Submetering is gaining momentum in residential, commercial, and industrial construction applications.

The shift to green, green construction and commercial operation has provided a catalyst for savings programs on everything from water to energy. Consider that every increase in the cost of a barrel of oil magnifies the importance of conserving energy. Savings cannot be achieved without first tracking electricity usage and potential waste.

More than ever, submetering is being applied in traditional residential, commercial and industrial applications to encourage conservation and increase productivity. This article describes what submetering is, why it’s important, and how to apply it effectively.

Submetering is typically installed by and for the homeowner and is not related in any way to the utility company providing the electric service. The owner of a multi-tenant commercial/residential or industrial building installs sub-metering equipment for the sole purpose of metering energy distributed within it. This is done to allocate costs or for internal billing purposes. In tenant billing applications, submetering guidelines governing usage and installation can be obtained from your local Public Utility Commissions (PUC) or local utility company.

Although submetering can also be used to perform most critical functions, such as equipment monitoring, trending, alarming, some maintenance, communication, and power quality analysis, the cash savings will primarily come from monitoring power consumption. .

Since the utility company provides electrical service to a building or facility, they install their own electric meter to measure kWh and, in many cases, electrical demand. These facilities are known as master measures or direct measures. They should not be confused with submetering.

1. By installing a master meter, the utility provides a single metering point at the electrical service entrance for the purpose of metering all electrical usage within the building. This is common for industrial and commercial buildings where a single business entity exists. It is also common in multi-tenant buildings, such as high-rise commercial or residential structures, where the building owner is billed for the energy use of the entire building. However, the building owner or manager must rely on some technological means to determine the actual usage of each tenant. This allocation is achieved by submetering or approximation.

2. By installing individual electric meters for each tenant in the building, the utility can direct the meter to accurately read and bill each tenant with the correct energy information based on actual usage. This method has become common practice in multi-tenant applications and has advantages and disadvantages over master metering.

Submetering has been used for many years to measure water and gas consumption. In general, building owners in urban areas provide all utilities to their tenants, including electricity, water, and gas. Many building owners saw the benefits of combining a single facility-wide utility with a privately owned sub-metering system to allocate actual electrical usage to tenants.

Many cost savings were achieved in new construction by simply billing the building owner for full energy use. Thus the concept of the “master meter” was born. The utilities provide a main meter for the building for each utility supply and the building owner would try to allocate the appropriate cost to each tenant. Although far from accurate, this concept stood the test of time because utilities in the past were relatively inexpensive.

The RUB (Ratio Utility Billing) method can be based on the number of tenants, the square footage of leased space, the number of people, or a combination of all of these factors. While RUB makes sense and installing a master meter is inexpensive, the method is never accurate for allocating energy costs. Tenants’ lifestyles can be totally different. An apartment with three tenants may use less electricity than a similar apartment with only one tenant. If everyone shares the bill, who cares if we turn up the air conditioning or leave the windows open and the heat on? Everything is averaged across all tenants. It doesn’t help much to go green or conserve dollars.

Submetering can determine the actual energy use of leased commercial space as a basis for energy billing or cost recovery. In commercial space, energy costs are typically included as part of the lease if they are not measured directly by the utility. Submetering can be very useful in allocating actual energy costs to each tenant. Sub-metering applications can also be found in any multi-tenant building with master metering and are very useful in determining energy costs for common areas such as lighting, parking lot lighting, and HVAC.

The potential benefits of undermetering in residences come from knowing which areas of the house are using what part of the total electric bill. The use of power by family members can also be monitored and adjusted. Finally, problem areas of insulation and air leaks can sometimes be discovered by variations in energy use by zones within a home.