[string] $FileDirectory = "C:tempMove by headerinput";
[string] $OutputPathHeat = "C:tempMove by headerHeatMeter";
[string] $OutputPathWater = "C:tempMove by headerWaterMeter";
[string] $OutputPathOther = "C:tempMove by headerOther";

foreach ($FilePath in Get-ChildItem $FileDirectory | Select-Object -
ExpandProperty
FullName)
{
    [string] $Header = Get-Content $FilePath -First 1

    if ($Header -match '#serial-number;device-identification;created;value-
                   data-
                   count;act-duration,second(s),inst-value,0,0,0;avg-
                   duration,second(s),inst-value,0,0,0;energy,Wh,inst-
                   value,0,0,0;volume,m3,inst-value,0,0,0.*') {
        Move-Item $FilePath $OutputPathHeat
    } elseif ($Header -match '#serial-number;device-
     identification;created;value-data-
                       count;fabrication-no,,inst-
     value,0,0,0;datetime,,inst-
                       value,0,0,0;volume,m3,inst-value,0,0,0.*') {
        Move-Item $FilePath $OutputPathWater
    } else {
        Move-Item $FilePath $OutputPathOther
    }
}

$RootDirectory   = 'C:tempMove by header'
$InputDirectory  = Join-Path -Path $RootDirectory -ChildPath 'input'
$OutputPathHeat  = Join-Path -Path $RootDirectory -ChildPath 'HeatMeter'
$OutputPathWater = Join-Path -Path $RootDirectory -ChildPath 'WaterMeter'
$OutputPathOther = Join-Path -Path $RootDirectory -ChildPath 'Other'

# get an array of Full path and filenames of the files in the input directory.
# because you want files only, add the '-File' switch.
# if you're on PowerShell version below 3.0, use:
# (Get-ChildItem $InputDirectory | Where-Object { !$_.PSIsContainer })
foreach ($FilePath in (Get-ChildItem $InputDirectory -File) | Select-Object -ExpandProperty FullName) {
    $Header = Get-Content $FilePath -First 1

    # test for a string in the header line that distincts it from the other files
    if ($Header -match ';energy,Wh,') {
        # the substring ';energy,Wh,' defines this file as a 'HeatMeter' file
        Move-Item -Path $FilePath -Destination $OutputPathHeat
    }
    elseif ($Header -match ';fabrication-no,,') {
        # the substring ';fabrication-no,,' defines this file as a 'WaterMeter' file
       Move-Item -Path $FilePath -Destination $OutputPathWater
    }
    else {
        # if both key substrings above did not match, move to the 'Other' directory
        Move-Item -Path $FilePath -Destination $OutputPathOther
    }
}

# test for a string in the header line that distincts it from the other files
switch -Regex ($Header) {
    # the substring ';energy,Wh,' defines this file as a 'HeatMeter' file
    ';energy,Wh,' { Move-Item -Path $FilePath -Destination $OutputPathHeat; break }

    # the substring ';fabrication-no,,' defines this file as a 'WaterMeter' file
    ';fabrication-no,,' { Move-Item -Path $FilePath -Destination $OutputPathWater; break }

    # if both key substrings above did not match, move to the 'Other' directory
    default { Move-Item -Path $FilePath -Destination $OutputPathOther }
}