I have an enclosed porch with very little insulation, it is typically very cold in the winter. However, there is a radiator in the enclosed porch. I have a gas boiler heating system in the house.
I'm assuming that attempting to heat the cold porch is wasting energy and cooling the water in the radiator and dropping the temperature of the water which is circulated to the other radiators in the house. I doubt I want to turn off the radiator loop for fear of freezing the pipes due to low winter temperatures. What is the best way to avoid excessive heat loss in my boiler system?
I considered building a sleeve out of foil bubble insulation to enclose this radiator, which would keep the pipes hot so they don't freeze, but reduce the cooling effect. Additionally, I would probably put foam pipe insulation on the input pipes that run under the floor to the radiator.
Best Answer
You are correct that having a hot radiator on what's effectively a cold space - the porch - is very inefficient and, presuming nobody's on the porch most of the time, wastes a lot of energy.
And you are correct that the hot water going into that radiator is being cooled in the process.
However, it is unlikely that the water is going to any other radiators, but rather it's going back to the boiler to be reheated. Nevertheless, you are right that stopping water flow to this radiator will save you on your heating bills.
But - if you stop the flow of water through the radiator, no amount of insulation will keep the pipe from freezing, because with no place for the cold water to go, the hot water in the rest of the system WILL NEVER reach the pipe you insulated. It's just like turning on the hot water in a cold bathroom - the water runs cold for a while even though the hot water is available elsewhere in the house.
On a cold enough day, the stopped pipe with water in it will freeze, no matter how hot the rest of the system.
The best solution to this is to remove the radiator completely. To accomplish this, you need to trace both the input and output pipes for the radiator in question back to an interior space that doesn't ever drop below freezing. The entire system will then need to be drained, and the input and output pipes cut off and capped so that the useless radiator can be removed.
EDIT:
Since you're looking for a short-term, this winter solution, here's what you can do for now to minimize the waste.