What will be the surface temperature of the metal enclosure when my heating system is running?
You will need to know what the operating temperature of your boiler or hot water heater is. Look at the temperature gauge on the boiler when it is cycling. The temperature gauge will show what the water or steam temperature is leaving at. The highest surface temperature would occur nearest the boiler. If the temperature gauge reads 180F, you would subtract the entering air temperature at the convector. The heating industry uses 65F.