Guide

Cooling your rental, the legal way

Straight answers on which ACs renters in Germany may install, what's forbidden, and how to stay cool without a permit.

Law & rules

AC in an Altbau or Listed Building: What Renters Are Allowed to DoOld buildings and heritage protection change the rules for cooling. Here is what you can install without permission, and where the façade is off-limits.6 min read AC and neighbour law in Germany: noise limits, condensate, and how to avoid disputesHow loud your AC may legally be, where the condensate is allowed to go, and how to keep the peace with the people next door.6 min read AC in a Rental Flat: When You Need the Landlord's Consent, and When You Don'tA plain-language guide to German tenancy law: permission-free mobile and window units versus fixed split systems, which need consent, an F-Gas-certified installer and a removal agreement.6 min read Are Portable ACs Allowed in a Rented Flat? Why Mobile Units Need No Landlord ConsentAs a renter, you can just use a mobile monoblock, a window unit or a sealed split. Here is the legal reason no landlord sign-off is needed, and the point where that stops being true.5 min read Split AC in a Rental: Is It Legal, and How Is It Different From a Permission-Free Mobile Split?A fixed split system and a permission-free mobile split sound similar, but the law treats them very differently. Here is what tenants in Germany can install without asking, and where consent becomes mandatory.5 min read Can Your Landlord Ban a Portable AC? What Tenants Are Still Allowed to DoWith portable AC units, landlords have far less say than most tenants assume. Here is where your rights end and when consent actually becomes mandatory.5 min read Which AC Can You Install as a Renter Without Permission?Mobile monoblocks, window units and sealed mobile splits versus fixed split systems: a clear yes/no list for renters in Germany.5 min read Which Air Conditioners Are Effectively Off-Limits for Renters in GermanyFixed split systems, wall penetrations and F-gas work aren't outright "illegal" for tenants, but three rules make them nearly impossible to install on your own. Here's what actually stops you, and what you're free to use instead.6 min read

Devices

Portable AC Electricity Cost: Realistic Monthly NumbersWhat a portable air conditioner really draws, how to calculate your own bill, and where renters cut costs fastest.6 min read AC vs Fan vs Evaporative Cooler: What Actually Cools a RoomA fan cools you, not the room. An evaporative cooler only helps when the air is dry. The one device that actually brings the temperature down is an air conditioner. Here's the honest breakdown in degrees, plus what German law allows.6 min read Portable AC Without an Exhaust Hose: Does It Actually Cool?No hose, no hole in the window, no hassle: it sounds great but barely cools a room. Here's why, and when an air cooler is still worth buying.5 min read Monoblock vs. Fixed Split vs. Mobile Split: Which AC Actually Fits a Renter?The three ways to cool a rented flat work very differently, and only some of them are yours to install without asking. Here's how each one works, what it costs you in comfort and effort, and which type a renter in Germany can actually use.6 min read Mobile Split Units: Quiet Cooling With the Compressor OutsideThe compressor sits outside and the room stays quiet. Why a mobile split AC needs no drilling and no permit in almost any rented flat.5 min read How Much Cooling Power (BTU/kW) Does Your Room Need? A Simple Sizing GuideToo small won't cool, too big wastes power. Here's how to find the right BTU or kW rating for your room in a few minutes.6 min read How Loud Is an AC? Decibel Values ExplainedHow to read decibels: what the spec-sheet number actually means, and when an AC is quiet enough for the bedroom.6 min read

Berlin & Brandenburg

Cooling a Berlin Altbau Flat: Why It Overheats and the Legal FixHigh ceilings, big windows, no shading: why Altbau flats turn into heat traps every summer, and which cooling you can legally set up as a renter.6 min read Why Berlin & Brandenburg Flats Get So Hot in Summer (and What Actually Helps)Old Gründerzeit walls, baking top-floor roofs and a city that stores heat like a stone. Here is why your flat turns into an oven, and the permission-free ways renters can cool it down.6 min read Cool Your Berlin Apartment Legally, Without Renovation or Landlord FightsSome air conditioners need a landlord's signature and a certified installer. A whole category needs neither. Here's where the legal line actually runs for renters.6 min read

Practical

Window Sealing for a Portable AC: The Right Fix per Window TypeA portable air conditioner is only as good as its window seal. Here's which sealing method actually works for tilt-and-turn windows, casements, box windows, balcony doors and skylights.7 min read AC as a Renter: Rent or Buy? Costs, Hassle and Storage ComparedFor renters, price is only half the story. What you're allowed to install, where the thing lives all winter and how much hassle you're taking on all matter too.6 min read Condensate Water in Mobile ACs: Where It Goes and What to DoEvery portable air conditioner pulls water out of the air. Here is where that condensate ends up, how self-evaporating units handle it, and what to do when the tank fills.5 min read Sleep Cooler in Summer: How to Use an AC and Cool Your BedroomHonest, practical tips for a cooler bedroom and better sleep in the heat, how to run an AC the right way, and which units renters in Germany can use without a permit.7 min read Set Up a Mobile AC in 10 Minutes: Step-by-Step, No DrillingNo drill, no landlord paperwork. Unbox a monoblock unit, seal the window, and cool your flat the same day.4 min read When Is an Air Conditioner Cheapest to Buy? Off-Season vs the Summer Price SpikeThe cheapest moment for an AC is almost never the moment you want one. Here's when prices actually drop, why it happens, and what renters in Germany are allowed to install.6 min read