My Smart(ish) Home

13/07/2020

A couple of years ago I moved house, and as I had been renting before this, I was determined to utilise this move to join the smart, green revolution. Working at the DCC and having an interest in technology, alongside having a young family whose future I wanted to invest in, meant I was happy with the long term commitments needed to make it all worthwhile.

Our primary driver was always about the environment, but as a man who loves a spreadsheet, I knew it would need to balance the books at some point.

My house is an old Cornish farmhouse, which was never designed around energy efficiency; when we moved in it had oil-fired central heating that cost over £1500 a year. Our electricity use was not much better, and our bills were often over £100 a month. We had never found a way of being frugal with our energy, no matter how much it cost us or how aware we were about the environment. All in all, our energy bills were approximately £3000 a year!

With the changes we have made, I estimate that our total bills will come down to somewhere about £500 a year - but we have had to invest significantly to achieve this. Quick calculations show that we would get our initial investment back in about seven years. It has not been a straightforward process, and we have six components that help us achieve both financial and energy savings. This is what we have:

- Solar Panels - 4kW installed, and on sunny summer days these provide enough energy to power the house for 24 hours. They also feed some of our green energy back to the grid.

- Tesla Powerwall battery - this stores 13.5 kWh and allows us to store excess energy from our solar panels, for use at night and other times when we need more power than is available from the panels. It also -- and this is key to the savings -- allows us to download electricity when it is cheap, taking advantage of Time of Use (TOU) tariffs. With our energy provider, the tariff is often as low as 2p kWh, and I believe we can get most of our energy needs at 6p kWh or less.

- Mitsubishi Air Source heating - this replaces our oil-fired boiler and is run on electricity, which can come from solar, our Tesla Powerwall battery, or the grid.  This is another hefty cost upfront, but you can get a Renewable Heat Incentive (RHI) grant for installing this, and the worse the energy efficiency of your house, the bigger the grant. In our case, the grant covers 90% of the cost of installation.

- Tado smart heating and smart radiator valves - this is cheaper to install and allows your heating to learn your habits, turn on and off based on your location, and have separate schedules for individual rooms. This means we are never heating unoccupied rooms, and we can still have all the comforts of central heating.

- Octopus Outgoing Export tariff - there are a few suppliers who now have TOU and export tariffs, and Octopus is really pushing this hard. As mentioned above, electricity can be downloaded when it is cheap, meaning that when the tariff is expensive, the battery can be used. Our supplier, at times, pays us to use electricity, and also offers a non-zero tariff for the energy we export. It is my intention that in the long run, we should be able to offset our standing charge through these two mechanisms. I will essentially become an energy trader!

- Finally, and the central foundation of this, is the smart meter. Without the smart meter, none of this green revolutionary technology would be economically worthwhile. All the pieces of the jigsaw above need the smart meter to work and drive the finances.

I am so happy now with the set-up, but there is still a long way to go before this something that is taken up by everyone. Currently, I have to manually configure my battery every day, based on the weather forecast, the tariff available, and my own estimate of our energy usage during the day. There is some IFTTT (If This Then That) programming hook-up that can be used for the Tado, and you can access an API (Application Programming Interface) for both Octopus and Tesla; but it is not mature enough for mass-market consumption. I often wonder if this is something my parents would use, and I think it is too complex for them. While my wife is much more technically literate than me, she would not have the interest or time to be logging onto apps every day to get the best out of the system.

I think that the DCC could be central to how this improves in the future, and I truly believe a revolution is underway.

By Oliver Bridges, Head of Data Science & Analytics