Short-term solutions on how to use smart home tech to save energy and money in Europe

Europe has entered an energy crisis and prices for electricity and gas are skyrocketing. Rates of €1/kWh and €3,40 per m³ of gas are not uncommon. People are turning to their friends in the Home Assistant community asking for help on how to save energy. With winter around the corner, they want a solution that they can apply before it gets really cold.

The goal of this post is to give an overview of things that Europeans can do to start saving energy and money today – even if they rent a home. The focus is on homes using radiators and a boiler connected to a thermostat.

Heating is a complicated topic and you will probably still have questions after reading this post. Don’t hesitate to join the Home Assistant community to discuss how to save energy (do make sure to search before asking a question). Join us in the forums in the energy category or come hang out in the #energy channel on our Discord chat server.

Take control of your heating

Most of your energy usage goes into heating your house in the winter.

Gas is more efficient than electricity to heat your house, unless you have a heat pump. So don’t turn off your gas heating and replace it with an electric heater as it will cost you a lot more money.

There are two ways of saving energy with heating. The first approach is to invest in more efficient technology to generate heat and improve the home insulation to stay warm. Things like getting a heat pump, improving insulation and getting thicker windows. Those things are not achievable before winter kicks in, so they are out of scope for this post.

The second way of saving energy is to use less of it. Governments have been advising to lower the overall temperature of your home, but putting the temperature too low can get a little too cold. Instead, you can be smarter about how you heat your home by installing smart thermostats, temperature sensors and thermostatic radiator valves (TRV).

Photo of a Shelly TRV

Smart Thermostats

A thermostat works by measuring the temperature. If the current temperature is below the target temperature set by the user, it turns on the heating until the home is the right temperature.

If you’re renting your home, you can skip this section as upgrading a thermostat is generally not an option.

The way a thermostat can help you save the most energy is by controlling the boiler, and preferably the boiler temperature. Heating the water is what drives the energy usage, so you wouldn’t want the boiler to heat the water to a higher temperature than is necessary to reach your target temperature.

Thermostats measure the temperature from the thermostat device. If the thermostat hangs in the last place in your home that gets warm, it might be heating more than you need. A smart thermostat can help by allowing you to pair extra temperature sensors to report the temperature in different rooms in your home. This allows the thermostat to turn off the heating earlier.

An extra bonus feature of a smart thermostat with remote control is that you’ll be able to change the temperature if you realize that you won’t be home at the scheduled time.

If you’re going to be in it for the long haul and want the easiest solution, you should invest in a smart thermostat that is part of a heating/cooling ecosystem that also has an API. Optimizing heating energy use is complicated and not something Home Assistant is good at out of the box. Instead, let that be managed by the ecosystem. The API allows you to still observe and influence it from Home Assistant to integrate presence and other data points the ecosystem is not aware of.

If you want full control over every part of heating your home, you don’t need to take the ecosystem route and instead invest in locally controllable thermostats, temperature sensors and TRVs and tie them together with Home Assistant. Here is an example to get started.

Recommended thermostats

It’s hard to give a single product recommendation here because there are so many different heating configurations and we are not aware of a single solution that works best in every case. Always check if the thermostat works with your boiler or other heating system you might use.

Home Assistant core developer Frenck researched this topic a couple of months ago for his own home and settled on Plugwise. It controls his boiler and radiators and has a local API to integrate with Home Assistant.

Another popular solution is Homematic IP. It too has a local API to integrate with Home Assistant.

Here at Home Assistant we prefer devices that work locally. Any device that stores your data in the cloud will eventually need a way to recoup the cost of hosting your data. It also means that if the company goes out of business, the devices tend to stop working. However, we understand that your priority today is saving energy. If the above solutions don’t work well for your home, you can also consider Tado.

We don’t recommend Google Nest because its ecosystem is not fully featured enough, as it does not support TRVs.

Thermostatic Radiator Valves (TRV)

A TRV will replace the existing knob on your radiator with a smart one. This works too if you rent: just swap the old knob back when you move out. Installation generally takes just 5 minutes.

A TRV works like the thermostat of your house, but at the level of your radiator: you set the temperature that you want to reach, and it will open/close your radiator to get to the controlled temperature.

Having a TRV allows you to tune the temperature in individual rooms based on your schedule and/or planned usage, like only heating up the bathroom in the morning and around bedtime.

TRVs should be used to opt a room in/out of heating. Because heating the water in your boiler is still the biggest use of your energy, you should not use TRVs to turn off all radiators in your home or to reduce the temperature throughout the home. This should be done at the boiler level (usually via the thermostat). Keeping your boiler at the right (and not too high) temperature required to heat your home to the desired temperature is the biggest energy saver move you can do.

Recommended TRVs

All three smart thermostats that we recommended are part of a product range that include TRVs. If you went with one of those, we suggest you stick to the ecosystem.

There are two devices that we recommend. Both work independently but also have a local API to allow plugging it into Home Assistant.

Shelly TRV

This device works standalone and does not require a hub. Battery life is claimed to be 2 years. It offers a local API and integrates perfectly with Home Assistant.

Buy Shelly TRV (affiliate link)

Aqara Smart Radiator Thermostat E1

The new kid on the block as it was just released. This TRV can be controlled directly from Home Assistant using Zigbee or via the Aqara hub. The hub can be locally integrated with Home Assistant via the HomeKit Controller integration.

Note: The vendor claims the device will support Matter in the future. It is unclear from their documentation if the device will speak Matter over Thread or that it will require their hub to expose the device over Matter. Our money is on the latter as that’s how they do HomeKit too.

Buy Aqara Smart Radiator Thermostat E1

Wrap up

Sadly, there is no golden solution to save energy that works for everyone everywhere. I hope that the above overview and tips will help you through the winter.

If some things are still not clear, don’t hesitate to join us in the forums in the energy category or come hang out in the #energy channel on our Discord chat server.


This is a companion discussion topic for the original entry at https://www.home-assistant.io/blog/2022/10/03/short-term-solutions-save-energy-and-money-europe/
6 Likes

Can I ask why the Zigbee Home Automation (ZHA) integration still lists Climate device type as “beta”?

https://www.home-assistant.io/integrations/zha

Climate for ZHA was initially merged to Home Assistant core in May of 2020 so should be mature now?

https://github.com/home-assistant/core/pull/35682

I think this is very much related to the blog post as it is what is needed for controlling TRV thermostats.

Oh, and what is the third TRV thermostat that you recommend? Noticed that you only listed two above?

My guess it’s a Z-Wave Plus TRV from Eurotronic/Aeotec, Fibaro, Danfoss/Popp/Nexa, or Everspring?

https://products.z-wavealliance.org/regions/1/categories/10/products

https://eurotronic.org/produkte/z-wave-heizkoerperthermostat/spirit-z-wave-plus/

https://store.danfoss.com/en/en/Climate-Solutions-for-heating/Radiator-Thermostats/Radiator-sensors/Room-sensor-eTRV/Radiator-thermostat%2C-Danfoss-Link™-Connect%2C-Adapter-type%3A-M30%3B-RA%2C-868-42-MHz/p/014G0002

https://www.everspring.com/portfolio-item/ac301-trv-thermostatic-radiator-valve/

Nice thread topic, thanks for starting this up!

What I am looking for since forever is a way to make my Brink thermostats smart. iow, how can I connect a HA supported thermostatic device to my current wired brand controlled setup. The proprietary Brink Klok thermostaat is supposed to support Open Therm, but also seems to have proprietary notifications on errors/clean filter etc.

If I could add some device in between to control the programme that would already fine.
Brink has a great heating system, but is notoriously low on connectivity, other than their own and ridiculously expensive Brink Home system…

maybe someone here has Brink, and successfully integrated their heaters into HA?

If my question suffices to open a dedicated thread, please move it and rename it to: How do I turn my Brand specific not connected thermostast into an open and connected thermostat…
for the Dutch readers, this is what I found on Tweakers but that is only about a Nest thermostat which itself has other limitations we dont like at Ha…

Has anyone a good solution for TRV for floorheating?

at the moment I’m in the process of building one manually using a stepper servo(still waiting for some parts form ali), but it would be great if there is some out of the box solution for this.

I already changed my thermostat with one based on tasmota opentherm and added smart switches for my 2 floorheating pumpt so I can manage the temperature of each floor level individually, but I want even more control per valve.

The problem with default radiotor knobs is that they get the current temperature locally, something which won’t work for floorheating.

It mentions, don’t use electricity. In my case I have solar power and I have multiple airco units that can heat up just fine too. Simple things like, during day open window for fresh air but close them before it becomes late because it will become too cold inside too.

So now i only heat up the living room for a small part with Airco unit, once the kids are to school (or in bed at night) i can turn it off and i don’t heat up the rest of the house (where you sleep it is fine if it is colder) i just need to wait and see how cold it needs to get untill i have to turn on the gas heating.

I don’t have floor heating, but the Eurotronic Zwave TRVs can be driven by an external (zwave) thermometer (expensive) or have a parameter that can be used to calibrate the internal thermometer to whatever temperature you wish. I have an automation which adjusts this parameter to make the internal thermometer be equal to one I have placed in the middle of the room. The differences are usually of order 2 degrees C and they vary Room to room quite significantly, so this should be done.

An airco unit is a heat pump, so that is good to use with electricity! :slight_smile:

2 Likes

Maybe this one?

https://wiser.draytoncontrols.co.uk/underfloor-heating-controller

It helps a lot if you maintain your heating system. Bleeding your radiators and wet underfloor heating improves a lot the efficiency.

Getting the heater maintained and cleaned by a professional can improve efficiency as well. It also applies to heat pumps.

For those looking for a cheap alternative to the very expensive TRVs from Shelly and co: eQ-3 BLE Thermostats.
They cost around 15€/each instead of 40-50€.

Since BLE is short range, you can use a 5€ ESP32 devkit board with tasmota as BLE to Wifi hub (or use it with ESPHome.

I am using this approach for 126 sqm with 8 TRVs and one ESP32. Total cost <100 €.

There are threads available but if anybody needs any help, just ask.

Just my two cents because the same setup with Shelly etc. would have cost three times as much (minimum). And with some luck you can buy the BLE TRVs really cheaply second hand because most people go wifi).

EDIT:
By the way, you can use the same ESP32 with Xiaomi Mijia BLE thermometer and hygrometer to monitor the temperature and moisture in more representative places. Combine those values with automations to optimize heating even further.
I am doing this this winter but have not started yet. It gives you great information on when to heat and where.

4 Likes

I only have floor heating in one room and that room and use Fibaro Heat Controller (Z-Wave TRV) in combination with their wireless termperature sensor which can acutally be bought togther as a starter kit for that purpose.

That’s not true, Gas boilers only convert so much Gas into Heat. Older boilers can be 80% or less efficient and the newer ones are only 90 something % efficient.

So it really should state Gas can be cheaper to heat your homes than electric due to the price difference of Gas vs Electric.

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Is there any way to see the cost of individual devices, which are using power monitoring plugs? I can add the sensor to the energy dashboard, but it’s just showing total watts and I want to see cost per usage, if possible.

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I have electric floorheating with Ensto BLE -thermostats, quite popular in Nordics. They don’t have open/documented api, but we are able to control those with this ESPHome integration GitHub - jumakki/esphome-ensto. Floor and water heating turns on when electicity is less expensive, based on hourly prices from Nordpool electicity market data ( GitHub - custom-components/nordpool: nordpool sensor for ha. ). This way we also awoid peak usage hours.

Also it is important to prevent mold from growing. Something HA is well equipped to do. With some cheap humidity and temperature sensors and the mold indicator I monitor the critical rooms (bathroom, kitchen, bedrooms) and get reminded to ventilate the rooms.

1 Like

It won’t show in the energy dashboard but you can easily do it with a template sensor. Just multiply your KWh reading by your cost per KWh.

In the states (in my experience at least) the amount you are charged per KWh isn’t reflective of your total cost so divide your total bill by your KWh used for past few months and average them to get a accurate number to use.

sensor:
#https://home-assistant.io/components/sensor.template/
  - platform: template
    sensors:
      device_cost:
        unit_of_measurement: "$"
        value_template: "{% set state = states('sensor.kwh_used') %}{{ state | int*0.16 if is_number(state) else '0' }}"

I guess it doesn’t specifically mention solar but I assume that is one of the things in this list:

If you’ve got it, great! You should definitely use it. Make sure you’re able to make enough electricity throughout the winter to cover a new electric boiler if you’re considering anything like that. But you’ll have some different math then most others.

If you don’t have solar then getting it before winter isn’t an option. Delays and costs of materials and installation are quite high at this point so banking on starting a project like that now and finishing before it gets real cold isn’t a good idea.

Thank you, I thought it would probably be a job for a template, but as I have no idea of the syntax, didn’t even try to create something!

Here in the UK we have a unit charge per KWh (currently 33.86p!) and a standing charge (52.64p).

I’m just looking for the cost per device, so the standing charge is irrelevant, so will just use the unit charge.

maybe this is something you are looking for:
https://homematic-ip.com/en/product/underfloor-heating-controller-12-channel-motorised
Homematic is not cheap but they certainly make good quality products and as the post mentions they are fully locally controlled
Good hunting for the right product!
B