kalt or warm?

The sneakiest ad words: kalt has nothing to do with temperature.

• die Kaltmiete = the base rent, WITHOUT the Nebenkosten
• die Warmmiete = the base rent PLUS the Nebenkosten in the ad (heating and running costs)

kalt + NK = warm: 400 € + 80 € = 480 €. Electricity and internet are usually extra bills on top.