4 Best Oil-Filled Radiator Heaters In 2024 (With ECO Thermostats)

Out of all types of space heaters, oil-filled radiator heaters are the most energy efficient. With the inclusion of the ECO thermostats, the best oil-filled space heaters can be used to heat up to 170 sq ft rooms at a minimal electricity cost (up to 70% lower running cost than regular heaters have). We are going to have a look at the list of the best oil-filled heaters currently on the market.

thermostat on an oil filled space heater
Main advantage of oil-filled heaters is that they are the cheapest to run due to smart ECO thermostats and no watts expended on the blower fan motor.

Essentially, all electric-powered space heaters transform almost 100% (90% to 98%, to be exact) of electricity into heating output (expressed in terms of BTU or British Thermal Units). Most space heaters use air blow-over heating coils to produce heated forced-air output.

Oil-filled heaters, on the other hand, will use the electric input to heat up oil inside the radiator. This gives good oil-filled radiators quite a few advantages over conventional forced-air space heaters, namely:

  • You don’t have to spend electricity to power the blower fan motor. This equates to the higher energy efficiency of oil-filled space heaters.
  • When you heat up the oil, it will retain the heat and heat up the space via convection (instead of forced-air heating). This keeps the temperature in the space more stable (fewer and less severe temperature swings).
  • ECO thermostats can adjust the heating output. While most forced-air heaters heat at full capacity 100% of the time, the best oil-filled heaters with thermostats can adjust the heating output to what you actually need and do not needlessly spend an excessive amount of electricity.
  • Due to heated oil, they can give away heat even 1 hour after you turn them off.
  • Quieter than standard air-forced heaters because they heat by convection and not by heated airflow (that can cause whooshing sounds like an AC).
  • Very important: Safety. Oil-filled radiators are considered the safest electric space heaters because they don’t have an exposed heating element and use overheat protection (all of the heaters listed below also have an ETL certificate for safety).

Of course, there are good oil-filled space heaters (energy efficient, reliable, have a silent operation, and are moderately priced) as well as bad oil-filled radiators.

Based on these qualities and specs, you can choose the best oil-filled space heater. We have done just that; further on, you will find the best oil-filled heaters from TaoTronics, RW Flame, Delonghi, and Pelonis.

First of all, however, let’s have a look at important metrics. These include the heating wattages (and BTU output), thermostats (very important) and how much does it actually cost to run an oil-filled radiator per hour, per day, per week, and per month:

Oil-Filled Radiator Wattage And Heating Output (Important: Partial Loads)

The worst space heaters are the ones that only have 1 wattage. That is a standard 1500-watt heater that only has two settings:

  • 1500-watt input producing 5118 BTU or heating output (regardless of the room temperature). This will cost $0.20 per hour to run all the time (given 1.5 kWh per hour electricity expenditure and $0.1319/kWh average electricity cost).
  • Turned off. No heating.

The oil-filled heaters have a big advantage here. In many cases, they have 3 heating modes, namely:

  • High setting: 1500-watt input producing 5118 BTU of heating output. At this high setting, it will cost $0.20 per hour to run an oil-filled radiator.
  • Medium setting: 900-watt input producing 3071 BTU of heating output. At this medium setting, it will cost $0.12 per hour to run an oil-filled radiator.
  • Low setting: 600-watt input producing 2047 BTU of heating output. At this low setting, it will cost $0.08 per hour to run an oil-filled radiator.
why oil filled space heater are inexpensive to run
3 heating modes all the best oil-filled heaters should have.

In short, the oil-filled heater can switch between $0.20/h, $0.12/h, and $0.08/h modes, depending on how much heating is needed.

That means that when the room temperature reaches let’s say 72°F, the oil-filled heater will switch from $0.20/h mode to lower $0.12/h or $0.08/h mode, or completely turn off.

The key specialty oil-filled radiators have is that they can be turned off but still provide heating. That is because the oil inside the heater is still hot and it will convert that heat indoors.

Obviously, it is important that the oil-filled radiator has a thermostat. With a thermostat, you don’t have to manually switch between 1500-watt, 900-watt, and 600-watt modes; a smart ECO thermostat will do that automatically for you.

This is exactly where the most energy is saved because the oil heater will only give away enough heat to maintain the 72°F temperature whereas standard heaters would just blast at 100% heating output, unnecessarily increasing the electricity costs.

Let’s look at which energy-saving thermostats the best oil-filled space heaters use:

Thermostats Employed By Oil-Filled Heaters

If you check different oil-filled heaters, you will see they have different names for their thermostats. This includes ‘Smart ECO thermostat’, ‘ECO thermostat’, ‘Smart thermostat’, and so on.

Regardless of the name, the key functionality you want from any of these thermostats are the following:

  1. Good enough temperature sensor to adequately and precisely measure the room temperature.
  2. Thermostat that is ‘smart’: This means it will automatically switch between different heating modes to adjust to the heating that is actually required (as measured by the temp sensor).

A good oil-filled heater with a built-in thermostat can reduce the energy consumption of an oil-filled heater by as much as 70% compared to a standard 1500-watt space heater without a thermostat.

Let’s have a look at how much does it actually cost to run an oil-filled heater:

How Much Does It Cost To Run An Oil-Filled Radiator Per Hour, Day, Week, Month?

Are oil-filled heaters expensive to run? Do oil heaters use a lot of electricity?

Well, compared to standard heaters, oil-filled heaters are the least expensive to run. They use comparatively less electricity.

We can quite easily calculate the electricity expenditure and running cost using this basic electric power equation:

Heater Running Cost = (Average Wattage × Electricity Price (per kWh) × Running Hours) / 1000

As you can see, the electricity price is the same for all heaters. We can also opt to run a heater for 1 hour per day, 8 hours per day, or even for 24 hours per day.

The key variable that reduced the energy expenditure is the ‘Average Wattage’.

A standard 1500-watt heater will run at 100% output all the time. Therefore it will have an average wattage of 1500 watts. Here is how much it would cost to run a standard heater per hour:

Standard 1500W Heater Running Cost = (1500W × $0.1319/kWh × 1h) / 1000 = $0.20/h

If you run it for 8 hours per day, this is a $1.60 per day running cost. That’s $11.20 per week and $48 per month.

In comparison, an energy-efficient oil-filled radiator with a thermostat will switch between 1500W, 900W, 600W, and 0W (shut off) modes. That means that the average wattage will be much lower. A realistic number would be 800 watts, for example. Here are the oil-filled heater running costs based on this reduced wattage due to smart thermostats and indirect heating (via heated oil):

Oil-Filled Heater Running Cost = (800W × $0.1319/kWh × 1h) / 1000 = $0.11/h

Such an oil-filled heater cut the running costs compared to a 1500W heater by 45%. It will cost:

  • $0.11 per hour to run (compared to $20 per hour).
  • $0.88 per day to run, given 8 heating hours per day (compared to $1.60 per day).
  • $6.16 per week to run (compared to $11.20 per week).
  • $26.40 per month to run (compared to $48 per month).

In short, given the parameters of this standard heater vs an oil-filled heater, you will save more than $20 per month by running an oil-fulled heater ($21.60/month, to be exact).

Obviously, the superior efficiency oil-filled heaters are more expensive than the standard heaters. While a standard heater can cost as little as $50, these oil-filled heaters can cost up to $200.

The key thing to remember here is that by choosing an oil-filled radiator you might be paying a higher upfront cost, but the running costs as much lower. That means that in some months (usually 1 or 2 winters), the difference in price will be covered by the electricity savings. From that point on, you are actually increasing the total savings compared to a standard heater.

With all this in mind, let’s have a look at the best oil-filled heaters with thermostats currently on the market:

Best Oil-Filled Space Heaters

Oil-Filled Heater: 1. DeLonghi TRD40615 2. R.W.Flame U5327 3. TaoTronics TT-HE005 4. Pelonis PH-14A
Photo: delonghi oil filled radiator best oil filler heater for large rooms delonghi oil filled radiator large oil filled radiator
Wattage Levels: Up To 1500 Watts 1500W / 900W / 600W 1500W / 900W / 600W 1500W / 900W / 600W
Heating Output:  Up To 5118 BTU 5118 BTU / 3071 BTU / 2047 BTU 5118 BTU / 3071 BTU / 2047 BTU 5118 BTU / 3071 BTU / 2047 BTU
Coverage: Up To 170 Sq Ft Up To 170 Sq Ft Up To 170 Sq Ft Up To 170 Sq Ft
Energy Efficiency: ECO Function Smart ECO Mode Smart Thermostat ECO Thermostat
Running Cost: Up To $0.20/Hour $0.08/h, $0.12/h, $0.20/h $0.08/h, $0.12/h, $0.20/h $0.08/h, $0.12/h, $0.20/h
Dimensions (W×D×H): 18.5×7.1×27.6 Inches 14.9×9.1×23.3 Inches 13.9×9.4×24.6 Inches 15.2×6.4×26.1 Inches
Price: $$$$ $$$$ $$$$ $$$$
Average Rating: 4.8 out of 5 stars 4.8 out of 5 stars 4.5 out of 5 stars 4.2 out of 5 stars
Availability: Check Price Check Price Check Price Check Price

1. Overall Best Oil-Filled Space Heater: DeLonghi TRD40615EBK

Premium Oil Filled Space Heater By De’Longhi_ De’Longhi TRD40615EBK
Wattage Levels: Up To 1500 Watts
Heating Output: Up To 5118 BTU
Coverage: Up To 170 Sq Ft
Energy Efficiency: ECO Function
Running Cost: Up To $0.20/Hour
Dimensions (W×D×H): 18.5×7.1×27.6 Inches
Price: $$$$
Rating: 4.5 out of 5 stars

DeLonghi enjoys the best reputation for engineering good and reliable oil-filled radiators. The best DeLonghi oil heater is the DeLonghi TRD40615EBK model which features the ECO function that can be turned on whenever you want to reduce electricity expenditure (works like a smart ECO thermostat). Due to multiple (more than 3) heating modes, it can be an extremely energy-efficient oil-filled heater.

As you can see from the wattage levels, the top wattage of DeLonghi TRD40615EBK is 1500 watts. The medium and lower wattages, however, are not listed. That means that the DeLonghi uses an advanced wattage level when the ECO function is turned on.

The fins on the DeLonghi TRD40615EBK are very thin and numerous. In comparison, the DeLonghi oil heater has up to 75% more radiant surfaces. That means that the overall temperature of the heater is lower and is thus safer to use. You don’t have any high temp places on the heater itself.

Obviously, because this is a DeLonghi heater, it will also have a higher price than comparable units that don’t have such name recognition. The DeLonghi TRD40615EBK costs about $150. This is about $50 higher price than many oil-filled heaters.

In short, the DeLonghi made a reliable and safe oil-filled heater. Due to ECO function and increased radiant surfaces, this is the best oil-filled radiator on the market. It is not surprising that it is one of the best-selling oil-filled heaters in the US and Europe:

DeLonghi TRD40615EBK Review

  • Special ECO function for electricity savings
  • Features variable heat output with more than 3 heating modes when on ECO
  • Thin fins means it has a 75% more radiant surfaces, adding to how safe it is to run
  • DeLonghi is the big brand name for oil-filled heaters
  • It is more expensive than other good oil-heaters (with a price tag of up to $150)
  • It is quite stable from left to right but it can be tipped over from the front or end if hit by strong enough force

2. Superb Energy Efficient Oil-Filled Heater: R.W.Flame U5327

Superb Energy Efficient Oil-Filled Heater_ R.W.Flame U5327
Wattage Levels: 1500W / 900W / 600W
Heating Output: 5118 BTU / 3071 BTU / 2047 BTU
Coverage: Up To 170 Sq Ft
Energy Efficiency: Smart Thermostat
Running Cost: $0.08/h, $0.12/h, $0.20/h
Dimensions (W×D×H): 13.9×9.4×24.6 Inches
Price: $$$$
Rating: 4.8 out of 5 stars

R.W.Flame U5327 uses the same basic principles that make all oil-filled heaters so energy efficient. We have the 3 heating modes along with a smart thermostat. It has a wide-wheel design that makes it very hard to flip (even if a cat or a child hits it), making it one of the safest oil-filled space heaters on the market.

With a top wattage of 1500 watts (12.5 amps on a 120V circuit), the R.W.Flame U5327 can produce up to 5118 BTU of heating output. This is enough to adequately heat up to 170 sq ft of living space with an 8 ft ceiling height, according to the heating ’30 BTU per sq ft’ rule of thumb for sizing heaters.

The energy efficiency comes with the 3 heating modes and the smart thermostat. This thermostat will only burn electricity when heating is needed. That means that the R.W.Flame U5327 will never unnecessarily waste electricity list most electric space heaters do.

Safety-wise, you get the overheat protection, along with a power indicator (to see if the heater is adequately plugged in) and the ETL certificate. The advantage R.W.Flame U5327 has over other oil-filled heaters is in its wide wheel positioning. You can see this wheel positioning in the photo above; it also has a built-in tip-over switch that will shut off the heater if the sensors tell it is sideways.

Similarly to TaoTronics, the R.W.Flame is not as well-known a brand as DeLonghi but because you are not paying for the brand, it costs a lot less (less than $100).

All in all, R.W.Flame U5327 is another example of superb energy-efficient and safe oil-filler heater that will consume much less electricity than the standard 1500-watt heaters:

R.W.Flame U5327 Review

  • High energy efficiency due to 3 heating modes + smart thermostat
  • Expectionally safe due to wide-wheel positioning
  • Will heat even after it is turned off (because the oil inside it is still hot)
  • Very affordable price because you are not paying for brand recognition
  • It’s not as well a known brand as DeLonghi or Pelonis
  • Has less heating surface area than other best oil heaters (resulting is locally higher temperature of the heater itself)

3. Energy Efficient Oil-Filled Space Heater: TaoTronics TT-HE005

Overall Best Oil-Filled Space Heater_ TaoTronics TT-HE005
Wattage Levels: 1500W / 900W / 600W
Heating Output: 5118 BTU / 3071 BTU / 2047 BTU
Coverage: Up To 170 Sq Ft
Energy Efficiency: Smart ECO Mode
Running Cost: $0.08/h, $0.12/h, $0.20/h
Dimensions (W×D×H): 14.9×9.1×23.3 Inches
Price: $$$$
Rating: 4.8 out of 5 stars

Out of all the oil-filled heaters, the TaoTronics TT-HE005 is the best one as far as safety, energy expenditure, and overall design are concerned. This is the go-to model for most homeowners.

As we have explained prior to this, the TaoTronics TT-HE005 has the standard partial load electric input with 3 heating modes (1500W, 900W, and 600W). The maximum 1500-watt heating output will be enough adequate to heat rooms with up to 170 sq ft (with 5118 BTU output)

After that, the medium 900-watt and low 600-watt heating modes kick in (as well as simply shutting it off, because it still gives away heat). These modes provide 3071 BTU and 2047 BTU, respectively.

The key part for the lowest possible electricity expenditure TaoTronics TT-HE005 has is the Smart ECO thermostat. This thermostat has a superb room temp sensor and will flip between different heating modes to provide two vital things:

  • Adequate heating with the least amount of kWh of electricity used.
  • Stable temperature (no temperature swings).

Safety features are the best as well. You have the auto shut-off function, as well as tip-over protection, and an all-important ETL certificate.

An additional factor that makes the TaoTronics TT-HE005 one of the most popular oil-filled heaters is the price. Given how good the Smart ECO thermostat is and the overall well-built heater, it is quite surprising that the price tag of such an all-encompassing heater is below $100.

All in all, the TaoTronics TT-HE005 is the one of the best oil-filled space heater on the market. It has it all – safety features, adequate 3-mode settings, Smart ECO thermostat, quite an aesthetic design – and it costs less than $100:

TaoTronics TT-HE005 Review

  • Best sensor-thermostat for adjusting the heating output
  • Smart ECO thermostat maximizes the electricity savings
  • Superb safety features: auto shut-off when overheating, tip-over protection, ETL certificate
  • A very affordable price point
  • Not appropriate for heating 300+ sq ft rooms (you would need 2 for that)
  • TaoTronics is not as well-known and established brands as DeLonghi, for example

4. Good Oil Filled Space Heater: Pelonis PH-14A

Good Oil Filled Space Heater_ Pelonis PH-14A
Wattage Levels: 1500W / 900W / 600W
Heating Output: 5118 BTU / 3071 BTU / 2047 BTU
Coverage: Up To 170 Sq Ft
Energy Efficiency: ECO Thermostat
Running Cost: $0.08/h, $0.12/h, $0.20/h
Dimensions (W×D×H): 15.2×6.4×26.1 Inches
Price: $$$$
Rating: 4.2 out of 5 stars

Pelonis PH-14A is another option if you are looking for a good best-selling oil-filled heater. It has the standard features that make oil-filled heaters so popular, like energy efficiency, safety features, and quiet operation.

We see the standard 3 heating modes with 1500W, 900W, and 600W electric inputs and 5118 BTU, 3071 BTU, and 2047 BTU heating outputs, respectively.

Some reviewers have pointed out that the ECO thermostat might be subpar, however. It only allows for 5 different temperature settings spanning from 65°F to 85°F.

With a price tag of about $100, the Pelonis PH-14A is also a viable choice if you are looking to save on utility bills by using an oil-filled heater:

Pelonis PH-14A Review

  • Standard energy-saving 3 heating modes
  • Very safe (ETL certificate, wide wheel positioning, overheat protection)
  • Still costs about $100
  • Subpar thermostats with only 5 discrete temp settings (from 65°F to 85°F)
  • Not as reliable as TaoTronic, RW Flame, or DeLonghi heaters

In short, we hope you now have a good grip on why oil-filled heaters are better than conventional space heaters. With the selection of the best oil-filled space heaters on the market from TaoTronic, RW Flame, DeLonghi, and Pelonis, we hope you will easily find a good oil-filled heater for your home.

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