Heat input rate
Approved Document J, Combustion appliances and fuel storage systems, 2010 edition incorporating 2010, 2013 and 2022 amendments, defines the heat input rate as: ‘…the maximum rate of energy flow into an appliance. It is calculated as the rate of fuel flow to the appliance multiplied by either the fuel’s gross or net calorific value. Note: Traditionally, the UK has used Gross values, most European standards use Net values. Thus for gas appliances it is now the norm to express this rating as a net value (kW (net)).’
See also: Rated heat output and rated heat input of combustion appliances.
And: Rated heat input.
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