Most of them when buying climate focus on the brand, performance or design of the device. But the real „invisible foundation” of the system is the piping. Poorly designed piping can reduce efficiency and lead to noisy operation, dripping and even serious breakdowns.
The rules for air conditioning are therefore also key factors for long-term operation, energy efficiency and warranty. In this article, we go through all the relevant regulations and practical considerations - in a clear yet professionally accurate way.
What are the basic rules of air conditioning?
- The pipe length and level difference must be designed according to the manufacturer's specifications
- The condensate pipe must be routed with an appropriate slope
- Copper pipes must be insulated
- Connections (flanging, sealing) must be professionally made
- Outdoor piping must be UV and mechanically protected
- The complete system must be installed according to the manufacturer and standards
These few points seem simple at first glance, but it's all in the detail. Here's what they mean in practice.
What are the pipes in an air conditioning system?
An split air conditioner a system of several elements working closely together.
Refrigerant copper tubes
The air conditioner works by circulating refrigerant. This requires two copper tubes: a thinner one (liquid side) and a thicker one (gas side). These transport the heat between the indoor and outdoor units.
The quality and proper design of copper pipes is critical. If, for example, the bend is too sharp or the diameter is inappropriate, the system's performance is impaired and the risk of failure is increased.
Condensate drainage pipe
During cooling, water will condense from the indoor unit. This condensate must be drained - and you do it properly. If this is not done properly, water can back up, drip or even soak into the wall.
Electrical wiring
There is also an electrical connection between the indoor and outdoor unit, which ensures communication and power supply. This is also part of the piping and cannot be done on an ad hoc basis.
Insulation and protection channel
Insulation of pipes is not optional. Inadequate insulation leads to condensation, heat loss and aesthetic problems. In outdoor or visible sections, pipes are often covered with ductwork, which protects and aesthetically conceals them.
Air conditioning pipe length and level difference - what does the system allow?
Air conditioning systems do not operate with unlimited pipe lengths. Each manufacturer gives precise limits.
Minimum and maximum pipe length
For most split air conditioners, there is a minimum length of pipe (usually around 3 metres) required for proper operation. If the pipe is too short, it can lead to unstable operation of the system.
The maximum length is typically between 15-30 metres (depending on the type). Exceeding this can cause a loss of performance and even compressor failure.
Level difference rules
It makes a difference whether the outdoor unit is higher or lower than the indoor unit. The level difference is also limited and if this is not respected, the circulation of the refrigerant will not be optimal.
When do I need to top up the refrigerant?
Extra refrigerant is often needed for longer pipelines. This should be calculated according to the manufacturer's specifications. If this is not done, the air conditioner will not cool or heat properly.
What happens if we don't respect the boundaries?
The consequences of inadequate pipe length or level difference:
- reduced performance
- increased energy consumption
- noisy operation
- reduction in equipment lifetime
Condensate drainage rules - where most people make mistakes
One of the most common sources of failure in air conditioning ductwork is condensation drainage. The condensate pipe should be designed with a continuous slope, usually at least 1-2% (1-2 cm per meter). This ensures that the water can flow away by gravity. If there is not an adequate slope, the water will stop in the pipe, flow back and even appear at the indoor unit.
If gravity drainage is not feasible (e.g. because there is not a suitable slope), a condensate pump should be installed. This is a common solution in condominiums or more complex layouts.
Condensation water cannot be discharged anywhere: dripping it onto the pavement, running it onto a facade or dripping it onto a neighbour's property is also legally prohibited.
Insulation and protection of pipes
Insulation is one of the most underestimated factors. Cold copper pipes are easily condensed by condensation. If not properly insulated, water droplets can appear on the wall, mould can develop and energy efficiency is reduced.
Outdoor piping protection
Pipes running outdoors are exposed to UV radiation, thermal fluctuations and mechanical damage. This is why proper covering or drainage is important. Ducted, concealed or colour-matched solutions can significantly improve the overall aesthetic appearance.
Concealed or external air conditioning ducting
When building new or completely renovating, it's a good idea to think ahead and hide the pipes in the wall. Aesthetically, air conditioning ducting in the wall is the best solution.
In the case of retrofitting, there is often no possibility of wall-cutting. In such cases, the solution is to install the drainage outside the wall, which is faster and easier to repair in the long run. If you do decide to chisel, you should not weaken the load-bearing wall and you should pay attention to thermal bridges and proper insulation.
Air conditioning mistakes - hard to spot as a layman
Most problems occur months later, for example:
- condensate backflow in case of inadequate slope
- refrigerant leakage in case of poor flange sealing
- poor insulation, condensation, mould
- loss of performance if the tube is too long
- rapid deterioration if inappropriate materials are used
These faults are often invisible to the layperson, but are clearly visible in operation.
Do I need a permit for air conditioning ducting?
In some cases, yes.
- Condominium rules: many condominiums have their own rules for installing air conditioning, especially where the facade is affected.
- Facade placement: the placement of the outdoor unit and piping can be both an aesthetic and a legal issue.
- Listed buildings: a separate authorisation procedure is required.
- F-gas regulation: work with refrigerants is only allowed for qualified personnel.
Air conditioning ductwork for new build - designed for the long term
One of the best decisions is to think about air conditioning during the construction phase, ideally during the mechanical design phase. It is worth determining in advance where the indoor units will be located and designing the ductwork accordingly. It may be practical to build the system in such a way that it is suitable for future expansion.
Summary - what to look out for in air conditioning ducting?
Air conditioning is not an area where compromise is worth making. A well designed and engineered system is more efficient, quieter, more durable and more aesthetically pleasing. Most importantly, all elements of the ductwork - from the slope to the insulation - must be professionally designed.
Let a professional handle your air conditioning!
Air conditioning is not a DIY category. Although many of the details may seem simple from the outside, in reality they require considerable expertise.
The SMARTAIR team during the entire implementation:
- works according to the manufacturer's specifications
- accurately scales the system
- uses aesthetic solutions
- planning for the long term
If you want to avoid problems later and be on the safe side, ask our experts for a quote. A well-designed system is more convenient and more economical in the long run.