The importance of changing air filters in HVAC systems
A simple task that can prevent a lot of damage
– by Albrand Veldhuizen, 14 August 2018
To operate smoothly and correctly, an HVAC system must be balanced. The proportions of recirculation and fresh air need to be defined carefully. Humidity, temperature, the amount of fresh air: everything has to fit together like a Swiss watch. And to keep the system in harmony, it’s crucial to carry out regular maintenance. One of the major components of a balanced system is the air filter. This article looks at the reasons why annual filter maintenance is so important for your HVAC system and what happens if it’s not performed regularly.
The function of an air filter
The primary purpose of an air filter is, of course, to filter air, preventing dust and sand from entering the air handling unit. There are special sand filters for places close to a desert environment, like the Mediterranean Sea or the Gulf of Oman, for instance. Sand and dust can travel for many miles before it drops down from the sky – there are reports of dust from the Sahara found in rain over Scandinavia and even Greenland.
The reasons to change the air filter
The air filter of your air handling unit needs to be cleaned or replaced regularly as dirty air filters have a negative effect on the balance of an HVAC system. As a commissioning engineer, I have seen first hand the results of preventive maintenance being neglected that could have been avoided if the filters had been cleaned or replaced on time. These problems include:
- Damage to the air handling unit
- Low pressure in the HVAC system
- Moisture and mould damage
Damage to the air handling unit
Once a filter is saturated, sand and dust can pour through and enter the air handling unit. This pollutes the HVAC system from the inside, while dust inside the fan damages the bearings. I have even encountered a situation where sand had accumulated around the cooling coil, acting like a block of concrete and significantly reducing the cooling capacity of the coil. The problem with sand and dust is that it gets into everything.
Low pressure in the HVAC system
Filters full of dust create a lot more air resistance. This causes the fan – following the path of least resistance – to pull air out of the recirculation duct, which results in an HVAC system under pressure. In this unbalanced state, warm and moist air that has not been conditioned by the HVAC unit enters the vessel. In addition to decreasing the comfort levels, this also affects the environment – I can recall several occasions where the wooden furniture on a yacht ended up damaged beyond repair.
Moisture and mould damage
Air filters full of sand and dust block the fresh air inlet, raising suction pressure inside the air handling unit and causing the condensate formed on the cooling coil to be pulled through the mist eliminator. I have seen mist eliminators full of mould, which are conducive to bacteria, bad odours and other aspects of an unhealthy environment.
How often should I change my air filter?
Environments – weather conditions, the direction of wind, the proximity of dry and dusty regions – can vary greatly, and the ideal frequency of air filter changes will depend on the area in which a vessel is sailing. If you wish to know exactly when you should change your air filters, simply check them to see how clean they are every week.
Of course, you can also always contact us if you have any questions or need advice. Download our Maintenance & Service brochure here to see what options we offer.
Albrand Veldhuizen | Commissioning Engineer
Albrand has been working at Heinen & Hopman since 2006. He has worked himself up to the position of Commissioning Engineer and nowadays he is stationed at one of the largest yacht builders in Germany. During his many years working onboard numerous luxury yachts, he has developed a great expertise in HVAC systems for superyachts.