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Electric Boiler for wet central heating

Last post Thu, Jul 02 2009, 11:54 AM by NWoody. 7 replies.
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  •  Thu, Jul 02 2009, 11:54 AM

    Re: Electric Boiler for wet central heating

    Andy

    Thanks very much for your response, it is very helpful. I hadn't actually considered a direct immersion heater but now that you mention it, it does make sense. I know that the immersion will take longer to heat the tank up but it's something I will consider now. We also have a wood/coal burning fireplace that will be replaced with a multi-fuel stove at some point, and the 'in laws' have a pile of dead trees for us to burn (as long as we chop some wood for them too!) that provides additional space heating.

    Thanks also for the advice re heat plates. As we have a suspended timber floor the noise/creaking could be an issue. We should easily be able to use sand/screed to fill the void as the timbers rest directly on concrete upstands at regular spacing, hence no need to beef up the timbers.

    I have a form from the local electricity board and will be sending this off shortly to confirm acceptable load. My electrician will be helping to fill it out so will get an idea of what we can install shortly.

    Thanks again for your help on this

    Nathan

    • Post Points: 5
  •  Tue, Jun 30 2009, 10:06 PM

    Re: Electric Boiler for wet central heating

    Nathan

    Yes, we've installed our system. So far so good although we've not had it in long enough to comment on overall running costs. We do have a very well insulated build, better than building regs and hopefully this will keep running costs down. (We also have a wood burning stove and access to lots of cheap wood.) Underfloor heating is a total joy and very unlike standard radiators. The one thing I would say is that we went for a direct heated hot water with a solar coil only. Our rational was that if the boiler is electric, it seemed a tad pointless to heat the water indirectly through the boiler and pump it through a coil in the hot water tank to transfer the heat to the water in the tank. Why not just use a dedicated immersor - using the self same 'lectricity - to heat it directly? Seems to me to be a more efficient method. Our boiler (Trianco Aztec 9kW) supplies heat only for the underfloor heating (downstairs in concrete screed) and radiators (upstairs). Again, our research led us to conclude that underfloor heating works best buried in a material with a good thermal mass. We looked into filling the voids between the upstairs joists with dry sand laid on plywood on battens but the problems outweighed the benifits - engineers being twitchy and wanting us to beef up the timbers being the main drawback. The benefits seem to be; a greater thermal mass, greater sound insulation and no creaking from heat plates - apparently something they don't mention in the sales brochures. Before committing to an electric boiiler, check with your elctricity board - not the supplier but the guys who maintain the infrastucture - that your local substation can handle the increased load. Wiring is also an extra cost as our boiler needed a dedicated MCB and RCD.

    Andy

    • Post Points: 20
  •  Tue, Jun 30 2009, 3:33 PM

    Re: Electric Boiler for wet central heating

    Hello

    Sorry if this is thread is long dead but I have just picked up on this debate. Philos4424, I have a similar problem. I have a 1960 3 bedroom bungalow that is in need of renovation. I live in Jersey (Channel Islands) so a somewhat different climate to W. Scotland but like you I have no mains gas and no oil tank at present. I am going to replace the existing hot water system (extremely old and probably dangerous electric boiler/tank with immersion heater under the sink) and install a new pressurised system with the tank in the loft. Current heating is Dimplex storage heaters (hugely ineffective and last quarter elec. bill was over £500).

    I have been considering my options and the rest of the thread pretty much covers my train of thought: Air source heat pump - too noisy (it is VERY quiet where I live); GSHP - expensive, borehole the only real option, probably will need topping up with electricity; Gas - not really something I'm considering as all gas is imported to the Island and therefore very expensive; Electric - Looking like a good option, and may retro fit solar at some point to provide additional hot water; Oil - Also something I'm really considering (oil fired central heating is common here).

    At the moment, the most likely scenario is to install an electric boiler with storage tank that can be fitted with solar (in the future) and wet under floor heating. I will be insulating the suspended timber ground floor between joists with rigid boards, heating pipes over and probably heat plates on top of that before floor finishes.

    If anyone has any experience on this and would advise against an electric boiler I would be greatful to hear your thoughts. Oil may be slightly cheaper to run but capital cost/whole life costing may still push me back to electric. Philos4424 have you now fitted your new system? What did you go for if so? Any advice would be much appreciated.

    Thanks in advance

    Nathan

    • Post Points: 20
  •  Wed, Feb 18 2009, 11:41 PM

    Re: Electric Boiler for wet central heating

    Hi

    If my experince is anything to go by forget air source heat pumps if the outside temperature is likely to fall below 5 degrees Celcius . You will have to run pump 24/7 and if you are lucky you may get 40 degress plus hot water .My system is made by Heatking ,12kw rated output,it is noisy and struggles to keep the underfloor heating going ,it is useless for the first floor fan assisted heaters (more like coolers ). I am now having to consider an electric boiler to boost the water temp for the radiators and give me domestic hot water.Economy 10 is worth considering.If you take the installation costs along with the high energy usage this is not a solution I would recommend .Electricity prices are a rip off,as are most of the utilities in the UK.

    • Post Points: 20
  •  Fri, Oct 17 2008, 11:52 AM

    Re: Electric Boiler for wet central heating

    I would highly recommend that you don't have a ground source heat pump fitted to the property as they do not work. I have just had one fitted and was told the system would heat the whole house and my hot water in the house. The sytem heats the ground floor of the house so most of the house is cold. the system only heats upto 30 degrees so the hot water will never be warm enough to use for showers or baths. We are dependant on an imersion heater in the hotwater tank which is expensive.

    The sytem is more expensive to run than gas and the hidden instalation costs are massive. Extra plumbing electrical instalation and ground work over all this came to over £2500. This does not includ the fitting of the sytem to the underfloor heating and ground loop.

    Lee

    • Post Points: 5
  •  Sat, Oct 11 2008, 12:24 PM

    Re: Electric Boiler for wet central heating

    Gabriel

    Thanks for the reply.

    Air source heat pumps have been considered and it's my understanding that they're quite large - like a big air conditioning unit, stuck on the outside of the house - and noisy. Also, I believe that they work well with UFH as the circulating water temp - 40 - 45 degrees I think - is lower than conventional rads which require about 80 degrees, and in order to get sufficient heat from a radiator it's surface radiating area needs to be almost doubled. Having said all that the major consideration I have is budgetary.

    With regard to the load test, already done and satisfactory.

    (Just looked at the Danfoss site and see that the unit has a much smaller external footprint than I thought. Still, the budget....)

    Anyway, I still need to think this through before committing to electric so any more advice from all out there appreciated.

    • Post Points: 20
  •  Thu, Oct 09 2008, 8:03 PM

    Re: Electric Boiler for wet central heating

    Hi,

    You've got 2 options really

    Air source heat pumps - Less expensive than Ground, but still costly as hell, starting at about £10K. May be worth it in the long run tho and will add to your "green" points, more info below..

    http://www.worcester-bosch.co.uk/homeowner/products/air-source-heat-pumps

    http://www.ecoheatpumps.co.uk/

    Wet heating system - you know what this is about, the company who invented it and also the economy 10 tariff (in conjunction with Scottish Hydro) have their website here...

    http://www.electric-heatingcompany.co.uk/

    If you go for the wet system, Eco 10 is the best tariff for that system by a mile. It either wont work, or ruin you, if you try any other tariff with it. If you go for Air source, it'll depend on the application you chose, however Eco 10 may still be your best bet.

    You may need to confirm the supply you have to your property can support the expected loads of these tariffs. Once you know what your going for and how much load you'll need, contact your distributor directly to confirm this. (if you do need an upgrade, budget at least 2k for this initially)

    • Post Points: 35
  •  Thu, Oct 09 2008, 1:16 PM

    Electric Boiler for wet central heating

    Hi, I'm new to this game so excuse if this has all been covered before.

    Basically, my dilemma is as follows. I'm in the process of building a three bedroom house on the west coast of Scotland. No mains gas, only oil or LPG. With geopolitics being what it is I don't want to use oil or LPG (the P being petroleum) to provide heat for radiators and underfloor heating, already installed. Ground source heat pumps are not an option although we are hoping to install a small solar panel to provide some domestic hot water. A wood burning stove will provide space heating in one room downstairs (and hopefully circulate throughout the rest of the house, which is very well insulated). Back boiler not an option due to layout. That leaves me with little option but to consider an electric boiler to produce hot water to circulate in the central heating system. (Our supply comes from a pair of privately run hydro-electric generators which feed the grid, so green issues are covered). I know electric heating is very expensive, even on Economy 10, which seems to be the best deal.


    As I said, the house is well insulated and we should really only require the central heating occasionally, but I am led to believe that underfloor heating is best used by keeping a background heat in the system - 15 degrees I think - even when not on. This would entail the boiler cycling 24/7, often outwith the E10 off peak hours. Also, the ability to warm the house outside the off peak periods without breaking the bank (and do they really need my help to do that) would be nice. Does anybody out there have any tips or suggestions with regard to the most economical way forward? Who does the best electricity only deal for this area - postcode PA31, Argyll - or are all suppliers available to me? I'm currently ( no pun intended) with Scottish Hydro, on a standard tariff. Are there better deals than E10? Has anyone had experience of electric boilers?

    Thanks in advance

    • Post Points: 20