How to test whether a timer will be worth your while to install at home
Posted by Echardt on February 9th, 2012
To enable you to do this test you have to have access to your electricity meter (from the utility/body corporate/landlord). In other words you must be able to take down readings from this meter yourself on a daily basis over the test period.
Remember, you first need to determine what is the average daily usage of kWh (units) in your household PRIOR to making any changes. This then need to be compared with the average daily usage after you have applied some changes.
The test:
On a day of your choice (day 1) take an opening reading on your electricity meter at any time of day, but make sure it is a time that would permit you to take future readings at more or less the exact same hour. Most single phase electromechanical electricity meters have 5 digits showing white numbers on a black back ground (three phased supplies have 3 x single phase meters or 1 x polyphase meter with 6 of these digits). You write down the reading as if writing down the kilometer reading from your motor car’s odometer. Ignore the red and white digits and or markings on the right most digit of the meter. These are decimals of one. Not needed for the test. Should you have an electronic meter, just take down the displayed reading as is. If 3 x single phase meters, take down each meter’s reading individually.
Now, for seven days here after, at the same time of day every day, continue to take down these readings. Remember, in any household the usage pattern vary daily (one day you do washing, the next day you do the ironing, you have one cooked meal a day, sometimes only once or twice a week, etc…this pattern normally repeats it self over a 7 day period). On day 8, you start switching the geyser/s off for as long as possible during the day (24hr period) over the next 7 days. For the purpose of the exercise, try and have it on only for an hour or two in the morning and/or at night just before the warm water is needed for bathing or to shower. Continue to take down the daily readings on your meter.
The difference between the readings daily is how much electricity you are using. For 3 x single phase meters, the sum of the 3 daily differences is how much you have used. Use the daily differences for every week to calculate the daily average for each week. These figures can now be used to determine what % effect the switching off of the geyser/s had. You probably will be completely taken aback by the difference! Remember that each and every household has it’s own level of comfort and unique usage pattern. Thus your test figures will not be the same as your neighbor’s, etc.
Applied to your ‘average’ monthly electricity bill, this % difference shows you how much money you possibly can save. Remember to apply the correct kWh rate as some municipalities use a two or three part tariff (fixed charges together with a separate kWh charge). Use only the kWh charge in this exercise.
Furthermore, your life style will determine how much more you will be prepared to do to improve the saving. Further measures such as cutting back on not only the geyser, but also on air conditioning usage, space heating, light fitting control, using gas instead of electricity to cook with, etc. Should you want to include these in a further week of testing, you will achieve an even larger difference between the weeks’ averages. However, for the purpose of determining the effectiveness of installing timer units, do the test for these measure only afterwards.
This saving will proof to you how cost effective the installation of a timer unit will be Vs installing a solar system (in existing homes/buildings!!!). Here in KZN a well known brand electronic timer with reserve will sit you back about R350 each. Allow a further +-R500 for labor to have it installed. Divide this total by the monthly saving you calculated and you will find how long in months it will take you to break even. Over the years I have found that it takes between 4 to 6 months for the normal average household to reach the break even point. Thereafter it is a ‘pure’ saving every month!
Compare the above with the cost of having a proper solar panel installed (get two or more quotes). Over and above the installation cost there of, keep in mind issues like future availability of spares for your solar system and the cost of these spares (mostly all imported…the future exchange rate!), the availability of and charges by qualified people to repair the system etc, etc Vs the simple effort to install a timer, the future replacement cost there of and the labor cost to do so (+- 15mins). Eish!! Make your own ‘informed’ choice.
Like I say, don’t believe me, believe your own findings!!
