While central heating is the most common and efficient way to keep your home warm, it may not always be enough, especially in small spaces or in rooms that are not frequently used.
In such cases, using a space heater as a supplemental heating source can be a great option.
However, it is crucial to choose the right size of space heater for your needs.
Factors to Consider When Choosing a Space Heater
Before we dive into the process of determining the appropriate size of space heater, let’s take a look at the factors that need to be considered.
| Factors to Consider When Choosing a Space Heater | Descriptions |
|---|---|
| A. Square footage of the room | The size of the room that needs to be heated is the most important factor to consider when choosing a space heater. It determines the heating capacity required to maintain a comfortable temperature. |
| B. Height of the ceilings | Rooms with high ceilings require more heating capacity as heat rises and gets trapped at the top. Hence, the height of the ceiling needs to be considered when choosing a space heater. |
| C. Insulation of the room | The insulation of the room determines how well the heat is retained. A poorly insulated room will lose heat quickly, requiring a higher heating output to maintain a comfortable temperature. |
| D. British thermal units (BTUs) | BTUs measure the amount of heat required to raise the temperature of one pound of water by one degree Fahrenheit. The higher the BTUs, the higher the heating capacity of the space heater. |
| E. Watts per square foot | Watts per square foot is another measure of the heating capacity required to maintain a comfortable temperature. The standard calculation is 10 watts per square foot, but it can vary based on the insulation, ceiling height, and other factors. |
| F. Heating output | The heating output of the space heater determines how much heat it can generate. It is usually measured in watts or BTUs. |
| G. Type of space heater | Different types of space heaters have different heating capacities and output levels. It is important to choose the right type of space heater based on your heating needs. |
Below are the recommendations based on our experience in installing various types of heaters over the past several years.
A. Square footage of the room
| Room Size | Square Footage | BTUs Required (20 BTUs/sq.ft.) | Watts Required (10 watts/sq.ft.) |
|---|---|---|---|
| Small | 100 sq.ft. | 2000 BTUs | 1000 watts |
| Medium | 250 sq.ft. | 5000 BTUs | 2500 watts |
| Large | 500 sq.ft. | 10000 BTUs | 5000 watts |
B. Height of the ceilings
| Ceiling Height | Additional BTUs Required (25%) |
|---|---|
| Standard (8 feet) | 0 BTUs |
| High (10 feet) | 25% additional BTUs required |
| Very High (12 feet or more) | 50% or more additional BTUs required |
C. Insulation of the room
| Insulation Level | Additional Heating Output Required |
|---|---|
| Poor | 25-30% additional heating output required |
| Average | Standard heating output required |
| Good | 10-15% less heating output required |
D. British thermal units (BTUs)
| Room Size | Square Footage | BTUs Required (20 BTUs/sq.ft.) |
|---|---|---|
| Small | 100 sq.ft. | 2000 BTUs |
| Medium | 250 sq.ft. | 5000 BTUs |
| Large | 500 sq.ft. | 10000 BTUs |
E. Watts per square foot
| Room Size | Square Footage | Watts Required (10 watts/sq.ft.) |
|---|---|---|
| Small | 100 sq.ft. | 1000 watts |
| Medium | 250 sq.ft. | 2500 watts |
| Large | 500 sq.ft. | 5000 watts |
F. Heating output
| Heater Type | Heating Output |
|---|---|
| Radiant | 600-1500 watts |
| Fan-forced | 1000-1500 watts |
| Convection | 500-1500 watts |
| Oil-filled | 600-1500 watts |
G. Type of space heater
| Heater Type | Heating Capacity | Pros | Cons |
|---|---|---|---|
| Ceramic | Up to 1500 watts | Quick heating, energy efficient, quiet | Can be expensive, high surface temperature |
| Radiant | Up to 1500 watts | Direct heat, no fan noise, energy efficient | Limited area coverage, high surface temperature |
| Oil-filled | Up to 1500 watts | Even heating, energy efficient, safe | Slow to heat up, heavy and bulky |
| Fan-forced | Up to 1500 watts | Quick heating, affordable, portable | Can be noisy, dries out the air |
| Convection | Up to 1500 watts | Even heating, energy efficient, silent operation | Slow to heat up, can be bulky |
Determining the Appropriate Size of Space Heater
Now that we have covered the factors to consider, let’s move on to the process of determining the appropriate size of space heater for your needs.
Calculation of the square footage of the room
The first step is to measure the square footage of the room that needs to be heated. This can be done by measuring the length and width of the room and multiplying them. For example, if the room is 10 feet by 12 feet, the square footage is 120 square feet.
Calculation of the BTUs required
Once you have the square footage, you can calculate the BTUs required to heat the room. The standard calculation is 20 BTUs per square foot for rooms with standard ceilings (8 feet). For rooms with high ceilings, add an additional 25% to the BTU calculation. Using our example of a 120 square foot room with standard ceilings, the BTUs required would be:
20 BTUs/sq.ft. x 120 sq.ft. = 2400 BTUs
Calculation of the watts per square foot required
Another way to determine the appropriate size of space heater is by calculating the watts per square foot required. As mentioned earlier, the standard calculation is 10 watts per square foot. Using our example of a 120 square foot room, the watts required would be:
10 watts/sq.ft. x 120 sq.ft. = 1200 watts
Comparison of the results to the available heater sizes
Once you have the BTUs and watts per square foot required, you can compare them to the available heater sizes. It is important to choose a heater that meets or exceeds the required heating capacity. For example, if the required heating capacity is 2400 BTUs or 1200 watts, you can choose a 1500-watt space heater or a 2500 BTU space heater.
Selection of the appropriate size of space heater
Based on the above calculations, you can select the appropriate size of space heater for your needs. It is important to note that the size of the room is not the only factor to consider. The height of the ceiling, insulation of the room, and other factors can affect the heating capacity required. Hence, it is always recommended to choose a slightly higher heating capacity than the minimum required.
Common Mistakes When Choosing a Space Heater
Now that we have covered the process of determining the appropriate size of space heater, let’s take a look at some common mistakes to avoid.
Relying solely on the wattage of the heater
Wattage is an important factor to consider when choosing a space heater, but it is not the only factor. The heating capacity required varies based on the size of the room, height of the ceiling, insulation, and other factors.
Neglecting the height of the ceilings
As mentioned earlier, rooms with high ceilings require more heating capacity. Neglecting the height of the ceiling can result in a space heater that is too small for the room.
Ignoring the insulation of the room
A poorly insulated room will lose heat quickly, requiring a higher heating capacity to maintain a comfortable temperature. Ignoring the insulation of the room can result in a space heater that is too small for the room.
Conclusion
Choosing the appropriate size of space heater is crucial for maintaining a comfortable temperature in your living spaces. Factors such as the size of the room, height of the ceiling, insulation, and heating output need to be considered when selecting a space heater. By following the above process and avoiding common mistakes, you can choose the right size of space heater for your needs and stay warm and cozy during the chilly weather.
