[Jetranger]

During last winter, I was watching an episode of 'Ask This Old House' and saw a new and really interesting home energy monitoring system being demo'd. The 'eMonitor' is a whole home, circuit level monitoring system with a web based 'dashboard' that allows the user to monitor their home power consumption and see where it is being used. I ordered two of these units(to cover most of the circuits in my home) and now have them installed and running for about a month.

So far, I have identified one MAJOR constant drain that I was able to eliminate and a few other 'phantom' loads I didn't expect too(my clothes washing machine draws 2 watts even when it is turned off and is not a fancy 'electronic' model, just an older 'manual' type, go figure).

I will post some pics a little later but I am wondering if anyone else here has the same device installed and what your experience is with it.


eMonitor

Ask ToH episode

 

[57]

Very nice unit. I like the way it works, but the sensors may be difficult to put in some panels and also the circuits in many panels are not properly labelled, or may include other "unknown" devices on that circuit. Most people probably should have an electrician install this since it's inside the panel.

I don't wish to take your thread off track, but you may not find much feedback due to the price of this unit. US$700. Wow! Did you find it for less? I also saw the ATOH episode with this unit (I record all the episodes) but when I found the rough price, it was out of my league.

Just as an FYI, some of us have purchased other equipment to monitor power. Jake and I recently purchased the Blue Line discussed in the following thread: It doesn't have a computer interface but for 1/10th the price it does provide a useful, less expensive option, especially if combined with a Watt Meter.

http://www.digitalhome.ca/forum/showthread.php?t=137646 (Revised)

Many of us on the forum also have various Watt Meters (about $25), as discussed in the following thread: These are useful for measuring anything 110V that can be plugged in (not hard wired). That's probably where most, if not all, of the parasitic/phantom draws are. I recently replaced my freezer after I found it drawing way more power than it did a couple of years ago (I rotate my Watt meter around the users regularly)

http://www.digitalhome.ca/forum/showthread.php?t=35430&highlight=parasitic

Using both we can manually track whole house and parasitic draws, of course not as elegantly as you. We look forward to your feedback regarding the eMonitor and a report of anything else you find.

 

[Jetranger]

Hi 57,

I actually read that thread before deciding to start this one. I have had the Black & Decker version of that same meter installed for about a year now and find it rather simplistic but useful none the less. I also have a 'Kill-a-Watt' meter and an EM100 by UPM but didn't find them to be particularly useful as they don't provide any output that can be graphed for an easier read.

I did spend a LOT of money on these, yes, but they are an exceptional way of monitoring total and circuit level consumption. As I state, I have already found one rather large load that was easily removed and should save me a considerable amount of money annually so I am extremely happy with them. Installation was quick and easy; I did it myself. Yes, some panels might be 'tight' and anyone not comfortable going inside their panel should have an electrician do the work (as stated in the installation manual that comes with the unit).

Your point about 'unknown loads' and mis-labeled circuits is a good one and during the installation and use of this system, one has the opportunity to correctly label the circuits and identify ones that have 'unknown loads' easily. I had this very thing happen during my installation and it is really good to have things all labeled correctly and know just what loads are on what breakers now.

One thing I have found is I am currently using more power for watching tv, both in the bedroom and the living room, than I am on my heating/cooling system. The graphical output makes analyzing the loads almost a no brainer and does a lot of the math for you along the way.

I have been in contact with 2 or 3 members of the executive at the home office and they are working diligently on improving the system all the time. There are some exciting additions planned for the near future and I am eager to see if they will be worth while integrating into my home.

I figured I would put this 'out there' and see if I was the only one so far. I hope others might find this when 'searching' and share their experiences. I'll post some pictures and charts in the next day or two.

 

[57]

I have already found one rather large load that was easily removed

What was it?

 

[Jetranger]

I'm a little embarrassed to say as I should have known better.

It was a USES RDES-1, Shunt Efficiency unit. It is supposed to improve power factor and make inductive loads, like motors, more energy efficient. I thought it would help with the Heat Pump operating costs but it turns out it was probably costing me more each year than ALL of my heating costs (not sure about this) as it was drawing about 1800 watts, 24/7. Strange thing is it doesn't heat up at all, not even warm to the touch. More importantly, it makes no difference to the load drawn by the Heat pump so I just shut off the breaker it is connected to the panel with.

I am losing the marginal filtering effects it might provide but I will take my chances as the reduced expense should afford me any replacements for equipment that might ever be affected because it isn't otherwise protected already.

 

[57]

...1800 watts, 24/7. Strange thing is it doesn't heat up at all, not even warm to the touch.

I don't think this is possible. 1800W is a huge amount of load and would create a huge amount of energy - heat, light, work, whatever. Perhaps the sensor on that unit was malfunctioning, or there was something else on the circuit - electric heater? Or perhaps the device(s) connected to the unit are what you're seeing on that circuit readout (heat pump?).

I'm guessing that your overall usage didn't drop significantly when that unit was shut off, rather there was only a drop in that circuit reading, unless of course, something else (huge) was switched off, on that circuit at the same time.

1800W would cost over $2000/year around here. The average load on my entire house (including electric hot water) is less. If I didn't have electric hot water, I'd be under 1kW average or roughly half of 1800W.

I believe the average Ontario electrical customer uses 900 kWh/mo, or about 1.25 kW (average)

Since you paid for that Shunt Efficiency Unit, you can probably turn it back on without any major impact on the overall electrical use in your home.

 

[cfraser]

Somebody once paid me a LOT of $$ )) to develop a power measuring device that would work for ALL power factors, 3-phase (I still have a prototype here). Nothing available commercially at the time could come anywhere close, obviously, they weren't totally stupid... And most current instruments can't come anywhere close. The purpose of this "instrument" was so people could evaluate the cost/benefits of power factor correction, and in some circumstances it is really good (the worst case must be an induction furnace). Can't do it with a regular meter, nor with even a fairly expensive one.

So what I'm inferring here is, and I don't know anything about your measuring device, is how well it is telling you the truth about your power factor "correction" device. Or about the installation of it. That is presuming the PFC thing can even do what it is sold to do. It must be mostly capacitive to do anything for inductive loads of course. It will take some careful measuring to determine if it's working, and in a typical home electrical environment you're going to need some pretty good stuff to measure PF/correction to even a marginally worthwhile level. edit: So be careful of your interpretation...I see 57 has already brought this up, me slow typist...

Also, do we, as consumers, even get billed by power factor? Will a better PF actually noticeably decrease our bill? I haven't even thought about this... I know they *used* to say don't much bother with PF for the typical home as there's no cost-benefit to improving it, unlike for industrial customers...

 

[ScaryBob]

I was able to eliminate and a few other 'phantom' loads I didn't expect too(my clothes washing machine draws 2 watts even when it is turned off and is not a fancy 'electronic' model, just an older 'manual' type, go figure).

A 2w phantom load is negligible and rarely worth doing anything about. Regulations, not yet in effect, regard phantom loads under 3w as acceptable, even under the strictest guidelines. Phantom loads over 7w are considered unacceptable.

...1800 watts, 24/7

The points regarding power factor (PF) are very relevant here. That meter is probably reporting 1800 volt amps (VA), which can be very close to zero watts with a purely capacitive load. VA also does not register on most hydro meters, which is why hydro loves customers who use capacitive devices to correct poor PF caused by inductive devices and penalizes customers who don't. I doubt the capacitive shunt is doing any good in this case. The correct way to use such a unit is at the motor (or other inductive device) only when it is operating. The capacitive shunt must also be sized to properly correct the PF for the size of inductive load. Unless there are large inductive devices running 24/7 or a known 24/7 PF issue, PF correction is not necessary. The main advantage of this unit may be to filter out high frequency transients (power spikes) in the power supply.

I know they *used* to say don't much bother with PF for the typical home as there's no cost-benefit to improving it, unlike for industrial customers...

PF is usually ignored for residential customers since the loss is typically small. However, power companies now measure the PF for the overall grid and apply a PF correction to consumer power bills. (At least they do here.) Industrial customers are penalized for a poor PF due to the effect it has on the power grid. Utilities measure PF and watts for industrial customers and bill them accordingly, based on the power (VA) they use, not just what shows up on the watt meter.

 

[Jetranger]

Pictures of my install

I know what you are saying. I turned it on again today, during a thunderstorm that rolled through, and it is showing as drawing just below 1600 watts, not the 1800 I thought. Anyway, it must be some kind of anomaly as it really doesn't get warm and is the only thing connected to that breaker. It's the unit in the middle of the first picture. The eMonitor to the right is the 'Main' unit and the other one is located in the Mechanical room where the Geothermal Heatpump is.

MAIN panel

Mechanical Room Sub-Panel

The antennas are not currently used but are for future system integrations.

 

[57]

I have had the Black & Decker version of that same meter installed for about a year now

1. If you still have this unit, what happens to the overall reading on it when you turn the USES on/off?

2. Does the overall reading on the eMonitor go up by 1600W when you turn the USES on?

3. On the eMonitor, is there a "check" where an overall reading is taken on the entire load and compared to the sum of the various circuits?

4. Have you compared the eMonitor overall reading with the B&D?

 

[cfraser]

The correct way to use such a unit is at the motor (or other inductive device) only when it is operating. The capacitive shunt must also be sized to properly correct the PF for the size of inductive load.

A very important point. And the way utilities and large industrial users do it, though they usually have some virtually constant base inductive load to compensate for. (Switching cap banks is the most dangerous thing that goes on in a switchyard, those things *explode* a lot, and they used to be filled with PCBs too LOL. Tried not to be around, or put them on manual if I had to be.) Not usually worthwhile $-wise for a consumer, and certainly there's nothing adequately large to even do the switching in the pictured box (not if you consider the ~1800VAR worth of caps have to be in there too).

Yes, I did notice that "correction factor" on my bill. There are so damn many "factors" in there I didn't glom onto what *that* particular one was. Eventually you (me!) just stop trying to interpret these things 100% rationally, and just look for glaring power measurement errors. At least I can determine if those make sense. What a disaster of incompetence and misrepresentation our Ontario electrical bills demonstrate...

 

[Jetranger]

LOL, the eMonitor might not stimulate posting but my attempt at PF correction sure has. (hence the embarrassment)

I don't have the full understanding of this level of electrical theory(obviously) but I did understand it was for more of a 'constant' draw but there would still be some benefit of having it connected in my home. When I get my next utility bill I should be able to tell if there is a significant difference as it has now been OFF for most of this past month. The measuring in the eMonitor is done with inductive Current Taps (CTs) that just 'clip' over the conductors where they come out of the breakers in the panel. Given the Shunt is (seemingly) inductors, chokes and capacitors (what the [email protected]#* do I know?), there is a good likelihood a CT is not the way to read power consumption from it. There just isn't enough time in a lifetime to learn everything I am curious about.

If I understand the comments correctly, I should remove the sensors from the shunt as the readings are incorrect and make use of them on another circuit in that panel. I knew I was taking a chance by adding such a device to my home but I thought it was worth a shot. I managed to find a 'much cheaper than retail' source for this so it wasn't nearly as expensive as it is generally advertised for. If it isn't showing up on my power bill, I will just turn it back on and move the CTs to different circuits.

As for the Phantom loads, everything adds up, in the long run. I know 2 watts is 'insignificant' but every little bit does count, at least that's how I feel about it.

Thanks for the great info guys. I really love the quality of some of the members here.

57, I'll do the tests tomorrow and post the results. The difference on the eMonitor with and without the Shunt is almost the same but the reading of the Heat Pump doesn't change, but now I understand why(at least I think I do). Cheers.

 

[Jetranger]

1. If you still have this unit, what happens to the overall reading on it when you turn the USES on/off?(\

No change in the reading of the B&D monitor, as near as I can tell.

2. Does the overall reading on the eMonitor go up by 1600W when you turn the USES on?

The reading goes up but by only about 1200W on the eMonitor. This is both with and without the Shunt CTs being connected so the answer to the next question is 'sort of'.

3. On the eMonitor, is there a "check" where an overall reading is taken on the entire load and compared to the sum of the various circuits?

There are two CTs on the main lines feeding the entire home and there is a 'Current Use:' window (no pun intended, I'm sure) that seems to show the Total Watts used at all times along with the main 'Speedometer' that also seems to provide the same info (including a digital readout of the same value). There is seemingly no option to view the difference between the measured circuits and the total, at least not at this time.

4. Have you compared the eMonitor overall reading with the B&D?

Right now, with typical 'idling' loads only, the B&D is showing 0.3kWh being used and the eMonitor is indicating 428 w/h. So there seems to be a difference of about 100W between the two and the Shunt is not in the equation as it is turned off right now.


It seems the Shunt technology and the eMonitor are not 'compatible' so, for now, I will just leave the Shunt breaker in the OFF position. It will be interesting to see if there is any appreciable difference in the monthly billing but I highly doubt there will be. Given that the billing is based on the meter reading and the B&D monitor is showing the Meter reading info, there should be no difference in the bill.

All this being said, I still really like the eMonitor interface as I am a visual learner and find looking at a graph or chart much easier to interpret than raw numbers on a sheet. I will post a couple of screen shots later to show as examples.

 

[57]

Thanks for that feedback. You may wish to advise PhD of your findings (incompatible device), perhaps pointing them to this thread...

 

[Jetranger]

Good idea, done.

 

[Jetranger]

ScreenShots, as promissed.

This is the top 2/3 of the main screen.

Details Zoom 1 shows a selected area of time. Watt values in the left column change as you move the mouse across the display and the line above '7:56PM' is where I had it when I took the screenshot.

This is a further zoom on the dinner hour, the blue peaks on the left of the previous picture. The colours are chosen by the system and seem to change at random. I have some comments on this to submit to the PhD people but I want to play with it a while longer in case I am missing something.

I am also preparing some larger copies of the above and a few more that I will post a link to once they are up. These are the biggest I am allowed to post here and are understandably a little hard to read but I hope you get the idea.

 

[Jetranger]

Response from PhD

I received a reply from the PhD people today and received their permission to post it to this forum. The distributing company is Energy Circle and all feedback goes through them so that is who they are referring to at the beginning of the reply.

******************************
“eMonitor Support wrote:
(Jetranger),

Energy Circle made us aware of an issue you had with a USESs Shunt device and your eMonitor. I will try to explain what is going on, though it is a little technical J

As you know power is simply the product of voltage times current. With AC power the current is constantly alternating, changing direction every 60th of a second. If you have purely resistive load such as an incandescent light, the voltage and current in the circuit are aligned and constantly changing direction every 60th of a second. Things get more complicated with the load is not purely resistive. A motor has large inductors (wire windings). When you run an AC current through a motor or any inductive device, the current waveform gets delayed relative to the voltage. i.e there is a small delay between the time when the voltage switches direction to the time when the current switches direction. The peak of the AC voltage waveform (should be a sine wave) does not occur at the same time the current waveform peaks. This delay is called the phase angle and is measured in degrees. Power Factor (PF) is the cosine of the phase angle. If there is no phase delay which is the case of a purely resistive load then the PF =1 (cosine(0). If there is phase delay then PF will be a value between 0 and 1. Most of the time the PF should be in the .9 – 1.0 range.

Currently the eMonitor measures the voltage and current separately and multiplies them together to calculate power. It does not take PF into consideration. This is called “Apparent Power”. The utility company meter measures “Real Power”. Real Power is simply the power calculation taking into account PF. If you multiply the Apparent Power by the PF you get Real Power. We are currently working on a new version of the eMonitor that will measure Apparent Power, Real Power and Power Factor.

The problem that you observed is simply power factor. Power factor can be inductive or capacitive. Basically any circuit that is not completely resistive has some power factor. The USES shunt is just a large capacitor. It is supposed to compensate for devices that have poor power factor. This will work fine if you have a bunch of motors running all the time that have large inductive loads that have a poor power factor. The large capacitor in the "shunt" will cancel/offset the inductive load and improve the power factor. The problem is that if the motors are not running, the "shunt" device will cause the house to have large capacitive power factor, creating the same problem that was being resolved.

There is nothing wrong with trying to employ power factor correction, but it is best done within the appliance or device itself. Most modern appliances employ some form of power factor correction in the appliance itself.

The reason that the eMonitor was reporting the strange numbers it is reporting apparent power. Without a large inductive load in your house, the USE’s shunt created a large capacitive load and poor power factor. The 1800W that you observed would be the portion of the apparent power that is not contained in the real power. This does not impact your energy bill, but there are actually large currents running in your wires between the utility meter and your shunt device. The fact that you were reading this large power reading indicates that your SHUNT device is over compensating for any inductive load that you may have.
You are billed on real power, not apparent power, so this would not affect your energy bill, but having large amounts of current running on his wires between the meter and his shunt device even when no power is being used in the house is not a good idea. In the future utility companies may start penalizing customers for having poor power factor.


If there is a large motor that has poor power factor, the best approach is to place the PF correction unit inside the appliance, so that it only is active when the motor is switched on.”



-ben

Powerhouse Dynamics
Technical Support"

*********************************

 

[57]

Thanks for this. Since I'm not an expert on electricity, I cannot comment well on their statements. They say:

...having large amounts of current running on his wires between the meter and his shunt device even when no power is being used in the house is not a good idea.

If this is the case, would the wires not get hot? Did you notice hot wires on that circuit 24/7?

If there's no real draw ocurring (as in when the heat pump is actually running) I don't see how the shunt could be "drawing" that much current 24/7, but as I stated, I'm no electrical expert and always found some electrical theory quite difficult.

 

[Jetranger]

I'm no expert either so I can't say for certain but I am inclined to think it has something to do with the charging and discharging of the capacitors in the Shunt. The breaker is only 20A and the wires are in the conduit you can see in the picture so I would have to take the panel cover off to check the actual wires for any heat. I suppose the conduit would have to get at least warm if this was an issue and I can't feel any appreciable heat to the touch.

I knew when I ordered the Shunt that it would likely be better installed in the same circuit at the Heat pump, it's intended 'most benefitting device', but the literature stated there would be other benefits to leaving it connected to the whole house at the main panel and this is how I installed it. I do run various other motorized equipment like woodworking tools but these too are only intermittent loads at best. The comment about sizing these PF correction devices to the loads was also something I was aware of prior to purchasing the Shunt but, again, the litterature suggested additional benefits that would be afforded to the whole house.

It is hard to say whether or not this unit helped protect any of the electrical equipment in my home last summer when it was hit by lightning or not as some things were damaged and most others were not. I think I will probably reconnect the Shunt once I am running the new version of the eMonitor but, for now, to help keep the calculations easier to see, I will leave it's breaker in the OFF position. I think I will do some more learning on PF too, while I'm at it. I have sent an email to USES but so far have not heard back from them in the 2 weeks it has been since I sent it.

As long as it isn't costing me anything extra when it is connected, I think it might be better to have it than not to. I am on the edge of the city and the power seems to flicker or go out every time there is a storm that rolls through. For a newer neighbourhood, you'd think all the power lines were covered in trees but they are all underground. I don't understand why the power is not more reliable.

 

[cfraser]

I would say that everything eMonitor Support said is 100% correct. Wow, you have a good connection, do you realize just how rare that is from CS in general?

Re the buried cables: probably, somewhere not too far away but something you can't readily see, the "last" pole before the burial is what is getting hit by lightning. You see, like in my residential subdivision neighbourhood of mostly buried cables, that "one" pole that's still there is likely the highest thing around, so it *always* gets hit by very local lightning. Pros and cons to that... I love watching pole-mounted stuff explode around here ("the" pole is at the end of my street, on top of a hill LOL), I can see three with binoculars and saw ALL three blow up during a storm last year...yeah, I was waiting for it...pathetic, but I do like thunderstorms...

I don't know if this'll help... In an AC circuit, a purely resistive load will cause the voltage and the current to be in phase, just as they would be in a DC circuit. In an AC circuit with a purely inductive load, the current will lag the voltage. In an AC circuit with a purely capacitive load, the current will lead the voltage. So what you want to do is match the inductive (motors) and capacitive (your shunt) loads so that they cancel each other out (i.e. lead and lag match) and the voltage and current are both in phase again, just as though your load was a "pure" resistance.

I'm sure you can see then, if your shunt does in fact "match" your motors, that having either one in the circuit by itself is just as bad re power factor. They have to be in *together* to "cancel out" and restore the power factor to close to 1 (i.e. current and voltage in phase).

The reason industrial users are penalized for poor PF is because there *is* essentially useless current flowing, current/power that is not doing anything useful. It is the *in phase* power that we call "real power", and that is the power that is doing real work. The "inductive" and "capacitive" power are not doing work, thus are wasted, yet the power utility still has to build their systems large enough to accomodate this wasted power. You improve your PF (if you were industrial), then the power utility can get along with smaller transformers/lines/generators/etc....you save them $$$, they save you $$.