Energy Saving Lighting

Energy Saving Lighting Projects account for a significant chunk of my business. Switching to LED lighting, will typically save a client 40-60% on their electricity costs, often more. With the recent hikes in electricity costs, that’s becoming more important to many businesses.

As a qualified lighting design engineer, I’ve been doing energy saving lighting projects for around 30 years. Long before LED lighting was on the market. Many things have changed as a result of LED, but the fundamentals of energy saving remain the same.

Energy saving Corridors

I’ve carried out energy saving projects in schools, colleges, universities, hospitals, factories, warehouses, offices, and all types of business premises. One of the most recent involved a college spread across 4 separate buildings. The main photo, and that above, is a recent college job, but could just as easily be a hospital, school or office. On that occasion, it’s abuilding less than 15 years old using T5 fluorescents, which were energy saving in their day. The most common projects though are small commercial/industrial units and offices. You don’t have to have large premises to save money on the running costs of your lighting.

Sodium FloodlightsI can still remember my first ever energy saving lighting job back in the early ’90s. The client had a large amount of 1000w tungsten halogen floodlights. The glass on the fittings was failing in wet windy conditions. The glass got very hot, and cold rain would cause it to shatter. The lamps also only lasted about 3 months. As the fittings were mounted at around 8-10m, they needed a cherry picker every time a lamp or glass failed. The solution was to change them to 250w sodium floodlights. Sodium lamps lasted 15 times longer than tungsten halogen, glass didn’t shatter, and their electricity consumption dropped by 75%. Payback on the job was less than 6 months. The technology has advanced, but the principles remain the same.

LED Lighting

LED lighting started to become a viable light source around 10-12 years ago. Like sodium etc before it, you get more efficient light that lasts longer. The most efficient of fluorscent or sodium fittings gave around 85 lumens per circuit watt.  An efficacy of 100-150 lumens per circuit watt is now the norm. A whole life of 15,000 hours was once the norm. 50,000 hours to L70, is probably the new norm. (See my article LED Lighting Buyer’s Guide for a full explanation on the life of LED Lighting.)

Fluorescent lamps will cease to be manufactured within the next 6 months. If you haven’t already looked at moving to LED, it’s inevitable that you will have to soon. As the stocks of lamps decrease, the price will inevitably rise, costing you even more. Eventually, stocks will run out.

Luckily, changing to LED is simpler, and less expensive than you think. I help clients do it every day. Here’s how:-

3d Lighting Design 2

Lighting Design

Artificial light is used for illuminating the tasks we carry out at work, play, for security and many other applications. Most of these tasks have recommended lighting levels etc. These recommendations cover how bright it should be, uniformity, glare etc. Where the light is for the tasks carried out by staff or customers of a business, the owners/managers need to make sure it’s right. Too much or too little light, bad uniformity, excessive glare etc, can lead to accidents, eye strain, headaches and more.

As a Lighting designer, I will calculate the right amount of light, uniformity, or glare for your given tasks. This is fundamentally important to energy saving lighting projects. All too often I see jobs where a client has changed the lighting to save money and the levels are dangerously low. Similarly, clients and contractors often change fittings one for one, and get levels that are too high. This often happens when changing old fluorescent modulars to LED. On many jobs, it’s possible to reduce the quantity, or use a lower wattage fitting, both will improve the savings. (See my short YouTube Video on The Value of Lighting Design for more on this.)

The key is to optimise your savings; maximum saving while providing the right lighting levels etc. There may not be only one right way to do this, but there are many wrong ways. The correct lighting is known to optimise employee productivity, increase retail footfall and more. In my opinion, any business looking at Energy Saving Lighting, should always be involving a lighting designer.

Energy Savings Calculations 1                       Energy Calculations Energy Saving calculations 2



Having designed your lighting, I’ll calculate your annual savings. Comparing the original fittings to the proposed fittings, again, requires knowledge to do it correctly. I see many companies, and online calculators which use lamp wattage for calculating energy savings. Your electricity consumption is charged on circuit wattage, not lamp wattage, the difference can be significant. Having been in the industry for over 30 years, I have the circuit wattages for 90% of lamp & control gear types. All types of fluorescent and discharge fittings have losses in the control gear. As an example, burning a 5ft 58w lamp, could use as much as 72w pepending on the type of gear. It’s 72w that goes through your meter, not 58w, so you pay accordingly.

I’ll calculate the cost of running your existing installation v the proposed installation. In addition to the monetary cost analysis, I include the Kg or tonnes of CO2 saved. Sometimes you need that to secure funding.

From your usage, and the life of the proposed products, I’ll calculate the life to L70, and the accumulated savings. This is where it’s fundamentally important to use quality products. As you’ll see from my Post on the LED Lighting Buyer’s Guide, Quality products can last many times longer than cheap ones. In that post, I give a common example, where quality fittings last over 3 times longer than cheap ones. This means that you will replace the cheap ones at least 3 times in the life of the quality ones! In the example shown, the quality fittings will last 18.2 years. Cheap ones at 50,000 hrs total life (15,000hrs to L70), would last 5.45 years. The quality fittings would save £469,540 in those 18.2 years. Cheap fittings would require to be replaced an additional two times in those 18.2 years.


You’ll see from the example above, the client saved £25,824 per annum, which represented a 76.77% saving on his lighting costs. The total cost of labour + material was circa £32k, giving a payback of under a year and a quarter. In addition, there are no lamps to change, so maintenance free.

Lighting design allowed us to reduce the quantities of fittings in many areas. Using Quality British Made fittings allowed us to use different outputs to optimise the lighting levels v energy consumed.


By calculating everything in advance of the installation, you’ll know exactly what you will get.


You’ll know that you’re getting the correct lighting levels etc.


Know what your annual savings, and whole life savings will be.


What life to expect from your fittings.


That you’ve chosen to work with a Lighting Professional, giving professional results.


The Really important bit:-

In this example the savings equate to £2,152 per month. The cost of funding the job would be less that £1000 per month over 3 years.

That means that the nett cost to your business is ZERO, as the savings will fund the job!

What that really means to you is that employing a Lighting Professional to look at your Energy Saving Lighting project is essential to get the best result.


Iain Ross MSLL


I am a qualified lighting design engineer, a Member of the Society of Light and Lighting, and have over 30 years in the industry.