Immersion heaters

J

Just the One

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So how much does it cost to leave your immersion heater on 24/7.

Does it work out very expensive?


Also, when I turn it on I can hear the immersion heater boliling away... kinda sounds like air hissing... I have checked that all joints are sealed so I don't think that it is air... is this normal - or perhaps a sign of something wrong with the immersion.
 
If it is running at full pelt then take the kW rating (should be marked on the head of the element(s) protruding through the tank) and multiply it by the number of hours that it is running for and by the relevant electricity unit cost [broken link removed]. However it is most likely on a thermostat so will not be running at full pelt all the time but the above approach should yield the worst case cost.
 
If you remove the cap you will find that the immersion heater is equipped with a thermostat which will (should) switch off the heater when the set temperature is reached. I wouldn't recommend running any type of heating appliance like this 24/7 though- immersion heaters generally have a short lifespan, relatively speaking.
 
Slightly off topic here so apologies for highjacking but I've always wondered...in a standard plumbing system in a house, built in the last 5 years, where does the steam that is produced by heating the water in the hot water tank go to? Does it stay in the hot water tank or vent in some way?

"Enquiring minds want to know"!

efm
 
Carpenter said:
I wouldn't recommend running any type of heating appliance like this 24/7 though- immersion heaters generally have a short lifespan, relatively speaking.
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I was wondering about that myself because we're in a GoldShield/NightSaver house for the past 10 years (next month!) and have generally left the immersion on the night rate to give us hot water for the full day and I was wondering if/when we should expect to have to replace the elements? I presume that when there's a problem they will simply fail rather than gradually decreasing in efficiency? Or should the elements be replaced as a matter of course after a certain period of usage?
 
If you are fortunate enough to live in a soft water area (or have a softener fitted) you can expect trouble free service until the element just gives up the ghost and blows. Limescale however is the biggest enemy of immersion heaters, as onyone who has to descale their kettle will know! I wouldn't go near the element until it gives trouble and then if you want to you can opt for a more expensive type of heater which is titanium coated (cue expense). These are purported to be more efficient/ reliable as they will resist corrosion and lime build up. Try Byrne Lycris's website (they're Wicklow based AFAIK) they manufacture storage cylinders for the domestic market.
 
Thanks for that - we seem to be in a soft water area (town end of Dublin 7) judging by the kettle (little or no scaling). Not sure if it helps but the hot water system is pretty efficient with sprayed on (?) integrated lagging on the tank and DIY installed lagging on the hot pipes so maybe that helps the immersion elements to do less work than if the system was less efficiently lagged? Anyway - thanks for the tips and the reference. Hopefully I won't have to tackle that job just yet though. :)
 
Be sure that all pipes connected to the storage cylinder are also lagged for a point at least 1m from the tank- this is a building reg. requirement which I posted info. on some time ago. Failure to do this can result in considerable and unnecessary losses also.
 
Actually they were not originally and if I'd known that it was an issue 10 years ago it would have gone on the snag list! Anyway, I lagged them myself after taking occupation of the house using those pre-formed and split lengths of pipe lagging that slip over the pipes. Must double check that I did all the relevant ones though.
 
Your house would have been completed prior to this building reg. i.e. pre 1997 so snagging wouldn't have been an issue. As for the relevant pipes, all pipes connected to the storage tank should be insulated (not just the obvious hot ones) as they all draw heat from the tank.
 
Thanks again for the tips. The house was completed in 1995 so presumably predates the relevant building regulations?
 
Be sure that all pipes connected to the storage cylinder are also lagged for a point at least 1m from the tank- this is a building reg. requirement which I posted info. on some time ago. Failure to do this can result in considerable and unnecessary losses also.
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Does this mean all of the pipework within the airing cupboard entering/exiting the loft should be lagged 1m away from the HW cylinder?
 
The regulations state (along these lines- I'm away from my desk at the mo) "all pipework connected to the hot water storage vessel should be insulated up to a point 1m away from the vessel or until they are hidden". You can download the actual document TGD Part L from the Department of the Environment's website- try oasis for the link.
 
Read the regs. on this but it also mentions "except pipes within the normally heated area of the building". Before I give the builder another snag and listen to the plumber moaning, does this definitely mean that all of the pipes connected to the HW cylinder in the airing cupboard should be insulated?
 
Geegee said:
Read the regs. on this but it also mentions "except pipes within the normally heated area of the building". Before I give the builder another snag and listen to the plumber moaning, does this definitely mean that all of the pipes connected to the HW cylinder in the airing cupboard should be insulated?
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I won't have access to the regs. until tomorrow, but my reading of the regulation is that unless a hot water pipe actively contributes to the heating of a habitable space then it should be lagged/ insulated. Thus for example flow and return pipes (buried in the concrete floors) feeding rads will not contribute directly to the heating of the room so they should be lagged. Likeswise pipework in an attic should be lagged, to prevent heat loss and freezing. But pipework with the first floor suspended timber floors need not be lagged as heat losses from the pipework will heat the rooms above and below the floor construction. The regs. specifically state that all pipework (see their diagram also) connected to the cyylinder must be insulated. So in answer to your core question "all of the pipes connected to the HW cylinder in the airing cupboard should be insulated". No debate.
 
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