Welcome to Koi Forum. Is this your first visit? Register
Results 1 to 13 of 13
  1. #1

    Heating running costs

    We have just done a search of new tariffs for our home energy because our 12 month fixed deal is coming to an end.
    Across the board electricity is going up.
    The cheapest we have found currently (06/04/21) has electricity approximately 5.8 times more expensive than gas per kWh.

    With this price differential heating a pond using a heat exchanger fed by your gas central heating is a no brainer IF it is practical to do so.
    Even ASHP can't compete in real world conditions unless ambient temperature is already high and therefore they probably aren't needed to do much heating anyway.

    I'm not going to heat our pond this way because A. I only heat when below 5.5C, so as a safeguard only and B. Any pipe runs would be excessive.
    I'm surprised that dedicated gas heaters are not more common - guessing the installation of new gas supply must be very high (I've never checked).
    These offer an effective cost COP (relative to electricity) as good as most ASHP with the difference that this is unaffected by very low temps and so is just as good when it's really cold and you really need it.

    What I will be doing is modifying the hot tub to be heated by the central heating. There's someone in our household who thinks that if I suggested 5.5C in the hot tub I might be the one that needs safeguarding!


    My DIY ponds from 1988 until present day.
    All can be found here:
    https://www.ukzero.com/pond.htm

  2. Thanks Ajm, davethefish1, dbs, Díster Thanked / Liked this Post
  3. #2
    Senior Member Rank = Supreme Champion Ajm's Avatar
    Join Date
    Mar 2018
    Location
    Durham
    Posts
    6,628
    Thanks / Likes
    13766
    Quote Originally Posted by Ukzero View Post
    We have just done a search of new tariffs for our home energy because our 12 month fixed deal is coming to an end.
    Across the board electricity is going up.
    The cheapest we have found currently (06/04/21) has electricity approximately 5.8 times more expensive than gas per kWh.

    With this price differential heating a pond using a heat exchanger fed by your gas central heating is a no brainer IF it is practical to do so.
    Even ASHP can't compete in real world conditions unless ambient temperature is already high and therefore they probably aren't needed to do much heating anyway.

    I'm not going to heat our pond this way because A. I only heat when below 5.5C, so as a safeguard only and B. Any pipe runs would be excessive.
    I'm surprised that dedicated gas heaters are not more common - guessing the installation of new gas supply must be very high (I've never checked).
    These offer an effective cost COP (relative to electricity) as good as most ASHP with the difference that this is unaffected by very low temps and so is just as good when it's really cold and you really need it.

    What I will be doing is modifying the hot tub to be heated by the central heating. There's someone in our household who thinks that if I suggested 5.5C in the hot tub I might be the one that needs safeguarding!
    Yeah safeguarding before she holds your head under the 5.5 water lol

    I don't have the luxury of choice on this one as we don't have a gas hook up to the house never mind the garden..

    I'll be doing that same as you mate heating to hold 6 ish and ill take the electricity bill on the chin as
    1) gotta be cheaper than restocking a pond
    2) sleep better know the fish are safe
    3) lot less stress

    Sent from my F5121 using Tapatalk
    Johnathan

  4. Thanks Ukzero, davethefish1, dbs, Díster, Gazkoi Thanked / Liked this Post
  5. #3
    Moderator Rank = Supreme Champion Feline's Avatar
    Join Date
    Aug 2013
    Location
    Somerset
    Posts
    6,168
    Thanks / Likes
    4819
    The ideal setup is to have either a zone valve off the main gas boiler, or a separate pond boiler for the winter, and then an ASHP to run over summer to get temperature stability at night and maintain growth temperatures (which you can rarely do for long in the UK because an unheated pond won’t stay above 22C for long at all.)

    I generally do heat my pond in summer, but this is mostly for free because I have a big solar panel installation on the house.

  6. Thanks Díster Thanked / Liked this Post
  7. #4
    Quote Originally Posted by Feline View Post
    I generally do heat my pond in summer, but this is mostly for free because I have a big solar panel installation on the house.
    PV solar panels are a saving grace with electricity and do skew the equation more towards ASHP in the Summer months so I would certainly do the same if I wanted to heat the pond over the Summer

    AJM - Absolutely agree in doing whatever necessary to keep the fish out of the hypothermia zone
    (guess poikilotherms can get too cold, so guess hypothermia could be an apt term?).
    My DIY ponds from 1988 until present day.
    All can be found here:
    https://www.ukzero.com/pond.htm

  8. Thanks Ajm Thanked / Liked this Post
  9. #5
    Senior Member Rank = Sansai Naoki Atsumi's Avatar
    Join Date
    Dec 2020
    Location
    Tokyo Japan
    Posts
    126
    Thanks / Likes
    132
    Quote Originally Posted by Feline View Post
    The ideal setup is to have either a zone valve off the main gas boiler, or a separate pond boiler for the winter, and then an ASHP to run over summer to get temperature stability at night and maintain growth temperatures (which you can rarely do for long in the UK because an unheated pond won’t stay above 22C for long at all.)

    I generally do heat my pond in summer, but this is mostly for free because I have a big solar panel installation on the house.
    https://tsuri-suru.com/wp-content/up...uion_graph.gif
    I am all for focusing on summer rather than year-round heating as you mention. If we take the water temperature of a typical unheated pond in Japan and make it a priority to keep it above 25įC for about a month and a half in mid-summer, how much can we expect to save in electricity or fuel costs by not heating the pond in winter and concentrating on summer (as our winter is often colder than you are)?

  10. #6
    Senior Member Rank = Jussai davethefish1's Avatar
    Join Date
    Apr 2019
    Location
    Bedworth
    Posts
    1,173
    Thanks / Likes
    2597
    don't get me started on the gas and electricity monopoly!

    gas and electricity prices are a big con really.
    to start with, it varys by area...WTF... national grid....!
    what they mean is, in more affluent postcodes they get away with charging more,
    to offset people who dodge the bills, and don't pay at all...


    you can get relatively good tariffs but have to do a lot of leg work.

    they will offer you there cheapest tariff... that they have to... by law....
    only, they don't have to offer you a tariff that they give to a price comparison website (much cheaper) as that doesn't count as an offer by them...

    but if you use the price comparison website and then contact them after they have received the change request.
    they most often will offer you a cheaper 'exclusive offer' in order to get around the laws regarding cheapest tariff offers.

    this is how i've set my fixed rate energy deals for the last 10 years with scottish power.
    my current one is 'Exclusive Help Beat Cancer Fix and Save March 2022 Online'
    electricity day rate 13.22p/kWh
    electricty night rate 07.01p/kWh
    gas 02.72p/kWh

    on the bigger picture a heatsource pump works well but needs space in front and ideally wants to be away from yours and nieghbours houses.
    it's just not practical for me on a fairly new housing estate as the houses are so close together...
    a guy down the opposite end of our close fitted air con to his house but got so many angry threats from neighbours about the compressor noise he doesn't use them at night anymore.

    my new build i'll be using my house central heating for most of the heating, backed up by a direct electric heater at night on economy 7 rate.
    so it will use it for a while at night as i don't want the boiler running between 12am-6am.
    i just need to decide whether to run the pond water to a heat exchanger on the house outside wall.
    ...or the central heating pipes to my filter house...
    The Solution to Pollution is Dilution

  11. Thanks john1 Thanked / Liked this Post
  12. #7
    Quote Originally Posted by davethefish1 View Post
    electricity day rate 13.22p/kWh
    electricty night rate 07.01p/kWh
    gas 02.72p/kWh.
    That's a very good deal in the current market
    But sadly isn't currently offered - now it's the 2023 version with electricity in the 17p range
    Last edited by Ukzero; 06-04-2021 at 04:24 PM.
    My DIY ponds from 1988 until present day.
    All can be found here:
    https://www.ukzero.com/pond.htm

  13. Thanks davethefish1 Thanked / Liked this Post
  14. #8
    Senior Member Rank = Jussai davethefish1's Avatar
    Join Date
    Apr 2019
    Location
    Bedworth
    Posts
    1,173
    Thanks / Likes
    2597
    Quote Originally Posted by Ukzero View Post
    That's a very good deal in the current market
    But sadly isn't currently offered - now it's the 2023 version with electricity in the 17p range
    this is the rip off.
    i never accept the standard 'advertised' offer rates.
    the call centres job is to get you on the highest 'cheap' tariff they 'legally' obliged to.

    but there are loopholes you can use to go round them, as they are also trying to attract new customers with juicey deals.
    'exclusive' offers are made individally, i negotiated my rate with scottish power.

    the rate i was originally offered was something like18p/kWh iirc as thier 'cheapest' deal.
    there's a thread on here somewhere where i detailed what i did....
    the hard part is finding it...
    The Solution to Pollution is Dilution

  15. Thanks Ajm, Díster Thanked / Liked this Post
  16. #9
    Moderator Rank = Supreme Champion Feline's Avatar
    Join Date
    Aug 2013
    Location
    Somerset
    Posts
    6,168
    Thanks / Likes
    4819
    I have the EDF electric car tariff that gives me half price units overnight (9pm to 7am) and all weekend. Since the solar panels are producing 100% of what we use in the day for at least 6 months of the year that turns out to be a very good deal for us, and then we get paid for what we generate with the feed in tariff too, even if we use it
    https://www.edfenergy.com/electric-cars/tariffs#offpeak

  17. #10
    That's another very good deal Feline.

    At our last house we had a FIT system fitted when the rates were really good. The installer fitted it incorrectly (we had no idea) and the old spinnng disk meter ran backwards when we produced an excess. So we got paid through the FIT and the system wound back our meter readings. We ended up with a nett annual electricity bill of less than £100.
    I looked at fitting PV panels on our current bungalow, but orientation and surrounding trees were against us.

    My DIY ponds from 1988 until present day.
    All can be found here:
    https://www.ukzero.com/pond.htm

  18. #11
    Senior Member Rank = Nanasai Spongebob's Avatar
    Join Date
    May 2020
    Location
    Greater Manchester/Iraq and Mozambique
    Posts
    644
    Thanks / Likes
    997
    Im not getting it! I think there's a big assumption that ASHP's are expensive and dont heat well in winter, wrong! There's a good vid here, an average month in winter, are we really saying gas is going to be cheaper than this? Averaged out over the year where an ASHP comes into its own over summer, im sorry but ASHP wins hand down. Plus its literally take it out the box, install in a couple of hrs, and a seven year guarantee if it goes wrong.

    9000 litre, fibreglass, BD/skimmer, Nexus 220, Draco, Remora i9 ASHP, Econbead 50 bead filter.

  19. Thanks Twhitenosugar Thanked / Liked this Post
  20. #12
    I promise I not anti-ASHP. We had one at our old house for the central heating.
    However, when air temp fell below about 6C the system switched to a conventional boiler because the ASHP COP fell to a point where it couldn't deliver the required heat and became expensive to run.
    If I wanted to heat our pond to 17C or higher I too would install an ASHP. If I could I would install gas heating for the Winter, but use the ASHP all year if I couldn't.

    Out of curiosity I just watched a video about data logging the Remora i12 ASHP, which shows some actual power consumption figures and costs.
    For one period in the Winter the ASHP consumed 73.9kWh which cost £11.40 (averages at about 15p kWh).
    The same kWh in gas (based on what I pay) is about £1.84. Electricity is about 6 times the price of gas (the differential has recently grown).
    In terms of heat transfer, a modern gas system and a good heat pump I will guess have similar efficiencies.
    However, ASHP produce more kW of heat than they consume in electricity, so if the ASHP is running with a COP of 6 or more then it is going to be as cheap or cheaper than a gas system and yes, much easier to fit.
    I couldn't find a COP/ambient temperature chart for the Remora so can't comment on its COP at low ambient temperatures.
    Charts I could find, which may be for less efficient ASHP of older designs, suggest maintaining a COP of 6 at low temperatures could be a challenge.

    Having said all that, as I have said, ASHP compared to conventional electric heating is also a no brainer.

    Having just changed my filter to air-lift with all 4" gravity feed and return I wouldn't be able to install a through-flow heater of any kind without adding a pumped loop.

    My DIY ponds from 1988 until present day.
    All can be found here:
    https://www.ukzero.com/pond.htm

  21. Thanks Twhitenosugar Thanked / Liked this Post
  22. #13
    Senior Member Rank = Nanasai Spongebob's Avatar
    Join Date
    May 2020
    Location
    Greater Manchester/Iraq and Mozambique
    Posts
    644
    Thanks / Likes
    997
    Quote Originally Posted by Ukzero View Post
    I promise I not anti-ASHP. We had one at our old house for the central heating.
    However, when air temp fell below about 6C the system switched to a conventional boiler because the ASHP COP fell to a point where it couldn't deliver the required heat and became expensive to run.
    If I wanted to heat our pond to 17C or higher I too would install an ASHP. If I could I would install gas heating for the Winter, but use the ASHP all year if I couldn't.

    Out of curiosity I just watched a video about data logging the Remora i12 ASHP, which shows some actual power consumption figures and costs.
    For one period in the Winter the ASHP consumed 73.9kWh which cost £11.40 (averages at about 15p kWh).
    The same kWh in gas (based on what I pay) is about £1.84. Electricity is about 6 times the price of gas (the differential has recently grown).
    In terms of heat transfer, a modern gas system and a good heat pump I will guess have similar efficiencies.
    However, ASHP produce more kW of heat than they consume in electricity, so if the ASHP is running with a COP of 6 or more then it is going to be as cheap or cheaper than a gas system and yes, much easier to fit.
    I couldn't find a COP/ambient temperature chart for the Remora so can't comment on its COP at low ambient temperatures.
    Charts I could find, which may be for less efficient ASHP of older designs, suggest maintaining a COP of 6 at low temperatures could be a challenge.

    Having said all that, as I have said, ASHP compared to conventional electric heating is also a no brainer.

    Having just changed my filter to air-lift with all 4" gravity feed and return I wouldn't be able to install a through-flow heater of any kind without adding a pumped loop.

    There doesnt seem to be much data for lower temps, but its really irrelevant. Those costs the guy did on the Remora i12 Inverter are for Dec/Jan, and as his data shows, that period his Remora regularly defrosts (mine does too at least 12 times a day when temp is below 8 degrees) Yet it still cost only1.32 per day over that period and that's heating to 17 degrees, well above ambient. As most only want to maintain above AA at 13, or above the danger zone at 5 ish, the costs would be pence per day. So even in the worst case scenario with the ASHP regularly defrosting the costs are still low. Come summer the COP is ridiculous on a Remora, the best out there, so the summer costs are going to be even lower. Where the gas price will be the same.

    I just feel most are basing assumptions on on/off units, where generally they have fitted a ASHP that's not large enough for purpose. The modern Inverter units are a whole different kettle of fish.
    9000 litre, fibreglass, BD/skimmer, Nexus 220, Draco, Remora i9 ASHP, Econbead 50 bead filter.

  23. Thanks Twhitenosugar Thanked / Liked this Post
 

 

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
All times are GMT +1. The time now is 12:55 AM. Online Koi Mag Forum
Powered by vBulletin® Version 4.2.3
Copyright © 2021 vBulletin Solutions, Inc. All rights reserved.

vBulletin Improved By vBFoster® (Lite Version), © UltimateScheme, Ltd.