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Evaluating the standby power consumption of smart LED bulbs
Dikel, E. Erhan; Li, Yunyi Ethan; Vuotari, Mark; Mancini, Sandra
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ContentslistsavailableatScienceDirect
Energy
&
Buildings
journalhomepage:www.elsevier.com/locate/enbuild
Evaluating
the
standby
power
consumption
of
smart
LED
bulbs
E.
Erhan
Dikel
∗,
Yunyi
Ethan
Li
,
Mark
Vuotari
,
Sandra
Mancini
National Research Council Canada, 1200 Montreal Road, M-24, Ottawa, Ontario K1A 0R6, Canada
a
r
t
i
c
l
e
i
n
f
o
Article history:
Received 2 November 2018 Revised 9 January 2019 Accepted 16 January 2019 Available online 22 January 2019 Keywords:
LED
Smart LED lighting Standby power consumption
a
b
s
t
r
a
c
t
Thereisanincreasingdemandforsmartdevicesinrecentyears.Oneofthelatestadditionstothelong listofthesesmartdevicesisthesmartlight-emittingdiode(LED)lightsources.Theyoffermany addi-tionalfeaturesinadditiontoprovidelight.However,likeallothersmartdevices,whentheyareturned off bythe userthrough asmartdevice, theystill consumeenergy.That standby powerconsumption, whenthebulbsareoff,soonbecomesanincreasingloadtothegrid.
Inthisstudy,weinvestigatedthecurrentsmartresidentialLEDbulbmarketandselectedthree sam-plesfrom30modelsthatareavailabletoCanadianconsumers.Wetestedthestandbypowerconsumption ofthosesamplesbyfollowingtheIEC62301standard.
Theresultsshowedthatthe standbypowerconsumptionof21SmartLEDbulbmodels (outof30) wasless than0.5W,whichresembles themaximumallowablestandbypower consumptionamountof asmartLEDbulb,ifthemanufacturersintendtocarrytheEnergyStarlogoontheirproduct.Although mostproductsarenotEnergyStarrated,itisapromisingresult.
Wealsofoundthatthestandbypowerconsumptionofthethreebulbsamplestestedforeachmodel wasgenerallyconsistent(thestandarddeviationwaslessthan0.02).Onlythreemodelshadonesample measuredwithahigherorlowerconsumptionthantheothertwosamples (highestdifference0.43W, lowestdifference: 0.06W, standard deviation higher than0.03). This internal consistencyor standby powerconsumptionamountinbetweensamplesareworrisome.
Althoughoursamplesizewassmall,webelievethatthefindingsfromourstudy enabledtogather enoughinformationtohaveabasicideaaboutthestatusofcurrentstandbypowerconsumptionofthe smartLEDbulbsinCanadianresidentialmarket
© 2019PublishedbyElsevierB.V.
1. Introduction
Devicesandappliancesindailylifearebecomingsmartenough to interact with their users dueto recent developments in digi-tal technology. Designers and manufacturers develop new smart products every day, in response toa high demandfrom usersof smart devices.Forinstance, asmart refrigerator cansend an up-datedshoppinglistasamessagetoitsownertoreplenishmissing foods,or thelightsin ahouse canturn onautomatically to wel-cometheownersassoonastheyparkedtheircar.
The light emitting diode (LED) technology developed rapidly inthe last decade.Consideringtheir energyefficiency,LEDswere initially marketed asan alternative to conventional light sources. However,lightingmanufacturersquicklyrealizedthatthepotential oftheLEDtechnologyisnotlimitedtojustenergysavingsorother advantages,such astheir longlifetimeorrobustness.LED lighting technology can also be implemented into home automation
sys-∗ Corresponding author.
E-mail address: erhan.dikel@nrc-cnrc.gc.ca (E.E. Dikel).
temsorhaveembeddedfunctionssuchassecuritycameras,Wi-Fi signalrepeatersorspeakers.
Manymanufacturerscombinedthe potentialsoftheLED tech-nology with the advantagesof mobile smart devices andstarted to develop smartLED bulbs. Users, who used toturn on andoff their light sources with a single wall switch, now also have the option to control the smart LED bulb’s spectral output to create adifferentatmosphereintheir environmentbyusingapplications ontheir smartdevices. Users don’t evenhave to be inthe same roomtomakethosechangesandtheycaninteractwiththeirlight sourcesfromanywhere inthe world,aslongasthey havean In-ternetconnection.
Although this high level of connectivity to the light bulb in-troducedsome benefits to the users,it also came witha hidden cost:standbypowerconsumption.When auserturnsoff a smart LEDbulbfromamobiledevice,thebulbstopsemittinglight; how-everitisconstantlyconsumingpower.Untilrecently,thisstandby power consumption used to be a problem only fordevices such astelevisions;however,itisnow beginningtobea serious prob-lemwiththe rapidincrease ofsmart LED bulbssalesworldwide.
https://doi.org/10.1016/j.enbuild.2019.01.019
72 E.E. Dikel, Y.E. Li and M. Vuotari et al. / Energy & Buildings 186 (2019) 71–79
Table 1
The smart LED models we selected to test.
Model Source or procuring Lumen output (lm) Comm. Price (CAD) ∗ # of bulbs/package 1 ♦ Best Buy 800 Android $129.99 2 ∗∗
2 ♦ Best Buy 600 Android $199.97 3 ∗∗ 3 ♦ Best Buy 750 Android $69.97 2 ∗∗ 4 Best Buy 800 Android $59.98 1 5 Home Depot 800 Android $14.98 2 6 Home Depot 550 Android $59.99 1 7 Canadian Tire 800 Android $19.99 1 8 Staples 530 Android $44.99 1 9 ♦ Best Buy 800 Android $34.99 1 10 ♦ Best Buy 800 Android $39.99 1 11 ♦ Best Buy 800 Android $59.99 1 12 Best Buy 1100 Android $74.99 1 13 ♦ Manufacturer’s store 980 Android $26.99 1 14 ♦ Manufacturer’s store 10 0 0 Android $13.99 1 15 Lowe’s 800 Android $79.99 2 ∗∗ 16 Lowe’s 805 Android $84.99 1 ∗∗ 17 Ebay.ca 600 Android $17.48 1 18 Ebay.ca 500 IOS $59.23 1 19 Amazon.com 500 Android $75.93 1 20 Amazon.ca 550 Android $34.99 1 21 Amazon.ca 600 Android $49.95 1 22 ♦ Amazon.ca 800 Android $64.99 2 ∗∗ 23 ♦ Amazon.ca 800 Android $74.99 2 ∗∗ 24 Amazon.ca 810 Android $36.99 1 ∗∗ 25 Amazon.ca 800 Android $64.64 1 26 Ebay.ca 550 IOS $29.47 1 27 Amazon.ca 800 Android $51.91 1 28 Amazon.ca 550 Android $22.99 1 29 Manufacturer’s web store 800 IOS $69.99 2 30 Amazon.ca 815 Android $19.46 1
∗The prices are as of July 2017, excluding additional costs such as currency conversion, tax and shipping. ∗∗These products are generally named as “starter kits” and include a hub in the package, which increases the price.
♦Models (1, 2, 3), (9, 10, 11), (13, 14) and (22, 23) are manufactured by the same company.
Thecompoundannualgrowthrateoftheglobalsmart LED light-ingmarketfrom2018to2023isestimatedtobe21.5%[7]anditis clearthat their standbypower consumptionwillbe an important issueinanearfuture[6].
This studyfocuses solely on the standby power consumption ofsmartLED bulbs. Threesamples of30 smartLED bulbmodels weremeasured byfollowing thegloballyacceptedIEC62301test procedureforstandbypowermeasurements.
2. Standbypowerconsumptionmeasurementmethod
2.1. Samples
Thefollowingconditionsandconsiderationsweretakeninto ac-countwhenselectingthesamplemodelsfortesting:
The primary focus was to test smart LED bulbs that are de-signedforresidentialapplications;thereforethebulbshadtohave anomnidirectionalA19form(familiar “Edisonbulb” look)andan E26(mediumbase)socket(mostdominantresidentialsocketsize). Bulbsalsohadtohavealumenoutputofatleast500lm.
For this study we selected 30 LED bulb models from 20 dif-ferentmanufacturers. Three samples from each chosen LED bulb model were purchased and tested for their standby power con-sumption. We aimed to select samples that represented a wide rangeoffunction,qualityandpriceoptions,butmoreimportantly, they should all be available to Canadian consumers both online andinstorepurchase.Table1summarizesthebasicpropertiesof thesamples,includinglumenoutput.
Fig. 1summarizesthedistributionofthe propertiesofthe se-lected smart LED bulbsamples asprocurement sources, approxi-mate price per bulb (including the cost of the hub, if the retail
packagecomeswithitoriftheoperationofthemodelrequiresit) andoperatingsystemoftheapplicationthatcontrolsthemodel.
Assuming an average Canadian consumer has access to both online and in store purchases; we used both sources to procure the samplesof smart LED bulbs.Among the selected30 models, 14products (47%)were procured fromonlineretailers (e.g. Ama-zon.ca,Ebay.ca) and16 products (53%) were procured fromlocal brick-and-mortarstores(e.g.BestBuy,CanadianTire,HomeDepot). Affordability was another criterion for sample selection. The bulbpricesin oursampleranged from$7to $75,1 dependingon
factorssuchasmanufactureroradditionalfunctions.Eightsamples (27%)were lessthan$30 per bulb,11samples (36%)were inthe $31–$50rangeand11samples(37%)weremorethan$51.
Currently there are two mobile operating systems used by smartdevices:Android andIOS. Themajorityofthesamples(27) couldbecontrolledbybothoperatingsystems,whereasthree sam-plescouldbe controlledbytheIOSoperatingsystemonly.All ap-plications(alsoknownas“apps”) fortheselectedmodels, regard-lessofrunningonIOSorAndroid,were availabletodownloadfor free.
Therewerethreedifferenttypesofconnectionprotocolsinour samples;Bluetooth,Wi-FiandHub(Gateway).TheBluetooth wire-less technology allows devices to communicate or transmit data and/or voice wirelessly over a short distance[1].Those products are usually sold as bulbsonly and they do not need a hub or a gateway.Thislowerstheretailprices andthe potential complica-tionsthatusersmightexperienceduringtheinstallation.However, with Bluetooth wireless technology enabled LED bulbs, it is not
1 Note that, for some samples the sale price includes the additional hardware such as the hub or gateway, therefore, this reflects as an additional cost in the $cost/bulb calculations.
Fig. 1. Selected properties of the smart LED bulbs samples.
possible to control the lights remotely or froma long distance2;
theusermustbewithinacertaindistancefromthedevicefor con-tinuouscommunication. Weselected13models,whichwere con-trolledbyBluetoothwirelesstechnology.
Wi-FiproductsneedarouterandacontinuousInternet connec-tion.Oncethesmart deviceisconnectedto theprivatelocal net-work throughtherouter, itis possibletocontrol thedevice from anywhereintheworldaslongastheuserhasaccesstothe Inter-net.InthisstudywetestedfivemodelsthatusedWi-Fi communi-cation.
Some smartLED bulbsrequireahub orgatewayto operate.A hubisphysicallyconnectedtotherouterbyanEthernetcableand it is usually used as the access point of an individual or group ofsmart devices.Itis saferandmoresecureto haveadedicated access point to control multiple LED bulbs in multiple rooms or spaces. Those products are usually sold asstarter kits, which in-cludeonehubandoneortwoLEDbulbs.Consumerscanpurchase additionalindividualLEDs,iftheywishtohavemorebulbsintheir spaceandexpand the sizeof their lightingnetwork.These prod-uctscanalsobeconnectedtoahubthatisusuallypartofasmart
2 Smart LED bulbs usually use Class 2 Bluetooth Communication protocol and transmit signals at 2.5 mW, with a range of approximately 10 m (32 ft.) [8] .
home.Thereisagrowingmarketforconnectedsmartdevicesand connectingLEDbulbstoahubwithotherdevices(e.g.thermostats, cameras,televisions,plugs,etc.)makes itveryeasy tooperateby theuser.Inthisstudywetested12samplesthatrequiredahubto operate.
Although the simple and primary function expected from a light bulb is to emit light, in the case of smart LEDs, nearly all samples had an additional function such as a timer, scheduling, messageandcallalert,energymonitoring,musicvisualizationand playbackpre-set lightscenarios.However, themostdominant ad-ditionalfunctionamongthetestedsampleswasthe“tunablecolor temperature”,whichenablesuserstochangetheappearanceofthe whitelightoutput(warm,neutralorcoolwhite)tocreatea differ-entatmosphereinthelivingenvironment.
2.2. Measurement standard and procedure
The internationally recognized standard for standby power measurementisIEC62301[5].Itispreparedby theInternational ElectrotechnicalCommission(IEC) andusedbynumerous authori-tiesworldwideasaguideforstandbypowermeasurements.
The IEC62301 standard definesits objective as “a method to testandtodeterminethepowerconsumptionofarangeof
prod-74 E.E. Dikel, Y.E. Li and M. Vuotari et al. / Energy & Buildings 186 (2019) 71–79
uctsonrelevantlowpowermodes,generallywheretheproductis notinactivemode(notperformingitsprimaryfunction)”.TheIEC standard also definesthe “low power mode” as a product mode thatfallsintooneofthethreebroadmodecategories,3 whichare
describedas:
- Off mode: Any product mode where the energy using prod-uct is connected to a main power source and is not provid-inganystandbymode,networkmodeoractivemodefunction and where the mode usually persists. An indicator that only shows the user that the product is in the off position is in-cludedwithintheclassificationoftheoff mode.
- Standby mode: Any product mode where the energy using product is connected to a main power source and offers one ormore ofthefollowing user-orientedorprotective functions whichusuallypersist:
◦ Tofacilitatetheactivationofothermodesbyremoteswitch, internalsensorsortimer;
◦ Include a continuous function: information or status dis-playsincludingclocks;
◦ Includeacontinuousfunction:sensor-basedfunctions. - Network mode: Any product mode where the energy using
productisconnectedtoamainspowersourceandatleastone network functionisactivated,butwheretheprimary function isnotactive.
The IEC 62301 standard covers all smart household electrical appliancesanditisnotwrittentobeusedspecificallytomeasure smartLED bulbs. Therefore,the definitions of thesethree modes arenot very clearand inour case, itwasnot easy to selectone specific mode todefine the function of smartLED lighting prod-ucts.4
Inthisstudy,weacceptedthatwhenasmartLEDbulbisturned off byusingthe applicationona smartdevice (which canbe ac-ceptedasa “remoteswitch”, asdefinedby theIECstandard);the bulbisina“standbymode”.
For this study, we developed a procedure to measure the standbypower ofsmart LEDsand applied strict anddetailed re-quirementswithrespecttothetestequipmentspecifications, envi-ronmentandprocedure,usingtheIEC62301standardasreference. We added one step to the test procedure, which isnot required bythe IECstandard,butisa requirementoftheU.S. Department ofEnergy test procedure methods5 specified at 10 CFR 430,
Ap-pendix BB [2]: We monitored the Internet connectivity through-outtheteststoensurethatthetestedsmartLEDbulbs,aswellas thesmartdevicethat controlledthebulbandthehuborgateway (if available) had an uninterrupted network connection. This did notinterferewiththerequirementsoftheIECstandard,butadded confidenceintheaccuracyoftheresults.Westronglybelievethat thistypeofmonitoringisnecessaryformeasuringstandbypower consumptionofsmartLEDbulbs;ifthebulblosescommunication withtherouterorgateway,itmaytrytoreconnect,whichwill re-sultinincreasedpowerconsumption.
2.3. Devices
Power supply: Weusedan IT7322programmable powersupply fromITech.Thispowersupplyfulfillsalltherequiredspecifications
3 The standard, however, added a note to that definition and highlights the fact that not all low power mode categories are present on all products, which is true for smart LED bulbs.
4 Refer to the Econoler white paper for more information about various attempts to find a better clarification of the standby mode of smart lighting systems [3] .
5 “Section 5.2.Test Method, Measurements, and Calculations Lamp” clearly states that the “lamp must remain connected to the network throughout the duration of the test”.
oftheIEC62301standard.ItalsomeetstheIEC61000-3-2 require-ments,whichspecifytherequiredsupplyvoltagewaveform.
Power meter: IEC62301 standardrequires apowermeterwith certain functionsto measure the standby power consumption of the devicestested. The Yokogawa WT310Epower meterwe used meets all those requirements,includingthe “harmonics function” requiredbythisstandard.
As mentioned earlier, the IEC 62301 standard is not written specificallyforsmartLEDdevices,thereforeitcanbeusedtotesta vastvarietyofsmartdevices.Dependingonthedevicetobetested anditsstandbypowerconsumption,theconfigurationofthe elec-tricalconnectionbetweenthepowermeter,thepowersupplyand thetestedproductcanvary.Sincethestandbypowerconsumption ofsmartLEDbulbsfallintothe“lowpowerload” category,as de-fined by the IEC standard, we did the recommended connection arrangements(voltagemeasuredonthesupplysideofthecurrent sensorofthepowermeter).
Tools to measure the test environment: The IEC62301 standard requires that the standby power measurements must be carried out in a room that has an air speed close to the product under testingoflessthan0.5m/s.The ambienttemperatureshouldalso bemaintainedat23±5°Cthroughoutthetest.Weuseda multi-function ventilation meter with an articulated probe (TSI/Alnor 9565-AVelociCalc®)tomonitorthetestenvironmentandvalidate
thattheairvelocityandtemperatureparameterswerewithin the acceptable range.Note thatall thethreedeviceslisted abovehad validcalibrationcertificatesatthetimeoftesting.
Test software: Yokogawa, the manufacturer of the power me-ter,offerssoftwaredesignedspecificallyformeasuringthestandby powerconsumption, whichmeets allthe requirementsoftheIEC 62301standard [9].Wepreferredtousethissoftware,becauseof itsusefulfeatures,suchasabuilt-inchecklist.Itisveryusefulfor theusertoavoidmissinganystepsbeforeandduringthe measure-ment.Afterthetestiscompleted,thesoftwaregeneratesareport, whichincludesthetotalharmonicdistortion(THD)measurement, crest factor, root mean square (RMS) voltage, aswell asthe fre-quencyandmeasurementperiod,inadditiontothestandbypower consumptionmeasurement.
Smart devices: The IEC 62301 standard does not specify any properties forthe smart devices used to control the products to betested.Inourcase,allsmartLEDbulbsampleswerecontrolled byan applicationinstalled onasmartdevice.6 Weused anApple
IPad(IOS) anda Samsung Tablet (Android) for our test,as dedi-catedsmartportabledevicesforthisproject.Wedeletedall previ-ous dataandapplicationsonboth devicesandreset themto fac-torysettingsbeforetesting.Wealsoidentifiedanddownloadedall theapplicationsneededtocontrolthesamples,fromtheAppStore (IOS)andtheGooglePlayStore(Android).
Router: An Internetconnection wasrequiredto testall models withoutaBluetoothwirelesstechnology.Aprivatenetworkwas es-tablishedinourlaboratory,dedicatedonlytothisproject.Weused aLinkSysAC1200Dual-bandWi-Firouter.Wekeptallfactory set-tings,exceptforthewirelessfrequency,becausealloftheselected smartLEDbulbmodelswithWi-Fiandhub connectionrequireda frequencyof2.4GHz.
3. Standbypowermeasurementresults
Wetestedthreesamplesfrom30selectedsmartLEDbulb mod-elsusingtheprocedureandequipmentdescribedabove.
Table 2 summarizes the standby power results, including the minimum,maximumandaveragestandbypowerconsumption.We
6 There are various smart LED products that can be controlled by a hand-held remote control, including on/off control, changing the CCT or the color of the light output.
Table 2
Standby power measurement results of the sample products. 7
Model number Standby power consumption of individual samples (W) Standby power consumption analysis S1 S2 S3 Min. Max. (W) Average
(W) St. Dev. 1 0.40 0.39 0.38 0.38 0.40 0.39 0.01 2 0.36 0.37 0.37 0.36 0.37 0.37 0.00 3 0.35 0.35 0.34 0.34 0.35 0.35 0.01 4 0.98 0.99 1.01 0.98 1.01 0.99 0.02 5 0.34 0.38 0.38 0.34 0.38 0.37 0.02 6 0.20 0.21 0.21 0.20 0.21 0.21 0.01 7 0.35 0.33 0.34 0.33 0.35 0.34 0.01 8 0.20 0.22 0.24 0.20 0.24 0.22 0.02 9 0.59 0.58 0.60 0.58 0.60 0.59 0.01 10 0.57 0.59 0.59 0.57 0.59 0.58 0.01 11 0.82 0.81 0.81 0.81 0.82 0.81 0.01 12 0.48 0.48 0.48 0.48 0.48 0.48 0.00 13 0.40 0.39 0.39 0.39 0.40 0.39 0.00 14 0.28 0.27 0.28 0.27 0.28 0.28 0.00 15 0.37 0.39 0.39 0.37 0.39 0.38 0.01 16 0.42 0.36 0.41 0.36 0.42 0.40 0.03 17 0.45 0.46 0.46 0.45 0.46 0.46 0.00 18 0.80 0.68 0.69 0.68 0.80 0.72 0.07 19 0.83 1.26 1.26 0.83 1.26 1.12 0.25 20 0.47 0.47 0.48 0.47 0.48 0.47 0.01 21 0.27 0.28 0.28 0.27 0.28 0.28 0.00 22 0.44 0.44 0.44 0.44 0.44 0.44 0.00 23 0.35 0.35 0.35 0.35 0.35 0.35 0.00
24 N/A N/A N/A N/A N/A N/A N/A
25 0.46 0.65 0.42 0.42 0.65 0.51 0.12 26 0.09 0.09 0.09 0.09 0.09 0.09 0.00 27 0.73 0.79 0.91 0.73 0.91 0.81 0.09 28 0.34 0.37 0.34 0.34 0.37 0.35 0.02 29 0.35 0.36 0.35 0.35 0.36 0.35 0.00 30 0.25 0.25 0.25 0.25 0.25 0.25 0.00
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A
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ConsumpƟon (W)
Tested Model
Fig. 2. Average standby power consumption of selected smart LED bulbs models.
includedthestandarddeviationofthestandbypowerconsumption amongthethreesamplestestedtoshowthedifference.
The resultsshowed that themajority ofthe testedsmart LED bulbs(21) usedlessthan 0.5W instand-bymode,andonlyeight models used more than 0.5W. Fig.2 shows the average standby powerconsumptionofthetestedmodelsinanascendingorder.
Data alsoshowedthat for24models,all threesamples tested usedvery similaramountsofpowerexceptforfew cases(Fig.3). Themeasurementsamongthethreesamplesofthemajorityofthe modelsweregenerallyconsistent.Onlyfivemodels(16,18,19,25 andSP2)hadastandarddeviationofmorethan0.03(seeTable2).
3.1. Comparing measured values with manufacturer’s claimed values
In our sample, ten smart LED bulb models had their standby powerconsumptionalreadymeasuredbytheirmanufacturers.The information about standbypower consumption values and other detailedinformationabouttheproductscanbefoundeitheronthe retailpackageoronthe manufacturer’sweb page(product speci-ficationlink). Notethatalthoughthe standbypowerconsumption valuesofthose tenproducts arepublicly available, thisdatamay notnecessarilybeaccessibletoallcustomers(e.g.printedtext on retailpackages),especiallyatthetimeofshopping.OnlyModel17 hadthestandbypowerconsumptionoftheLEDbulblistedonits retailpackage.Wecomparedtheclaimedstandbypower
consump-76 E.E. Dikel, Y.E. Li and M. Vuotari et al. / Energy & Buildings 186 (2019) 71–79
0.00
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(W)
Model Tested
Fig. 3. Standby power measurement results of three samples of each model.
Table 3
Comparison of claimed standby power consumption versus our results. Model number Standby power consumption (W)
Claimed by the manufacturer Our measurement results
Sample 1 Sample 2 Sample 3 Minimum Maximum Average Difference ∗ 1 0.1 0.40 0.39 0.38 0.38 0.40 0.39 + 0.29 2 0.2 0.36 0.37 0.37 0.36 0.37 0.37 + 0.17 3 0.2 0.35 0.35 0.34 0.34 0.35 0.35 + 0.15 9 0.55 0.59 0.58 0.60 0.58 0.60 0.59 + 0.04 10 0.55 0.57 0.59 0.59 0.57 0.59 0.58 + 0.03 11 0.5 0.82 0.81 0.81 0.81 0.82 0.81 + 0.31 12 0.55 0.48 0.48 0.48 0.48 0.48 0.48 −0.07 13 0.5 0.40 0.39 0.39 0.39 0.40 0.39 −0.11 14 0.5 0.28 0.27 0.28 0.27 0.28 0.28 −0.22 17 0.5 0.45 0.46 0.46 0.45 0.46 0.46 −0.04 ∗ The difference between the standby power consumption of the tested product, claimed by the manufacturer and the average result we found by measuring three samples.
tionwithourmeasurement resultsandtheresultcanbe seen in
Table3.
Ourresults showedthatthe averagestandbypower consump-tionof Models 1,2,3, 9,10 and11were higherthan the values claimed by the manufacturer. The values measured for Model 9 andModel10wereslightlyhigherthanthemanufacturer’sclaimed values(0.04Wand0.03W).Althoughthestandbypower consump-tion of Model 2 andModel 3 is not very high compared to the claimedvalues (0.17W and 0.15W), in the case of Model 1 and Model 11, there is a significant difference (0.29W and 0.31W) between the measured and the manufacturer’s claimed standby power consumption (0.1W and 0.5W compared to our average measurements of 0.39W and0.81W).Since all three samples of thosetwomodelsconsistentlyshowedhighervalues,we are con-fidentthatthestandbypowerconsumptionofthesetwomodelsis muchhigherthanthatclaimedbythemanufacturers.
For Models 12, 13,14 and17 ourmeasurements showedthat the maximum standby power consumption was lower than the manufacturer’s publishedvalues. Especially in the case ofModel 14,themeasuredaveragestandbypowerconsumptionwas0.28W forallthreesamples,whichissignificantlylower thanthe manu-facturer’sclaimedvalueof0.5W.
Manufacturers of seven models claimed that their smart LED productsare consumingeither0.5W or0.55Wat standbymode. Althoughthe source for 0.55W is not clear, 0.5W wouldbe the maximumallowable standbypower consumption ofa smart LED
bulb, if the manufacturers intend to carry the Energy Star logo ontheir product[4].Therefore,itseems likesome manufacturers aimed to keep the standbypower consumption of their product belowthat level,althoughtheirproductsdidnotcarrytheEnergy Starlogo.Onlythreemodels(Models1,2and3),manufacturedby thesamecompany,hadtheEnergyStarlogoontheirproductsand usedlessthanthe0.5Wupperlimit,asrequired.
3.2. Categorizing the models according to the IEA tiers
Measurementsforsixparameters(energy-efficiency,life, color, operation, health and environment) are required to define the threeperformance tiersoftheIEA [6].However,dueto time and budgetconstraints,inthisstudy,wecollecteddataforonly energy-efficiency;therefore,thecontentofthissection isforinformation purposesonly.
Table 4 summarizes the values for efficacy and maximum standby power, defined for energy-efficiency parameter, required to categorize the smart LED products into one of the three per-formancetiers.
Efficacy calculations requirethe lumen output andthe power consumptiondataofthelightsourceatdefaultstate.Weusedthe manufacturer’s claimed values for the lumen output and power consumptionvalues,assumingthattheyweremeasuredwhenthe bulb was at defaultstate. However, mostof the LED bulb mod-els havevarious outputmodes andthelumen output andpower
Table 4
The three performance tiers defined by IEA.
Tier 1 Tier 2 Tier 3 Energy-efficiency parameter Efficacy (lm/W) 65 90 ≥125
(65–89) ∗ (90–124) ∗
Maximum standby power (W) 0.3 0.5 ≤0.2 (0.5–0.31) ∗ (0.3–0.21) ∗
∗The ranges of the values in parentheses are our addition to the table.
Table 5
Categorizing models according to IEA tiers.
Note that if the model does not have a tier classification and is represented by “N/A”, it is because the measured value is above or below the tier range.
consumptionvaluesmaynotbenecessarilymeasuredbythe man-ufacturerwhentheproductisatdefaultstate.Weusedtheresults from ourstandbypower consumption andphotometric measure-mentstodefinethe“maximumstandbypower”.
Table 5 shows how our 30 samples fitted the IEA’s quality andperformancetiersbyusingtheabovementionedassumptions.
It is important to note that when categorizing the tested smart LEDbulbmodels,therearemultipleunknownandunclearvalues. Therefore,theclassification approachin thistable isfor informa-tionanddiscussionpurposes only.TheIEAtiercategorization isa combinationofmultipleparameters, soitisnot righttouseonly oneparametertocategorizeamodel.
78 E.E. Dikel, Y.E. Li and M. Vuotari et al. / Energy & Buildings 186 (2019) 71–79
Among 30 LED bulbmodels,12 ofthem fitto Tier 1forboth standbypowerconsumptionandefficacyvalues.Someproductsfit toonly one of thesetwo measurements (sixmodels Tier 1only, threemodelsTier2only).Insomecases,theLEDmodelfitstoone tierforonemeasurementandanothertierforthesecond measure-ment(sixmodelsTier1/Tier2andonemodelTier 2/Tier3).Only twomodelsdidnotfittoanyofthethreeIEAperformancetiers.
4. Discussion
We measured three samples from each selected LED bulb model.Thestandbypowerconsumptionofsomeofthethree sam-ples for various models showed significant differences. For in-stance, the first sample of Model 19 (19-S1: 0.83W) used less standby power than the other two samples (19-S2: 1.26W and 19-S3: 1.26W). The second sample of Model 25 (25-S2: 0.65W) usedmorethantheothertwosamples(25-S1:0.46Wand25-S3: 0.42W).We purchasedall threesamples fromthesamesupplier, andcheckedtheversionandbatchnumberofthesamplesto en-surethattheyall matched,sodifferentmanufacturingtime or lo-cation would not be the cause of that difference. In both cases, theconsumptionoftheothertwosampleswasveryclosetoeach other.Thesedifferencescouldbeduetoarandomanomaly, how-ever,theycouldalsobeduetothelowqualityoftheproduct com-ponents,orjustduetoarandomdefectiveproductthatmissesthe qualityinspection.Itisimpossibletoknowtherealreasonbehind thesedifferenceswithsuchasmallsamplesize.
The standby power consumption of 21 models wasless than 0.5W. As mentioned, 0.5W is the highest acceptable standby power consumption of smart LED bulbs to have the Energy Star rating.Onlythreeofthe30samples(Models1,2and3)hadan En-ergyStarrating(allthreemodelsweremanufacturedbythesame company)anditisnotcleariftheremaining27productsintended to meet anyother energy-saving program. However, most ofthe manufacturers aimed tokeep the standbypower consumption of theirproductslowerthanacertainvalue.Thisindicatesthat man-ufacturerspayattentiontothestandbypowerconsumption,while theyaredesigningtheirsmartLEDproducts.
Thesamplesizeinourstudywasverysmall,therefore,itisnot easytoidentifytheexactcharacteristicsofthestandbypower con-sumptionoftheselected smart LEDbulb modelsandreach solid conclusions.
5. Conclusion
In this study, we tested the standby power consumption of threesamples from 30smart LED bulb models, by following IEC 62301 standard.Our samplesize was too smallfor reaching any solidconclusions,butsomekeyfindingsfromthisprojectare high-lightedbelow:
- Thestandbypowerconsumptionof21SmartLEDbulbsmodels (outof30)waslessthan0.5W.
- Generally, the standby power consumption of the three bulb samples tested for each model was consistent (the standard deviation wasless than 0.02). Only five models included one sample that presented a higher or lower consumption than the other two samples (highest difference 0.43W, lowest dif-ference:0.06W,standarddeviationhigherthan0.03).
Duetothelimitedtimeandbudget,itwasnotpossibleto cat-egorizeall30 samplestotheIEA’s quality andperformance tiers. However,ifweuseonlybothstandbypowerconsumptionand ef-ficacytocategorizethetestedmodels,12modelsareTier1only.
The results of thisstudyprovided an overview ofthe current status of the smart LED lighting products available forCanadian consumers.However,moredetailedinvestigationshouldbecarried
outinthefuturetogainabetterunderstandingaboutthese light-ingproducts:
- Increasing the sample size would provide more robust data andwouldbetter identify theproperties ofthe various smart LEDsmodelsavailableonthemarket.However,selectingalarge quantity ofmodels anda largenumber ofsamplesfrom each modelmaynotbeacost-effectiveapproach.Theresultsofthis study already separated the tested LED products into certain groups, such as the IEA Tiers. In future studies, fewer mod-elscould beselected torepresenteachgroup, anda relatively largernumberofsamplesfromeachmodelshouldbetested. - In our tests, due to time constraints, we decided to procure
each LED model from the same vendor. It was a safe strat-egy to avoid potential delays due to shipping. However, ac-quiring samples from different vendors and various locations acrossCanadawouldgiveamorediversesamplerange.We be-lievethatdifferentproductionbatcheswithpotentiallydifferent properties(production plant, date ofmanufacturing, firmware version,etc.)ofthesameproductwouldgeneratemorerobust results.
- In future studies, when calculating the standby power con-sumptionofmodelswithahub,thehub’sconsumptionshould be measured separately and added to the total consumption. Thisway,theconsumptionofthemodelswithahubcould be comparedseparatelyifneeded.
- Ourphotometric test resultsindicated that the measured CCT valuesof“constantCCT” productswerequiteclosetothevalues claimedbythemanufacturers.However,wedidnotseethat ac-curacyforthemodelswith“tunableCCT”.Unlessthiswasdue tothe designof theapplication (no optionforusers toselect aspecificCCTvalue),thereasonforthisinconsistencymustbe investigatedtoproviderecommendationstothemanufacturers. - Eachmodelwetested, unlessmanufactured bythesame com-pany,camewithacustomapplicationtoaccesstothefunctions ofthe LED product it controlled. During testing, we observed that some applications were very easy to use whereas others werenot.Ahumanfactorsstudydesignedtoevaluatetheuser’s abilitytousefeatures such ascolortemperatureorlight level changing would be particularly valuable. Identification of po-tential issues would help manufacturers improve their future softwareandinterfacedesign.
Acknowledgments
This report is a product of NRC project A1-012274, part of the NRC Construction Research Centre, High Performance Build-ingsProgram.FinancialsupportwasprovidedbyNaturalResources Canada, OfficeofEnergy Efficiency. Adviceandguidance received fromtheNRCanOEEteamincludingMichelineBrown,Pierre Gal-lantandRobSinglehurstisgreatlyappreciated.Wearealso partic-ularly gratefulfor theconstant technicaland administrative sup-portgivenby ourcolleaguesattheNRC: HeatherL.Knudsen,Guy R. Newsham, DavidFothergill, ChristineBrûlé, Chantal Légerand CarolineGorman.Assistance providedbyWilliamStephensonand SteveGurrofElectromatewasgreatlyappreciatedduringthe iden-tificationandpurchasingoftherightprogrammablepowersupply, andmodificationandcalibration ofthe powermeter.Theauthors arealsogratefultoTrevorNightingale(NRCConstructionResearch Centre,HPBProgramLead)forhissupport.
Supplementarymaterial
Supplementary material associated with this article can be found,intheonlineversion,atdoi:10.1016/j.enbuild.2019.01.019.
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