eMonitor: Passivhaus (Passive House) Whole House Electric Energy Monitoring System

eMonitoring the Heartbeat of a Passivhaus/Passive House

eMonitoring refrigerator power consumption over time

Ever since I saw a presentation at the PHIUS convention in Maryland some years back, I had considered implementing a whole house energy monitoring system for our home as I am a stickler for obtaining real-world performance data regardless of projects I work on.  But the events of the last six weeks--as documented in the of the previous three part series of articles--have prompted me to implement a comprehensive whole house energy/electric monitoring system.

I opted for Powerhouse Dynamics eMonitor.  They are not inexpensive and require a minimum of a two-year "cloud-based" monitoring contract, but I believe this system will more than pay for itself.  You are able to run an extensive amount of reporting of the data which is "continuously" collected.  You can even use your smartphone to access the data real-time as there are apps for both the iPhone and Android systems.

A quick snapshot of the top five consumers of electricity

The older system (which I purchased) is the eMonitor24 24 circuit CT monitoring system.  Unlike the newer eMonitor4-24, the eMonitor24 requires direct CT clamping via a wired connection to the base control unit, meaning the panels have to be exposed.  This isn't a problem in our case as they are isolated in the mechanical room.

eMonitor base control module and CT clamps

I didn't even need to read the manual as installation and configuration was a snap.  Once the control module is connected to your network via its ethernet connnection, it quickly phones home and downloads any software updates required.  Configuration takes place on the Powerhouse Dynamics web portal. 

eMonitor phoning home to retrieve software updates automatically

Already I have found some pigs of energy usage (some of which I already suspected) and unnecessary phantom/vampire loads. As you can see in the below image, the wine cooler is continually sucking 200+ watts (it doesn't appear that the compressor is shutting off).  That's costing me nearly nearly $24 a month in electric, alone.  I have since pulled the plug and will be looking for a more energy efficient appliance.  (Note: You'll also notice some spikes in electric exceeding 1000 watts.  That's because our plumbed super-automatic Miele Espresso maker also shares the circuit.)

eMonitoring Wine Cooler: $0.78/day or $23/month

Without eMonitor, I was only able to take brief snapshots of electric usage with an amp clamp.  With eMonitor I am able to get a two dimensional picture over time (just like an EKG).  I absolutely love it.  eMonitor enables me to observe patterns of compressor operation for the refrigerators, the mini-splits, and the heat-pump hot water heater.  The system can also be configured to alert you to particular set conditions--for example, a power failure (through loss of connectivity). 

I also found the our refrigerator as configured was using a more power than what was otherwise suggested on its EnergyStar label.  Granted it is the largest side-by-side shipping and we programmed the coldest freezer set temperature, but we were a bit surprised to see its impact on consumption.  We have since tailored back the temperature to a more reasonable -18C for the freezer and +1C for the refrigerator.  We feel getting the extended storage capacity of food with colder freezer temperatures are worth the trade off.  We have already seen a modest reduction of compressor operation.

Using coldest temperatures comes at a cost and blows the EnergyStar estimates out of the water

As stated in my previous article, it helped me identify a configuration shortcoming with the placement of the mini-split in the basement in the proximity of the hot water heater.  And now that the minis have been cleaned and are operating more closely to what they should, their power consumption has been largely tamed.

Estimated Monthly Cost of Family Room Mini Split: A Wonderful $28 for February ($0.154/kWh)

Over time, I will be able to get a handle on how the house is actually performing relative to the design goals expressed in the PHPP model and coupled with a whole house room to room temperature monitoring system, I should be able to get a complete handle around our real-world energy consumption.

If we ever decide to incorporate an active grid-tie photovoltaic system, I should be able to now accurately size one according to our actual power consumption requirements.  I will publish more data as I collect sufficient amounts.

eMonitoring usage from Jan 31st, 2014 - Feb 3rd, 2014 of circuits

I have found the eMonitor system a thoroughly well-sorted out and refined whole-house energy monitoring system.  Every home owner, builder, retrofitter of super energy efficient buildings such as a Passivhaus (Passive House), should include one in their arsenal of tools.  It is a wonderful feedback mechanism to your actual accomplishments and can also point to areas where you can improve/tweak your designs.  It is one heck of a teaching tool and it enables you to effectively manage an track your overall energy consumption before you get the bill from the utility company.