and thermostat cycle which might slow initial room temp rise.

I like their bulk but others might struggle say if tried to move up down stairs - my sister has a bad knee and needs to use thr banister handrail - and it's a 2 hand job.  So I went and bought here another for upstairs last time her gch was out for few days. 

And mines has a timer which I have set to off peak 3x per day here and in past left on when away from home as frost protection rather than my more powerful lr nsh even on min etc.

And you get non oil filled by e.g. Dimplex these days that look similar to oil filled rads without the oil inertia delay.

 

bob2302

The problem with convectors is that they produce a plume of warm air like a mushroom cloud. You end up getting what's left over after heating the ceiling and walls. Radiators can be a bit better by producing more radiant heat which can heat you directly, if you are close to it. If you can stand the noise, fan heaters do a much better job of mixing heat into the air, they are very good for quick boosts.

Personally I prefer the old fashioned bar heaters, the near infra-red is more effective than the far infra-red from radiators. The modern halogen heaters are technically better, but I find the light too glaring.

Gerry1

Plug-in electric room heating is a bad idea except for a few specific instances.

It's fine for occasional brief use e.g. in a shed or garage where there's no other form of heating available, but as each kWh is about four times as expensive as gas it doesn't make sense to use it as the main source of heating on a permanent basis.  It might be acceptable to take the chill off a bedroom when retiring and rising, assuming the room isn't used in the day and the door can be left open so that you don't get damp and mould.  However, a quick blast from a fan heater might be better.

If you can't get gas and you own the property and plan to stay a reasonable time you'd be better off with oil, storage heaters or a heat pump.  If you rent and it's all-electric with no storage heaters you might be better off moving.