Thermal Images - SENSE Energy Monitor

I have a Thermal Imaging Camera (TOPDON TC004) on loan to me. I took an interesting picture of my SENSE Energy Monitor during normal use. The monitor unit does not have any issues, but I thought the information was interesting enough to share.

The picture was taken inside my house (conditioned space) in the Utility Room which had a temperature of 83.0 F degrees on 7/19/2023. (South Texas). The Utility Room closet always runs slightly higher in the summer than the rest of the house. There is no HVAC vent duct inside the closet.


The red square is the temperature of the SENSE monitor = 109.1 degrees F
The green square is the closet temperature. = 83 degrees F.
The white square is measuring the wire temperature = 87.2 degrees F (I wasn’t aiming at the wire. it was just the center of the photo.)
There is a vertical reference color bar on the right side of the photo. 83 F to 109 F

Actual normal photo of my installation. The brown metal box holds a TD-69 delay timer.



Your image is cool! At the same time, the Sense unit in the picture is warm. Is it warmer than expected? I made an estimate using this online calculator:

Input data:
Heat source power, Q = 5 Watt (maximum value given at Technical Specs – )
Temperature of case = 42.8 degrees C (equivalent to 109.1 degrees F from your picture)
Ambient temperature = 28.3 degrees C (equivalent to 83.0 degrees F from your picture)
Thermal resistance = 800 (for natural convection based on the table on the linked page)
Heat sink size = 6.6 cm by 13.7 cm by 3.2 cm (per Sense Technical Specs, link above)

Output from the online calculator indicated that the desired heat sink size is nearly equal to the actual heat sink size. This tells me that what you observe is reasonable.


Here is the Thermal image of a KASA HS-110 smart plug.

This unit has been working correctly with no errors. I am sharing my photo for everyone’s knowledge base.


Room temperature of 78.5 F.
The max heat is located in the upper portion of the module. = 109.1 F
The vertical reference color bar is on the right-side in the photo.
The white square indicator is the temperature near the center. = 100.1 F

There is no continuous electrical load on this device. Nothing was plugged in to it. It is successfully communicating to my SENSE monitor. So the only heat load is from the WiFi communications to the SENSE unit.

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The on/off relay for the HS-110 is located on the front upper right region. Pretty sure that that would be the biggest heat dissipater in the HS-110, since it introduces a little bit of series resistance into the 120V circuit. The thermal image squares with that.

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Another thermal picture image…

Schneider-Electric Wiser Device (linked to SENSE):
Wi-Fi Switch SP/3-Way with Energy Monitor - White
Model: SQR141U1WHW
Wiser Smart Switch


Room temperature is = 75.8 degrees F. (green square)
Heat from Wiser device = 81.8 degrees F. (red square)
The center of the photo is 77.6 degrees F. (white square)
All switches are in the "OFF’ position. No electrical loads thru any of the switches.
Device is working normally and correctly. It is successfully communicating to my SENSE monitor.
There is a vertical reference color-bar on the right-hand side of the photo.
The device is mounted in a PVC 3-gang electrical box.

Actual photo.

The unit on the photo has nothing connected.
No load, so no resistance, no heat built up in the relay other than just being ON (magnetized core)
Also: the switched power supply is on the top, and surprise: hot air accumulates in the top of the unit.


Another interesting thermal image of a Ground Fault Circuit Interrupter (GFCI) outlet mounted in my kitchen. This device is not linked (and never was) to my SENSE monitor (no WiFi communications). When I first viewed this photo, I thought I had a bad GFCI outlet. I went to all my other 17 GFCI outlets installed in my house and took the same picture. I got the same thermal readings. There is no LED indicator light mounted in these standard name-brand outlets. Nothing was plugged in (or had been plugged in) to draw any power thru the outlet.

The room temperature was 76.7 degrees F (green square)
GFCI device temperature is 92.2 degrees F (red square)
Middle of the picture is 83.9 F (white square)
There is a vertical color reference bar shown on the right side of the photo.


I had no idea that a GFCI outlet could use that much power and create that amount of heat load.

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Your discovery that GCFI outlets waste energy 24/7 is news to me, but apparently not to others. I found several websites that discuss the topic. The one I liked best (Minimizing GFCI vampire / phantom load loss and heat? Which model is most efficient? - GreenBuildingAdvisor) explained why they need to draw load all the time.


GFCI’s are an important safety device for every home. I also wasn’t aware that they are a heat producer. If you live in a cold climate, then you probably wouldn’t care, but if you live in south Texas (like me), then that becomes another source of heat that requires cooling.

It seems to me that it might make more sense to install a single GFCI breaker on dedicated circuits instead of individual outlets at each location that produce the additional heat load. This is something you would want to consider when building a new home.

@jefflayman Thanks for posting the additional technical information on GFCI’s.

So from your post, I have 17 GFCI outlets installed in my house using 2.2 watts each. That’s another 37.4 watts of vampire electrical energy that I need to account for in my “Always ON” list. Adding that amount to my list will give me an estimated number that more closely matches what SENSE is calculating.

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Great point @jefflayman and @Dcdyer !
One more thing to add to the Always On list. AFCI/GFCI Circuit Breakers are also vampires - According to Siemens, The electronics of an AFCI/GFCI circuit breaker draw approximately 12-15 mA => 1.8W per breaker.

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