Why is the Pyroclassic sometimes shown as having a 4kW heat output and sometimes 15kW?
The 4kW rating for the Pyroclassic IV comes from the efficiency and emissions testing procedure. This heat output test is a byproduct of other tests and it is acknowledged throughout the industry that this method of testing disadvantages fires with a higher thermal mass.
In light of this the New Zealand Home Heating Association (NZHHA) established a standalone testing procedure specifically designed to measure the actual kW output of a fire in the laboratory environment. The Pyroclassic IV is only one of a few fires to have been tested with this procedure and the results have confirmed the Pyroclassic IV is capable of providing a genuine 15kW of heat for your home.
A more accurate way of measuring how well a wood burner will heat you home in the real world is to look at the space heating rating which is usually shown in m2. The higher the area shown the better the fire will be to heat the whole home. The Pyroclassic IV is rated up to 250m2, which is one of the highest ratings of any domestic wood fire.