BTUs are our standard of measurement for fan forced heat output, but what does that really mean? British thermal unit or BTU is a unit of heat equal to the amount of heat required to raise or cool one pound of water one Fahrenheit at one atmosphere pressure. It essentially measures the power of the unit via energy production.
Another important thing to understand about heating power is watts. Watts are a measure of power or the rate of energy consumption by an electrical device when it is in operation. It is calculated by multiplying the Voltage x Amperes.
The next logical question you may ask is many square feet can a 5000 BTU heater heat?
There is a lot more to it than just square footage. To find out the heat load on any room or home consider having a load calculation performed. This process evaluates the size of the room, the location, construction features and architectural design of your property. You also need to take into consideration how well the room or home is insulated. A freestanding electric heater may heat a room outfitted with hardwood floors and a bank of windows differently than a room with wall-to-wall carpeting and a single window with curtains.
Other room features that may effect heat output are high ceilings, large open spaces and staircases. With a portable electric heater (which is what you're talking about if it's 5,000 BTU), you can estimate heating capacity with the 10 - 15 watt per square foot rule of thumb. To convert from watts to BTU, multiply watts by 3.4. You can also figure in exactly how many degrees Fahrenheit you are looking to increase the temperature and how many square feet your space is.
How many watts/BTUs per hour does an electric fireplace give off?
On average, all standard units produce 4600 BTUs per hour. Built-in models which can be hardwired for 240V can produce up to 8900 BTUs. Infrared heaters produce about 5200 BTUs per hour. By comparison, a standard space heater produces only about 5100 BTUs or 1500 Watts an hour, making electric fireplaces the more efficient and aesthetically pleasing choice.