To determine the size of oil-filled radiator you need, you should consider the following factors:

• Room size: Measure the length and width of the room to calculate the square footage. The larger the room, the more watts you will need to heat it effectively. As a general rule, you should aim for 22 watts per square meter in temperature zone 1. Heater Shops room calculator provides the most suitable radiator wattage for your room size and forecasts the models ability to obtain and maintain an ambient temperature of 21°C.

• Insulation: The quality of your buildings thermal insulation affects the size of radiator you need. Rooms with poorer heat retention may require a larger radiator to effectively regulate the ambient temperature. The number of windows in the room or if its an attic room can also affect the insulation quality.

• Location: The recommended size of radiator you require can vary depending on where you are in the country. For example, the UK is divided into four temperature zones, and the rule of thumb in temperature zone 1 is to add 22 W per square meter.

Based on the above factors, you can use the following as a general guide for the size of oil-filled radiator you need:

• 2500W 9 Fin – 25m2: The most powerful oil-filled radiator available, suitable for large rooms like meeting rooms, event spaces, or studio apartments.
• 2000W 7 Fin – 20m2: Suitable for medium-sized rooms.
• 1000W 11 Fin – 10m2: Suitable for small spaces like sheds or greenhouses.
• 800W 9 Fin – 8m2: Suitable for student accommodation or small bedrooms.

Remember that its better to choose a size larger than the minimum required as the operating cost is the same as for a smaller one with the same heat demand. The difference is that the larger radiator can contribute more heat during the coldest days.