mk1_man

Hi, for what its worth I have the 7kW Vaillant Arotherm plus alongside the Vaillant 250litre cylinder. Very happy with the performance, overall a scop of 4.8 since installation in Sept. I heat the water once in the early hours to 60 degrees so not exactly the most efficient way of doing things even though it is set to ECO mode. I don't mind as this is when the electric is only 5p/kWh. Heating once to this temperature is enough to last us all day and we bath (large 800 x 1800) each day and its enough. I would advise going to a 300l if you can fit it in, ours is in the loft so restricted to the 250. Bonus with Vaillants is that they are 600mm wide as opposed to majority at I think 550mm so generally shorter than others. Not sure where comments of mini coils come from, the 250l is 2.4m2 and the 300 is 2.8m2. Quantity isn't always better than quality. Not sure what you area of house is and if you have underfloor or not but our 7kWh has performed brilliantly with +5 COP being the norm on heating. We are 250m2 with underfloor on both floors however upstairs is never on apart from bathrooms. The heatpump generally ticks over at around 500 - 600 watts consumption which is amazing. One option is to install yourself or get a local plumber to install this way you can avoid the inflated costs that majority of MCS companies charge. We purchased the heatpump and cylinder ourselves and then used an MCS umbrella company to do the heat loss calcs, paperwork, 7 year warranty, BUS application etc. Our install ended up being cost neutral one we received the £7.5k grant. I then invested some of the money I would have spent if i had gone the usual route by investing in some batteries so that we can run the whole house 24 x 7 on cheap overnight electric (5p/kWh). This I feel is a better option than tying into OVO scheme where you only get the 15p against the heat pump only and not the rest of the house consumption. There is potential that they may end up controlling your heating schedule also? what ever route you take, going all electric with heat pump is best thing we ever did 🙂

I was on Cosy previously and it does work well especially if you have batteries. The three different periods allows you to spread the heat from your ashp over the day instead of trying to condense into a single cheap block. A best of both worlds is Tomato energies Lifestyle tariff, gives you 6 hours at 5p/kWh during the night but also another 4 hours during the day at 14p and the rest of the time it is still less than the cap price unlike Octopus offering where you get penalized between 16:00 - 19:00 I have used 244 kWh in last 7 day at a cost of £12.34

Yes, I have batteries (no solar) and charge them up overnight at 5p and then run the house for rest of the day from them. So far I haven't had to pay for any additional electric so looking good. My opinion is that it is better to spend on batteries than it is on solar especially when its the winter when you need the electric for the heat pump and generally no solar at that time. I calculate my payback is 3 - 4 years however I did source some great deals on my batteries. I am planning on installing solar myself in the spring but to get MCS install the figures just don't add up and there is no guarantee of long term SEG payments? Even without batteries I would seriously consider Tomato Energy Lifestyle, it gives 6 hours at 5p kWh, 4 hours at 14p and the rest at 24p so the average is still pretty good. A lot of people on the Tomato Energy forum appear to be running this way i.e. without batteries.

I am on Lifestyle with Battery storage option :

I think its more a case of their logic attempting to steer you to the best tariff for yourself i.e. if you don't select battery or EV you don't get the option of 5p overnight instead they offer their version of Cosy. Bottom line is that they don't check what you have so just choose the best option that gives you the tariff that you think works best for you.

Each battery has its own built in BMS its just that the four AOLithium batteries are not communicating with each other or the inverter. All is working well and nicely balanced.

Hi @JamesP Reason for the two different types of batteries is that I originally managed to source 2 x 5kWh ( better not get it wrong twice ! ) Sunsynk batteries al almost 1/2 price, however when I came to expand decided to go with more generic 'server rack' type batteries as you can purchase at much better prices. As long as batteries are of same fundamental design, in this case 16S (2.3 - 3.4v cells) in series with integrated BMS then you can mix and match quite happily even though manufacturers don't like you doing it. The two Sunsynks are connected to and managed by the inverter via can bus the other four batteries are wired in parallel as 'dumb' batteries. The state of charge and discharge is the same across all of the batteries and works really well. I installed inverter and batteries myself. The inverter automatically decides when to use the batteries and feed electric into consumer unit based on a simple timed schedule. Same for when it charged the batteries from the grid. I charge batteries between 00:00 & - 06:00 along with heating hot water and running the heat pump at slightly higher temperature just to boost the slab ready for morning. I don't see why batteries couldn't go in your plant room, mine are located in attached garage. Lifepo4 batteries are extremely safe however not sure I would have them inside the house?

I now have 2 x Sunsynk 5Kw CATL batteries and 4 x AO Lithium 5Kw's total investment has been £3600 for the batteries. All purchased on 18 month 0% free credit card with logic that I can deduct 18 months of tariff savings off the cost of the batteries before they become a real cost.

Its been a week since I migrated to Tomato and couldn't be happier. Yesterday I used 33kWh at a cost of £1.65 House is nice and toasty, plenty of piping hot water so the other 1/2 is happy also 🙂

Not sure, at the moment not a lot but I understand this is something they are looking at. For export you don't have to be with same company as your import though. For myself the cost saving of the import massively outweighs export gain. I have yet to install solar but struggling to make the sums work. When I need it i.e in the winter months for the heat pump solar production is next to nothing. I firmly believe battery is a better way forward initially with solar afterwards. Not sure what other peoples thoughts are?

Well so far so good. I switched to Tomato Energy Lifestyle tariff on Wed as scheduled. Now on 5p kWh 00:00 - 06:00 and using this to charge my batteries. The standing charge is only 44p and the peak rate if I did choose to use it is still below cap rate, whats not to like. I have shifted hot water heating to midnight and ramped up the temp from 48 degrees to 55 degrees (Vaillant R290) and to be fair not that much of a drop in cop but massively cheaper. So far managing to run 24x7 off batteries. I have to say there is a lot of bad press about TE but I have found everything great, I called them yesterday and they picked up the phone within a few rings and answered my query. The MyWatts portal is working fine, a bit clunky but does all you need. They are supposed to be bringing out a dedicated app early next year. With EON Next appearing to pull the option for battery only users ( I have no EV ) then there is little options other than TE for me but at 5p kWh I would still have chosen them.

Have invoked the switch, as of Thursday I should be with Tomato, fingers crossed all goes smoothly.....

I would love to stay with Octopus, issue is that as I have no EV the best tariff is Cosy at 12.72p / kWh and a 65.84p standing charge. EON Next and Tomato Energy are the only ones that do the same deal for battery storage instead or with EV. EON Next at 6.9p for 7 hours or Tomato Energy at 5p midnight through to 6am and then another 4 hours at 14p during the day / evening. Bonus is there standing charge at 44p. I am not an energy specialist so don't know if this is sustainable but surely the same was said of Octopus when it started and now look where they are. If Tomato Energy folds I can simply move back to Octopus. Moving saves me more than 1/2 my existing monthly bill which quickly adds up to a substantial sum and hopefully with reduce the break even point for my 30 kWh of battery storage.

I am not sure companies can charge anything they want against the variable direct debit, just the electric you have used. Surely this is better than paying too high a dd and building up a credit that you then struggle to get back? There is some noise about poor service but I think a lot of this is due to growing too quickly. They have been around a while and also rebranded a number of times over the years but I understand this is the first time they have entered the domestic market. They are certainly disrupting things, isn't this a good thing. My feeling is that Octopus has got a little comfortable of late. My other gripe with Octopus is that you need to have an EV to leverage the cheap overnight rates. I have 30 kWh battery storage so in a week probably use as much if not more than the average EV driver but yet I can't get a cheap tariff with them. With Tomato Energy ( and EON Next ) you can. I am just about to pull the trigger, will keep you all posted.

Hi, Just wondering if anybody had switched to the Tomato Energy Lifestyle tariff - 00:00 - 06:00 @ 5p kWh and a couple of cheaper hour during day at 14p the rest just below capped price. Seems like a great option if you have some batteries or even if you can batch heat during early hours including the hot water?

https://www.air2heat.co.uk/mcs-umbrella-scheme Paul was fantastic throughout.

Hi, we are in middle of a deep refit of 1960's house 250m2, triple glazed, good levels of insulation, dug out floors retrofitted with ufh (best thing we ever did) and initially ran on a Viessmann boiler. This summer I replaced it with a Vaillant Arotherm plus 7kW. The route I took after getting multiple quotes was to purchase kit and install myself but claim the £7.5k grant via umbrella mcs company. This route worked great for us and made the install cost neutral. The money we saved was placed into 25 kWh of battery storage running via a Sunsynk 5.5kWh inverter (solar still to be installed) now running the house 24 x 7 @ 5p kWh (Tomato Energy) and couldn't be happier.

I have been using Cosy (with batteries) and it has been great. However now looking to move over to Tomato Lifestyle. They offer midnight to 6am at 5p and then 9:30 - 11:30 at 14p also 22:00 - 23:59 at 14p, rest of the time at 23p and none of the expensive period between 16:00 and 19:00. Bonus is that the standing charge is only 44p Even without batteries this would be far cheaper than any standard tariff and if you did your hot water run in the early hours at 5p and possibly increased the temperature during this period also it could work really well. With batteries its a no brainer 🙂

What heat pump do you have? We have Vaillant Arotherm + 7kWh unit with UFH. We have it running solely using weather compensation and its been running great, even with the temp dropping last cuple of days internal temp stays constant. The flow temp rises and falls automatically dependent on external temp. Has been running at around 27 degrees flow (same at manifold) but today with 0.5 degrees outside this morning it rose to 32 degrees and then later this afternoon dropped back to 29.

I am using a 5kWh Sunsynk inverter. I have two Sunsynk batteries with comms to the inverter so charge / discharge is all good. The additional AOLithium batteries I am adding are being added in 'dumb' mode so are only connected electrically in parallel via the +ve & -ve 48v terminals. There is no active comms between them or to the existing Sunsynk batteries. As they are all same 16S architecture they charge and discharge in harmony. £649 ind free delivery and the cables (normally around £50 - £80) is an absolute bargain and too good to resist 🙂 the plan is to charge overnight and run the rest of the day on batteries. Payback circa 2 - 3 years. I have just been looking at the Tomato Lifestyle tariff, this gives 00:00 to 06:00 at 5p /kWh and a couple of other cheap periods a little like Cosy.

Hi all, I am currently using Octopus Cosy alongside 10 kWh of battery storage (no solar yet) it means we have been running our heat pump and the rest of the house at 12.72p kWh 24x7 I am currently looking to increase my battery capacity to 20kWh by adding an additional pair of 5kWh rack storage batteries due to an amazing deal of £649 each inc delivery ( https://www.amazon.co.uk/AOLITHIUM-Lithium-Battery-LiFePO4-Lifespan/dp/B0BS9BL6M9/ref=asc_df_B0BS9BL6M9?mcid=2881ba6285a83c6f9a20979621681b40&tag=googshopuk-21&linkCode=df0&hvadid=697230221025&hvpos=&hvnetw=g&hvrand=3251995294949021747&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9046567&hvtargid=pla-2198438482546&gad_source=1&th=1 ) I am now considering moving to the Eon NextDrive tariff that offers 00:00 to 07:00 at 6.7p /kWh and running off the batteries for the rest of the day. Just wondering if anyone was doing similar?

Hi, I just ran the primary pro insulation straight through the cavity wall. Its a nice tight fit and creates good seal. I have seen the plastic tubes and finishing bezels? Don't think they are required myself.

The insulation is Primary-Pro, brilliant stuff and possibly the best for external use. I am however going to be putting a sort of lid over it made up of some 40mm xps foam board I have. Conscious of need to maintain air to the anti-freeze valves.

Same here, using batteries on the Cosy tariff. Charge them during the off peak periods and run the house, heat pump etc from the batteries during the other periods. Works really well. DIY install of Sunsynk 5kW inverter and two of their batteries. Just need to get some solar panels now

I don't entirely disagree with you re the £7.5k grant, however its available so why not use it. What they need to do is reduce the grant to say £3-4k but remove requirement for it to be installed by MCS certified companies. They are simpler to install than gas boilers so why tie the process up in red tape which a limited number of companies profit from. Its the same with removing vat from insulation as an incentive, you can only access vat free insulation if you then pay through the nose for a certified company to install it. Why can't I simply purchase 10 rolls of insulation myself from say B&Q and not pay the VAT on it.