Oil-filled electric heaters are safe, very quiet and able to provide high-quality single room heating; they are not designed to provide a quick heating or for extensive use.
Oil-filled heaters are among the most efficient small electric heaters. They heat like common baseboard heaters.
Oil filled heaters...
Only are efficient in small closed spaces/rooms;
are designed to heat an entire room, by heating its air;
have slow response times;
have large warranties (5-10 years);
new units have programmable timers and different temperature settings;
have prices between $50 and $100
running costs can be very high, if wrongly or used extensively.
Oil filled heaters parts
These heaters employ a heating element/resistance in a bath of oil. Their working principles are simple: the resistance heats the oil while the equipment is On, which in turn heats the surrounding air – and the room - by way of natural air movement.
Oil Electric heaters safety
Oil filled heaters do not pose the problems of unvented gas-fired heaters, or the side effects of radiant electric heating; they do not require a fresh air supply, and they provide a draft-free heating.
Since they do not use fans, they are absolutely silent. And they are also extremely safe; electric oil-filled heaters do not overheat and aren't a cause of burn injuries.
Most units have now an overheat safety cut-off function (to automatically shut off the heater).
Oil radiators are room space heaters
Like electric baseboard heaters, oil heaters are of convection type. In other words: they are designed to heat an entire room by heating the air, rather than being focused on heating the people in the room.
They work best in closed spaces, that is, in rooms that can be sealed off, by closing their doors.
Some oil-filled heaters are designed to also provide directional and spot heating; but that's not their ultimate goal, and there are better heaters (of radiant type) at doing it. Unlike small radiant heaters, they do not provide a quick heating.
Since they are designed to heat entire rooms, expect also a greater power consumption.
Advantages and disadvantages
Oil filled heaters have advantages and disadvantages over other heaters: they do not provide direct heat; they have slow response times, but they provide high quality heating and are safe and very quiet.
Oil filled electric heater timers and other features
New models have at least three power settings: low (say, 500 watts), medium (say, 1000 watts) or high (say 1500 watts, for a quicker heating).
They may have a programmable 24-hour timer thermostat; it's standard, now.
Other important features: wheels; antifreeze and frost function; overheat safety cut-off function (to automatically shut off the heater).
Best oil-filled electric heaters
The Energy Star program does not currently label space heaters and has no plans to certify them in the near future. Largely that is due to the fact that all small electric heaters have the same intrinsic energy efficiency. So, there is no non-profit public organization rating oil-filled eletric heaters.
That doesn't mean that oil-filled electric heaters are all the same.
For customer reviews: Amazon.com.
Oil Filled Electric Heater prices and running costs
Expect prices between $50-$100, and large warranties: up to 10 years. Look for models of well-established brands with extended warrranties - a sign that they trust the product they are selling.
As to the running costs, keep in mind the basics behind their use: oil filled electric heaters are not intended for extended use. They are a good option for small well sealed-insulated rooms, or to supplement other types of heating, or for moderate climates with very short periods of cold weather.