Lighting in the 19th, 20th and 21st centuries

This post is in two parts, the first is Chapter XV of the 1894 edition of "The Handbook of Household Management and Cookery" by W.B. Tegetmeier which gives a description of the options for lighting the home in late 19th century England.  The second has been compiled from family experiences in the 20th and 21st centuries.

Chapter XV - Lighting: Candles, Petroleum, Benzoline, and Gas Lamps, Their Management, etc.

99. Flame, which gives the light employed in our houses during the absence of the light of the sun, is always produced by the burning or combustion of inflammable gas.

When a candle is lit, the fat, wax, or other material of which it is formed, is melted, then drawn upwards into the flame by the attraction of the wick, it is there heated so strongly that it is converted into gas, which burns as fast as it is made, thus producing the flame.  In oil lamps the same happens, and in gas burners the gas burns as it escapes.

100. The gas which is burnt to give us artificial light, whether obtained from coals and supplied through pipes, or produced in the burning of a lamp or candle, consists chiefly of two substances, namely, hydrogen, which is always a gas, and carbon, which when not united with hydrogen or any other substance is usually a black solid, like charcoal or soot.

101. Both these substances burn in the flame, uniting with the oxygen of the air. The hydrogen in burning forms water, a large quantity of which passes off from every flame in the form of vapour or steam. Many gas lights in a close room make the air very damp, and the moisture they produce may often be seen settling on the cold glass of the windows, or even running down the walls. The carbon or charcoal when burnt forms carbonic acid, an invisible gas. When there are many gas lights in a badly ventilated room, or even one in a room that is not ventilated at all, the air becomes very unwholesome from the presence of carbonic acid gas.

102. If there is not enough air to enable both the carbon and the hydrogen to burn, the hydrogen burns first, and part of the carbon passes off in the form of smoke. By putting any cold pieces of metal, glass, or earthenware into a flame, the carbon is prevented from burning and settles on the metal or glass, covering it with black soot.

103. Candles, which were formerly very generally used, give out very little light and are the dearest mode of producing light.

Much may be learned of the nature of flame by watching attentively that of a common candle; at the bottom is a pale blue light which is caused by the fresh air rising against the flame and producing the perfect burning of both the carbon and the hydrogen; in the interior of the flame is a dark centre which consists of the unburnt inflammable gas rising from the wick; this cannot burn until it reaches the air outside. The outside of the flame is very bright it is there only the gas burns.

If a smalls slip of wood be held for a moment steadily across the centre of a flame, it will be seen that the part in the middle is not burnt, only that which was at the outside of the flame.

104. The oil used in lamps is of two distinct kinds. The fat greasy oils, such as seal or whale oil from animals, and olive or colza oil from vegetables.  obtain a good light from these fat oils it is necessary to make the flame hollow, and admit air into the interior, as is done in what is termed an Argand burner.

In order to cause a strong current of air through the flame of an Argand, a tall glass chimney is requisite.

105. The mineral oils, called paraffin or petroleum oils, are the cheapest oils in use They contain a very great amount of carbon or charcoal, and if they are burned without a chimney this escapes into the air in dark clouds of black smoke. These oils, therefore, require to be burned in a properly constructed lamp, so that sufficient air shall be sent against the flame to consume all the carbon.

The best paraffin lamps are those with a single flat wick, which is able to be turned to any required height above the wick tube A, by small toothed wheels turned by a handle, B. The large quantity of air required by the flame rises up through the cone or cap c, and is directed against the sides of the flame, producing a complete combustion of the carbon, and a very brilliant light.

Paraffin or petroleum oils were formerly sold containing much volatile inflammable spirit. At the present time no mineral lamp oil must be sold which is dangerous.

Petroleum lamps are perfectly free from danger if properly used. The oil-holder should be of glass, as if made of metal, it is apt to become heated. The lamps should always be filled before dark, and never after being lighted.

Any oil spilled on the outside should be carefully wiped off, or it will produce a disagreeable smell when the lamp is used. To light a petroleum lamp the glass chimney should be removed, then the wick turned above the slit in the cone, and when lighted instantly turned down again; the chimney should then be put on and the wick turned up so as to produce a large bright flame without smoke, but so as to produce the full If the flame, when the lamp burns without smell. flame is turned down low, there is no saving of oil, as a large quantity is sent off in vapour and produces a most disagreeable smell.

106. Sponge or spirit lamps are made for using the very inflammable spirit termed benzoline. They are filled with sponge or cotton wool which is moistened with benzoline, the wick-holder is then screwed on and the wick turned up level to the top; when lighted a small flame, rather greater than that of a candle, is produced. As the benzoline is very inflammable these lamps should never be trimmed after dark, or near a fire, as the vapour may take light. If trimmed in the day-time, and only enough spirit poured in to moisten the cotton wool, they are quite safe, and are the cheapest source of a small light. When used as night lights they should always be placed under a chimney as the vapour escapes and smells when they are turned down low.

Coal gas is unquestionably the cheapest source of light, but it's economy is not so great as is generally imagined ; the flame cannot always be brought where it is wanted, consequently a much greater amount of light is necessary than when movable lamps are employed.

For small rooms, the two-hole, or fish-tail burner is best, being cheap, simple, and capable of causing a very perfect combustion of the gas. With this burner the flame is spread out into a thin, flat sheet, by the two currents of gas striking against one another. In a fish-tail burner the gas should always be turned on so as to cause a full-sized flame without flickering, as otherwise the gas is not perfectly burnt. A large-sized burner should not be used where a smaller one will answer. The flame gives a much brighter and steadier light when placed horizontally with the flat sides turned up and down, than when burned upright in a glass globe, when the flame always flickers and is injurious to the eyes. An ordinary-sized fish-tail consumes from three to four cubic feet of gas per hour, and gives the light" of from six to nine candles.

Where a great amount of light is required a circular or Argand burner is more economical than the fish-tail.  In most burners the chimney is too high ; this causes too strong a current of air, and a great loss of light ensues. An Argand with a ring having fifteen holes, should not have a chimney more than seven inches high. Such a burner will consume about five cubic feet of gas in an hour, and give an amount of light equal to that of fifteen sperm candles.

In all cases where gas is used, the room should be ventilated, or the air will become very unhealthy from the great amount of carbonic acid and vapour of water produced.

Explosions sometimes occur when gas has escaped from a leaky pipe or a burner that has been left open, The explosion is generally caused by some person taking a lighted candle to discover the leakage, when the escaped gas takes fire instantaneously, and burns with a violent explosion. Whenever there is a strong smell of escaped gas, the main cock at the meter should be immediately turned, and the doors and windows opened to allow the gas to escape. No attempt should be made to search for the leak with a light, but notice should instantly be given to a gas-fitter.

The above describes the experiences of the old ladies of the family who were grateful for light that could be turned on or off with the flick of a switch, as girls, it has been their job clean grates, lamps and deal with soot, ashes, damp and lamp black.  Electric lighting started appearing in public places in the 1880s in the form of arc lamps which with electricity costing the equivalent of £5/kwh were expensive to run.  In the 19th century, electricity was a luxury product.

In our family homes started to be wired for electricity in the 1920s.  Typically, a room had a central pendant, maybe some wall lights in the living room and some movable lamps which plugged into wall sockets.  Incandescent bulbs were the main source of light for the better part of a century.  Bulbs got brighter, lasted longer and dropped in price but the main option was 40W, 60W or 100W bulbs which had a life of 1,000 hours and produced roughly 10 lumens/watt.  They had a secondary role as room heaters.  Some homes with water tanks in the attic had light suspended over the tank in the hope of preventing freezing and burst pipes in winter.  When electricity was first installed and the principal use was lighting, consumption was generally less than 1,000 kwh/year.  Wartime austerity reduced this to well below 500 kwh/year, but when peace returned there was a steady increase in consumption as new uses were fount for electricity.

Small fluorescent lamps known as Energy Efficient bulbs (a.k.a.CFLs) started appearing around 2005, initially they had an output of 30 - 50 lumens/watt and were expensive.  but it made economic sense to replace 100 watt incandescent lamps with 20 watt CFLs.  In 2009 European countries introduced legislation to phase out incandescent lamps.

In 2012, we started replacing CFLs with LEDs.  LED lighting has developed rapidly, some early offerings did not win the hearts and minds of consumers, but some of the current products produce around 80 - 100 lumens/watt and are a simple swap with CFLs and incandescent bulbs.

Simulation and Sustainability (15) - Think differently

In the second half of last year I wrote a short and simplistic simulation in Python designed to explore ways in which a typical household could increase its consumption of wind and solar energy by the including storage in it's energy economy.  Several scenarios where explored and written up as posts as part of this blog, this one is some thoughts on the project. The link at the bottom of the page points to the original posts.

The concept is simple, a household has, say, 10 kwh of electrical storage and by some yet-to-exist technology which gives it the ability to "buy" electricity from a variety of suppliers.  It makes use of  sustainable energy  when it is available and if there is a surplus stores it for use when the sun does not shine (i.e. at night) or when the wind does not blow.   It first checks to see if any solar energy is available on a local grid and if none is available it sees what wind farms can offer and finally when the storage is exhausted, falls back on conventionally generated supplies.

As with many simulations, there are a lot of assumptions and arbitrary rules, so the conclusions suggest a direction of travel rather than precise estimates of how such a system might behave.  Renewable currently account for roughly 15% of the electricity consumed in the UK, by incorporating storage into a home's energy system, an individual house might increase this to 50 - 80%.

Whilst wind and solar generation are critical technologies in a sustainable energy economy they are both weather dependent sources and require either storage or a  backup in the form of gas fuelled power stations to bridge the gap between intermittent supply and regular demand.  The pattern of investment that seems to be emerging is that offshore wind farms are incremental to conventional capacity and this raises the question: "Is it possible to displace some fossil/nuclear capacity by increasing the use of energy storage".

When I first started thinking about a simulation to explore this idea I had in mind the lead-acid battery packs used by fork lift trucks, however, since then products like Tesla's PowerWall have become available and these have the advantage of being packaged as consumer products.  As electric vehicles become more common, the profile of electrical energy storage will become more familiar.  It also raises the possibility of using the family car as part of the household energy supply.  For example, most cars do very little, often sitting around car parks at the end of the commute, if during that time, the car is charging itself on wind or solar generated electricity, it might return home with a surplus which can be used to light the home and cook the evening meal (I appreciate there might be some complexities in this scenario).

The current electricity supply model has evolved on two assumptions:

• That supply and demand can only be synchronized by adjusting the output of generators
• There is no limit to consumption

If these constraints are relaxed, alternatives forms development emerge.  Storage helps with the first item and the second is a challenge.  People do not buy energy, they purchase the benefits it provides.  One example of a technology which delivers this is LED lighting.  A decade ago our home was lit with incandescent bulbs and it consumed 20 kwh/day, now with LEDs we are down to 4 kwh/day and we can still see to read.

The potential to re-apply investment in energy infrastructure is illustrated by a hypothetical nuclear power station.  Say it costs  £20 billion and several years to build a 2,000 MW unit.  If the average home consumes 4,500 kwh/year, this imaginary project with a load factor of 90% can supply approximately 3.6 million homes.   This very simplistic calculation suggests that one power station represents an investment of £5.5k/household.  This is similar to the cost of a 10 kwh storage unit.

Sustainable energy sources are unlikely to fully replace conventional ones but there is scope to investigate some alternatives.

This link provides a description and pointers to related posts:

• Doris - A thought experiment in progress

Economics, LED Lighting and Sustainability

Economics and sustainability do not sit comfortably together.  Fossil fuels are convenient and after more than a century of development the devices which consume them are reasonably efficient and in some respects cheap.

Things that are tagged as "sustainable" or "green" often have a premium either paid directly by the owner or indirectly by a third party in the form of a subsidy.  Ideally, sustainable technologies should deliver the same benefits for the same cost as traditional technologies.

My experience with LED lighting suggests that it meets these criteria.  I bought my first LED lamp approximately 4 years ago and it did not win the hearts and minds of my family.  I'm guessing but I think it produced 50 - 60 lumens per watt which was only a modest improvement on CFLs which lit the house, however, the real problem was the fact that the light came from a surface rather than a sphere, thus the diffuse light reflected from ceilings was lost.  About two years later, some small LED globes started appearing with an output of around 400 lumens and maybe an efficiency of 60 - 70 lumens/watt.  These worked well and some 10 watt CFLs were replaced with 5 watt LEDs.  Recently, the "right" product appeared in the form of a globe lamp with an output of around 900 lumens and an efficiency of 90 - 100 lumens/watt.  We are now replacing 20 watt CFLs with 10 watt LEDs.

The benefits of moving from CFL to LED appears in the electricity bill, we currently consume about 1,500 kwh/year making the bill, excluding standing charges, roughly £250/year.  I extracted the graph above from my account on the energy suppliers website.  It needs treating with caution as I'm not sure it compares like-with-like.  I'm guessing that the "similar house" means one in the same postcode area and that the "efficient house" is the lower quartile for that postcode area, so all the graph tells you that our home uses electricity than our neighbours, possibly because we have LED lighting.

Let's take this experience to some illogical conclusions.   Say, an investment of £250 in LED lighting reduces a home's electricity consumption by 200 kwh/year most of the reduction taking place in winter when the demand for energy is highest.  Compare this with a hypothetical rooftop PV installation costing, maybe, £5,000 which produces 2,000 kwh/year mostly during the day in summer when the demand for energy is lowest.  Which technology gives the best environmental outturn?

LED Lighting in an Edwardian House

LED lighting is becoming a mature technology.  It is an affordable technology and in the right environment can reduce energy consumption and costs.  It has taken some time and some product evolution to make them work in our Edwardian semi, but progress is being made.

When the house was built in 1901 it was lit by gas, an extensive network of pipes can be found beneath the floorboards and in the walls.  The living room was lit by a gas chandelier and a mantle over the fireplace.  This scheme was short lived and electric lighting appears to have been installed around 1910.  Typically, each room had a single ceiling fitting and I guess there were some standard and table lamps for sewing, reading and writing.  Later owners added some wall lamps.  When we acquired the house in the early 1990s, the living room was illuminated with approximately 1,500 lumens supplied by one 100 and two 40 watt incandescent lamps.

In 2006 the household electricity consumption with incandescent lights was around 25 kwh/day, sometime around the end of the year I spent approximately £100 and replaced the incandescent bulbs with CFLs and the consumption quickly dropped to 10 kwh/day.  The early CFLs fell a little short of expectation, the life, whilst longer than that of an incandescent bulb was less than the 8,000 hours stated on the packet and there was a short delay before the bulb emitted enough light to read by.  After a couple of years, the technology matured, failures were rare and the price started to fall.  The information on the packaging suggests that the luminous efficiency of CFLs is about 50-60 lumens/watt which is a significant improvement on incandescents which are around 10 lumens/watt.  The great thing about CFLs is that they were a straight swap for the incandescents.

Sometime in 2012(?) I purchased a couple of LED lamps for a cost of around £25.  Whilst these entertained me, they did not win the hearts and minds of my family and have been banished to my workroom.  There were two issues, the first was that the light emitting element was a surface not a quasi sphere like the CFL, thus the diffuse light from the ceiling was lost making the room appear dark.  Secondly, the individual LED elements were small making them distractingly bright.  This fine example of  rustic Bauhaus is still my desk light:

The problem of glare has been partly solved by changing light shades to ones which provide an element of diffusion.  However, there is a limit to the amount of modification that is economically possible, replacing light fittings and adding new ones is expensive, not least because of the redecoration that is needed afterwards.

The attraction of LED lighting is the high luminous efficiency, current LED lamps seem to be capable of 80 - 100 lumens/watt.  Thus whilst we have been using 40 watts to light a room with CFLs, this might drop to 20 watts or less with LED's.  This is not going to have the effect that the migration to CFLs did, in part, because the process is taking place slowly, but out household energy consumption is drifting downwards.

For a couple of years, "360" degree bulbs which can substitute CFLs have been available.  The first ones I found were small with an output of around 300 lumens for 3 - 4 watts, a couple of these have replaced 10 watt CFLs in passages where lights are left on all night and we have probably achieved payback in about 12 months.

This lamp in the picture might be the breakthrough which displaces CFLs in our house given time.  This one appears to draw about 4 watts and produce about 400 lumens, the elements are larger than previous versions so glare is not such a problem and it fits in existing light fittings.  My guess is that larger versions of this will become available as the technology evolves.

Starting over

Not too far from where I live is a house that was built sometime in the 1980s, I guess it was none too comfortable to live in.  Whilst it was being partially demolished, I did not see any signs of insulation, just a lot of windows with rotting frames and a load of rusting radiators.  Technically, it is being extended, but in reality, it is being rebuilt.  The roof is well insulated, the walls have a 100 mm layer of polystyrene and the windows are double glazed.  Not wanting to be a nosey neighbour, I have not enquired about the heating system, however, I know that a wood burning stove was installed in a similar development and has yet to be lit.  Retrofitting a property to that standard would be difficult and expensive and unlikely to pay-back.  That statement is based on a study of my own home where you could spend a lot of money, not be much warmer and would lose the character of an airy Edwardian semi.

Sustainability is much easier to attain with a clean start.  I am currently working on (more accurately "staring at") an electrical storage project.  Storage is one of the key components in a sustainable energy economy, but batteries are DC devices and my home is wired for AC.  AC is a logical choice for distributing electricity, but increasingly it is consumed at DC.  Some time back I did a quick survey on how we use electricity in our home and produced this graph, this suggested that only 15% of electricity has to be consumed at 240 volts/AC or in other words the washing machine and vacuum cleaner.  Some things like the fridge are available in low voltage DC forms, computing and entertainment devices all have power supplies to shift from high voltage AC to low voltage DC.  We are slowly migrating the lighting from CFL to LED devices.  Each LED light bulb has its own power supply circuit for AC to DC conversion.

Even though most things use low voltage DC, distribution within the house is 240 volts AC,  That was a logical way of doing things in the 1920s when electricity was first installed and all appliances used AC, the better part of a century later, there may be some value in examining household distribution. 

If storage were to be part of the household energy system without any radical changes in wiring, the first step would be go from 240 volts AC to 12 or 24 volts DC for battery charging, the battery would be connected to an inverter to get back to 240 volts AC to go through the ring mains, devices connected to these would then drop it back to low voltage DC.  This would be a complex and inefficient system and one which is not going to get built any time soon.  The small DC storage project is all DC, albeit with some level shifting, and is relatively simple.

I stumbled over another example of the complexity of legacy systems.  When the railways moved from steam engines to electric motors, high voltage DC was chosen because at the time only DC motors could provide the high starting torque needed to get a train moving.  Modern electric trains (so I am told) use AC motors.  Thus the grid feeds trackside substations with AC, this is converted to DC for the trackside rails, the train then converts it back to AC.  I doubt if the losses in this system are great, but the result is a complex system with DC for traction and 3 phase AC for everything else.

In the UK there is a debate over how to curb emissions which can be grossly oversimplified to nuclear versus the renewable technologies such as wind and solar.  My own view is that there should be different paths for "old" systems and "new" developments.  For the legacy systems which are based on large amounts of uninterrupted energy from fossil/nuclear sources, the key technologies are conservation and energy management.  It is valid to determine if it is possible, practical and economic to build new systems which are more or less dependent on renewable resources which are discontinuous (the Sun does not shine at night and the wind does not always blow), these would incorporate appropriate technologies, e.g. LED lighting and storage.  It's so much easier to design these things from scratch and not have to mess with the past.

LED Lighting

My first experience of LED lighting was in 2009 when I used a 12 volt 1.5 watt lamp as part of a very small solar powered system.  This device consisted of a cluster of conventional white LEDs, whilst it was not a solution to lighting the home, it was used in the garden where it was suspended over a table so we could see what we were eating (and drinking).  For a very small input of energy, we were saved from our son's early attempts at barbecuing and filled in the time by reading a newspaper.

I've been aware of LED lighting as an emerging technology, so in 2012 a purchased a 7 watt unit which whilst being similar in appearance to an incandescent lamp, consisted of a light emitting surface and a not very effective diffuser.  Sadly this did not win the hearts and minds of my family, however, it is now mounted in a standard lamp and directed upwards at a white ceiling, provides a pleasant ambient lighting effect with limited impact on the electricity bill.

At this point, it seemed that LED lighting would work well where only direct lighting was required, for example in a desk lamp.  So early in 2013 I invested £5 in a 3 watt "spot" lamp which works very well.  My working area is now lit with 10 watts of LED lighting.

Over a seven year period, the energy used to light my work space has dropped from the 200 watts used by incandescent lamps in 2005 to around 10 watts with LED devices in 2013.

Ever since the days of gas mantles and oil lamps, most homes have been illuminated with a combination of direct and diffuse lighting.  With the advent of electric incandescent lamps, the most common lighting scheme was a single 60 or 100 watt lamp hanging from the ceiling, if you were posh there might be a couple of wall lights with candle shaped bulbs and readers of "Homes and Gardens" had standard lamps with lace shades, known to some as "tart's knickers".

Until recently, there has not been readily available LED lamp with the geometry to provide a point source of light with enough output to bounce off walls and ceilings.  However, I have just purchased a 3.5 watt LED which has an output of 230 lumens which is capable of replacing some 10 - 18 watt CFLs.  More importantly, my wife thinks this is a good idea.

Over the next few months we will experiment with LEDs around the house.  I guess we may have to add some more fittings and make some adjustments to completely replace CFLs.  This will allow the steady reduction in our electricity consumption to continue.  Whilst I'm interested in energy conservation, I won't/can't make massive capital outlays, however LED lighting does not require this and equally important pays back in between three months and three years.  This makes economic sense.

Over the past few years our electricity consumption has steadily fallen from more than 20 kwh/day to maybe less than 5 kwh/day.  This has been achieved by doing little more than taking account of energy consumption as household items have had to be replaced and a general awareness resulting from reading the meters occasionally so that we are aware of what we are consuming.  I hope that I appear normal and not obsessive.

This has lead me to the opinion that much energy policy is based on supporting high priced capital items such as roof-top PV (feed-in tariffs) and ground source heat pumps (renewable heat incentive).  Whilst I accept that there might be some merit in these schemes, they only appeal to people with surplus cash resources who are not a large part of the population.  They also act to create a perception that energy sustainability is expensive, whilst if done properly can reduce energy costs.  My current view is that low cost technologies which can be adopted by a large proportion of the population should have a higher priority.  I suggest that LED lighting, energy meters placed in the kitchen which display the current energy bill as well as the amount of energy being consumed and zoned heating would significantly lower domestic energy consumption.

The business model used by energy companies is also part of the problem, at 25 kwh/day I am a good customer, at 3 kwh/day I'm less attractive and possibly a nuisance, yet the economy as a whole needs viable energy suppliers, that problem requires a better mind than mine.

Blogger's Note

It's sometimes fun to take an argument to its illogical conclusion.  I sometimes read small chunks of The Guardian on my phone around 05:00 in the morning when it is still dark, to avoid waking my wife I don't turn on the bedside light.  Whilst a liberal press can guide my mind, I do have to turn on a light to find my way to the lavatory safely, thus it is unlikely that smartphones will replace domestic lighting.