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Andrew Love
Jul 1211 min read

Sustainability Pathway 2024 July – Saving Domestic Energy

Introduction

We’ve somehow managed to get halfway through the year without broaching the topic that most people think of first when someone says “sustainability” – saving energy! If you’ve been following this series you’ll know by now that sustainability is a far broader topic than just “saving energy” but in this month’s Sustainable Pathway study, we’ll look at what can be done around the house to save energy.

 

We’ve been applying some of the material in this blog around the church and have achieved some impressive savings in energy usage. Our approach to saving energy isn’t to diminish the light and temperature of our environment to uncomfortable levels (although excess usage obviously should be avoided!) but to look at the most efficient way of achieving appropriate levels of light and heat and to consider controls to make sure that those levels are only being maintained when required. In some cases we’ve identified that the levels of light and heat were less than what was appropriate and have managed to improve the environment while still reducing energy use! (Find a bellringer and ask how the light levels in the ringing chamber increased when we cut the energy usage to 20% of the previous figure!)

 

We won’t consider generating renewable energy (e.g. through solar panels) this month – that will feature in November’s study.

Heating Controls

How many times have you heard people ask “Have you turned your heating on yet this year?” To me, this is a rather old-fashioned question that indicates that the controls on the hearing systems are inadequate.

A modern heating system will have a controller that allows the user to express their wishes in the form of “in this time period I want this space to be at this temperature” – and as these rules are true all year around they can set it and forget it! In warmer months, the heating system doesn’t need to do anything to achieve the temperatures programmed, so it simply doesn’t come on. If there’s an unusually cold day in June, it comes on – but for a good reason. Manually switching heating off in summer is therefore a symptom that the heating controls are not capable of turning the heat output (and hence energy input) off when not required! This might be the case if the controls consist of a separate time switch and thermostat, where one temperature can be maintained at set times of day, but there is no ability to maintain a different temperature at other times of day, so the time switch is often overridden leading to wasted energy. Many older installations don’t even have a thermostat so the heating comes on at set times regardless of the ambient temperature! Updating heating controls is relatively inexpensive and non-disruptive, and can cut energy use dramatically.


Not all areas of a house need to be the same temperature – rooms are used at different times of day, bedrooms can be cooler than other living areas, and spare bedrooms only need to be heated when someone is likely to be using them! Some heating systems split larger houses into different zones, where each zone can have its own programme, but the easiest way of regulating heat for each room is to fit thermostatic radiator valves (TRVs). These sense the temperature in the room and increase/decrease the flow of water into the radiator in that room to maintain a desired room temperature. You’ll need a plumber to fit these but it’s a quick and non-disruptive job compared to fitting zone valves. The latest variant on TRVs is radio-controlled valves that talk to a central programmer so that different temperatures can be set for different times of the day and the temperatures can be adjusted remotely (often via a smartphone app).


What temperature should the thermostat be set to? Expert advice (see https://energysavingtrust.org.uk/take-control-your-heating-home/) is to choose the lowest comfortable temperature, typically between 18°C and 21°C. With young babies the temperature should not be above 20°C.  To the shame of our species, we’ve got used to overheating our homes in the last few generations, so once you’ve turned the heating down and acclimatised for a few weeks, consider whether you could turn it down further!


There are companies that sell integrated smart heating control systems, including Nest (owned and powered by Google), Hive (owned by Centrica = British Gas). These offer friendly user interfaces, remote control and the ability to learn your routine and how fast your house heats up. While these are definite improvements on older heating control systems, there are drawbacks:


There are some thermostats that offer much of the functionality of a Nest or Hive, including remote access, without being quite so dependent on a third party cloud service – these include the Tado V3 (see https://www.screwfix.com/p/tado-v3-wireless-heating-hot-water-smart-thermostat-starter-kit-white/141kt). To us, these appear to be the “sweet spot” between functionality and security/resilience.


If you need assistance with setting the controls for your heating system to achieve a comfortable, efficient home environment, or would like advice on upgrading your existing heating controls, please don’t hesitate to let a member of the Creation Care team know and we will offer our support.


LED lighting

There are may ways of turning electricity into light; the one that many of you probably learned about at school was putting electricity through a thin wire until it glowed white hot (“incandescence”) – this generates light, but also a vast amount of heat that in many cases isn’t wanted! Since then newer technologies have been developed, including fluorescence and most recently light-emitting diodes (LEDs). None of these are 100% efficient – even LEDs are only about 40-50% efficient (further research is ongoing!) but they still take a tenth of the energy required to light up a room than an incandescent lamp would do.


It’s pretty obvious that energy can be saved by changing older, less efficient lightbulbs for newer LED lightbulbs. In most cases the efficiency change is so significant that it’s worth doing even if the older lightbulb still has some life it it. This section aims to help you do that successfully while improving the quality of light around you. It’s entirely possible for most houses to use 100% LED fittings, although some fittings are tricker to convert than others.


Our forefathers got a bit lazy when talking about lightbulbs. What we're interested in when we choose a bulb is how much light it gives out, not how much energy it sucks in, but we still talk about a “60 watt” light bulb (or for non-incandescent lamps such as LEDs “60 watt equivalent” where the supplier has determined their own basis for equivalence ) and measure them by energy usage. There are perfectly good units to measure light output (i.e. what we want!) including Lumens, and these are gradually becoming more commonly used. The chart below gives a useful comparison of these units for different types of lamp – note this is a couple of years old and newer LED lamps are even more efficient:


When choosing a lamp for a particular room or area, there are may factors to consider:

  • Brightness – how much light is required?

  • What type of “cap” (the bit with the electrical contacts) should be on the lamp to fit the lamp fitting. The best guide to these I’ve ever found is at https://www.bulbs.com/learning/basechart.aspx 

  • What shape of bulb is required? Just because the cap fits doesn’t necessarily means that the body of the lamp will fit into the fitting!

  • What colour of light is required? This isn’t just about exotic multicoloured lighting – even if all you want is plain white light, there are a range of shades of white! This range is usually described in terms of “warmth” where the warmer whites have a slightly red/orange hue and the colder whites have a slightly bluer hue – this is often most noticeable where these lamps have been mixed giving a rather unpleasant effect. Warmer whites are good for relaxing areas and cooler whites are better for areas where work is being done. The “colour temperature” of white light is measured in Kelvin (K) where 2800K is a warm white, 400K is a cool white and 5000K is a daylight equivalent.

  • Does the map have to be dimmable? Many LED lamps aren’t dimmable but some are – look out for this on the packaging. Even the dimmable ones have to be used with a compatible dimming switch. The easiest advice here is to try it; it if doesn’t work, use the bulb in another non-dimmable fitting!

Note: Some LED lamps have a built-in dimmer that can be operated using an app over wifi, or by operating the switch twice in succession. Some can even change between a warm and a cool white!

  • If the lamp is to be used with a motion sensor or time switch this usually isn’t a problem.


The reduced heat output is a bonus in many cases; with uplighters and bedside lights in particular, reducing the external temperature of the fitting eliminates the risk of people burning themselves of the fitting or even starting a fire by leaving something flammable too close to the fitting.


The increased life of the lamps means far less less climbing of ladders to replace lamps!

If you have low-voltage lighting (usually 12V halogen spotlight fittings) there are occasionally issues when changing these to LEDs as the transformer that reduces the voltage supplied to these fittings has a minimum load, below which it might not work reliably. If this is the case it is possible to change all but one of the lamps for LEDs, or to get an electrician to change the transformer for one suitable for use with LEDs. However, if you are calling an electrician in for this, it might be worth considering whether to change the fittings for ones which work at mains voltage, as these are typically more efficient and more reliable.


Two factors you shouldn't have to think about:

  • EMI ("electromagnetic interference") – cheap LEDs can generate interference that affect nearby radio receivers.

  • Audible noise  - some very cheap LED lamps have been known to let out a high-pitched whistle.


For these reasons it's worth buying good-quality LED bulbs from somewhere reputable. We’d recommend:

  • Ikea – good quality, good range and good prices.

  • The church buys some of its LED bulbs from https://www.lights.co.uk – their fittings are rather expensive but they stock a rather good range of LED lamps at reasonable prices.

  • Branded bulbs from other outlets e.g. supermarkets.


Next Steps:

  • Why not make it an aim to make your home (or other premises!) as close to 100% LED lighting as practicable in 2024?

  • There may be lights that it's not practical to replace – the loft light probably doesn't see enough use to justify changing it until the bulb fails! Remember what we wrote in the January study about finding the right balance between embodied and operational carbon. I used to think it was worth waiting until lamps failed, but carbon balance showed it was better to replace them there and then.

  • List all your non-LED lamps (include table/bedside lamps, external fittings etc) and identify which you can change.

  • External lighting should be directional and pointing downwards – this avoids confusing wildlife and polluting the sky with light to the detriment of astronomers!

 

We want everyone to have a successful transition to LED lighting, and to end up not only with a more sustainable home, but with better light quality – this is an opportunity to reassess what you've been living with for years! Over the years your needs will change and your eyes will change. When we light the church we try to do so inclusively for those whose eyes aren't as young as they were!

 

Do let the Creation Care team know if you'd like to adapt your lighting but need assistance (whether to choose the LED lamps or to get at a hard-to-reach fitting to fit them!)


Where do you get your energy?

So far we’ve talked about using less energy. It’s also worth ensuring that the remaining energy that you use can be supplied with minimal carbon emissions. Firstly, this means that electricity should generally be preferred over gas – burning gas (and other fossil fuels) invariably generates carbon emissions, but a proportion of our electricity is produced without carbon emissions (e.g. through solar, wind, hydro and nuclear power plants). How big is that proportion, and what can we do to make it bigger?

Plenty of electricity suppliers offer a high proportion (even 100%) of low-carbon generation through “green tariffs”. These still use the same distribution network as the normal electricity supply but commit to generating the same amount of power that you take out of the network in a low/zero-carbon manner. It’s important to check what they mean by “green” as for some suppliers it might be:

  • burning biomass (more acceptable than fossil fuel if fuelled with waste material, less good if woodlands are being cut down to provide the fuel (e.g. see https://www.bbc.co.uk/news/science-environment-68381160 about ancient woodland pellets being shipped around the world and burned in Drax power station!)

  • selling the renewable part of their existing energy generation mix to customers signing up for a green tariff and selling the non-renewable part of their existing energy generation mix to the other customers – so they’ve not changed their overall energy generation mix at all!


Some energy companies are 100% renewable (so they can’t simply re-apportion their existing generation mix) and some have a strong environmental ideology what means that they’re more likely to “do the right thing” on your behalf! As an example, Ecotricity don’t offer the cheapest tariffs but reinvest their profits into low-carbon initiatives – so the excess income compared to a cheaper provider is doing something worthwhile.


While not using less energy, you can reduce the carbon emissions related to your energy usage by planning to use energy when the UK National Grid system has the greatest proportion of non-carbon based energy available. The “carbon intensity” of electricity varies throughout the day; it is typically lower at night when industrial demand is lower but nuclear power stations are still turning out their maximum capacity, and of course it is lower on sunny and windy days when there is plenty of renewable energy. Conversely it gets higher (dirtier) at times of high demand and/or low supply availabilty. You can see it in real time at https://www.nationalgrideso.com/future-energy/our-progress-towards-net-zero/carbon-intensity-dashboard.

Plan to take advantage of this – if you can set your dishwasher / washing machine to come on overnight it will perform the same task while causing less carbon to be emitted. Many modern machines have timers built in (e.g. to delay the start by a couple of hours); if yours doesn’t have this function, a plug-in timeswitch can be used instead. There are special tariffs for electric vehicle owners to charge overnight at a very cheap rate (and apps to time charging) – these also enable carbon emission reduction. A downside of setting energy-hungry appliances to operate overnight is that if they develop a fault it is less likely that this will be noticed at an early stage; we’d recommend that a smoke detector is installed in the same room as the appliance.


Many energy suppliers offer a “demand flexibility service” where (maybe a dozen times a year) they will send their customers a notice (typically 6-12 hours in advance) offering a discount in return for them reducing their energy usage for maybe 30-90 minutes when demand is predicted to come close to outstripping supply. This makes financial sense to the energy providers as the cost of covering the shortfall using inefficient short-term generation is higher than the cost of incentivising their customers to use less energy. It’s also a more sustainable solution – not only is less energy being used, but the sources of short-term generation are often some of the most polluting (e.g. diesel generators) – there’s usually good reasons (and legal limitations) why they’re only run as a last resort! If your supplier offers a demand flexibility service it’s therefore worth signing up and supporting it; you’ll need to have a smart meter to take part so your supplier can see when you’re using electricity. These periods where demand gets close to outstripping supply are typically 17.30 - 18.30 on colder, windless winter days, but can occur at other times.


Further Reading


What’s coming up this month?

  • Discussion: Those interested are invited to an informal discussion of this month’s topic during post-service refreshments on Sunday 21st July at 11.15 - 12.15 in the corner of the hall. Please come along and share your questions and your experience of and issues encountered investigating domestic energy saving; you can share as much or as little as you wish about what you have learned!

  • The 2024 Big Butterfly Count is being held between 12th July and 4th August – details are at https://butterfly-conservation.org/discover-and-learn/activities-and-resources/big-butterfly-count-2024. Download the ID guide, spend 15 minutes counting butterflies and day-flying moths and then submit your results. You can repeat as many times as you wish!

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