Octopus Agile Smart Energy Cost Monitor Up and Running

mmmmikey

A hayfever day yesterday so I stayed indoors and made this:

It works like a thermostat but instead of switching things on when the temperature falls below a certain level, it switches them on when the cost per kWh of electricity falls below a certain level. The two levels I have set are my solar panel export rate and most recent E7 night rate.

I have a Smartthings home network so this works wirelessly for me - anything with a smart switch can be set to monitor the "cost-stat" and switch itself on accordingly. The only thing I'm controlling with this at the moment is an immersion heater, which switches itself on when the cost of "bought and paid for" electricity falls below the amount I get paid for exporting solar energy.

The black wire coming from the top of the immersion heater controller goes to a sensor that monitors the hot water temperature.

The effect of this is to increase my export payments by more than I increase my electricity bill - hope that makes sense. It was very easy to make and set up. The hardware is just two Sonoff smart switches turning off LEDs in a case made of a bog standard pattress and blanking plate. Needs doing carefully of course because there are mains voltages involved. The Sonoff switches are triggerred by IFTTT which was painfully simple to set up.

Is anyone else using IFTTT with Agile for anything?

QrizB

Very ingenious, I'm impressed!

I have a Zigbee smart switch on my immersion heater but I haven't done anything ITTT-ish with it yet, mostly because I'm on a more conventional dual-rate tariff and my cheap-rate period is entirely predictable.

Shedman

QrizB said:

Very ingenious, I'm impressed!

I have a Zigbee smart switch on my immersion heater but I haven't done anything ITTT-ish with it yet, mostly because I'm on a more conventional dual-rate tariff and my cheap-rate period is entirely predictable.

@QrizB Out of interest what is the make and model of your Zigbee immersion smart switch (presumably a 16A one)?  Any issues with it.

@mmmmikey very impressive use of Sonoff switches

mmmmikey

Yes, be interesting to know that @QrizB - I couldn't find a Zigbee switch with a big enough rating when I looked so ended up buying a WiFi one like this:

https://www.amazon.co.uk/dp/B0B5GM2QRT?psc=1&ref=ppx_yo2ov_dt_b_product_details

It also has the advantage of a temperature sensor which is something else I needed, and it integrates fine with Smartthings.

QrizB

Shedman said:

@QrizB Out of interest what is the make and model of your Zigbee immersion smart switch (presumably a 16A one)?  Any issues with it.

and

mmmmikey said:

Yes, be interesting to know that @QrizB - I couldn't find a Zigbee switch with a big enough rating when I looked ...

I'm pretty sure it's this Aubess / Tuya product, the WHD02:
https://www.ebay.co.uk/itm/165784774599

https://www.ebay.co.uk/itm/364205877529

They come in 10A and 16A ratings, although I've not taken them apart to see if they change anything other than the label! I bought a twin socket pattress (like this), used one side for the fused spur and put the smart switch inside the other half behind a blanking plate. The plate is translucent enough (and my airing cupboard dark enough) that I can see the status LED on the Zigbee switch through it without needing a hole. (Plan B was going to be to cut a hole in the pattress and glue the Zigbee swith in place, with the LED and button on the outside but the wiring still on the inside.)

No problems yet, after 18 months or so.

My Zigbee hub is the SilverCrest one from Lidl. I've also got a handful of smart sockets and a couple of smart lamps.

mmmmikey said:

... so ended up buying a WiFi one like this:

https://www.amazon.co.uk/dp/B0B5GM2QRT?psc=1&ref=ppx_yo2ov_dt_b_product_details

It also has the advantage of a temperature sensor which is something else I needed, and it integrates fine with Smartthings.

That's a clever piece of kit, good choice.