heating_celsius_degree_hour = degree_Celsius * hour = °C_HDH
heating_celsius_degree_day = degree_Celsius * day = °C_HDD
heating_fahrenheit_degree_hour = degree_Fahrenheit * hour = °F_HDH
heating_fahrenheit_degree_day = degree_Fahrenheit * day = °F_HDD
# Remove when moving to pint 0.21, which adds % symbol
percent = 0.01
