Water Heater
Hi All
Being brand new to caravaning I would like to know everyone thoughts on whether you would leave a water heater switched on all the time you are connected to a mains supply onsite? Or would you turn it off after let's say an hour? Not sure which way to go on this one all your comments would be most helpful
Ansley
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Agreed. Leave it on. It's thermostatically controlled so will switch itself off when up to temperature and you'll then not need to heat the whole thing from cold.
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If, on the other hand, you are on a metered supply and paying for what you use .... then turn it off ! Keeping a tank of water hot unnecessarily will always use more power than just heating it when you need it, even if it does cool down somewhat in between.
Personally, even if unlimited electric is included in the site fee, I would still turn it off simply because I hate waste. Ultimately the overall cost of electricity will be reflected somehow in the fees.
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On present van with Alde heating the heating is set to 'ON'. Although pump and radiators are not operating the boiler keeps water hot. On last van with electric immersion I generally left it on on site purely because switch was in the airing cupboard and not immediately to hand.
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I disagree that turning it off will save electric. Letting the thermostat do its job means it will only use a little power every now and then to bring it up to temperature. Turning it off means using a lot of power to heat from cold.
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Maybe depends how often and how much hot water you intend to use. We normally only use it for washing up in the van, turn it on for 20 minutes or so before we need it and then off. Agree with TW though, there's probably not an awful lot of power saving given the limited volume of water involved.
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There you go, Gatewaya89, just do what suits you best 👍🏻
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Put ours on when we arrive on site then turn it off when we leave. If on hard standing I drain it down before we leave. If not I drain it when we get back to the storage site.
I agree that keep turning it on and off is less economical than just letting the thermostat do it's job plus you always have hot water to wash your hands with.
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fully correct. I could show you the maths/physics but heating 1kg of water by 1 degree C requires 4185 Joules of energy (supplied by electricity or gas).
So using a thermostat means you only have to heat the water by a few degrees every so often and is less wasteful than the same amount heated from cold.
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no, see above answer
a thermostat will mean it only uses electricity when needed not all the time0 -
Rate of loss of heat from a hot body to the ambient environment will always be greater if the differential between the two temperatures is greater. As your water tank cools, the rate of loss of heat decreases. If you maintain it at maximum temperature constantly (ie thermostat cutting in-and-out to maintain the temperature) more heat will be wasted to the environment.
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if you want to discuss Newton's law of cooling we can! (which is what you're saying) but you can't just use that in isolation and you have to look at the heat loss and how it happens, and so you're only quoting half the story. You are quoting the classic how to keep your cup of coffee hot by adding or not adding cold milk.
Your 'statement' is correct but your tank will be insulated so that the heat loss from it is kept to a minimum so that the heat loss you talk about doesn't apply.
Imagine a bottle and a thermos flask. You put the same amount of liquid at the same temperature in both. Both the bottle and flask have the same outside and inside temperatures. The thermos inside at at 80C and outside it could be 20C, and the same for the bottle. Now according to your statement both should lose the same amount of heat and both should cool down at the same rate? Do they? Of course they don't, the same thing applies to you caravan tank.
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"Now according to your statement both should lose the same amount of heat and both should cool down at the same rate?"
No, because the 'bodies' in this case are the bottle and the thermos flask. The external surface temperature of the thermos flask will be lower and therefore the rate of heat loss will be lower. (lets assume for simplicity that the external surface area of each container is equal). The heat loss from the thermos is still however finite.
(Of course if the insulation of the hot water tank were perfect, then it would never loose any heat, and it doesn't matter whether you switch the immersion off or not ....... except that you might end up with a tankfull of hot water which goes to waste
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I always turn mine off when going out for the day. The tank is reasonably insulated & I have added a polystyrene box cover. I find that the water after being out all day is still reasonably hot.
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Why worry........you are on holiday..............!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
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The external surface temperature of the thermos flask will be lower and therefore the rate of heat loss will be lower.
Yes, well done you've got there, because it (the flask) is insulated, in the same way as your hot water tank is! but not as efficiently
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Don't you just love the way a forum discussion evolves
Just leave it on like you do at home . If we were really concerned about the impact caravans have on the environment we wouldn't drag them around the country and Europe massively increasing our individual carbon footprint?
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I certainly would not worry about the very small heat loss from the insulated boiler, because it will be lost to the inside of the Caravan, which you will be trying to keep warm in cold weather or on hotter days the loss will be insignificant as the differential between the two temperatures will be even less (See: Newton's law of cooling) and the "maths/physics of heating 1kg of water by 1 degree C that requires 4185 Joules of energy (supplied by electricity or gas)" as pointed out by Cornersteady.
Leave it on.
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As Mr Scott would say: you cannae change the laws of physics
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just out of interest, water takes the the second highest amount of energy for any subtance to heat it by 1C, While water needs over 4000 joules per Kg for every 1C, copper only needs 385. Not a lot of people know that...
It means higher heating costs to heat it v keeping more water in us and on the planet.
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On my van a Lunar Quasar the water temp is only controllable if you use gas, on electric it heats up to approx. 65deg and just keeps on going , we usually leave it on but I sometimes get a niggeling worry that it could be doing harm.
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what model of heater do you have? Also I'm confused, if it heats up to 65C and stays at 65C it can't keep on going? It must switch itself off at 65C or it would get hotter?
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If one wanted to be miserly one could replace the on/off switch with a timer and have hours of fun deciding when next the water would be needed hot to set the timer.
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