PeaceFair Pzem-004T Energy Meters


We have negotiated discounts from the normal list prices of the hardware supplied by PeaceFair. Please send us a message if you would like details of the discounts available.


We are very pleased to be able to announce that Laura from PeaceFair has joined the ESPproMon Community.

So if you have any questions regarding the PeaceFair Pzem-004T please post them in this section.

Over the coming days we will also be adding details of some of the features of the Pzem-004T that you might not have noticed yet.



Thanks @Costas @Paul for this nice organization and the imposed information lying around for us!


What are the pins defined for control In/Out from ESP 8266 module. Thanks


@iocircuits have you wired up your PeaceFair Pzem-004T as per Connecting a PeaceFair Pzem-004T to an Espressif ESP8266 ?

The RF transmitter and relay pins are covered at Timer control of your home appliances


Thanks for your comments Mike. Have you wired up your PeaceFair Pzem-004T hardware?


NO I did not receive it yet ( these days the postal service in Greece is unbelievable bad. I am expecting long delay that may run up to 50 days ( I hope not but… ). )


@mikekgr sorry to hear that, where does the tracking number indicate your Pzem-004T is at the moment? Presumably it shows the location as somewhere in Greece, right?


RY551886353CN check it…


Sent you a PM @mikekgr


We have been advised of a couple of deliveries from Peacefair that are taking longer than usual and we are actively monitoring the lead time from order placement through to receipt.

Conversely there have also been a few receipts that seem to have arrived very quickly.

From what we can tell there doesn’t seem to be any correlation between your location and how long it might take for the hardware to arrive.

It looks, at the moment, simply down to the luck of the draw. What we will say though is that you should expect it to take a month for delivery and that anything less than this is a bonus.

Obviously holidays and big sales events like 11/11, Christmas and Chinese New Year will extend the lead time so you should take this into account.

We made a conscious decision not to hold stock of the hardware ourselves but this is something we will review on an ongoing basis.


Another couple of units have been received from PeaceFair so there is currently only one outstanding delivery that we are aware of.

Even if you are not planning to use the ESPproMon app on your Android or iOS smartphone then you might still want to consider purchasing some of the energy monitoring hardware that is available from companies like Open Energy Monitor and PeaceFair.

The hardware will generally work fine without our app but we feel ESPproMon enhances the system in a way that is unique to us.

Google Nest and British Gas Hive have similar products with much larger marketing budgets than us so you have probably read or seen more about their smart home devices than you have our offering.

But where we differ from Google and British Gas is in our flexibility and our considerably lower entry point. With the Nest and Hive you are generally looking at upwards of $200 but the hardware required for our home automation product can be as little as $30.

We don’t restrict our users to proprietary hardware and many of you will already have USB or LAN cameras etc that you can hook up to our system. Why buy cameras from British Gas and Google for their Hive and Nest, not so smart systems, when you already have perfectly adequate cameras.


If you are still not sure why the ESPproMon app is better than similar home automation products like Hive from British Gas in the UK and Nest from Google you might want to take a look at our handy 1 page PDF documents that outlines the differences.

Now available to view online or download from Peacefair Pzem-004T with ESPproMon Smartphone App.


Last known outstanding Pzem’s arrived today so the proMon (ESPproMon user) can work on them over the Christmas break.


Well, I finally crawled under my counter (for the third time in this month long process) and hooked up the final sensor connection for my Pzem display…

My motorhome has 30A rating. But in the old RV park I am in, I am plugged into what is best described as a “kitchen” outlet… a dual socket outlet with each socket on its own (presumably 15-20A) breaker. So my main AC panel is using one outlet and the 2nd outlet is used on another 12 gauge line that I installed to an inside outlet that feeds my Deep Freezer and AC in the summer / IR furnace in the winter.

My Pzem is plugged into the “main” line… note the wonderfully “stable” voltages I endure here :wink:

I literally had to cut into this wire and hook this split core, single handedly :persevere:… I couldn’t fit both arms in.

I started with basics and space heater (on high) and pictured water kettle… 22A :fearful: Mental note, heater or kettle, NOT both (the Park’s breakers are NOT accessible by us tennents) :stuck_out_tongue:

Then down to basics plus the addition of bedroom/workbench space heater (on high)… 12.5A.

And finally with basic lights, computers and such… about 8A.

Next step, hookup to an MCU… but since all my Wemos D1 Minis are currently in use, I am just waiting for a couple of NodeMCUs on the slow boat.


We get asked from time to time what the typical pay back period is for a Peacefair Pzem-004T bridged to an ESP8266 with the ESPproMon smartphone app.

For us the payback period should have been about 2 weeks but it actually took around 4 weeks. When we installed our Peacefair Pzem-004T the “background” level of electricity being used was around 500W as shown on the image above. At the time we wrongly assessed that a few laptops and our fridge would be pulling around 500W.

After a couple of weeks we checked the actual power usage of the fridge and it was considerably lower than what we had assumed i.e. closer to 100W than the 400W estimate.

So we set about trying to establish what was pulling the extra 300W. The only thing we could think that might be using the electricity was our water pump. The pump should just be running when water is run off from the taps but it turns out it had been running 24/7 for about a year.

So our energy meter covered it’s initial capital outlay in less than a month. Now hopefully most of you will not have faulty water pumps but the monitor certainly helps inform you how much certain household appliances are using. In our case we were pleasantly surprised how little the fridge was using and how much the water pump was using.

At $30 or so for a complete system with the option to remotely control home appliances and add surveillance cameras we think it’s money well spent.