
Thinking About Smart Home Power Usage - niemyjski
https://blakeniemyjski.com/home-automation/thinking-about-smart-home-power-usage/
======
function_seven
> _The real shocker was when I decided to measure only the Wemo mini smart
> plug with nothing connected was costing me $0.31 /day._

I can't buy this. That's 3,100 Wh each day, or roughly 130W constant usage.
That much energy being dissipated in the plastic housing would be burning hot
to the touch, or melt it.

I'd wager he's off by a couple orders of magnitude. 1.3W is much more likely
for a smart plug to draw.

The 55W his Echo is drawing is suspect for the same reason. That's more power
than almost any idling laptop.

~~~
floatingatoll
To calculate the math more correctly, a 1W smart plug is contributing
$0.09/month to the $400 electrical bill quoted. This is a stellar example of a
micro-optimization, in programming terms.

Focusing on big spenders like "anything with a pump" and "anything that
generates heat" would contribute significantly to reductions.

I once upgraded video cards, reducing my computer's power draw by 180W and
lowering my electric bill accordingly. This was back in the early days of CFLs
(they were terrible) so it may not seem like much, but it was on 24/7 and that
was the power at idle. I think it worked out to something like $10/month of
savings, which was quite noticeable for my total bill of $50 or so.

~~~
function_seven
> _... and "anything that generates heat" would contribute significantly to
> reductions._

I never measured it, but there was one area that I quickly put a Tasmota plug
on. My stereo receiver under the TV.

One day I was putting around the den and I noticed a lot of heat emanating
from the credenza under the TV. It was my Sony receiver just sitting there,
dutifully amplifying the null input from the turned-off TV.

So I added the plug, and told Home Assistant to turn the receiver on whenever
the TV was on, and turn it off when the TV is off. My guess is that I'm saving
20-40W this way. $2-$4 a month.

(FWIW, this is the first time I've ever been glad to have a "smart" TV. The
only feature I use on that TV is the ability for Home Assistant to see it)

~~~
Relys
Home Assistant is great! I flashed a cheap ES8266 RGB Led controller with
ESPruna firmware and hooked it up to HA over MQTT. What are some of your
hardware recommendations? I also have a Zigbee/Z-Wave dongle for the RPi, so
I'm not limited to WiFi only.

~~~
function_seven
I use a Conbee II dongle with deCONZ for all my Zigbee stuff, and try to use
Zigbee wherever possible.

The Hue bulbs are great, and also act as repeaters, so I have those sprinkled
throughout the house. But they're expensive, so I used Sengled bulbs for most
of my fixtures. The Sengleds are endpoint-only, though. So I mix those two
bulbs to keep the mesh dense but also save some money.

All my door sensors are the SmartThings units. I use a mix of SmartThings and
IKEA Trådfri motion sensors. One SmartThings water leak detector in the
basement, a SmartThings button, and a Trådfri 5-button remote.

I started this just to have a convenient way to control lights. My house is
really old, and almost all lighting is table- and floor-lamps that I would
have to walk around and turn on and off. Or ceiling lamps with pull cords.

But after getting into Home Assistant, I started going a little nuts with the
automations.

My favorite one: A month ago I was getting ready for bed when I realized I
left my oven on all day long. For 12 hours it was keeping the oven at 375˚F.
But then I realized that I already have a motion sensor in the kitchen, and if
I just moved it to the door of the oven, the built-in temperature sensor could
be used to remind me that the oven was left on. So now I have a rule in my
automations.yaml: If the kitchen temperature exceeds the living room
temperature by more than 10˚F for more than an hour, send a notification to my
phone that I left the oven on.

------
cushychicken
We used to use those Kill-a-Watt probes at work to classify smart home device
power draw.

Emphasis on "used to". They are not very accurate at all, and the sampling
interval over which they take data on wall power draw is slow enough that you
will miss important changes in current draw on your DUT. We have since
switched over to expensive, calibrated Agilent power analyzers with better
time resolution.

The post is well intentioned, but I challenge his data collection methods. His
tools are not up to the task he has set himself to. It is not nearly as simple
as the folks who sell Kill-a-Watt's would have you believe.

~~~
Bedon292
Do you have some of that data available? I think his data does seem off, but
all these always on devices have to be costing something right? Curious what
that cost actually is.

~~~
TeMPOraL
> _but all these always on devices have to be costing something right?_

They probably are; that depends on how badly they're designed. But that
doesn't mean they _should_.

Consumer devices aren't usually as efficient as they could be with some more
design work, which I think makes people have a wrong reference point about how
much power is needed to do things. As a counterexample and a way to reset the
reference, consider e.g.:

\- That there exist radio devices that are designed to run for _years_ off a
single CR2032 battery.

\- That there are microcontrollers that can still execute your code while
drawing nanoamps.

\- My 9 m.o. kid has a plush moon with a string attached to it; when you pull
it, it plays a loud melody (that part is mechanical) and flashes LEDs for ~30
seconds. Both are powered from the mechanical energy of your pull.

The way I see it, a typical device on standby and/or a typical wall wart not
charging anything shouldn't pull more than some micro- or even nanowatts. So
they shouldn't cost you more than a hundredth of a cent a month each. Now of
course they do, there are probably some engineering constraints here (like
more complicated devices wanting to keep RAM powered), and there are
definitely business constraints (low-power design is more expensive). But to
me, a device whose standby mode is noticeable on the power bill is simply
broken.

------
peckrob
My utility also installed smart meters recently - the Focus AXRe with
Gridstream RF. It theoretically has Zigbee in it. It even has the Zigbee logo
on it. I haven't figured out if I can read it yet, but in fairness I also
haven't put a lot of work into figuring it out either. At the very least I
could not get Smartthings to see it. So if anybody knows anything more about
this meter I would love to know. :)

But I DID discover that my utility, buried down in like 5 menus on some random
screen of the account portal, offers a usage graph at 15 minute intervals.
It's not real time - it seems to be delayed by 1-3 hours - but it is _far_
better than getting a surprise bill. And while it used some weird SAP JSON
interface, I could deduce what was what and could get the data out of it.

So I whipped up a script to basically scrape this "API" and shove the data
into InfluxDB. I also added daily scrapes for the billing page and the rate
page so I know when I was billed and how much the current rate is. This is
because my utility bills at a lower rate for the first 1,400 kwh, and a higher
rate for everything over that. I was not able to discern any pattern to when
the bills were issued and the utility company was very unhelpful in this
regard, just "sometime ever 27 to 35 days depending on holidays and weekends."

This [0] is the result of combining all the data. While I would really like
realtime data directly off the meter, even being delayed a few hours is better
than a random surprise $370 bill. I've written enough scrapers in my life to
know it will probably break at some point, but it's been humming along nicely
for the last few months.

[0] [https://imgur.com/a/SwdHnCV](https://imgur.com/a/SwdHnCV)

~~~
azdle
I couldn't find anything called a "Focus AXRe", looking at a few different
products that came up for "Gridstream RF" the compliance docs only list that
they're zigbee coordinators, not endpoint devices. ex:
[https://zigbeealliance.org/zigbee_products/gridstream-rf-
enh...](https://zigbeealliance.org/zigbee_products/gridstream-rf-enhanced-
focus-ax-zigbee-enabled-endpoint/) see 8.1 on pg 7. AFAIU, that means it
expects to control other zigbee devices, not report to coordinators like the
ST hub.

You could see if you can find your actual meter here:
[https://zigbeealliance.org/zigbee_products/?product_type=cer...](https://zigbeealliance.org/zigbee_products/?product_type=certified_product&se=Gridstream+RF)

------
aequitas
In the Netherlands when smart meters where introduced one of the requirements
was that the meters should have a port with a defined standard (DSMR[0]) which
could be used by the house occupant to read metrics for themselved. The
standard is pretty well setup with newer versions giving per second power/gas
usage readings in human parsable ascii over rs232 on an rj11 connector.

[0]
[https://www.netbeheernederland.nl/_upload/Files/Slimme_meter...](https://www.netbeheernederland.nl/_upload/Files/Slimme_meter_15_9e94f87c14.pdf)

~~~
huseyinkeles
I have an implementation [0] of DSMR for esp8266 that I integrated to home
assistant over MQTT.

[0] -
[https://github.com/WhoSayIn/esp8266_dsmr2mqtt](https://github.com/WhoSayIn/esp8266_dsmr2mqtt)

------
rconti
Seems stunning that you could charge an electric car for 8 months without
realizing you're not on a TOU plan.

We've got an EV and rooftop solar, and while I knew it was going to be an
arbitrage scheme to begin with (with Net Metering, you don't use your solar to
charge your car, you absolutely don't want to charge your car while the sun is
shining), it was surprising to me to what extent usage had nothing to do with
production. They're 2 entirely different things you treat entirely separately.

I thought I understood NEM2.0 pretty well (here in CA). Instead of the old
NEM1.0, where 1kWh of generation = 1kWh of usage credit, it's bucketed by time
of day. I actually thought NEM2.0 would be better for us than NEM1.0 -- we
have generous peak hours (1pm-7pm) so we generate a TON of electricity off the
roof at up to 38c/kWh during the day, and consume most of our power at much
lower rates overnight. So 1kWh generated might be worth 2kWh into the car!

What I didn't factor in was that NEM2.0 credits are bucketed by month, and the
consequences of that.

Yes, it means we generate very little in the winter, while our usage is just
as high as in the summer, but that would wash out over the course of a year..
except for tiering! It hadn't crossed my mind how much tier 2+ usage we'd have
in the winter. Which means it actually can pay off to charge the car at work
in the winter, while it's pointless in the summer.

We're on a grandfathered TOU plan that I wanted to keep for those generous
generation credits, but I'm thinking of moving to an EV plan because the
_much_ cheaper charging rates might offset the more-generous peak hour timing
and credits. (peak would be 4-9pm though, which means we generate less during
peak, and we also use more at peak, since typically we get home around 7pm,
all of our evening usage would still be at peak).

------
barbegal
The problem of saving power with small household devices is similar to the
problem with micro-transactions. The overhead of connecting devices into a
smart system is far greater than the recovered cost in terms of both money and
energy. A smart switch can easily run to $100 to purchase and install and $10
a year to run. So it needs to save you ~$20 a year to be worthwhile. For large
appliances that are regularly used such as swimming pool pumps, air
conditioners, scooter or car chargers then it can be worthwhile.

I'd like to see smart blinds and curtains become more popular as windows can
act like a giant highly efficient solar panel heating your home up when the
conditions are right. Sadly again the cost of setting up and maintaining such
a system could be ~$100 a year so only certain buildings would actually see a
return on investment.

~~~
tbyehl
'Dumb' timers and thermostats have existed for a long time, the value of
something smarter isn't necessarily about reducing power consumption.

I put smart switches on my exterior lights to run them on a schedule. The
value proposition was 'People don't arrive to darkness because we rarely
remember to turn them on.' I'm trading an increase in consumption for utility.

My 'dumb' pool pump timer died and I replaced it with a more expensive smart
model. Now, in addition to running the schedule, the pump also runs when the
temperature approaches or drops below freezing. It may be running more or less
than under the 'I manually override the timer when it's unusually cold and I
remember' scenario but the value proposition was 'Prevent a pipe burst because
I forgot to turn it on.'

------
gulfie
[https://permies.com/w/better-world](https://permies.com/w/better-world) :
this covers this exact topic... in several different ways.

Most of the electricity being used in the Wisconsin winter is going to be for
heating. The best dollar ROI is typically weather stripping and insulating
followed by using a heat pump ( preferably ground looped ), and of course the
best choice might just be a rocket mass heater.

For passive solar options :
[https://www.builditsolar.com/](https://www.builditsolar.com/)

------
lutorm
We recently installed two Curbs (energycurb.com) in our house and it's not
only been very educating but also made it possible to zero in on the largest
consumers. Upgrading the water heater to a heat pump unit took us from barely
breaking even on our PV to a daily surplus of about 3kWh. The next largest
consumers are the file server running 24/7 in the basement and my work
machine.

------
rconti
Side note: Has Disqus ever worked, for anyone?

I've tried dozens of times over the past few years. It never provides a
'logged in' comment box. Once I login, if i try to login again, it complains
about a form submission error. I've never bothered to troubleshoot because
mostly I want to avoid using Disqus but a couple times a year I decide to give
it a go, and.. nothing. I have or had an account, which doesn't seem to work.
I've also tried to use Twitter integration, which seems the least-bad (because
my twitter account is rarely used for anything anyway).

~~~
reificator
Sounds like an adblocker or something blocking a resource that Disqus
"requires" in order to function.

~~~
rconti
I don't run 'em, but could be something built into Safari. I always figure
"oh, maybe it's an early product, they'll fix it".. but disqus has been around
awhile :)

------
Someone
I never understood the claim that smart switches on LED lightbulbs will
conserve energy. The duty cycle of the average light bulb is fairly low; I
would guess they are switched on for <10% of the time, on average.

If so, adding a ‘smart switch’ that uses 0.5W to a lighting fixture that has a
10W LED light bulb increases its average power usage by about 50%. You must be
fairly sloppy to make that a gain, compared to a manually operated switch.

~~~
bcrosby95
Lots of people have gotten lazy about turning off lights since LED is so
cheap. E.g. I think our kitchen light is on around 12 hours per day because
the switch isn't very convenient. Or the garage light - if it's left on during
the day, it probably won't be noticed until morning.

Also kids tend not to turn lights off.

But yeah, even if you are saving money, smart switches are pretty expensive.
It will take a while to recuperate the extra $ and time invested.

I would focus on switches that control several lights at once. E.g. our garage
lights use 100 watts in all. Kitchen uses 65. Hallway 50.

~~~
thatfrenchguy
> Also kids tend not to turn lights off.

Teach your kids ? What is this laziness of saying "kids won't do X" ?

~~~
bcrosby95
Its called reality. Kids are people, not machines. Parenting is more
comparable to pushing on a string than writing a program.

I've seen some people spend 17 years (and counting) trying to teach their kids
to turn off the lights.

Much less your average 5 year old, most of which probably lack the mental
awareness to always remember to turn off the light when they leave a room.
Hell, my 5 year old almost ran barefoot over shattered glass because she
really wanted to throw something in the trash - she forgot the glass was there
about 10 seconds after we told her not to come over here while I cleaned it
up.

------
MayeulC
Incidentally, I was wondering how a "smart" home could centralize power
distribution to use less energy.

Yes, the hub would be always on, but you get to kill every sleeping device,
such as the TV, "smart" lightbulbs by making the hub control them directly,
phone chargers and various transformers plugged in the outlet, idling
computers, etc.

Just ask the hub to turn on your computer, for instance.

------
zamalek
The real usage is DNS. I set up a PiHole last week and... Wow. 70% of requests
are my fiance's echos (my Google devices, which I am trying to convince her
with, are below the noise floor, go figure).

The privacy concerns are real, but I actually use smart assistants a good deal
of time when I am at home.

------
millstone
In winter, assuming you have a gas-powered furnace, isn't this "wasted"
electrical usage environmentally beneficial, by reducing your use of natural
gas for heating?

------
pathartl
Are you in the Milwaukee area by chance? Funny that you post this today, We
Energies just called me today to notify me they were installing a new meter
for our unit.

------
kcmastrpc
How do you turn off smart bulbs which require power to retain connectivity
settings/configuration?

~~~
mikequinlan
My Hue smart bulbs retain connectivity and configuration settings when powered
off (via the light switch). If they didn't it would be awful -- you would have
to reconnect and reconfigure every bulb in the house after each power outage.
I assume the data is stored in some kind of flash memory.

~~~
filoleg
My personal guess would be that the settings are stored either on the Hue hub
or within the app you use to connect to it. Mostly because, I've noticed,
after someone turns off my Hue bulbs by accident by flipping the switch and
then turns them on, they don't get restored to the same scene setting as they
were before. I have to manually change back to the scene it was on before
being powered off.

On another hand, after reading some articles a while ago that mentioned
security issues surrounding smart bulbs (when it comes to selling them to
someone after using them in your own home due to some persisted settings), I
bet that your theory could be correct as well.

~~~
inferiorhuman
That changed with updated bulb firmware. Initially bulbs would reset to their
default state on power on, but they're now able to save state. The way I read
it this behavior is not dependent upon the hub or app.

The Phillips app is so junky I just use the hard power switches somewhat
frequently.

[https://huehomelighting.com/new-power-feature-to-retain-
colo...](https://huehomelighting.com/new-power-feature-to-retain-color-when-
turned-back-on/)

~~~
filoleg
Luckily, their protocol is interoperable, so I don't think you are required to
use their app, even for their initial setup (not 100% sure on the last part,
but I am about 90% there).

Their lights work great with HomeKit, as well as many other devices do. So
instead of having a separate app for Kasa switches, app for Hue, app for LiFX,
and an app for Nanoleaf, I can control them all straight from HomeKit.
Considering that this is easily doable, it seems totally possible to do this
with something other than just HomeKit as well.

~~~
inferiorhuman
_Their lights work great with HomeKit, as well as many other devices do. So
instead of having a separate app for Kasa switches, app for Hue, app for LiFX,
and an app for Nanoleaf, I can control them all straight from HomeKit.
Considering that this is easily doable, it seems totally possible to do this
with something other than just HomeKit as well._

Ehhh... I can't speak to the rest of the HomeKit integration but the Siri
stuff isn't so great either. First it required upgrading the hub, it still
only works with Philips bulbs (even though the Hue can control other smart
bulbs like IKEA whatevers). After setting it up I still get "device not
responding" responses from Siri at least 1/5th of the time.

Using a different app would potentially improve the problems between the hub
and phone, but not between the hub and the zigbee devices.

------
hotswapster
I had this scenario too. I purchased PowerTag by a Schneider Electric and then
tied this into Home Assistant via Node-red. This gave me usage on individual
circuits and automation resulted in a 40% reduction in energy usage.

For curiosity I wired in an SDM eBay brand meter and it was within 1% of the
Industrial grade PowerTag.

Another option is emonpi and it’s easier to install than both of the above.

Happy metering! (Oh and you’re lucky, Power in Australia is $0.28/kWh

