Smart Home Blog

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Octopus Energy have updated me on the new Intelligent Octopus Go tariff prices, which come into effect from the 1st April. The standing charge has gone up but, the cheap rate is now just 5.2p/kWh. Given that 98% of my usage is time-shift to this cheap rate period, this will have a noticeable positive impact on my bills. These prices are very likely to go up a LOT in July though when the price cap changes and the full impact of clown Trump is in effect.

Super sunny today and I got sunburnt whilst out filming and shooting the Lotus Emira with Emma (daughter) 🙁 I spent too much time in her MX-5 (roof down) filming with a GoPro attached to the outside of the car.

The best day of the year for solar generation by some margin! 64.5kWh generated and 57.8kWh exported at 12p/kWh (£6.94).

This graph shows my extension solar generation and it shows how the sun hits the East side of the roof, which then goes slightly in shade, then the West side takes over. Our house faces 20° off South, so the West side generates more and longer into the day.

A great start to April. So far this month, we have averaged over 40kWh per day 🌞

Now that my gas is costing more (5.7p/kWh) than my cheap night rate (5.2p/kWh) electricity, it makes a lot of sense to use electricity to pre-heat my hot water tank. This has both environmental and financial benefits. I should be able to get our gas usage down to near zero.

I'm using my smart home to intelligently switch on the immersion heater from 02:15 to 04:15 and this uses my relay board to switch power to the 3kW immersion heater via a 25A contactor.

Our water meter was changed to a 'smart meter' this month, so I thought I would download the Anglian Water app and see if it told me anything useful. The data was very random and seemed to be based on historical data only. The Anglian Water helpdesk told me that the data connection is not being installed until September! 😮 I have to go outside to get meter readings and submit them manually.

The Octo-Aid app is showing that my Tesla Powerwall is doing a fabulous job of keeping our usage on the cheap night rate period (5.2p/kWh). 99.9% of our usage is at this rate.

The best day of the year for solar generation again with 68.2kWh generated and 63.4kWh exported at 12p/kWh (£7.61).

Someone asked me why I charge my Tesla Powerwall every night to 100% and then run my home using this stored power during the day. The answer is simply to shift all my usage to the 5.2p/kWh rate and to export nearly all of my solar at the 12p/kWh rate. This is best thing to do from a financial perspective. This is also why I avoid charging the CUPRA Born using solar and aim to always charge it at night.

In theory, I could also discharge the excess battery storage but, the conversion losses involved make this less financially beneficial. There is also a chance that the battery will run out of stored energy earlier and I then end up paying the peak rate cost of electricity (27.8p/kWh), which would negate any small benefit from doing this. Our typical daily usage is about 15-16kWh and the Tesla Powerwall stores 13.5kWh. It doesn't need to power our home from 23:30 to 04:30 (cheap rate period), so this is just about the optimal battery size for our usage.

Another best day of the year for solar generation again, with 70.6kWh generated and 66.7kWh exported at 12p/kWh (£8.00).

And one more best day of the year to end the month, with 70.8kWh generated and 64.3kWh exported at 12p/kWh (£7.72).

Our April solar energy generation was 1485kWh. The South facing roof generated 970kWh, lower than the 1034kWh generated in 2025. The East facing roof generated 219kWh. The West facing roof generated 299kWh. Our worst day was 15.7kWh, the best 70.8kWh and the average was 49.5kWh.

We exported 1335.6kWh at 12p/kWh (£160.27) and imported 610kWh (>95.5% at 5.2p/kWh). This import includes EV charging. Our energy bills will be negative for this month.

Our actual home usage was 484kWh with a high of 18.4kWh, a low of 13.1kWh and an average of 16.1kWh.

We did 886 miles in the CUPRA Born this month and put 206kWh into the car at home. We did a few charges away from home to take Emma (daughter) to Heathrow, for her Miami F1 trip.

This is our generation history, showing the impact of the new extension solar.

Octopus Energy have updated me on the new Intelligent Octopus Go tariff prices, which come into effect from the 1st May. This is just one month after they went down 🙁 The standing charge has gone up again and the cheap rate is now just 6.9p/kWh. Given that most of my usage is time-shift to this cheap rate period, this will have a noticeable negative impact on my bills.