Dual-rate electricity meters

Today you can often hear about someone putting a dual-rate electricity meter, which allows you to save money on your electricity bills. What it is and how the two-zone tariff works – in the article.

The amount of electricity consumed is very different depending on the time of day. The peak time period is between 5pm and 11pm. At this time, people come home from work and begin to actively use household appliances. The second peak is the morning peak – from 7 to 10 o’clock . This is the time when everyone is awake, going to work and study. During the daytime, consumption drops slightly (compared to the morning), but remains at a fairly high level. The least electricity is consumed during the night hours – from 23 to 7 am.

Particularly high load is observed in the evening – it is several times higher than the daytime level. Such peak loads are a test for the power system. In order to shift some of the activity to the most unloaded period – the night hours – different tariffs were introduced for “peak” and night hours, or, as they say, two tariffs “day” and “night”. Sometimes the difference in cost is significant – you can save up to 50% or more. This is not bad, but for separate metering of consumption you need a two-tariff electricity meter.

Externally, such meters are practically no different. What changes is their “stuffing”. Inside there is a small processor, which separately counts the amount of energy consumed in specified time intervals.

How profitable

To say unambiguously profitable installation of a two-tariff electricity meter or not is impossible. Tariffs in each region of Russia are set separately. In some regions, the difference between the night tariff and the single tariff can be 3-4 times. But, most often, night charges are less by about half (compared to daytime charges). And even under such conditions, you can save quite a large amount – 1/3 of the monthly charges and more. However, for this purpose it is necessary to transfer the work of electrical appliances to the night time. Tariffs for some regions of Russia are given in the table. According to it you can estimate the difference in tariffs.

Having analyzed the table, you realize that not everything is as rosy as it seemed. In some regions, where daytime tariffs are much higher than single-rate rates, the savings are in question. Nighttime benefits are eaten up by overpayments during the day. In such areas, it is necessary to carefully calculate everything (see below). When calculating, you should take into account that you will buy a new two-tariff electricity meter with your own money, as well as reprogram it if necessary. So for some time you will just pay off the invested funds. And no one is immune to changes in tariffs or legislation. And it may well happen that in a few years it will turn out that you pay more for a two-tariff meter than for a single-tariff meter. There are already many such cases.

What you can save money on

Modern household appliances can have a delayed start function. Thanks to it, you can do laundry at night, wash dishes in the dishwasher, cook breakfast (multicookers, bread makers and other similar appliances). Some people even heat water in storage boilers at night, closer to morning, by setting timers on them. Besides, quite a lot of “regular” appliances work at night – refrigerator, air conditioners or heating appliances. So, it may well be that the consumption at night will be higher than during the day.

If the tariffs in your region are “normal” and there are savings, it makes sense to put a dual-rate electricity meter in large families where consumption is high. Such a system is beneficial for “owls” who go to bed far past midnight. Their main activity is at night, so the main consumption will be during the lowest rate. But to determine exactly whether this innovation will give you any tangible benefit or not, you can only after calculations.

Determining cost-effectiveness

First, you need to find out the two-zone and single-zone tariffs in force in your region. Then, for a few days (better – a week) to conduct an experiment Transfer all possible technical processes at night, and track how much electricity you consume at night tariff, and what – the daytime tariff. The readings will have to be recorded manually at 7am and 11pm. You have to record them to decimal places, so the calculations will be more accurate.

The readings collected for the week are summed up – separately daytime and separately nighttime. Multiply by the corresponding tariffs. You get the amount you will pay when you switch to a two-zone tariff. To have something to compare with, you calculate the total amount of electricity consumed (adding up the night and day parts) and multiply it by the single-zone tariff. Now you can calculate the difference and assess whether it is worth it.

Manufacturers and prices

Electricity meters of any type are single-phase and three-phase. Two- and multi-tariff ones, too. In this, as well as in appearance, there are no differences. The difference is usually in the price, but it is understandable – more complex equipment has a higher cost.

The most demanded on the market are two-tariff electric meters of the Moscow Plant of Electrical Measuring Devices (MZEPa). The point is not so much in quality (it is, by the way, average), but in price – these are the most inexpensive of the metering devices of this type. The company produces two-tariff energy meters SOE-55. They are available in eight modifications. They differ in the value of the maximum current for which they are designed, the number of zones that can be programmed. Any model can have two types of housing: for installation on a Din-rail or in a special box. The price of two-phase electric meters SOE-55 – from 20$ to 30$, and this – in the retail network.

Energomera meters are available with the marking 102 in 4 modifications, with the marking 208 – in two. Each of the modifications can be made in several cases – in a standard case for mounting in a box and with protrusions for DIN-rail. There is also a housing with a remote readout indicator.

According to reviews not bad units, differ products of this brand powerful terminals for connection, which is always good. Also have a warranty period – 5 years from the date of release. At prices – simple models cost about 23$, with a remote control – 130$.

Quite popular products of the Moscow company “INCOTEX” – Mercury meters. There are three modifications of multiphase meters of this brand: Mercury 200, 203 2T, 206. They can count 4 different tariffs, it is possible to program up to 8 zones in a day, set 8 types of days (sometimes weekends and holidays are also counted at a preferential rate). It is possible to set up to 12 seasons. Cost from 25$ to 70$ (depending on the degree of “trickery”).

Connect a two-tariff electricity meter in the same way as a single-tariff meter. There is no sense to dwell on it, everything is described here.

How to take readings from a dual-rate meter

Most dual-rate meters have LCD screens on which some numbers change with a certain frequency (usually once every 10 seconds). What these digits denote is written in the passport, which must necessarily be in the kit. But usually, there are:

• Date.
• Current time.
• Total amount of consumed electricity. When this parameter appears on the screen, either the figure T or the inscription total is displayed. This parameter is not necessary for day-night charging. It is rather of a reference character.
• The amount of electricity at the day tariff. It is denoted by T 1 or T 1,1. This parameter should be recorded.
• The amount of electricity at the night tariff is T 2 or T 1.2. This parameter is also needed.

These parameters are always displayed. The current voltage and frequency can also be displayed. This is reference data, so that you can control the parameters of the network.

When determining the payment for electricity on a dual-rate meter, you should have four digits – two, written off from the meter for the previous month, two – removed just now. You subtract them in pairs – T1 from T1, T2 from T2. The resulting difference is the number of kilowatts consumed in each zone. This amount is multiplied by the corresponding tariff, the sums are added up and the total cost of consumed electricity is obtained.

To make it clearer, here is an example. The meter is installed in St. Petersburg, a house with gas stoves. Readings of the previous month:

• T1 – 325.2 kW
• T2 – 278.8 kW

Readings taken just now:

• T1 – 417.7 kW
• T2 – 332.6 kW

Determine the difference:

• T1 = 417.7 – 325.2 = 92.5 kW
• T2 = 332,6 – 278,8 = 53,8 kW

Calculating the sum:

• Day tariff T1: 92.5 kW * 3.91 rubles/kW = 361.675 rubles
• At night tariff T2: 53.8 kW * 2.30 rubles/kW = 123.74 rubles

Total amount: 361,68 + 123,74 = 485,42 rub.

At the same time it is possible to estimate whether the use of a dual-rate meter is profitable in this case: let’s find the total amount of consumed electricity by adding T1 and T2, multiply the obtained figure by the single-zone tariff:

The total amount of electricity consumed is 92.5 + 53.8 = 146.3 kW, the total amount is 146.3 * 3.84 = 561.792 rubles.

According to these results, we can conclude that it is quite profitable to install two-tariff meters in St. Petersburg. With this small consumption, the saving is 76.32 rubles.