The master unit displays a number representing the current total of "heating value".
The value is necessarily approximate as various grades of oil have slightly different heating values.
This is more easily calculated from the higher heating value than when using the preceding definition and will in fact give a slightly different answer.
The difference between the two heating values depends on the chemical composition of the fuel.
Unless stated otherwise the lower heating value is used in the remainder of this text.
Which definition of heating value is being used significantly affects any quoted efficiency.
Mockernut has the second highest heating value among the species of hickories.
The rest is mostly carbon monoxide, which has a fairly low heating value already.
(See section 4 of this page and heating value).
Be within a specific range of heating value (caloric value).