What Is an Electricity Sub-Meter? Meaning and Example

In many Bangladeshi buildings, especially older houses, markets and buildings where one owner holds a single connection from DESCO, DPDC, Palli Bidyut or another distributor, there is only one official meter for several flats or shops. To know how much electricity each unit uses, the landlord installs smaller meters after the main meter. These are called electricity sub-meters. If you are a landlord deciding how to bill tenants for power, or a tenant trying to understand your bill, this glossary entry explains what a sub-meter is, how it works, and how a fair bill is calculated.

Electricity Sub-Meter: A Simple Definition

An electricity sub-meter is a meter installed on the supply to one part of a property (a flat, a shop, a floor or a common area), downstream of the main meter that the electricity distributor uses to bill the owner. The distributor only reads and bills the main meter. The sub-meter is read by the landlord or building management, and its readings are used to divide the main bill among the users.

In short:

• Main meter: official, belongs to or is registered with the distributor, billed to the account holder.
• Sub-meter: private, installed by the owner, used to allocate the cost internally.

Sub-Meter vs Separate Meter vs Prepaid Meter

Where separate official meters are available, many landlords prefer them because the tenant deals directly with the distributor. Sub-meters remain common where getting separate connections is difficult, costly or not allowed for the building's setup.

How a Sub-Meter Works

A sub-meter measures electricity in kilowatt-hours (kWh), usually called "units". Each month, the reading is noted. The difference between this month's reading and last month's is the number of units used by that flat or shop. The landlord then applies a rate per unit to calculate the charge.

Sub-meters may be:

• Analogue (mechanical): rotating disc and number wheels. Cheap, but harder to read accurately and can wear out.
• Digital: electronic display, more accurate, some with memory of past readings.
• Private prepaid sub-meters: some buildings use sub-meters where tenants recharge through the landlord's system. These need careful, transparent management.

Worked Example: Calculating a Sub-Meter Bill

For example (illustrative): a house has one main meter and three flats with sub-meters, plus common lights and a water pump. For one month:

The main meter bill from the distributor for the same period shows 750 units and a total bill (including all charges on that bill) of Tk 7,500.

Step 1, average cost per unit: Tk 7,500 / 750 units = Tk 10 per unit (illustrative; actual tariffs vary and are set by the regulator).

Step 2, common use: 750 total units minus 650 sub-metered units = 100 units used by common lights and the pump. Cost: 100 x Tk 10 = Tk 1,000.

Step 3, each flat's own use:

• Flat A: 220 x Tk 10 = Tk 2,200
• Flat B: 280 x Tk 10 = Tk 2,800
• Flat C: 150 x Tk 10 = Tk 1,500

Step 4, common cost: if the agreement says common electricity is shared equally, each flat adds Tk 1,000 / 3 = about Tk 333. If common electricity is covered by service charge or rent, this step is skipped.

Check: Tk 2,200 + Tk 2,800 + Tk 1,500 + Tk 1,000 = Tk 7,500, exactly the main bill. The landlord has neither lost nor gained money on electricity.

Our detailed guide on electricity sub-meter billing covers slab tariffs, demand charges and VAT lines on the main bill in more depth.

Why the Average Rate Method Is Fairest

Electricity tariffs in Bangladesh are generally set in slabs, where higher consumption can be charged at higher rates, and bills include other charges. When one main meter serves several units, the combined consumption may fall into higher slabs than each unit would on its own. Using the average cost per unit from the actual main bill shares that effect fairly and guarantees the total charged to tenants equals the total paid by the landlord.

Some landlords instead pick a round figure such as "Tk 12 per unit" that is higher than the actual average. That creates a hidden profit on electricity and is a common source of disputes. Tariffs are regulated by the Bangladesh Energy Regulatory Commission (BERC); a landlord reselling electricity at a markup may also raise questions under the rules governing distribution. Keep it simple and honest: charge what you actually paid, shared by use.

Reading Sub-Meters Correctly

1. Choose a fixed reading date every month, ideally close to the main meter's billing date.
2. Read all sub-meters and the main meter on the same day.
3. Take a clear photo of each meter display showing the date.
4. Record the readings in a register or spreadsheet, with previous and current readings.
5. Share the photo and calculation with the tenant along with the bill.

Tip: Label every sub-meter clearly with the flat or shop number, and keep a small diagram of which sub-meter feeds which unit. Mix-ups between two meters are a surprisingly common cause of wrong bills.

Sub-Meters in Markets and Shops

In markets and shopping complexes, sub-meters are very common: one bulk connection for the building, and a sub-meter for each shop. Shopkeepers are usually very sensitive to electricity costs because lights and fans run all day. Best practices:

• Use digital sub-meters and replace old analogue ones that may have drifted.
• Separate common area lighting, lifts and escalators onto their own sub-meters so they can be charged through service charge transparently.
• Where a generator supplies power during outages, record generator supply separately if possible and agree how fuel costs are shared.

For how generators and IPS systems fit into tenant arrangements, see load shedding, generators and IPS for tenants.

Installing a Sub-Meter

A sub-meter should be installed by a qualified electrician, with proper cabling, a breaker for each unit and a sealed box to prevent tampering. Consider:

• Accuracy: buy a meter of reliable quality with a clear display.
• Location: a common meter room or corridor where both landlord and tenant can read it, not locked inside one unit.
• Safety: correct wire sizes and breakers to avoid overheating.
• Rules: check with your distributor whether there are conditions on sub-metering or on supplying electricity to other occupants through your connection. Requirements can differ by distributor and connection type.

Handling Disputes Over Sub-Meter Bills

A tenant who feels their bill is too high may be right: a faulty meter, a wrong reading or a wiring mix-up happens. Handle it calmly:

1. Read the meter together with the tenant.
2. Compare with the previous three to six months; summer bills are naturally higher when air conditioners run.
3. Check the calculation and the main bill.
4. If the meter seems faulty, have an electrician test it or swap it with a known good meter for a month.
5. Correct the bill if there was an error, and put the outcome in writing.

For example (illustrative): Flat B normally uses around 250 units, but this month shows 480. The landlord and tenant check and find that Flat B's sub-meter was wired to also supply the stair lights after a recent repair. The electrician corrects the wiring; the extra 230 units (480 minus 250, estimated) are moved to common use for that month.

Sub-Meters From the Tenant's Side

If you are looking at a flat or shop where electricity is billed through a sub-meter, a few questions before signing will save arguments later:

• Where is the sub-meter, and can I read it myself at any time?
• Which lights, sockets and appliances are on my sub-meter, and is anything shared (stair light, pump, roof light) connected to it?
• How is the rate per unit calculated, and will I see the main bill?
• On what date are readings taken, and will I get a photo?
• How is common electricity charged: in the service charge, in rent, or shared by units?
• If the building has a generator, how is generator power during load shedding charged?

Note the reading on the day you move in and on the day you move out, and ask the landlord to sign both. That simple step protects both sides at the start and end of the tenancy.

Understanding seasonal changes

Many tenants are alarmed when the bill jumps in April or May. In Bangladesh, fans, air coolers, air conditioners and refrigerators work harder in the hot months, so usage often rises sharply between spring and early autumn and falls in winter. For example (illustrative): a flat that uses 150 units in January might use 320 units in June if one air conditioner runs every night. At an illustrative average of Tk 10 per unit, the bill rises from 150 x Tk 10 = Tk 1,500 to 320 x Tk 10 = Tk 3,200. That difference, Tk 1,700, comes from real use, not from a faulty meter. Comparing the same month in the previous year is usually more meaningful than comparing with last month.

Sub-meters encourage saving

When each household pays for its own use, people tend to switch off lights and use appliances more carefully. Landlords can support this with LED lighting in common areas, efficient pumps and timer switches for stair lights. Our guide on energy saving in rental buildings lists practical ideas that reduce bills for both landlord and tenants.

Common Mistakes With Sub-Meters

• Charging a flat rate per unit higher than the actual average cost.
• Reading sub-meters on different days from the main meter.
• No photos or records of readings.
• Common area use hidden inside tenants' bills without explanation.
• Old analogue meters never tested for accuracy.
• Sub-meters inside the tenant's flat where the landlord cannot read them without entering.
• No clause in the agreement explaining how electricity will be billed.

What to Write in the Rental Agreement

A clear clause prevents most disputes. It should state that electricity is measured by a sub-meter, the reading date, the calculation method (average cost per unit from the main bill), how common electricity is handled, the payment date, and how disputes about readings will be resolved. For example: "Electricity will be charged monthly based on the flat's sub-meter reading, at the average cost per unit of the building's main meter bill for the same period. Readings will be taken on the last day of each month and shared with the tenant with a photo."

Related Terms

• Main meter: the distributor's official meter for the building or connection.
• Unit (kWh): the measure of electricity used; 1 kWh equals using 1,000 watts for one hour.
• Slab tariff: a pricing structure where different levels of consumption are charged at different rates.
• Demand charge: a fixed charge on the bill based on sanctioned load.
• Prepaid meter: an official meter where the user buys credit in advance.

Final Thoughts

An electricity sub-meter is a simple tool that lets a landlord divide one main electricity bill fairly among several flats or shops. Used honestly, with accurate meters, same-day readings, photos and the average-cost method, it keeps everyone's bill tied to what they actually use. For other utilities in a rented home, see utility bills in a rented flat.

If you bill several units by sub-meter every month, Bariwala ERP (বাড়িওয়ালা ERP) includes sub-meter electricity billing: you enter the readings, it calculates each unit's charge and adds it to the monthly invoice alongside rent and service charge, so tenants receive one clear bill.