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  • FIRST POST
    • AngelaDub
    • By AngelaDub 29th May 17, 2:07 PM
    • 10Posts
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    AngelaDub
    Boiler for electric-only flat
    • #1
    • 29th May 17, 2:07 PM
    Boiler for electric-only flat 29th May 17 at 2:07 PM
    Hi all, I had such great advice about my storage heating query and together with other threads on the forum I now have a plan to solve our heating problem.

    But now I have to move on to the hot water supply problem. Background: electric only flat using Economy 7 because storage heaters. 2 bedroom flat with 2 occupants who both work away all day. No access to gas.

    Our electricity bill was very high so we switched off the heating and it dropped by a third and then switched off the immersion heater water tank and it dropped by another third to about 40 GBP per month. We now regularly check the meter and keep the immersion heated water off. (Heating off too.)

    We have been quite happy keeping immersion tank off because we have pretty good electric showers. To wash my face and wash the pots & pans I just boil a kettle. Dishwasher handles the rest.
    However, occasionally we might want to have a bath. And the pressure of the hot water from the electric showers could be better, we love high pressure showers.

    These are our showers, we have two showers like this (not allowed to post links so remove the spaces): https ://ibb.co/cd2PQv

    This is our current immersion heated water tank, looks really old doesn't it? (not allowed to post links so remove the spaces): https ://ibb.co/jcTZsa

    So, we're looking to upgrade our hot water supply. Keeping the monthly electric bill low is important to us. Initial outlay is obviously a consideration but we are willing to save up for a good system.

    Ideally we'd like to be able to remove the electric showers and have high pressure hot water. We'd like to know what the best options are for upgrading our system - what is the best type on the market, and anticipating not wanting to spend the Earth, what are the best alternatives?

    One option we're considering is an electric combi boiler? Does this make sense on Economy 7? We've also heard about the type where the mains in heated through a tank of hot water which heats up at nighttime?

    Any advice would be so greatly appreciated as we're feeling really overwhelmed and suppliers just want to sell us their product. Thank you so so much.
    Last edited by AngelaDub; 01-06-2017 at 9:18 PM. Reason: More background info needed & fixing links to photos of heater and shower
Page 2
    • coffeehound
    • By coffeehound 3rd Jun 17, 8:16 AM
    • 973 Posts
    • 1,571 Thanks
    coffeehound


    I believe these showers contain an internal pump which would indicate either they are being fed from a header tank, or that the mains pressure is low..
    • EachPenny
    • By EachPenny 3rd Jun 17, 1:41 PM
    • 1,142 Posts
    • 984 Thanks
    EachPenny
    Our electricity bill was very high so we switched off the heating and it dropped by a third and then switched off the immersion heater water tank and it dropped by another third to about 40 GBP per month. We now regularly check the meter and keep the immersion heated water off. (Heating off too.)
    Originally posted by AngelaDub
    Before investing a lot of money in a new system you'll need to do some maths to make sure the cost is justified by the benefit. There may be some other low cost things to do to cut your bills without much outlay.

    In your first post you said switching off the immersion heater cut the bill by 'another third' to about £40 per month. First off, is this bill based on actual consumption during the month, or is it the amount of your direct debit which may reflect previous higher consumption? Is the 'third' accounted for by the immersion heater actually £40 - i.e. your original bill was £120?

    That's the first issue of concern - if the immersion heater is costing £40 per month then assuming a cost of about 7p/kWh for E7 electric then it would be using over 18 kWh per day - a typical immersion heater is about 3kW, so it would need to be running constantly for over 6 hours a day to cost that much.

    My 3kW immersion heater will fully heat a standard size cylinder from cold in about 3 to 4 hours. So there's either something wrong with the figures, or something wrong with your immersion heater.

    You need to narrow down the cost of running the immersion heater - if it is on a timer correctly limiting it to the E7 hours of your meter, your storage heaters are off, and you use minimal other electricity during off-peak hours, then the 'night' meter readings should give a fairly accuate measure of the amount of electricity the immersion heater is actually using. Checking the 'night' readings every day for a week or so will give you a good idea of the cost (excluding the standing charges you'd have to pay anyway) of actually using the immersion heater.

    The cylinder insulation is obviously poor, but you should also look at insulating the hot water pipes, especially the first couple of metres from the draw-off point on the cylinder. I would also want to check the pipework some time after you last use any hot water to make sure the hot contents of the cyclinder aren't circulating around the pipework and keeping it warm to the touch - it shouldn't happen, but it sometimes does.

    The other thing to get checked (but you'll need an electrician to do it) is whether the immersion heater has a thermostat. If not then it will run continuously all the while the timer is 'on'. Not only is this wasteful but it is also potentially dangerous. If there is a thermostat, is it set to the right temperature and actually working?

    If you have a correctly working thermostat the immersion heater will heat the contents of the cylinder and then switch off. My hot water will then remain hot enough for washing up up to 48 hours later, that's with a pre-lagged (but old) cylinder, but with the insulating jacket correctly fitted to yours then you should have hot water for washing up at least into the evening.

    Finally, rather than changing the size of your cylinder, one way of reducing electricity use is just to heat a smaller amount of the contents. If you do only have an immersion heater in the bottom of your cylinder the following won't work, but if you have a top fitted immersion heater and it is only a short one, then it will only heat the water you need for face and hand washing and washing up. This is what I do, and in the summer my hot water - including a quick shower - costs under 12p per day.

    If you do go ahead with changing the cyclinder then having one with both top and bottom heaters will help you minimise running costs. And if you can put up with the slight inconvenience of having to plan ahead or waiting for the water to heat up, then only heating the whole cylinder when you actually have the occasional bath (even at day unit prices) may work out cheaper than always having a bathfull of hot water on standby.
    Last edited by EachPenny; 03-06-2017 at 1:43 PM. Reason: Typo
    "In the future, everyone will be rich for 15 minutes"
    • poppasmurf_bewdley
    • By poppasmurf_bewdley 3rd Jun 17, 10:06 PM
    • 4,942 Posts
    • 5,087 Thanks
    poppasmurf_bewdley
    Thanks Robin9 for answering. We own the flat so would be happy to replace the old cylinder with a modern one if it were to save electricity.


    We are doing a test: Currently the cylinder heating is on a timer and only heats between 2am and 5am to take advantage of the Economy7 tariff. In the morning the water is piping hot and this evening I will check if it is still hot enough. We have access to our meter so I can work out how much this costs us to run the heating of the cylinder for 3 hours a day only.


    If the water is not hot enough this evening, would it be better to improve the lagging on the current old cylinder or to replace with a modern cyclinder. Isn't the current cylinder really big for just two people, especially seeing as our showers are electric showers and don't use the cylinder water.


    Thanks again for all your help!
    Originally posted by AngelaDub
    Why not reset your timer to 5am-7am to give you an extra two hours worth of hot water, especially in the evening.
    There are not enough superlatives in the English language to describe a 'Princess Coronation' locomotive in full cry. We shall never see their like again". O.S. Nock
    • lstar337
    • By lstar337 5th Jun 17, 9:14 AM
    • 3,093 Posts
    • 1,630 Thanks
    lstar337
    The other problem you have with that tank is the low head (from the header tank on top of it) meaning low water pressure, not very good if you want a mains shower - in fact you probably can't run a shower from it at all. A new unvented cylinder would give you a better pressure - is your cold water pressure good ?
    Originally posted by molerat
    If anything like my old flat (it probably is) the shower is connected directly to the mains inlet anyway. They wouldn't run it off the header tank when it is that low. I wouldn't go to the trouble of an un-vented cylinder, they are more money and trouble than they are worth.

    @molerat The hot water pressure is terrible, especially in the kitchen! The cold water pressure is good.
    Originally posted by AngelaDub
    Yes, that isn't likely to change tbh. I had the same thing in my old flat. The tank/header were on the same floor as the hot taps, so not enough 'head' to push any kind of real flow through the tap. (you may find a new part-l cylinder is slightly taller/thinner giving you a small increase in flow).

    We would love higher hot water pressure - can the unvented cylinder still work to take advantage of Economy7 and be on a timer switch, etc. ?
    Originally posted by AngelaDub
    Your choice, but I have seen enough posts on this forum about un-vented cylinders to keep me away from them for ever.
    • lstar337
    • By lstar337 5th Jun 17, 9:18 AM
    • 3,093 Posts
    • 1,630 Thanks
    lstar337


    I believe these showers contain an internal pump which would indicate either they are being fed from a header tank, or that the mains pressure is low..
    Originally posted by coffeehound
    Can't see anything to indicate a pump on there. Plus a pumped shower would empty the tank/header too quickly.

    More than likely it is connected directly to the mains water inlet.
    • coffeehound
    • By coffeehound 10th Jun 17, 9:05 AM
    • 973 Posts
    • 1,571 Thanks
    coffeehound
    Can't see anything to indicate a pump on there. Plus a pumped shower would empty the tank/header too quickly.

    More than likely it is connected directly to the mains water inlet.
    Originally posted by lstar337
    My parents have a shower identical to the one in the photo which contains a pump. These are small boost pumps intended for use where the water supply pressure is low, rather than power-shower high-flow pumps.

    That said, they might well have made the same model without the pump so it might be an ordinary un-pumped instant electric shower.
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