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Saturday, 7 March 2015

The cost of progress - 10 steps to calculate a brighter future.


Thinking of buying a replacement bulb but are worried about the epic price tag?  Especially the latest and greatest LEDs.  Do you see a barrage of statistics but the consequence of this overload of information is leading you to greater uncertainty, stress and worry?

Sadly, I don't have a solution for all of that but, maybe, the following calculator will help alleviate part of your stress, worries and concerns.  And you only need to take 10 steps to use this free, no strings attached, javaScript calculator.

It's designed to allow you to see the financial implications, such as savings for a change to, or retrofit of, a bulb.  That could be simply a change in wattage, a change in technology such as LED or both. Manually performing the mathematical calculation isn't difficult to do but it's extremely tedious.  So it's much more advantageous to let the computer browser do the laborious work on your behalf.

Note the initial values in the calculator are preset with the most common question scenario I've been asked.  Simply change the values appropriate to your installation and hit the "Calculate" button.


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Index.


  1. What this, Retrofit Lighting Cost Calculator, will allow you to do.

  2. What about our boat and my children's tree house?

  3. What if the change is more than just changing a bulb?

  4. What if a salesman is trying to take me to the cleaners?

  5. It all sounds good...  So what's the catch?

  6. Retrofit Lighting Cost Calculator





What this, Retrofit Lighting Cost Calculator, will allow you to do.


If you so choose, this calculator will allow you to look at several scenarios or changes, purely from a financial point of view, in quick succession.  It will generate a small report with some of the most commonly asked questions regarding your proposed choice. It will calculate the theoretical time it takes for you to see a return of investment (ROI). While playing with this free tool you might get some interesting results, which could be a surprise to you. It certainly was to me when I played with it!

As the price of electricity climbs, the speed of the theoretical return of investment can be quite stunning even with an infrequently used light fitting. Hopefully this calculator will help expose that fact. Equally you can be blinded by the hype and fall foul of excessive costs, which can seriously extend or wipe-out your ROI.  Hopefully this lighting calculator will also expose that fact.

Please note this calculator is just my opinion and does not constitute advice.  Please double check the results yourself before making any decision based on its findings.
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What about our boat and my children's tree house?


This free calculator will allow you to look and consider lighting installations in locations you may not use throughout the entire week or even the whole year. So if you've a boat, caravan, shed, tree house, summer/winter home, etc, then you can enter the duration of your usage in a slightly easier format than most other web based calculators, that I've found.

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What if the change is more than just changing a bulb?


There's also an option to add an additional, "one off cost," such as having to replace a transformer or needing electrical remedial work, which is handy if you're changing lighting technologies.  Sometimes it's pertinent to take the opportunity to change the light fitting as well as the bulb. The, "one off cost," option allows this value to be incorporated into the results so you can see its effect on the ROI.

Although the calculator is designed to look at a single bulb installation, for multiple bulb installations, assuming the same type, simply multiply the result by the number of installations in question.  This is simple since the main part of the calculation drudgery is performed by the automatic calculator.

  • This additional calculation step wouldn't be hard to add to the calculator but I though it better to have one less step for both simplicity and clarity. If there is enough demand for such a feature extension I will add it to the lighting retrofit calculator.

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As stated before, just to note that when this web page initialises, it automatically populates the values in the lighting calculator with the most common lighting scenario I've come across to date.  You merely change these default values in the 9 locations for yours, and then hit the, "Calculate" button as the 10th step. You can see the template of the report below the entry section of the calculator and the values are populated with the results when you click the calculate button. If you wish to change any value merely change the required field and hit the "calculate button to generate a new report with the updated values.

  • I have not added a "reset" or "clear" option but again if there is a demand that would not be difficult to add.  The usual trick on a browser is to either reload the page or force a reload with the F5 key (pressed twice).  Not sure what happens on a tablet as I do not have access to one at the moment. :-(

What if a salesman is trying to take me to the cleaners?


Where costs are particularly wayward and it's calculated that you will not recover your investment, the javaScript lighting cost calculator will attempt to give a suggest maximum target price point to recover the cost:
  1. Within the lifetime of the bulb.
  2. Within a five year period.
The five-year period is based on your entered usage level and will only be calculated if the lifetime of the bulb is greater than 5 years.  Most manufacturers specify a notional lifespan in hours.  The calculated yearly usage is based on the manufacturer's lifespan in hours divided by your indicated yearly usage in hours. Essentially, if you use the lighting a lot then the calculator will calculate a shorter lifespan for the bulb than if you rarely use the lighting.

  • Manufacturers of domestic lighting LEDs tend to assume a yearly usage of 1000 hours per year. This calculator will base the bulb's lifetime on "your usage," not this arbitrary figure which is equivalent to 2.74 hours each day.

In both cases where a suggested maximum price point is calculated, it is also dependent on your original bulb choice or current bulb values you've entered. If you're replacing a power hungry, short lived and expensive bulb, the target maximum price point will be higher than if you're replacing a relatively low energy light that's quite cheap to buy and has a long lifespan. The idea of the maximum target price point suggestion is so you have an idea where the bottom line price is located to ensure an ROI. Obviously, the lower the price of the bulb the better, but if you're paying more than the target maximum value you will not see an ROI.

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It all sounds good...  So what's the catch?


The reason I chose 5 years is because, I believe, this is the typical write-off time for "consumable" company assets and it also seemed like a reasonable length of time "expectation," generally. Beyond 5 years the changes in cost due to inflation make all of the predicted times and values unreliable.  All values in the report take no account of inflation and unrealistically assume both static prices and costs. Of course, this makes long term predictions unreliable and the results should be considered for your personal interest only.

The maximum target values are only calculated if the return of investment is not achievable. I have not automatically included the target value cost in the report as it would make it too confusing to read.  If you want to see the values then put a ridiculously high value in the replacement bulb cost option and hit "calculate." The result/s will be displayed at the top of the report.

Jump to calculator

Please note this calculator is just my opinion and does not constitute advice.  Please double check the results yourself before making any decision based on its findings.





Retrofit lighting cost calculator


1. Select the wattage of your current bulb from the pull down menu:

Enable JavaScript for this calculator to work

2. Now enter the lifetime (in hours) of your current bulb or select from the options below.
  • You can use the radio buttons below to select a common type if you're not sure of the specific lifetime in hours.
  hours.


-Incandescent  -Halogen   -CFL -Fluorescent tube   -LED
  • Alternatively, if you know the lifespan you can directly enter the life expectancy, in hours, above.
3. Enter the cost of the bulb here:    £     $   ¥      
4. Select the wattage of the alternative/retrofit bulb you're considering:



5. Enter the lifetime (in hours) of the alternative/retrofit bulb or select from the options below.
  • You can use the radio buttons to select a common type if you're not sure of the lifetime in hours.
  hours.



-Incandescent  -Halogen   -CFL   -Fluorescent tube   -LED
  • Alternatively, if you are more familiar with the life you can directly enter the life expectancy, in hours, above.
6. Enter the cost of the replacement bulb here:



7. Enter any additional one off cost here, if applicable:
8. Enter your electricity unit cost per kilowatt hours here:

9. How frequently will you use these lights? Select usage options below:
  • Note: When low energy bulb manufacturers calculate the lifetime, they tend to assume 2.74 hours a day or a convenient 1000 hours a year.
  • If you have a boat, holiday home or caravan, you may not even be using it for the full year.
of the year, of the week and in a day.
10.

The results:

With the information you've entered into the calculator, I have calculated* the payback period or ROI will be :

Time
.


  • *( Please take this "headline" value with a pinch of salt as this is a manufacturer's approximation, so you can easily be out by a large percentage. )
  • ( The computation is much more precise than the information it is fed with. Vague information "cannot" be made more precise, so please bear that in mind when you see the output from this or any other calculators. )
  • Note if the payback period is greater than 5 years there may be significant changes in the unit fuel costs as well as the purchase price of any unit bulb. These changes coupled with inflation make for a totally unreliable figure, which is beyond the scope of this calculator. Only take these figures as a guide and an indicator rather than some sort of scientifically derived computation. For a much more illuminating breakdown, please see the report below:
Using the values you've entered, the lifetime** of the retrofitted bulb would be :

Time

  • **(As above, please take this value with a pinch of salt as this is a "manufacturer's approximation," so you can easily be out by a large percentage.)

    • I hope you don't get confused by the results of the calculations in this calculator. Although I calculate to the precision of an "hour" this is really an artifact of enthusiastic programming on my part.
    • At some point in the future I hope to write a post on what the lifetime actually represents as it can be both ambiguous and misleading.

The cost of the retrofitted bulb, to you, over its lifetime*** will be :

Time

***(Which includes both the purchase price of the bulb and any one off installation cost, if entered.)

The yearly cost based on your usage plus a proportion of the bulb's purchase price will be :

Value

(This value "excludes" the one off installation cost.)

The price of only the electrical power consumed during the year will be :

Value

This means, if you retained your original choice for the equivalent lifetime of the alternative retrofitted bulb, of time . Which means that you would need to replace the original bulb x and would represent a total equivalent cost to you of:

Value

When compared to your proposed bulb, the total lifespan of the original bulb would be :

Time
.
(This is calculated using your usage data and makes a massive assumption that the manufacturer's lifetime is accurate and exact.)

Consequently over the equivalent length of time, this bulb will need to be replaced :

x

During the equivalent lifespan of the replacement bulb. Your current bulb would have a yearly cost of :

Value

(Again, I have taken the liberty of including the unit purchase price in this calculation. To have a meaningful number means that the replacement bulb cost must be included within this value.)

The equivalent cost of electrical power consumed over one year will be :

Value



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Please note this calculator is just my opinion and does not constitute advice.  Please double check the results yourself before making any decision based on its findings.

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