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.

  • As you mentioned a boiler, is this a steam or forced hot water system?
    – mikes
    Feb 22, 2013 at 19:53
  • Forced hot water, not steam.
    – Benzo
    Feb 22, 2013 at 19:59
  • 1
    Just an update. I didn't do anything and left the radiator on in the porch. However, because the rest of the house is well insulated and the furnace did not need to kick on frequently, the radiator froze and began leaking. I just had to remove the radiator all together. Pro tip: Don't install a radiator in an un-insulated porch (Don't blame me, it came with the house)
    – Benzo
    Oct 23, 2014 at 13:55

2 Answers 2


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.


Since you're looking for a short-term, this winter solution, here's what you can do for now to minimize the waste.

  2. DO turn down the radiator to as low as you can get it without shutting it off. You don't want it to have a chance of freezing.
  3. Wrap the radiator in blankets to keep in the heat it does generate and conserve energy as much as possible.
  • I agree that this is probably the best long term solution. I'm also looking for short term solutions for this winter. I'm not really too enthusiastic about taking apart my heating system until the summer, when I have plenty of time to deal with it.
    – Benzo
    Feb 22, 2013 at 20:33
  • 1
    Edited my answer to give you a shorter term solution. Feb 22, 2013 at 21:04
  • Provided there are shut off valves for this section, why not just shut it off and drain it to leave it empty, but potentially useful should the porch be ever insulated in the future?
    – theUg
    Dec 26, 2013 at 22:36
  • If you can completely empty the pipe, that's fine. If. Dec 30, 2013 at 13:14

I suggested my mother have a contractor blow insulation into hers, and the improvement is amazing. Her area is a sunroom (a long room with 10 windows that was obviously an addition to the original structure) but in the winter it was as cold as the outdoors and was therefore used only in warm weather. Now she is able to spend time in there four seasons a year.

I'm not sure if this answer satisfies your request for an immediate fix, but it will definitely help with heat loss. If you do not want to hire a contractor, you can probably do it yourself one weekend.

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