Appliance monitoring

A list and short description of each appliance energy monitor available in New Zealand. This site also lists home energy monitoring devices, standby power eliminators, and hot water energy saving devices available in NZ.

Appliance energy monitoring

Appliance energy monitors plug in to a standard wall socket. No installation required. Plug in and start measuring and monitoring the daily power cost to run appliances. Some appliance power cost monitors can also forecast daily, monthly and yearly usage.

Elto EMA-1 Power Meter

The Elto EMA-1 is a low cost plug in wattage cost monitor. It records kwh usage and cost. It supports two different rates and day of use settings for night/weekend rate electricity where available. Battery backup retains settings and data when the device is not plugged in. It also displays additional technical indicators: line voltage, current, frequency, power factor.

At least two versions of the meter exist. The manufacturer uses the same model number for both versions - even though there are significant differences. The version called 'type 2' on this website contains a dedicated metering chip able to calculate power use more correctly for a wider range of appliances. The version called 'type 1' on this website is based on a less complex analog circuit design. Find out if you have 'type 1' or 'type 2'.

This website provides instructions for both meter types and many similar models.

Online retailers in NZ include Dick SmithMitre10JaycarEcoInnovation, Offline retailers in NZ include The Warehouse and Bunnings.

Wellington City Library has an energy conservation lending program making this meter available to users @$5 for 10 days.  

In New Zealand CDB Goldair imports and wholesales the Elto brand. The EMA-1 is manufactured in China by Cixi-Yidong Electronic Co, Ltd.

EMA is an acronym for Electronic Multifunction Analyser.

Technical details

Internal photographs and technical details of the EMA-1 - 'type 1'.

Internal photographs and technical details of the EMA-1 - 'type 2'.

A summary of differences is available here.

The manufacturer gives both devices exactly the same model number and identifier.

Efergy EgoSmart Wifi

A smart monitoring and appliance control socket with standby elimination and cost estimation. Requires Android or iPhone and existing Wifi.

Monitor energy consumption in real time and get energy use history and cost. Switch appliances on/off remotely. Set custom timers for switching appliances on and off. If required switch groups of appliances on up to 100 smart sockets.

Efergy NZ (NZ Version)
Trademe (NZ Version)

Gadgeteer (US Version)
PC Advisor (UK Version)

Mort Bay Energy Saving Power Board

This is a 5 outlet power board with an appliance energy monitor built in. The energy monitor is identical in operation to the EMA-1. The same instructions apply. 

Retailers include Mitre10

Mort Bay also produce the Mort Bay Home Theatre Power Board and Mort Bay Smart PC Power Saver. These are standby eliminator devices without a metering function.

Power-Mate (PM10A / PM15A / PM10AHD / PM10AHDS) 

A sophisticated and accurate purpose designed appliance power meter with inline plug and socket. Displays cumulative & predicted measurement of power consumption, running cost per hour, per week, per quarter or per year. Measurement down to 0.01W making the unit ideal for accurate standby power analysis of small devices. Display of cents to 4 digits. Also has analysis of Power-Factor, Apparent Power & Reactive Power (VA & VAR)(+/- 0.01 to 1 leading/lagging). Custom greenhouse gas (CO2) emission settings. Available as a standard 10 amp version and a 15 amp version for larger loads.

The manufacturer support page lists a model PM10AHDS with serial interface for connection to a computer.

Power-Mate Lite (PML10A)

A simplified and lower cost version of the Powermate. Features an LCD screen with backlight and a simplified user interface. An operator can disable the display of unnecessary information - this could be very useful when lending the device to non- technical users.

Wellington City Library has an energy conservation program making this meter available to users @$5 for 10 days.


Discussion area for appliance energy monitoring. No registration needed.


 28/11/2010 13:04Benjamin SHi EMA-1,
just wondering if you were going to put up a page on power factors (in general) - I know it's complicated, however I've seen a few meters that don't have it and some that do and I don't know if one will track costs correctly over the other...
 25/02/2011 13:00Robin WatsonI have purchased the EMA-1 and the line frequency starts off as 50 Hz. However, after a day or two, this shows as 52 Hz or 53 Hz.

Is the unit faulty, or is this normal to not show the correct line frequency?
 27/06/2015 03:51EMA-1 [Moderator]Hi Benjamin S, In theory the meters with accurate power factor monitoring will provide better cost accuracy. But in practice this level of accuracy is not usually required or achieved and there are other attributes of monitor design and implementation which may have greater influence on cost estimation. It is likely to be more important for 'odd' cases than everyday needs.