Household Energy Consumption

Introduction

This analysis looks at exploring energy consumption in households across two days: 1/2/2007 to 2/2/2007.

Global Active Power (killowatts)

Frequency plot of power consumption levels.

suppressPackageStartupMessages(require(data.table))
data<-fread("household_power_consumption.txt")

data_feb <- subset(data, Date=="1/2/2007" | Date=="2/2/2007")
par(bg=NA)
 hist(as.numeric(data_feb$Global_active_power), 
       col="red",main="Global Active Power",
       xlab="Global Active Power (killowatts)")

Consumption over time (per minute)

z <- data.frame(dnt=strptime(paste(data_feb$Date,data_feb$Time,sep=" "),"%e/%m/%Y %H:%M:%S"),
                  power=as.numeric(data_feb$Global_active_power))
par(bg="NA")
plot(z$dnt,z$power,type="n",xlab="",ylab="Global Active Power (killowatts)")
lines(z$dnt,z$power)

Energy Consumption Split by Meter Type

z <- data.frame(dnt = strptime(paste(data_feb$Date,data_feb$Time,sep=" "),"%e/%m/%Y %H:%M:%S"),
                  sub1= as.numeric(data_feb$Sub_metering_1),
                  sub2= as.numeric(data_feb$Sub_metering_2),
                  sub3= as.numeric(data_feb$Sub_metering_3))

plot(z$dnt,z$sub1,type="n",xlab="",ylab="Energy sub metering")

legend("topright", 
         pch=c(NA,NA,NA), 
         col=c("black", "red", "blue"), 
         legend=c("Sub_metering_1","Sub_metering_2","Sub_metering_3"),
         lwd=1, lty=c(1,1,1),
         cex=1.0)

lines(z$dnt,z$sub1,col="black")
lines(z$dnt,z$sub2,col="red")
lines(z$dnt,z$sub3,col="blue")

Various plots

This section will plot, in the following order: top row first, left to right:

Global power consumption (by Killowatts)
Global power consumption (by Voltage)
Energy Consumption split by meter type
Global Reactive Power Consumption

  z <- data.frame(dnt = strptime(paste(data_feb$Date,data_feb$Time,sep=" "),"%e/%m/%Y %H:%M:%S"),
                  power=as.numeric(data_feb$Global_active_power),
                  sub1= as.numeric(data_feb$Sub_metering_1),
                  sub2= as.numeric(data_feb$Sub_metering_2),
                  sub3= as.numeric(data_feb$Sub_metering_3),
                  volt=as.numeric(data_feb$Voltage),
                  powerre=as.numeric(data_feb$Global_reactive_power))
par(mfrow=c(2,2),bg="NA")

with(z,{
    plot(z$dnt,z$power,type="n",xlab="",ylab="Global Active Power (killowatts)")
    lines(z$dnt,z$power)
  })
  with(z,{
    plot(z$dnt,z$volt,type="n",xlab="datetime",ylab="Voltage")
    lines(z$dnt,z$volt)
  })
  with(z,{
    plot(z$dnt,z$sub1,type="n",xlab="",ylab="Energy sub metering")
    legend("topright", 
           pch=c(NA,NA,NA), 
           col=c("black", "red", "blue"), 
           legend=c("Sub_metering_1","Sub_metering_2","Sub_metering_3"),
           lwd=1, lty=c(1,1,1),
           bty="n")
    lines(z$dnt,z$sub1,col="black")
    lines(z$dnt,z$sub2,col="red")
    lines(z$dnt,z$sub3,col="blue")
  })
  with(z,{
    plot(z$dnt,z$powerre,type="n",xlab="datetime",ylab="Global_reactive_power")
    lines(z$dnt,z$powerre)
  })