HVAC system regulates the quality of the air that circulates through your home. In the event of negligence, it could impact the health of the people living in your house. The issues are more severe in the winter months and when opening windows and doors isn't the best alternative.
Moisture gets accumulated in duct panels regularly. This could result in mold growth inside the ducts in the future. The spores of the molds pollute the air in your home and can lead to allergic reactions for your pets and family members alike.
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The most frequent symptoms of mold allergy are breathing problems and wheezing sounds when breathing, and noses that are clogged with mucus.
If the air conditioning ducts within your house are large then rodents and other insects could be living within the ducts. Make sure that these guests are kept out of the HVAC ducts at all times.
If you have snow-like deposits in the ducts of your HVAC system. Clean that nasty stuff out of the ducts as quickly as you can.
Always have your air conditioning ducts cleaned by trained experts. You and your family's health is dependent on it. There are a variety of reputable companies available that offer services for air conditioning (including repair and installation).