Aeotec Home Energy Meter 8 ZWA046

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I am looking for a current detector to automate an HVAC system during a power outage. I have a geothermal system, a propane fireplace, and a propane backup generator. The idea is to depend on the fireplace where possible, and use the generator to run the zones the fireplace cannot reach. The fireplace creates heat directly far more efficiently than the generator creates electricity, so the intent is to automatically optimize the propane consumption during a long outage and make sure no zones get too cold. I have had an outage of over 30 hours in sub zero temps.

I have easy access to the generator output wires, and easy access to 120V to power a device. The new Aeotec Home Energy Meter, ZWA046 looks perfect for my application. However, it is shipping in November and is not on the supported device list. In fact, I did not find it by searching the forum.

So, what are the odds that a generic driver will work? Creating a driver would be new for me, but might be a fun learning experience. Is it likely this will be supported natively?

Thanks!

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No way of knowing until someone has one to play with, but it looks to be a standard ZWave 800 device (LR capable) which would say that a driver could be developed for it if required.

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It sounds like in an outage, you're depending on a standby generator for heat.

How cold is "too cold"? Like, freezing?

I'm thinking you could sprinkle some electric heaters, set to a low temp, in places like bathrooms where the water could freeze. (Does geothermal use air for distribution? I have no idea). Perhaps that would be less consuming of propane than the geothermal.

Maybe you should have some plans for if/when the standby generator isn't working?

If you had to abandon your house, how much water would you have to drain? I have an oil boiler with hot water distribution, so that would freeze and burst pipes. Although now, with pex, I don't know what the story would be for new houses.

The propane fireplace probably has a blower? That could run on a battery or little inverter generator. I power most of my house with a 2000w Honda, including the oil boiler, with the notable exception of the well pump.

You could pipe in one or two propane heaters for backup. Maybe something that doesn't need electricity.

Anyway, I'd consider planning for when the standby generator stops working and you still have propane. And maybe if you run out of propane and can't get more, lol.

Perhaps solar, to limp along anyway.

Sorry for the stream of consciousness. I think about this stuff, especially with winter coming.

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Thanks for your thoughts, and I also like to think about it this stuff!

Please note that this is at a vacation home we use frequently year round. Additional detail:

Too cold means cold enough to damage plumbing. In the Upper Midwest, the common pattern is that after a severe snowstorm (which is the primary cause of electrical outages), the temperature plunges, often to well below 0 degree F. PEX is usually fine, but copper and especially fixtures are vulnerable to cracking. We do not drain the pipes when we leave, and if we did, we would go much less often. Also, we frequently have others use our place, and would not count on them to do so.

The primary heating system is electric geothermal. There are four active zones in winter, two radiant floor heat and two forced air zones. All are normally powered by electricity. It is a fairly large system with over 1000ft of buried heat transfer pipe in several wells.

We have two devices that consume propane. One is the standby generator, the other is a fireplace. The whole geothermal system can be operated via the generator, but the efficiency of the internal combustion engine plus the losses in electricity production means less than 25% of the energy in the propane is converted to electricity. On the other hand, the fireplace is more like 65-70% efficient. So, in an outage, I have the fireplace take over heat production in one zone, using the blower to recirculate for that portion of the house. The rest runs on generator. There is no practical additional backup. A battery system would buy some time, but the generator is relialble and self tests frequently, so that seems like marginal benefit at best. We do have a nice south facing roof plane, but it is shaded by a 200+ old pine tree that is not going anywhere. Also, based on my experience at home, solar production in the winter in this part of the country is pretty meager.

So, to get back to the home energy meter, I want to do the following automatically:

  1. Detect that the generator is operating by using the meter to detect current from the generator flowing into the transfer switch.

  2. Use Rule Machine to change thermostat settings in the forced air zone with a fireplace to make the fireplace the primary heat source, while using the inefficient generator electricity production for the rest of the house.

  3. Revert the thermostat settings after power is restored.

The only tricky part is detecting the generator operating. I get a notification from the generator’s app, so I can do all of 2 and 3 above manually, but what fun is that? And I would like it to work if the internet service is out due to a storm

Hope this is interesting. I would be very interested in alternative ways to detect the generator operating.

Thanks!

5

I have a Generac standby generator.

The transfer switch has a dry contact switch meant for this. I've wired it up to an Ecolink contact sensor (it has screws for this).

So, when the transfer switch status changes I get a notification, and lights turn on, etc.

edit: I could take a picture, if you want.

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Thanks. I would be interested. My transfer switch is a Kohler, but they could be similar.

The only other thing I would need to be concerned about is how to get the signal from the transfer case to a dry contact switch mounted indoors. Or find a z-wave dry contact switch that rated for very cold temps.

The ZWA046 is rating to -26F. So if I go that way, I could easily mount it outside in the transfer switch box.

Thanks again!

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My transfer switch is inside the basement, as is the Ecolink contact switch.

I'm in the Albany, NY area, at 1500', so temps can get low. We usually go below 0F several times a winter.

I do have an identical Ecolink switch in the plastic gate control box that sees ambient temps that has been working great.

It's in a plastic box, vs the transfer switch's steel. You'd have to get a signal through the metal box. Maybe it would work. Or, put the contact sensor in a water tight box attached to the transfer switch exterior, and run a couple of little wires to the inside of the switch box.

From what I've read, not lately though, the Kohler's transfer switch has more "smarts" than Generac, where the brains are more generator centric. So, there may not be much parallels between the two.

There ought to be somewhere on your system with dry contacts for transfer switch status. They use them for alarm notifications, blinking red lights, or whatever.

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I also have the same concerns about whether the transfer switch case would act as a Faraday cage.

I have easy indoor access to the cable that carries the generator current. So cutting it, exposing the cables for the current clamps, slicing the cables, putting it in a metal box, and mounting the energy meter controller outside the box would should be pretty straightforward. It would also allow me to monitor the current being consumed, which I am confident I will find a use for.

Thanks again!

9

UPDATE!

I received the Aeotec ZWA046. I installed it in an electrical box with the clamps on the utility lines. Since there is no driver, I used a community one for the old version:

This offers drivers for both single phase and 2 phase power. The US is single phase, two pole as I understand.

The driver does clearly does not work correctly, but it works well enough for my purpose. I decided to use the utility power status as a proxy for my generator running. The reason is that I do not know what the reasonable minimum current the generator will provide in a house with all the lights off, the HVAC off, and all the appliances idle. However, if the utility power is down, the power it delivers should be zero.

The driver does provide power readings! I am not convinced they are accurate, since the two clamps are showing odd current results, but it does not really matter, so long as it shows a power reading of zero when the utility is down. I am finding that I need to manually refresh the meter to get updated readings, but that is no big deal and I can live with a pretty long interval. I will start with ten minutes. I will play around with the driver settings and see if there is another option.

By the way, the z-wave long range signal must be pretty strong. I had no problem with the meter being located in a closed outdoor electrical box. It connects just fine.

So, if you need a brute force way to see if your utility power is down, this seems like a decent approach. If you need accurate measurements, hopefully we will get a native driver or someone will create one.

Thanks and all comments and suggestions welcome.

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I'm thinking about buying one of these (actually 2, because I have 400A service). Was wondering if you'd mind giving a review of how it's working for you including using the old driver for the new device. Anything to be aware of before I drop $200?

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So far it appears to be working pretty well. While some of the clamp measurements do not make a lot of sense, the value I care most about, total power, seems pretty accurate. I say that because when I add a known 240 V load, (like 48amps of electric car charging), the total power seems to change by the correct amount. It is possible that is related to those being 240V loads. Comparing values for current and voltage is a bit confusing, possibly due to a lack of understanding on my part. For example, power divided by 240V is consistently close to what the driver reports for current on clamp 1. Clamp 1 is on one pole, which I think should be 120V?

It works great for my purposes, since all I care about is whether power is zero or not zero.

I hope there is an official or updated community driver at some point.

Hope this helps, please send questions and please let me know what you learn as you go.

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not sure why you would use a custom driver .. at least for the old version there is a built in official driver "aeon home energy meter"

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Thank you! I did not know it existed. When looking up the new meter I found the community driver and assumed it was the only choice.

However, I tried the driver and I am not optimistic. It appears to be oriented to the previous device being battery operated. There was no "refresh" command. Just "configure" and "reset." I waited and did not see any change in value.

If you think I am missing something please let me know!

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14

Holy crap. You've got the 800 LR version!
I've had an old one for a few years now.
It's been kicking out a power reading every 5 seconds all that time.
I had some problems initially, as shown in the following thread.
I wound up editing the driver a tad.

And on this thread, CT orientation as well as the power supply plug source (leg) is important, to avoid negative numbers, lol:

My memory is hazy on the whole subject.
I do remember trying to understand all the parameters, and giving up. :slight_smile:

15

Useful info, Mike--thx!

I have the gen 5 running for nearly identical reasons as yours in my own home--working well. I'm looking at the gen 8 for a rental property that is split into 3 units. I'd like to use each of the gen 8's 3 clamps (wiring in the home makes that doable) to individually monitor units A, B, and C to properly apportion utility bills.

Does the Hubitat's now-aging community driver individually expose each of the clamps. Currently, mine only exposes 2 power readings for obvious reasons--are you able to separately see the third one?

Thx!

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This is a very nice unit.
My old one has also been working for years.
It would be nice if there was an official driver that would support the new 8 model.
A device can be great but without a driver, it's just a lump of whatever.
@bobbyD , @bcopeland ?

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I dread the time my 100 series dies and have to upgrade. I still have the 500 series somewhere in a drawer that I never installed. They didn't change the clamps but they changed the connectors, so can't upgrade in place, but I digress. I added the new one on the list of future driver enhancements.

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My 500 series has been reliably kicking out power readings the at the default 5 second interval for years now. Awesome. Just have this weird LR obsession. :slight_smile:

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Agreed on all counts. And thanks @bobbyD for the future driver.

@mike26 and others, I'm assuming then the current driver will NOT support the rev 8's 3-clamp setup... I figured.

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Sorry for the slow response. I only say single phase and two phase community drivers. With three clamps, I believe you need three phase. And great thanks to bobbyD for a future driver.

If you have the meter, I would play with the drivers anyway. My values do not make complete sense (again thanks for the future driver) but is still totally fine since all I care about is whether the power reading is zero, indicating a utility outtage.

I am attaching the device commands page from mine so you can see what is reported.

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image1751×1241 209 KB

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