Piso WiFi Electricity Cost Audit: Measure Your Own Machines, Month by Month

Up: Business · Also in Business, Vendo and Setup: Best Location and Permits.

Electricity is easy to ignore in a Piso WiFi business because it looks small per machine. It is also easy to misjudge, because a machine, an access point, a modem, a fan, a charger, or a desktop timer can all draw power at the same location, and the total over a month is what you actually pay for. An electricity cost audit is simply a careful count of what is plugged in, how much power it uses, and what that power costs on your own bill. It is not a guess, and it is not a figure copied from another operator.

This post walks through the audit in steps: list your devices, find wattage from labels and manuals, record meter or plug readings, calculate kilowatt hours with the formula, apply your own electricity rate from your own bill, build a monthly total, compare months, and spot waste. It ends with a blank worksheet you can copy, and one illustrative example that is labelled as an example only.

No rate, wattage, or monthly cost in this post is a standard figure. Every number that matters must come from your own equipment and your own bill.

Step 1: List Every Device at the Location

Start at the power strip, not at the machine. Write down every device that runs for the Piso WiFi setup at that location, including devices you may forget because they are small or shared with the shop.

A typical list may include:

• The vendo machine control board and coin slot assembly
• The access point or access points
• The modem or router feeding the machine
• A SIM modem, if used
• An outdoor antenna or extra access point, if used
• A power supply or adapter for each device above
• A fan or cooling device inside the enclosure, if fitted
• A sub vendo unit, if used
• A desktop timer or charging station, if the location runs a combo setup
• A UPS, if fitted, noting that a UPS itself uses power while charging

List devices per machine and per location separately. Two machines in different locations do not share one electricity total, and a combo setup with desktops will use far more power than a single outdoor machine. If a device is shared with the shop, such as a router that also serves the shop, note that it is shared, and decide how you will split its cost. The simplest honest method is to note the shared device separately and either count its full cost against the business or record an agreed share, and to use the same method every month so months stay comparable.

Step 2: Find Wattage From Labels and Manuals

Wattage tells you how much power a device draws. Find it from the device label, the power adapter label, or the manual, not from a website listing for a similar looking device. Labels usually show volts and amps, watts, or both.

If the label shows watts, use that figure. If it shows volts and amps only, multiply volts by amps to get an approximate watts figure for that device. Note whether the figure is a maximum rating or a typical draw, because a power adapter rated for a maximum may normally draw less. Where a manual gives both a maximum and a typical figure, record both, and use the typical figure for your monthly estimate, with a note that it is an estimate.

Record the wattage per device in your worksheet, with the source, such as label, adapter, or manual. If you cannot find a wattage for a device, do not guess a value and treat it as measured. Leave that row blank, note it as unknown, and use a plug meter reading for that device instead, as described in Step 3. An audit with one honest blank is more useful than an audit with a guessed figure presented as a fact.

Do not copy wattage from another operator’s post for your machine. The same type of board, access point, or adapter can have a different rating depending on the exact model, and a wrong wattage copied in Step 2 will make every later step wrong.

Step 3: Record Meter or Plug Readings

Wattage gives you an estimate. A meter reading gives you a measurement. Use whichever method fits the device, and record which method you used for each row.

Plug meter readings

A plug meter sits between the wall socket and the device, and shows power use over time. It is the best method for a single device, or for a whole machine plugged into one strip. To use one:

1. Note the date and time you start, and the meter reading at the start.
2. Leave the machine running normally for a full period that includes a busy time and a quiet time, ideally a full week, so the reading covers real customer use rather than an idle hour.
3. Note the date and time you finish, and the meter reading at the finish.
4. Write down both readings and the exact number of days covered, because the monthly calculation in Step 5 needs that period.

A short reading during a quiet hour will understate use. A reading that covers only a busy afternoon will overstate it. A full week is a fairer base for a monthly estimate than a single day.

Whole location meter readings

If you cannot meter a single machine, use the location electricity meter. Note the meter reading at the start of the month and at the end of the month, and note any other large loads that changed during that month, such as a new fridge or a desktop added to the shop. A whole location reading is less precise for one machine, but it is still useful for comparing one month with the next, as long as you use the same method each month.

What to record, every time

For each reading, record: device or location, meter type, start date and reading, end date and reading, number of days covered, and any notes about power cuts, new devices, or unusual use during the period. A reading without dates is hard to turn into a monthly total, and a reading without notes is hard to explain when next month looks different.

Step 4: Calculate Kilowatt Hours With the Formula

Electricity is billed in kilowatt hours, usually written as kWh. One kilowatt hour is one thousand watts used for one hour. The formula is:

kWh = watts divided by 1000, multiplied by hours used

Work through it device by device:

1. Take the watts figure for the device from Step 2, or the average watts from a plug meter reading if you have one.
2. Divide by 1000 to convert watts to kilowatts.
3. Multiply by the number of hours the device runs in the period you are measuring. For a machine left on all day, that is 24 hours per day. For a device switched off at night, use its actual hours on.
4. The result is the kWh for that device for that period.

If you used a plug meter that already reports kWh, use its reported figure directly, and note that it is a measured figure rather than a calculated one. Keep measured and calculated figures in separate columns where possible, so you can see which totals are estimates and which are measurements.

Add the kWh figures for all devices at one location to get the location total for the period. Do not add devices from different locations into one total, or you will lose the ability to spot which location is wasting power.

Step 5: Apply Your Own Electricity Rate From Your Own Bill

Your electricity rate is the price you pay per kWh, and it comes from your own bill, not from an article, a forum post, or another operator. Bills differ by provider, by area, by tariff, and by month, and a bill may show more than one charge, such as a supply charge, a delivery charge, and taxes or other fees, depending on your provider.

To find your rate:

1. Take a recent bill for the location.
2. Find the total amount charged for electricity use, and the total kWh used, for the same period.
3. Divide the total amount by the total kWh to get your effective rate per kWh for that bill. This effective rate includes the charges shown on that bill, so it is the fairest single figure for your audit.
4. Note the bill month, the provider, and the effective rate, and use that rate for the audit month that matches it as closely as possible.

This post deliberately gives no peso per kWh rate. Any rate printed here would be wrong for many readers, because rates differ by provider and change over time. Use your own bill, and recalculate the rate when a new bill arrives with a different total. If your bill is hard to read, ask your provider to explain the charges, and keep that explanation with your audit notes.

Multiply the location kWh total from Step 4 by your effective rate per kWh to get the electricity cost for that location for that period. That is your monthly cost only if the period was a full month. If the period was a week, scale it carefully, as described in Step 6, and label it as an estimate.

Step 6: Build a Monthly Total and Compare Months

A single month tells you a cost. Several months tell you a pattern. Build the monthly total the same way every month, so the comparison is fair.

For each location, each month, record:

• Total kWh for the location
• Effective rate per kWh from the bill for that month
• Electricity cost for the location
• Sales or collections for the same month, from your sales records
• Notes on changes: new devices, power cuts, longer opening hours, or a machine left on during a closure

To scale a weekly plug reading to a monthly estimate, multiply the weekly kWh by the number of weeks in the month, or more simply, multiply the daily average kWh by the number of days in the month, and label the result clearly as a monthly estimate from a weekly reading, not a measured monthly total. Replace the estimate with a full month reading when you have one.

Compare months by asking three questions:

1. Did kWh rise while sales stayed flat? If yes, something is using more power without earning more, and Step 7 applies.
2. Did cost rise while kWh stayed flat? If yes, your rate changed, and the cause is the bill, not the machine.
3. Did one location rise while others stayed flat? If yes, the cause is local to that location, not a general price rise.

Keep at least six months of monthly totals before you judge a trend. One high month can be a hot week, a power cut recovery, or a bill timing difference. Three rising months in a row are a pattern worth acting on.

Step 7: Spot Waste

Waste in a Piso WiFi setup is usually heat, old parts, or machines left running with no customers. Check for each of these in turn.

Heat

A hot enclosure, a hot power supply, or a hot access point is wasting power as heat, and heat also shortens the life of boards and adapters. Check for blocked vents, a fan that has stopped, a machine in direct sun, or a power supply that runs hot even when the machine is idle. Fix ventilation and shade before you buy a larger power supply, because a larger supply will not fix a blocked vent.

Old power supplies and adapters

An old or failing power supply can draw more power, run hot, or deliver unstable voltage that causes reboots and session loss. If one machine uses noticeably more power than an identical machine at another location, compare their power supplies and adapters first, and test with a known good supply if you have one. Replace a supply that runs hot, buzzes, or smells of heat, and record the replacement in your log.

Machines left on with no customers

A machine left on overnight at a location with no night customers still draws power all night. That may be a fair choice if night customers exist, or if the machine needs to stay on for remote checks, but it should be a decision, not a habit. Check your sales by time of day for each location. If a location has no sales for a long overnight stretch, consider the trade off between overnight power cost, overnight sales, and the risk that a switched off machine is not ready for the first morning customers. Do not switch a machine off overnight without telling regular customers, and without checking whether your platform or licence needs the machine online for updates or reporting.

Other waste to check

• Access points left on at full power where customers sit close by, when a lower setting would still cover the seating area. Check your platform or access point settings, and change them only if you understand the setting and can test signal afterwards.
• Extra devices left plugged in after a combo service ended, such as a desktop timer or charger that is no longer offered.
• A UPS that is always charging a failing battery. Check the UPS battery and replace it if it no longer holds charge, rather than leaving a faulty battery on charge all month.

Fix one waste item at a time, then compare the next month with the previous month, so you can see whether the fix actually saved power. Changing three things at once makes it impossible to tell which change helped.

Blank Worksheet

Copy this worksheet, one copy per location per month. Fill it from your own labels, readings, and bill. Leave any field blank if you do not know it, rather than guessing.

Field	Your entry
Location and machine identifier
Month
Device 1 name, watts, source of watts (label, adapter, manual, plug meter)
Device 2 name, watts, source of watts
Device 3 name, watts, source of watts
Extra devices, each with watts and source
Hours each device runs per day
Total kWh for the location for the period
Period covered (dates, number of days)
Reading method (plug meter, location meter, or calculated from watts)
Bill month and provider
Total bill amount for the period
Total kWh on the bill for the period
Effective rate per kWh (total bill amount divided by total bill kWh)
Electricity cost for this location for the period
Sales or collections for the same period
Notes (power cuts, new devices, changes, waste found and fixed)

Illustrative Example Only

The example below is an illustrative example only. It is not a real measurement, not a typical machine, and not a standard cost. Its numbers are made up only to show how the formula works, step by step, so you can repeat the same steps with your own figures.

Illustrative example only: suppose a setup has devices totalling 100 watts, running 24 hours per day, for 30 days. Step 1: 100 watts divided by 1000 equals 0.1 kilowatts. Step 2: 0.1 kilowatts multiplied by 24 hours equals 2.4 kWh per day. Step 3: 2.4 kWh per day multiplied by 30 days equals 72 kWh for the month. Step 4: suppose the bill for that illustrative month shows an effective rate of 10 currency units per kWh. Then 72 kWh multiplied by 10 equals 720 currency units for the month. That 720 figure is the result of the made up inputs only. It is not a real cost, not an average cost, and not a figure you should budget from. Replace every input with your own watts, your own hours, your own days, and your own bill rate, and your result will be your own audit figure.

Frequently Asked Questions About a Piso WiFi Electricity Cost Audit

How often should I audit electricity costs?

Monthly is enough for most operators, using the same worksheet each month. Audit sooner if a bill jumps suddenly, if you add a device or a combo service, or if a machine starts running hot or rebooting.

Can I use a wattage figure from the internet for my machine?

Only as a rough starting point, and never as a measured figure. The same type of device can have a different rating by exact model. Use the label, adapter, or manual for your own device, or a plug meter reading, for any figure you will budget from.

What if my bill does not show a single per kWh rate?

Use the effective rate method in Step 5: total bill amount divided by total bill kWh for the same period. That gives one fair figure for your audit, even when the bill lists several charges.

Is it worth auditing a single small machine?

Yes, because the audit also catches waste, such as a hot power supply or a machine left on with no customers, and because the same worksheet scales to several machines. For the wider question of whether a machine covers all its running costs, see How to Start a Piso WiFi Business: Costs, Location, ISP Choice, Permits, and Honest Income Factors.

Should I switch machines off overnight to save electricity?

Only after checking overnight sales at that location, telling regular customers, and confirming your platform does not need the machine online overnight. A saving that loses the first morning customers, or breaks reporting, may cost more than it saves.

What is the most common cause of a sudden electricity rise?

A new device, a failing power supply running hot, a machine left on during a closure, or a rate change on the bill. Work through the monthly comparison questions in Step 6 to separate a power rise from a price rise before you change anything on the machine.

What to Read Next

If you want the wider business picture, including how electricity fits with internet, licence, and maintenance costs, go to How to Start a Piso WiFi Business: Costs, Location, ISP Choice, Permits, and Honest Income Factors. If you monitor several machines and want to compare electricity use across locations, go to Piso WiFi Multi Machine Monitoring. If a hot power supply or a rebooting machine needs fixing, go to the Troubleshooting guide.