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Author Topic: Why do energy saving lightbulbs contain mercury?  (Read 25931 times)

Offline turnipsock

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Re: Why do energy saving lightbulbs contain mercury?
« Reply #25 on: 28/03/2008 00:47:25 »
The easy answer to saving on heating power is to wear more clothes. Long Johns are a portable heater.

Some politician said something about making the whole country use energy saving bulbs by such and such a year. They clearly don't understand the central heating system. Anyway energy saving bulbs are a lot more damaging in their production.

Or old bathroom light has run for about 8 years as well. It went four days ago and has not been replaced and nobody has missed it. I do seem to have some infra red properties in one eye.

One good thing about energy saving bulbs is that they take a bit of time to get up to full brightness, which means they don't hurt your eyes when you first switch them on in the midle of the night.

I wonder if the idea of using long johns instead of a heater could be expanded to using a head torch instead of normal lighting?
 

another_someone

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Re: Why do energy saving lightbulbs contain mercury?
« Reply #26 on: 28/03/2008 03:20:43 »
If you REALLY wanted to cut down on energy use you would not have central heating, which heats all rooms all the time, even though no one may enter them for a whole week- there's a lot more than 15% to be saved there. High powered fan heaters and radiant heaters could 'follow you' around your home; you would be almost unaware of the way your heat was getting to you and you would save a packet.

It is no more difficult to switch off a central heating radiator than to switch on an electric heater.

If you are constantly allowing a room to cool down and get warm again, you will have a lot of condensation in the room, which will more than offset any savings in your heating bill with increases in repair bills.  By all means, if you are not using a room for weeks on end, then switch off the heating in the room and allow it to cool down, but don't expect to switch the heating on and off like toy do a light bulb.

Also, allowing one room to cool down while heating a neighbouring room is only valid if you have good internal thermal insulation within the house.  Most houses maximise the thermal insulation (even then not always very effectively) between the interior and the exterior, but make no significant effort to thermally partition the interior.

On the whole, most people who use central heating are paying less for their heating than those heating each room separately.  In part this is because heating by gas is more energy efficient than converting the gas to electricity, distributing the electricity across the grid, and then converting the electricity to heat; and few people have a gas heater in each room.  Gas heaters are also a safety liability (so is is gas central heating, but the risks are managed in a single sealed unit rather than the risks associated with an open gas fire, let alone a gas fire in each room).
 

lyner

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Re: Why do energy saving lightbulbs contain mercury?
« Reply #27 on: 28/03/2008 23:19:17 »
A water-filled radiator takes a lot of energy to get it hot enough to warm the room; there is a huge time lag, compared with a radiant  / fan electric heater. You could enter the room, spend half an hour in there and leave before the average radiator had any appreciable effect. The radiator would need to have several times the normal power output and would have a larger water capacity - another waste of energy.
To compare local electrical heating with GCH you need to do much more than compare the cost of delivering electrical power to the device with the cost of providing the hot water in the system. There is a further distribution system involved and there are pipes all over the place which lose heat under floorboards etc; just observe how fast they cool down when the boiler stops.
 The total cost of comfort is what is relevant here and it may be necessary to think laterally rather than to hang on the what we know and love. To make a fair comparison you would need to factor in the cost and convenience of adding extra insulation, replace all existing equipment and also the control system. I think the water-based system has several shortcomings in the modern context.

Conventional central heating is nice but expensive. It wasn't introduced as a result of today's factors but as a luxury which we could all (?) afford. We just accept the cost and are reluctant to do without it.
You just don't need a room to be warm if you're not in there but you can demand that it warms up fairly quickly when you go in. Condensation is not a problem if there are no cold surfaces. There has to be less heat flow from a warm room to the window of an unheated adjacent room than keeping that adjacent room warm. Yes, there is little attention paid to internal insulation, nowdays, but it would be cheap to install (and injecting foam into internal walls would not even involve building regs).
In many houses there are heated rooms where no one goes for days on end. This must use more energy than necessary; can there be any question about this?
Of course it's true that a well insulated house would need very little energy to keep it warm - about the amount that is used for lighting, perhaps.
Apart from being sexy technology, do the new lamps really have that much going for them, bearing in mind that we could all wear thicker clothes and save much more money / energy by operating our heating a couple of degrees lower?

 

another_someone

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Re: Why do energy saving lightbulbs contain mercury?
« Reply #28 on: 29/03/2008 04:11:33 »
But if you are constantly heating and cooling rooms as one moves in and out, how can you avoid there being cold surfaces as the surfaces warm up less quickly than the air?  The problem is that the materials that make up the walls of our rooms is they have a high heat capacity which is good at insulating the rooms, but very slow to warm up or cool down.  If we have an inner metal surface in the rooms, then this would help, but it means major changes to the design of our rooms.

Central heating may have been a technology that replaced earlier means of heating (such as open fires) in the 1960s, but it is actually more efficient than many of the technologies it replaced (and much healthier than things like paraffin heaters, or even poorly maintained gas heaters, both of which can be dangerous in the house).
 

lyner

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Re: Why do energy saving lightbulbs contain mercury?
« Reply #29 on: 29/03/2008 19:25:52 »
Who is 'cooling' the room? There will be no 'cold surfaces' compared with the ambient air at the time the local heater is turned on. There need be no air below dew point. When the heater turns on, the existing air will just get less humid - no more water will become available.
The thermal inertia of the fabric is not really relevant when a powerful radiant heater is concerned. If you spend much time in the room then it will all have warmed up; if you leave after a short time, only the air and surfaces (and you) will have warmed up.
What is so special about having every room warm when no one is in it? Sounds a total waste to me.
 

another_someone

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Re: Why do energy saving lightbulbs contain mercury?
« Reply #30 on: 30/03/2008 06:25:08 »
If the room does not cool, then there is no need to heat it - so you have a contradiction there.

The assumption in what you are saying is that you rapidly need to heat a room because it has been allowed to cool down in your absence, so ofcourse the surfaces would have cooled down also.

If you spend much time in a room then it really does not matter what means you are using to heat it.  This debate is about rooms where you do not spend much time, but will occasionally enter the room, and will seek to rapidly heat up the air while not having time to heat up the surfaces, thus the warm air, carrying moisture, will then condense that moisture on the cold surfaces.

Even the moisture in your breath will be more likely to condense on the cold surfaces.
 

lyner

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Re: Why do energy saving lightbulbs contain mercury?
« Reply #31 on: 30/03/2008 12:38:56 »
1.
Quote
thus the warm air, carrying moisture,
Where does this moisture come from? If it comes from your breath, it implies you are in the room for a long time - so it would be warm and, low humidity.
2. I'm not expecting the room to cool down a lot; though, if it does, you are wasting even MORE energy keeping it warm with radiators working all the time. Would you include your garden shed in the central heating loop? I don't think so, so I am right in principle!
3. We have to assume the same conditions for both systems. A well insulated house would need very little heat input. Why not just use the lights then?
4. Many tens of pounds a year just to keep rooms warm is an expensive way of preventing condensation.

5. Do you have shares in a central heating company A-S?
6. Good insulation goes without saying.
 

another_someone

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Re: Why do energy saving lightbulbs contain mercury?
« Reply #32 on: 31/03/2008 03:20:35 »
1.
Quote
thus the warm air, carrying moisture,
Where does this moisture come from? If it comes from your breath, it implies you are in the room for a long time - so it would be warm and, low humidity.

Your breath will contain moisture, but the air itself will contain humidity even if just drawn in from outside.  Ofcourse, in some rooms, like the kitchen and bathroom, you have other causes of moisture as well (and I not only have the heating on in the bathroom, but actually have a dehumidifier, which is rated at 60W consumption, permanently switched on).

2. I'm not expecting the room to cool down a lot; though, if it does, you are wasting even MORE energy keeping it warm with radiators working all the time. Would you include your garden shed in the central heating loop? I don't think so, so I am right in principle!

I have no problem with switching off heating in rooms one very rarely ventures into, but the debate is whether, in those rooms one regularly enters, central heating is any disadvantage, or even an advantage, over distributed heating systems.

The spare bedroom has the radiator permanently switched off, except when I am expecting guests - but I can do this with central heating, and I don't need rapid response heaters.

4. Many tens of pounds a year just to keep rooms warm is an expensive way of preventing condensation.

Not when you consider the cost of repairs due to rot caused by condensation.
 

Offline techmind

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Re: Why do energy saving lightbulbs contain mercury?
« Reply #33 on: 31/03/2008 12:10:16 »
I can't help but thinking (as I suspect sophiecentaur does) that this amount of problems of condensation indicates a problem with excess humidity, and that keeping everywhere heated to avoid it is a poor workaround.

Where is the humidity coming from? Is steam from the bathroom or kitchen being poorly managed? Use lids on saucepans, switch off kettle promptly, use some kind of air-extract when cooking. Ditto for bathroom - better to air the bathroom (with the door to the rest of the house closed) for 20mins after a bath/shower than to heat the whole house forever!
Are you regularly drying washing inside the house? FAR better to dry it outside or in an airy outhouse/conservatory. Do you have heavily-used non-flued gas heaters (combustion by-product being water vapour)?

A small amount of air circulating in the house (a couple of windows ajar) while letting a little heat escape ought to help considerably with the humidity issues.
 

lyner

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Re: Why do energy saving lightbulbs contain mercury?
« Reply #34 on: 31/03/2008 19:29:53 »
Quote
but the air itself will contain humidity even if just drawn in from outside
Not at all; if the outside air is actually 100% saturated, as soon as it comes inside and its temperature rises, the humidity goes down. You will only get condensation if that air gets COLDER than it was when outside. Whether you use your system or mine, the idea is that inside is warmer than outside.
Bathrooms and kitchens are the source of extra water and could cause condensation elsewhere. But a small temperature differential between inside and outside is enough to act as a 'pump' as long as some air leaves the house.
Air flow can be a problem if the prevailing wind is working against you but I still feel that CH is not the most economical way of dealing with what is, in fact, a different problem from heat loss.
 

Offline skeptic

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Why do energy saving lightbulbs contain mercury?
« Reply #35 on: 10/05/2008 20:32:46 »
There is mercury in florescent light bulbs, and the common energy saving light bulbs (there are different technologies) are basically miniature fluorescent light bulbs.

On the other hand, the amount of mercury in the light bulbs is far less than most people have in the fillings in their mouth.
But, how much mercury is there in enough bulbs to fill every socket in every American(or World)household and business? That's the amount that will be going into public landfills(and into our groundwater), if the current agenda succeeds in total elimination of incandescent bulbs.
 There is currently a DEQ program for some commercial bulbs that requires businesses to ship spent bulbs to a recycling center, because of the groundwater pollution potential. But it is only partially effective, with the help of "watchdogs" to report noncompliance. They will have a harder time enforcing this on the public, especially with bulbs that can slip into a garbage bag unnoticed. People will more likely ignore the warnings, like they do with their batteries. The eventual result is the blaming of the Water Company for HEAVY METAL POLLUTION.
 

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Why do energy saving lightbulbs contain mercury?
« Reply #35 on: 10/05/2008 20:32:46 »

 

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