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  • FIRST POST
    • blizeH
    • By blizeH 3rd Oct 19, 1:34 PM
    • 1,282Posts
    • 583Thanks
    blizeH
    With gas boilers potentially being banned in new homes from 2025, should we look at alternatives now
    • #1
    • 3rd Oct 19, 1:34 PM
    With gas boilers potentially being banned in new homes from 2025, should we look at alternatives now 3rd Oct 19 at 1:34 PM
    We need to replace our boiler ASAP and I'm wondering if it's worth looking at heat/air pumps? They're very expensive on the up front cost but it looks like in the (very) long run the savings make it worthwhile?


    I'm a bit concerned about the work involved though, and the physical space it uses. Any thoughts please? Thanks
Page 2
    • mmmmikey
    • By mmmmikey 13th Oct 19, 10:29 PM
    • 447 Posts
    • 731 Thanks
    mmmmikey
    A thought going through my mind here is that given the high usage you may find it's more efficient and cost effective to separate water heating from central heating. Possibly solar hot water panels heating a suitably sized thermal store using immersion heaters on E7 for boost?
    • mmmmikey
    • By mmmmikey 13th Oct 19, 10:31 PM
    • 447 Posts
    • 731 Thanks
    mmmmikey
    ....again throwing round ideas but have you considered a biomass boiler as an alternative to a HP?
    • Reed_Richards
    • By Reed_Richards 13th Oct 19, 10:33 PM
    • 608 Posts
    • 375 Thanks
    Reed_Richards
    Pumping heat is like pumping water up a hill. The higher the hill the more power it takes to pump the water. Pumping heat, the bigger the temperature difference between where you pump the heat from and where you pump it to, the more power it takes. So an air source heat pump efficiency will vary a lot depending on the outside air temperature. The lower the air temperature, the lower the efficiency yet the higher demand for heat inside the house. In principle an ideal heat pump will always be at least as efficient as direct electric heating (an electric fan heater for example). But in practise some heat is lost from the refrigerant when it is outside the house and the worst-case scenario is that the pipes freeze and the heat pump stops working.

    The ground acts like a big thermal store so if you dig down a little you find that the temperature varies less with the seasons than the air temperature.
    Reed
    • Solarchaser
    • By Solarchaser 13th Oct 19, 11:28 PM
    • 199 Posts
    • 264 Thanks
    Solarchaser
    Would this allow you to more efficiently use an inline direct electric heater to boost the temp above the store temperature which is optimised for heat pump?
    Yeah, generally you would be looking at heat pump to do bottom of cylinder and say a 3kw or 6kw element in the top.
    https://www.advanceappliances.co.uk/product/47-electric-combination-boiler-ecb-210/

    Something like that, is what I'll be going for.
    I haven't decided if I'm opting for solar thermal for bottom ring, or just dual electric element using solar in summer and e7 overnight in winter.

    I believe coastalwatch and possible Mmmmikey have bought this system already.
    The link is for a 210 cylinder, but the company does a range of sizes.
    They are very expensive for a hot water cylinder, but saves any contamination/legionella etc problems
    • Hexane
    • By Hexane 14th Oct 19, 12:35 AM
    • 169 Posts
    • 198 Thanks
    Hexane
    I don't know how many million families live in flats in UK, but for many of them Heat Pumps(all types) are impractical. Apart from the noise issue how do you mount and access the units on, say, a 20 storey block?
    Originally posted by Cardew
    There are large blocks of flats in the USA and India that have air conditioning units on them. Have seen similar in Spain. They are ugly and presumably expensive to mount and to service, but they are fitted and they work.
    7.25 kWp PV system (4.1kW WSW & 3.15kW ENE), Solis inverter, myenergi eddi & harvi for energy diversion to immersion heater. myenergi hub for Virtual Power Plant demand-side response trial.
    • Martyn1981
    • By Martyn1981 14th Oct 19, 7:35 AM
    • 9,731 Posts
    • 14,657 Thanks
    Martyn1981
    5 showers & 1 bath per day suggests a household of 6 persons & therefore a reasonably large house?

    If the above is true, then 32000 kWh doesn't seem unreasonable.

    For comparison, 3 of us managed to consume 27910 kWh of gas last year & we're already up to 17000 this year - now with just 2 of us.
    Originally posted by 1961Nick
    Wowza - I simply can't comprehend that level of gas consumption. That's four to five times ours, despite a four bed house (loft conversion) and size for size, heating should go down with higher occupancy, not up. Have you considered closing windows and doors in the winter?
    Mart. Cardiff. 5.58 kWp PV systems (3.58 ESE & 2.0 WNW)

    For general PV advice please see the PV FAQ thread on the Green & Ethical Board.
    • Martyn1981
    • By Martyn1981 14th Oct 19, 7:57 AM
    • 9,731 Posts
    • 14,657 Thanks
    Martyn1981
    There are large blocks of flats in the USA and India that have air conditioning units on them. Have seen similar in Spain. They are ugly and presumably expensive to mount and to service, but they are fitted and they work.
    Originally posted by Hexane
    I've got a friend who lives in an upstairs flat in terraced row (not quite a block of flats - but I'm getting there).

    He has good loft insulation, only the front and back room have a single external wall, and 'underfloor heating' (the flat below him). He has basic leccy heating, and I have suggested a heat pump (small A/C unit), but heating is so little that it makes the economics questionable ..... but I am stressing the environmental gains from the COP.
    Mart. Cardiff. 5.58 kWp PV systems (3.58 ESE & 2.0 WNW)

    For general PV advice please see the PV FAQ thread on the Green & Ethical Board.
    • Cardew
    • By Cardew 14th Oct 19, 8:41 AM
    • 28,022 Posts
    • 13,866 Thanks
    Cardew
    There are large blocks of flats in the USA and India that have air conditioning units on them. Have seen similar in Spain. They are ugly and presumably expensive to mount and to service, but they are fitted and they work.
    Originally posted by Hexane
    I owned an apartment in a large block the USA with an Air to Air ASHP/air-conditioner. However like virtually every apartment block I have seen in the USA the design called for the units to be mounted on the flat roof.

    A less than satisfactory solution is to have them on a balcony.

    I stayed for one night in a single storey cheap motel near Boston that had an external unit. It was a disaster, noisy and the internal unit vibrated excessively.

    To retro-fit to blocks of flats in UK would be impractical.
    • 1961Nick
    • By 1961Nick 14th Oct 19, 8:47 AM
    • 1,165 Posts
    • 3,782 Thanks
    1961Nick
    Wowza - I simply can't comprehend that level of gas consumption. That's four to five times ours, despite a four bed house (loft conversion) and size for size, heating should go down with higher occupancy, not up. Have you considered closing windows and doors in the winter?
    Originally posted by Martyn1981
    It's my next project now that electricity import is solved (75% reduction).

    Gas consumption is split 9Mwh DHW, 18Mwh CH & I'm targeting a reduction to 20Mwh without any lifestyle changes. I'm hoping a new boiler & Hive thermostatic rad valves will get me there.

    DHW is an issue because of the small cylinder size & the need for consecutive showers in the morning. To enable that, I'm running the boiler flow temperature & cylinder temperature considerably higher than is ideal.
    4kWp (black/black) - Sofar Inverter - SSE(141°) - 30° pitch - North Lincs
    Installed June 2013 - PVGIS = 3400

    Sofar ME3000SP Inverter & 5 x Pylontech US2000B Plus Batteries - 12kWh
    • roddydogs
    • By roddydogs 14th Oct 19, 9:21 AM
    • 6,471 Posts
    • 2,799 Thanks
    roddydogs
    No, because everyone knows that that date can't be met.
    • JKenH
    • By JKenH 14th Oct 19, 9:30 AM
    • 1,150 Posts
    • 3,313 Thanks
    JKenH
    It's my next project now that electricity import is solved (75% reduction).
    Originally posted by 1961Nick
    Sorry to hear about your divorce, Nick.
    Northern Lincolnshire. 7.8 kWp system, (4.2 kw west facing panels , 3.6 kw east facing), Solis inverters, Solar IBoost water heater, Mitsubishi SRK35ZS-S and SRK20ZS-S Wall Mounted Inverter Heat Pumps, Nissan Leaf (plus some ICEs )
    • Martyn1981
    • By Martyn1981 14th Oct 19, 2:13 PM
    • 9,731 Posts
    • 14,657 Thanks
    Martyn1981
    It's my next project now that electricity import is solved (75% reduction).

    Gas consumption is split 9Mwh DHW, 18Mwh CH & I'm targeting a reduction to 20Mwh without any lifestyle changes. I'm hoping a new boiler & Hive thermostatic rad valves will get me there.

    DHW is an issue because of the small cylinder size & the need for consecutive showers in the morning. To enable that, I'm running the boiler flow temperature & cylinder temperature considerably higher than is ideal.
    Originally posted by 1961Nick
    Unless your current boiler is seriously faulty, I think you may be disappointed. Our combi is now 21yrs old, and as I've said, we are looking at 6,000kWh's of gas all in this year*, and I still haven't switched to 'big boy' trousers yet, just shorts and a t-shirt.

    *Typically 7-8k before ASHP, and has been as high as 12k, back 20yrs before better insulation, draft proofing, and CWI.

    Are you absolutely certain your meter isn't connected to the whole street?

    25kWh's per day for DHW? Have you got a swimming pool?

    I'm starting to wonder if my gas meter is faulty, I assumed my figures were normal(ish), at least for this board.
    Mart. Cardiff. 5.58 kWp PV systems (3.58 ESE & 2.0 WNW)

    For general PV advice please see the PV FAQ thread on the Green & Ethical Board.
    • 1961Nick
    • By 1961Nick 14th Oct 19, 3:20 PM
    • 1,165 Posts
    • 3,782 Thanks
    1961Nick
    Unless your current boiler is seriously faulty, I think you may be disappointed. Our combi is now 21yrs old, and as I've said, we are looking at 6,000kWh's of gas all in this year*, and I still haven't switched to 'big boy' trousers yet, just shorts and a t-shirt.

    *Typically 7-8k before ASHP, and has been as high as 12k, back 20yrs before better insulation, draft proofing, and CWI.

    Are you absolutely certain your meter isn't connected to the whole street?

    25kWh's per day for DHW? Have you got a swimming pool?

    I'm starting to wonder if my gas meter is faulty, I assumed my figures were normal(ish), at least for this board.
    Originally posted by Martyn1981
    The boiler is fine according to British Gas who maintain it.

    It's a 20 year old Ideal that's around 75% efficient - moving to a modern condensing boiler will improve the efficiency into the 90's.

    I also have a pack of 5 Hive thermostats that I really need to make a start on fitting. The ultimate goal is to get one on every rad so that the boiler is 'on demand' by room rather than the temperature in the hall.
    4kWp (black/black) - Sofar Inverter - SSE(141°) - 30° pitch - North Lincs
    Installed June 2013 - PVGIS = 3400

    Sofar ME3000SP Inverter & 5 x Pylontech US2000B Plus Batteries - 12kWh
    • michaels
    • By michaels 14th Oct 19, 10:55 PM
    • 23,026 Posts
    • 105,093 Thanks
    michaels
    Unless your current boiler is seriously faulty, I think you may be disappointed. Our combi is now 21yrs old, and as I've said, we are looking at 6,000kWh's of gas all in this year*, and I still haven't switched to 'big boy' trousers yet, just shorts and a t-shirt.

    *Typically 7-8k before ASHP, and has been as high as 12k, back 20yrs before better insulation, draft proofing, and CWI.

    Are you absolutely certain your meter isn't connected to the whole street?

    25kWh's per day for DHW? Have you got a swimming pool?

    I'm starting to wonder if my gas meter is faulty, I assumed my figures were normal(ish), at least for this board.
    Originally posted by Martyn1981
    I did the maths above that shows that 12 showers a day is 41kwh for hot water.

    The space heating i am not so sure why we do 20kwh pa. We do have 150m2 heated to 17 between 11 and 5 and 21 the rest of the time but we use all the rooms so using remote rad valves wouldn't make much odds. I guess we might be able to get away with only heating downstairs in the day and upstairs in the evening but would this really make mush difference. Epc says mid b lifted from mid c due to PV. We also somehow use 8000 kWh of leccy pa not including 1500 of own use PV (and another 1500 via iboost), no idea where that goes, 2500 for the car but where does the rest go?
    Cool heads and compromise
    • Martyn1981
    • By Martyn1981 15th Oct 19, 8:25 AM
    • 9,731 Posts
    • 14,657 Thanks
    Martyn1981
    I did the maths above that shows that 12 showers a day is 41kwh for hot water.

    The space heating i am not so sure why we do 20kwh pa. We do have 150m2 heated to 17 between 11 and 5 and 21 the rest of the time but we use all the rooms so using remote rad valves wouldn't make much odds. I guess we might be able to get away with only heating downstairs in the day and upstairs in the evening but would this really make mush difference. Epc says mid b lifted from mid c due to PV. We also somehow use 8000 kWh of leccy pa not including 1500 of own use PV (and another 1500 via iboost), no idea where that goes, 2500 for the car but where does the rest go?
    Originally posted by michaels
    Cheers, and yep, I'm also interested where it goes. Incredible how it adds up. Perhaps some of this climatisation (though you and Nick might be better than me and Wifey), but the house is about 20C in the heating months, starts to get a bit too warm around 21C. In the warmer months, i actually find the comfort level around 22C, but that'll presumably be down to drafts from open doors, windows etc, and I'm typically barefoot.

    Another consideration, possibly is what is called here 'the Cardiff Bowl', as hills sort of trap heat, so temps might reflect the heat store of the sea (actually Bristol Channel), whereas you only have to go 10-20 miles inland, and several hundred feet up to 'enjoy' much colder temps.
    Mart. Cardiff. 5.58 kWp PV systems (3.58 ESE & 2.0 WNW)

    For general PV advice please see the PV FAQ thread on the Green & Ethical Board.
    • JKenH
    • By JKenH 15th Oct 19, 8:50 AM
    • 1,150 Posts
    • 3,313 Thanks
    JKenH
    I did the maths above that shows that 12 showers a day is 41kwh for hot water.

    The space heating i am not so sure why we do 20kwh pa. We do have 150m2 heated to 17 between 11 and 5 and 21 the rest of the time but we use all the rooms so using remote rad valves wouldn't make much odds. I guess we might be able to get away with only heating downstairs in the day and upstairs in the evening but would this really make mush difference. Epc says mid b lifted from mid c due to PV. We also somehow use 8000 kWh of leccy pa not including 1500 of own use PV (and another 1500 via iboost), no idea where that goes, 2500 for the car but where does the rest go?
    Originally posted by michaels
    Have you considered ASHPs (wall mounted aircon units)?

    I have been doing an exercise monitoring the 3.5kw ASHP in our 38sqm lounge. For the last few days we have had the oil CH turned off so the rest of the house is unheated other than the kitchen at the opposite end of the house where for the last two days I have been running an ASHP for 10 hours. We also have a 750w heater on in the bathroom for 30 minutes in the morning. Yesterday with outside temperatures ranging from 6C to 12 C the lounge ASHP used 3.4 kwh over 12.5 hours, an average of 272w/hr. Scaling that up to 150sqm would work out at 1.07 kw/hour. For say an average 12 hours a day that is about 13kwh per day. Over a 200 day heating period it would be 2600kwh.

    Now, I imagine it will use more heat when the weather gets colder but even so it would still I imagine be less than what you are currently using. The figures above were with the lounge door and curtains open for 10 hours. In the evening with the door and curtains closed it used 187w/hr to maintain a 22C temperature which on a standard tariff is about 3p an hour.

    I have found that if I run the ASHP for shorter periods the power consumption per hour of running is higher (which is as one would expect as most power is used bringing the room up to temperature.)

    I had posted the following on the Solar/ASHP after monitoring the unit over a week averaging about 7 hours a day.

    “over a week I have run my 3.5kw ASHP for heating 50.9 hours and used 21.1 kwh - an average of 415w per hour on an Eco Automatic setting with the thermostat set at 23, 24 or 25C. I am assuming that as the ASHP is mounted just below the ceiling it will take the temperature measurement there. The equilibrium room temperature achieved with door open measured 1m off the floor has been on average 21C (max22C) from a starting temperature of 17,18, or 19C first thing in the morning. Outside temperatures have ranged from 1.5C at 8am(coldest) to 17.5C at 4pm (warmest).”

    I switched the unit on at 4.30 this morning to take advantage of E7 for the start up phase and i wanted to know if the average consumption would fall further if running for a longer day. I had read somewhere that the units are more efficient when working less hard. I will update either on here or the solar/ASHP thread.
    Northern Lincolnshire. 7.8 kWp system, (4.2 kw west facing panels , 3.6 kw east facing), Solis inverters, Solar IBoost water heater, Mitsubishi SRK35ZS-S and SRK20ZS-S Wall Mounted Inverter Heat Pumps, Nissan Leaf (plus some ICEs )
    • 1961Nick
    • By 1961Nick 15th Oct 19, 9:15 AM
    • 1,165 Posts
    • 3,782 Thanks
    1961Nick
    Have you considered ASHPs (wall mounted aircon units)?

    I have been doing an exercise monitoring the 3.5kw ASHP in our 38sqm lounge. For the last few days we have had the oil CH turned off so the rest of the house is unheated other than the kitchen at the opposite end of the house where for the last two days I have been running an ASHP for 10 hours. We also have a 750w heater on in the bathroom for 30 minutes in the morning. Yesterday with outside temperatures ranging from 6C to 12 C the lounge ASHP used 3.4 kwh over 12.5 hours, an average of 272w/hr. Scaling that up to 150sqm would work out at 1.07 kw/hour. For say an average 12 hours a day that is about 13kwh per day. Over a 200 day heating period it would be 2600kwh.
    Originally posted by JKenH
    Taking this a step further, an ASHP running on batteries charged on a TOU or E7 tariff would only cost 1.5p for a kWh of heat (assuming COP 4). Any overnight direct running on the lower tariff could be as low as 1.25p.
    4kWp (black/black) - Sofar Inverter - SSE(141°) - 30° pitch - North Lincs
    Installed June 2013 - PVGIS = 3400

    Sofar ME3000SP Inverter & 5 x Pylontech US2000B Plus Batteries - 12kWh
    • GreatApe
    • By GreatApe 15th Oct 19, 11:52 AM
    • 4,070 Posts
    • 3,002 Thanks
    GreatApe
    Have you considered ASHPs (wall mounted aircon units)?

    I have been doing an exercise monitoring the 3.5kw ASHP in our 38sqm lounge. For the last few days we have had the oil CH turned off so the rest of the house is unheated other than the kitchen at the opposite end of the house where for the last two days I have been running an ASHP for 10 hours. We also have a 750w heater on in the bathroom for 30 minutes in the morning. Yesterday with outside temperatures ranging from 6C to 12 C the lounge ASHP used 3.4 kwh over 12.5 hours, an average of 272w/hr. Scaling that up to 150sqm would work out at 1.07 kw/hour. For say an average 12 hours a day that is about 13kwh per day. Over a 200 day heating period it would be 2600kwh.

    Now, I imagine it will use more heat when the weather gets colder but even so it would still I imagine be less than what you are currently using. The figures above were with the lounge door and curtains open for 10 hours. In the evening with the door and curtains closed it used 187w/hr to maintain a 22C temperature which on a standard tariff is about 3p an hour.

    I have found that if I run the ASHP for shorter periods the power consumption per hour of running is higher (which is as one would expect as most power is used bringing the room up to temperature.)

    I had posted the following on the Solar/ASHP after monitoring the unit over a week averaging about 7 hours a day.

    “over a week I have run my 3.5kw ASHP for heating 50.9 hours and used 21.1 kwh - an average of 415w per hour on an Eco Automatic setting with the thermostat set at 23, 24 or 25C. I am assuming that as the ASHP is mounted just below the ceiling it will take the temperature measurement there. The equilibrium room temperature achieved with door open measured 1m off the floor has been on average 21C (max22C) from a starting temperature of 17,18, or 19C first thing in the morning. Outside temperatures have ranged from 1.5C at 8am(coldest) to 17.5C at 4pm (warmest).”

    I switched the unit on at 4.30 this morning to take advantage of E7 for the start up phase and i wanted to know if the average consumption would fall further if running for a longer day. I had read somewhere that the units are more efficient when working less hard. I will update either on here or the solar/ASHP thread.
    Originally posted by JKenH

    Which tariff do you use?

    The EDF off peak for 8p a unit (other times 16p) seems good especially because off peak is defined as all weekend and weekdays 9pm to 7am so there are more off peak hours than on peak hours

    And because you have solar that will cover mostly the 16p on peak times
    • GreatApe
    • By GreatApe 15th Oct 19, 12:01 PM
    • 4,070 Posts
    • 3,002 Thanks
    GreatApe
    I did the maths above that shows that 12 showers a day is 41kwh for hot water.

    The space heating i am not so sure why we do 20kwh pa. We do have 150m2 heated to 17 between 11 and 5 and 21 the rest of the time but we use all the rooms so using remote rad valves wouldn't make much odds. I guess we might be able to get away with only heating downstairs in the day and upstairs in the evening but would this really make mush difference. Epc says mid b lifted from mid c due to PV. We also somehow use 8000 kWh of leccy pa not including 1500 of own use PV (and another 1500 via iboost), no idea where that goes, 2500 for the car but where does the rest go?
    Originally posted by michaels

    You might have big energy vampires

    My parents had their boiler on 24/7 because their tank was set at a higher tetemperature than their boiler hot water temp. For example the tank was sending s singal for more heat until the tank got to 65 centigrade while the boiler was set to 60 centigrade

    This meant the pump was on 24/7 every day of the year
    And the uninsulated pipework from the tank to the boiler was constantly 60 centigrade

    The result was some 800KWh of electricity just wasted for nowt and an unknown number of gas units probably 3-5 MWh of gas

    I suspect millions of heating systems are set wrongly like this

    There is also another common problems which is that radiators are wrongly sized
    My home is like this the living room radiator is too small so I have to set the boiler to 90 centigrade to keep that room warm. This meas the boiler is not operating at condensing temperatures but less efficient range


    I feel wet heat pump systems would be even worse than this
    While perfectly fitted systems would probably work done in the real world with careless or sloppy or uneducated installers the result will be much worse and much less forgiving. My brother has a full heat pump system. Some of the outside copper pipework isn't even insulated. It's ridiculous I've mentioned it to him but he is too lazy or doesn't quite get the concept that the hot water from the heat pump running though maybe 3-4 meters of uninsulated copper pipe isn't s good idea. Hasn't been a winter with it yet and if it freezes... Bye bye coper pipe. Actually I should mention that to him I don't think he has considered the freezing pipe bursting
    • JKenH
    • By JKenH 15th Oct 19, 12:19 PM
    • 1,150 Posts
    • 3,313 Thanks
    JKenH
    Which tariff do you use?

    The EDF off peak for 8p a unit (other times 16p) seems good especially because off peak is defined as all weekend and weekdays 9pm to 7am so there are more off peak hours than on peak hours

    And because you have solar that will cover mostly the 16p on peak times
    Originally posted by GreatApe
    I am with Bulb on an E7 tariff at about 15p/9p including VAT? I had a look at the EDF MSE special tariff on line but couldn’t find the bit about weekends being E7. That would appeal to me so if you have a link could you put it up here please.

    Thanks
    Northern Lincolnshire. 7.8 kWp system, (4.2 kw west facing panels , 3.6 kw east facing), Solis inverters, Solar IBoost water heater, Mitsubishi SRK35ZS-S and SRK20ZS-S Wall Mounted Inverter Heat Pumps, Nissan Leaf (plus some ICEs )
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