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Oil Filled rads


ToughButterCup

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That was going to be my question.

The only reason I can think for wanting oil filled rads is that they run at a lower temperature and can be covered over more safely i.e. wet washing.  Though I would never recommend coving radiators of any sort.

 

If you want to heat air, heat the air.

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  • 4 years later...

As a codicil to this, you need to be deeply suspicious of any power claims for these radiators.  I thought that my old rad was big and clunky so I got a couple of these Freestanding Oil-Filled Radiators at a nominal 1½ kW from Screwfix.  My intent was to control them from my HA system using power monitoring smart plugs.  No matter what power setting you choose, they only output roughly half a kilowatt.  Yes you can toggle between the ½, 1 and 1½ heater options but the heater heats the oil and cuts out when the oil is about 50°C. The oil does a convection circulation through ducts in the fins and hence the fins only heat up to about 45°C or so.  If you do the fins have a total surface area of ~1 m² at a  Δt ~ 25°C.  Radiative + convective emission is going to be ~20W/K/m² so the radiator can only output ~½ kW tops.

 

At the 1 kW setting the heater switches on a 1:1 mark:space ratio; at the 1½ kW setting the heater switches on a 1:2 mark:space ratio.  Hence the effective output is always ½ kW.

 

My old  big and clunky had external baffling and the (i) the internal fins could run a lot hotter without a surface scald risk, and (ii) this double structure ducts the air through the rad, thus improving specific emission.  Double bonus = about 1¼ kW output.  🙄

 

Edited by TerryE
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@Temp, yup it's really a design flaw / characteristic mismatch with the market labelling. One would expect a radiator marketed as 1500W is capable of heating at roughly that output.   Reading a range of review on Screwfix and Amazon, they broadly fall into one of extremes:

  • (The user only needs ½kW): wonderful little heater *****
  • (The user only needs more than ½kW): useless; doesn't heat the room *

Each only cost me £30 + another £10 for the MQTT-enabled SmartPlug with power monitoring, so I will use both at opposite ends of the landing during the coldest months so I can use my HA system to top-up the upstairs heat using off-peak electricity.

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  • 1 year later...
On 03/01/2018 at 12:04, ProDave said:

If you must have oil filled http://cpc.farnell.com/search?st=oil filled radiator But they are more expensive than convector heaters

 

I have just been searching the forum for posts on oil-filled rads, because my "big old clunky" has finally given up the ghost after 20 years, and TBH the most informative posts are my own. 🤣  I've been through a number of supplier sites and Amazon and the postings continue to be misleading quoting the electrical heating element power rather than the actual typical thermal output.  I note that the CPC technical datasheets on the site that @ProDave linked to do quote an actual thermal power O/P so 👍 for CPC. 

 

I also note that many now include some form of embedded micro control with timer and remote options.  I want a dumb heater where I can (statically) switch select the heater power that I want, and then control the timing and actual energy use through a Tasmota smartplug and my HA system.  CPC lists some nice simple models.  Simple is good as far as I am concerned.

Edited by TerryE
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For no nonsense simplicity you can't beat these available almost everywhere for about £20.  Ugly as an ugly thing but basic 3 power levels and a thermostat.  I have several used for heating the static caravan when we were in it and not used since.  *

Convector Radiator Adjustable Thermostat Carry Handles Standing Heater 2000W - Picture 1 of 5

Almost everything else seems to have over complicated electronic controls to comply with LOT20 an EU directive that for some strange reason we seem to think we still have to abide by (but lets not discuss that)

 

* not entirely true.  One is still in use controlled by my PV diverter to turn the heater on (set to it's lowest 700W power) on the rare occasions when surplus PV exceeds the 2.8kW of the immersion heater.

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1 minute ago, ProDave said:

I have several used for heating the static caravan when we were in it and not used since

Me too.

 

And oil-filled ones can make a real mess when they leak.

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