Home Improvements with Home Assistant

by Blog

Within our OpenDSR project, Carbon Coop is working to bring together a number of different software elements to support low-cost standards-based demand side response.

We are building tools to:

  • report householder energy usage
  • broadcast “power shaping” events which shift energy usage to different times
  • schedule householder appliances to switch on and off during these events
  • report the amount of energy shifted and the reduction of the max power during these events

Once we have finished developing these tools, we will offer a Demand Side Response service, that will be available all of our members, to help reduce carbon emissions and save money!

To do this as effectively as possible with our small software team, we are basing our work on Open Source software as much as we can.

Open Source is at the core of the software team’s ethos, and we are delighted to build on public projects and contribute back when we can.

Home Assistant

One of the larger building blocks we are working with is a project called Home Assistant.

Home Assistant (HA) is an open source home automation project that puts local control and privacy first. It is used and developed by a worldwide community of tinkerers and DIY enthusiasts.

To get to grips with HA and some of the capabilities, I set up the system in my own home by installing it on a Raspberry Pi.

Installation was fairly straightforward, but at the time I didn’t have any home automation devices to connect it to!

I live in a tenement style flat in Glasgow, and live a fairly low tech life. I don’t have a TV, much less a smart TV. I don’t have smart light bulbs or blinds, and a smart door bell wouldn’t be appropriate for my shared building.

My current heating system is a gas combi-boiler with radiators around the flat. It’s not a cold flat so I rarely use the heating system, and haven’t looked into making it “smart” (as some Carbon Co-op members and staff have done).

But, I had some DIY planned, and it was the perfect chance to add some “intelligence” to my home.

Goodbye fireplace

Glasgow tenement flats were built over 100 years ago and were first heated with a coal fireplace in each room. My flat is actually built over an old coal mine, so I suppose there were no energy security issues back then!

When I first moved in, the fireplace had been badly blocked up with a piece of plywood stuck to a fireplace surround.


Changing this was one of my top priorities, but I couldn’t decide what would work best.

I grew up with solid cast iron heat sources – an oil fired Aga was the heart of my family home, and the open fire was converted to a wood burning stove years ago. I wanted a taste of this in my little flat – feature to point the furniture at – but in a way that was more appropriate for low carbon city living.

I considered installing:

  • Gas stove – plumbing would be needed, meaning I would have to disturb my floorboards. It also felt backward to be considering more fossil fuel appliances.
  • Wood burning stove – I love the look, feel and ritual of a wood burning stove, but running one in a city is totally inappropriate. Glasgow already has terrible air quality and I didn’t want to make it any worse.
  • Wood pellet stove – nice idea but prohibitively expensive. I was also worried about sourcing pellets locally.

Then I had the idea of installing an old cast iron radiator. The style was right but plumbing it into the central heating system would mean running pipes and lifting floor boards. Thankfully, I discovered there is an electric version available – and that’s when I realised that this could be a perfect opportunity to start learning about home automation.

WiFi Enabled Switch

The OpenDSR project involves intelligently operating heating systems. One of the smart devices we will be using is the Shelly 1 Wi-Fi relay switch.

The Shelly 1 is designed to be wired inside an electrical outlet box and can be used to turn on and off any mains electrical appliance (or a larger contactor as we are doing in OpenDSR).

I got a Shelly to start working on the integration and quickly had it setup with my Home Assistant installation.

It took a little longer to get the radiator installed – I decided to pair it with some reclaimed tiles which meant I had to learn a bit about tiling first. Last week I finally got the tiles grouted, the radiator filled and wired the radiator element to my Shelly switch. I can now toggle the radiator from my phone, computer or the hardware switch.

Next Steps

This radiator probably isn’t the most energy efficient way to heat my home, but with Home Assistant I can take some steps to make sure that it is not carbon intensive. Scotland produces a huge amount of renewable energy – mostly from wind power. I really like the idea of using this locally sourced electricity rather than imported gas to heat my home on a windy, wet Glasgow day.
The carbon intensity of the grid is available from an API and I have started working on a simple Home Assistant component that queries this. I plan to integrate this component with the switch to only enable the electric radiator when the carbon intensity is low.

The next step is to upgrade the Shelly1 to the Shelly1 PM which includes a temperature monitor. With a bit of data I should be able to calculate in which conditions it’s more efficient to use the gas central heating versus when it’s better to use the electricity.