Cold weather tips: Stopping your pipes from freezing

To_be_confirmed wrote: »

Some people here need to catch up on their physics 101 regarding lightbulbs...

I believe you are one of these people also

To_be_confirmed wrote: »

Firstly, 100W is hardly going to send off cold air back to the artic. But when people are comparing heating an attic to heating a living room, something critical is being forgotten.

(Since no one else gave this example, I presume this is aimed at me) The example of the living room versus attic was rather crude in physics terms, but it was given to point out that if 2KW of heat energy escapes from an insulated room (25-30 degrees difference), what hope does a 0.1KW (20 times smaller) heater (i.e. Light bulb) have of heating a non insulated room (5-10 degrees different). Admittedly, probably not the best example.

To_be_confirmed wrote: »

The rate of heat flow between a and b depends on the temperature difference between them. I.e. how fast heat is conducted depends on the temperature difference between a room and the garden outside. So a room which is heated 20 or 30 degrees hotter than outside is going to need quite a lot more heat than a room heated to 2 or 5 degrees above outside temperature.

Correct, aka Newton's law of cooling. However you have to factor in all aspects of this law, including heat transfer coefficient, which will be quite different between an insulated room and a non insulated attic.
It seems a lot of people believe because their attics are insulated, that their tank/pipes will be protected more, as the cold won’t get into their attic. In a lot of cases this is incorrect since the insulation is between the top floor and attic space, rather than the attic space and outside. In this case the chances of the tank/pipes freezing increases, as the heat is held below the attic and the attic space gets colder, increasing the likelihood of freezing. Of course, if the insulation is laid correctly over the tank/pipes and not under the tank, there should be no freezing as long as heat is coming from below!

To_be_confirmed wrote: »

Secondly, though it's open to correction, ALL the energy from a 100W lightbulb is going to result in heat sooner or later. That visible light is going to be absorbed by various things so it's going to result in heat, for example. Besides, 80% or thereabouts is emitted as non-visible light energy, aka heat.

Yea, pretty much, except what light is reflected, is lost travelling through the atmosphere and escapes from the space. Most light bulbs give off 90% of their energy as heat and only 10% light. Yes a lot is in the UV and IR spectrums.

To_be_confirmed wrote: »

Finally, a good chunk (I don't know how much) of the heat is the radiated infra-red-light kind of heat. That's going to heat in some way or another, all the surfaces it shines on. I don't think the convective air flow thing is particularly important. If the air has already frozen the pipes, it's not going to cool them no matter what sort of breeze blows! Pipes don't suffer from wind chill:rolleyes:

Eh, no :rolleyes: Even if the light bulb dissipated 100% of its energy as infra red heat, what percentage do you think would hit the pipes from a non focused bulb above the pipes? Even if it was 1%, the amount of heat transferred would be 1W. Even still, the max amount of heat that can be provided is 100W for the given space. Wind chill??? If you mean convection, you can’t just discount convection like that. Of course freezing air flowing around frozen pipes won’t make any difference, but freezing air flowing around non frozen pipes will! They will freeze faster due to the increased airflow. This is the principle a car radiator or convection heater works on. Admittedly the pipes don’t have anything like the surface area, but convection still counts.

To_be_confirmed wrote: »

Apologies if I went a bit nerdy there but I felt that people shouldn't be given the wrong impression. The facts are that leaving a strong light on in the attic will make a small but significant difference to keeping pipes ice free. It's not a guarantee but it sure as hell will make a lot of people sleep more soundly and less likely to be forced to leave the tap running. Especially if they are too immobile to haul up heaters or put up makeshift insulation!

For something to be a fact, it has to be proved. You have not done that.
In a tiny room with tank and pipes taking up most of the space and insulation shielding the room from the outside, I would accept that a 100w bulb may make a difference of a few degrees. You can’t otherwise say it will make a difference, due to the complexity of the other external factors involved like:
The size of the space being heated, The insulation between outside and inside, The insulation between house and attic, Insulation between bulb and tank/pipes, Outside temp, Heat provided from the house below, Water temp, Size of pipes, Material of pipes, Water flow, Thermal transfer between materials.
I think with the extreme temperatures outside, a lot of people had their mains water cut off due to pipes freezing outside. Not much can be done about this besides burying the pipes deeper, adding insulation, heating the water (somehow) or keep the flow running (these will only slow down freezing process and obviously aren’t practical).
Also a lot of people had their attic pipes/tanks freeze, due to either lack of insulation (over their tank), or heat in the right places (i.e. the room directly under their tank).
Either way, leaving a tap running (while helpful) is irresponsible. We seem to be experiencing longer periods of temperatures below zero. This day in age, there is not much excuse for not having proper loft insulation, considering the price, the savings and the grants available. The majority of people have heating. Of course there is always the odd exception

Joey the lips wrote: »

This put me asleep long ago. You can spout all the physics you want an old school plumber will tell you that a light bulb positions in close prox to the water tank prevents it freezing it does not thaw it. It stops it in the first place.

I dont care what physics says. It has been practicised for years. Just look at the old stock of houses around dublin

As for anyone believing me. I could not care less. It was a "Suggested" idea. If you really want protection get up there this summer and lag all the pipes and lag the tank.

It's nice to know people bother to read all of a post before replying:rolleyes: My point was that it will make a small but significant difference. That degree or two that the pipes in the vicinity would be heated by could make the difference between them freezing or not, or at least prevent the pipes from going too far below 0 to cause them to crack!

I cannot believe you "spouted" that at me when I never said it would thaw anything! I didn't come here to prove people wrong, I said it to clarify that a bloody bulb does make a small difference and that every little helps:mad:

Bubblehead, the fact I was getting to is that a 100W lightbulb will make a small difference. You put caveats on what I said but the point is still there. Outside temp can be below zero but pipes won't necessarily freeze. The amount of frozen pipes I heard of were nearly always after a night of temps below -6.

That's all I'm going to say in this thread.