What does BTU mean? Why are BTU’s mentioned when talking about heat and heating appliances? How are you supposed to decided what BTU is right?

There is a ton of mention about BTU output, BTU input, and thermal/combustion/overall efficiency, but they all refer to different measurements.

Here’s is a glossary of heating terms that will be helpful to understanding what they mean and why they are associated with heating appliances.

BTU OUTPUT: This is the amount of heat that the appliance is capable of exiting into your home after all deductions for fuel moisture, unit heat exchanger design and exhaust temperatures are taken into considerations. It is very rare that a manufacturer or a reseller of the product will publish this because it is hard to determine with so many factors such as fuel quality, installation, venting and maintenance habits. If the person trying to sell you an appliance is touting how much heat their unit will produce, he or she is talking about the BTU input and not the actual output of the appliance. Make sure that you clarify which one they are talking about. It’s important to know you are talking about the same thing.

BTU INPUT: This is the amount of heat that the appliance is capable of producing on any given heat setting (if published for multiple settings) or the total heat capacity (this is normally what is done) when the appliance is on its highest setting. Some manufacturers list the minimum heat capacity and the highest heat capacity to give you a range. If it is not printed on the owner’s manual or on the testing label (this is required and must have either BTU input or output listed) then be sure to ask the reseller which he is stating.

THERMAL or HEAT TRANSFER EFFICIENCY: This is where the “rubber meets the road” in a heating appliance. Thermal or Heat Transfer Efficiency is the ability of the appliance to transfer the heat from inside of the appliance directly into your home. This is usually the lowest number on the efficiency scale and very rare is it ever published because there are numerous factors that apply and will change depending on installation, operation, maintenance and home environment. Probably not wise to ask the salesman what this is because we do not want to make him or her feel bad when they have that deer in the headlight look. Typically only the manufacturer will know this information and rarely will release it.

COMBUSTION EFFICIENCY: This is the efficiency that the fire itself is burning, right at the combustion source. Unfortunately some manufacturers and sales people will tout this efficiency to claim that their appliance is better than another to get you to purchase theirs. You need to show them just how intelligent you are and tell them that taking into consideration fuel quality, fuel moisture, venting configuration, operational and maintenance habits, etc. etc. that there is no way that their appliance can have a overall efficiency of 97+ %.

OVERALL EFFICIENCY: This is the average efficiency at which an appliance will perform. Most reputable manufacturers will list this efficiency and identify that it is overall efficiency. It is important to remember that when a manufacturer has to increase the air to an appliance to get it to burn poor quality fuel, the overall efficiency suffers as a result and that means you will burn more fuel, heat less area and have considerably more maintenance.

American Energy Systems is happy to help you find any of this information about MagnuM brand appliances, as well as help you find the right heating option for your needs.