Factor 1:When we built the house, becuse of mistake we had to put 15cm of celotex insulations in the floor under the underfloor heating tubes.

Factor 2: My brother, who did the underfloor heating put in 20mm piping in which is bigger the usal British way.

Factor 3: The heatpump is bigger oversized for the house.

Factor 4: I use the immersion heater to make the hot water so that the heatpump can focus on only heating as we only have 6 hours to run it.

Factor 5: I never used to use the backup heating in my hetpump as it is not needed when u use it normal. 24/7 Also your cop goes down when it kicks in. But when the electricity is almost 5 times cheaper it doesn't really mater and it only kicks in below 0 Celsius outside temp.

Factor 5: I turn up the weather comp so the flow temperature is higher.

I have to admit when it is really cold the upstairs, where I have radiators that does kick in for short time, but I have never seen the downstairs kick in. The temperature downstairs kept nice and warm about 21.5-23c.

Having said that it's likely to go up to £800 after we decided to fix Octopus Go for the next 12 months. I was thinking our off-peak usage is about 75% to 80%. While that's the case during winter months, for the whole year we are averaging 85% too. 

If I were to design a combined tariff for all renewable tech combined, I would do the following. Two off-peak slots, 12:30 am to 5:30 am and then again from 1 pm.to 4 pm, at around 12p over kWh (average of Fixed Octopus Go and Cosy Octopus off-peak rates for our region). This will enable people who need more charge into their EVs who don't want to be restricted by just 3 hours off-peak of Cosy in the morning. This would also enable heating the hot water during afternoon off-peak slots. Usually DHW takes about 1.5 hours to 2 hours during the winter months, and it means heating has to run at full pace again after DHW run as indoor temperatures do drop a bit if house is not heated for a couple of hours in the winter. We can also run appliances like dishwasher during the afternoon off-peak slots, charge the batteries again and put some heat into the house. So, we can avoid touching the grid from 4 to 7 pm which invariably happens with Octopus Go in our case. Also, as the off-peak import rates at 12p would be same as export rates at 12p, there's no incentive to charge off-peak and export later during peak PV generation months. But, for consumers with larger battery capacity or South West/West facing panels, export during the 4 pm to 7pm will help the grid from April to August. Overall, it wouldn't be much different financially, but just suit consumers with all the renewable tech better. Or may be it will just suit our house better!!

i have a full years costs in for running the house on electric, heating, cooking, EV, ive averaged £60/month for the past year, 85% of my usage being at the cheapest cosy period of 8hours

My yearly SPF is 3.89

My average unit cost was 12.56p/kW

My energy bill this year is 47% using cosy6 tariff than using Gas Boiler.

if I was on a standard tariff i would only just break even

i read yesterday government is “looking” at the ridiculous cost of how electricity is priced per kWh per day. Linking it to Gas price is arcane and punishing businesses in UK

According to BBC news, US electricity costs 6.5p/kW, UK 26p/kW

Makes sense about holding off the battery expansion with a 20 year payback, end of the day renewable tech investments should give financial returns too.

In the winter period, i boost the temp during the 8 cosy hours by 0.5C, and the 4-7p period drop it by 0.5C

This gave me 85%+ usage off the night rate, i have a 5kW battery. I worked out i would need 10kW battery to take me to 95%+, that would take 20years to payback so not viable unless battery prices halve this year.

Now were in the summer usage period, heat pump is set to maintain only overnight until 7am when cheap cosy ends, then i switch to solar for the day

Thankfully my house holds the heat really well so I only ever need to heat during the time Ev tarrifs is on

Wow that is good to know! Thanks for sharing.

However in my case the import tarrif and the time of cheep EV time.is better with Eon Next. It makes a big saving with my usage. Thankfully my house holds the heat really well so I only ever need to heat during the time Ev tarrifs is on. I need the cheapest possible tariff so I can do all heating hot water dishwasher etc in that time.

Here is a little summary Octopus GO v. Eon Next drive

-Night rate 36% cheaper

- 20% Longer EV time 

- Day rate 14% cheaper

- Standing charge is 5p/ day cheaper 

• Andris

. I belive Octopus made that change too

@toodles It would be good if Octopus designd a tariff for customers who have all types of renewable tech at home. They have heat pump, EV or solar/battery specific, but not one that combines all into a consolidated tariff. I have some thoughts but not sure how to feedback to Octopus.

Would I be right in thinking that EV tariffs came about when battery capacity made it possible for subscribers to ‘download’ perhaps 30 kwh’s or more from the grid during the period of lowest demand? With home battery capacities reaching similar figures, I wonder if any of the suppliers, (Octopus, I’m looking at you in particular!) might be considering extending the EV tariff to include large domestic energy storage systems? Just wishful thinking I suspect, but, one can dream. Regards, Toodles.