As a heating expert with years of experience in the field, I understand the importance of selecting the right heating solution for your home. The calculation of the required heating capacity for a house or a room is a critical step in ensuring comfort and efficiency. Let's delve into the factors that influence this calculation.

Firstly, the size of the room is a primary consideration. As you've mentioned, a general rule of thumb is to allocate 80 Watts per square meter for heating. This is based on an assumption of average insulation and heat loss. For an 18m2 room, this would translate to a minimum of 1,440 Watts of heating capacity, which is why a 1.5kW heater might be chosen.

However, the actual heat requirement can vary significantly based on several other factors:


1. Insulation: The level of insulation in your house plays a pivotal role. A well-insulated house will have lower heat loss, thus requiring less heating capacity. As you've noted, in a better insulated house, the heat loss can be as low as 50 Watts per m2.


2. Climate and Location: The climate of your region, including average winter temperatures, will also affect the heating needs. Homes in colder climates will require more heating capacity.


3. Room Usage: The purpose of the room and the number of occupants can influence the heat requirement. For instance, a living room with frequent use may need more heat than a seldom-used guest room.


4. Building Materials: Different building materials have different thermal conductivities, affecting how quickly heat is lost.


5. Orientation and Window Size: Rooms with larger windows or poor exposure to sunlight may lose more heat.


6. Infiltration: The amount of outside air that enters the house, which can be influenced by drafts or poor sealing, will also affect heating needs.

Considering these factors, if your house is better insulated, the heat loss for an 18m2 room could indeed be closer to 900 Watts, suggesting a heater in the 1kW range could suffice. However, it's always prudent to consult with a heating professional who can assess your specific situation and provide a tailored recommendation.

Remember, choosing the right heating capacity not only ensures comfort but also plays a significant role in energy efficiency and cost savings. Investing in a heating system that is appropriately sized for your needs can prevent unnecessary energy waste and ensure that your home is heated effectively and economically.

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So a room that is 18m2 in size will need a heater that can provide at least 1,440 Watts of heat (18x80W).... so you would choose a 1.5kW heater. In a better insulated house, the heat loss can be down to just 50 Watts per m2, and in this case an 18m2 room size will only need 900 Watts of heat.read more >>