How do HVAC systems work?
Heating, ventilation and air conditioning (HVAC) systems are made up of different components that all work together to keep your home at a specific temperature. Some of these components are easily visible, while others may be hidden in walls, ceilings, attics or outdoors. HVAC systems contain many different parts — here are the main ones you should know about:
Thermostat: This is the part of the HVAC system that you see mounted on your wall. It is where you set the temperature for your home. The thermostat measures the ambient temperature in the room and when the air gets too hot or cold, it triggers the system to start circulating air.
Condensing unit: Located on the outside of your home, the condensing unit contains refrigerated gas that it cools to a liquid form, before pumping to the evaporator coil. This is also where hot air from the system is pushed to the outside.
Evaporator coil: When the refrigerant gets to the evaporator coil, it is turned back into a gas, cooling off the coil along with any air that passes through it.
Furnace: If you are heating your home instead of cooling it off, the air will pass through the furnace. It uses heat pumps, solar energy, electric resistance or combustion to heat the air that passes through it.
Vents: After air flows through the furnace or evaporator coil, it continues its journey through the ducts and is pumped into your home through the vents.
There are different types of HVAC systems, but most should have some version of the components listed above that work together to achieve air cooling and heating.
How do HVAC systems affect indoor air quality?
As the main source of air circulation and indoor-outdoor air exchange during the summer, your air conditioning system plays an important role in the indoor air quality of your home. Because buildings are largely closed off from the outside world, it is easy for pollutants, such as dust, pollen, moisture and dangerous gases, to accumulate in the air indoors.
This buildup can be even worse in energy-efficient homes that are designed to minimize outdoor air ventilation caused by unsealed windows, doors, crawl spaces and attics. The lack of airflow might make your electricity bills lower, but can increase indoor air pollution levels.
Living with these increased levels of indoor air pollution may lead to adverse health effects, including worsened allergy and asthma symptoms and, if certain pollutants are at high levels, long-term respiratory problems.
According to the Environmental Protection Agency (EPA), the levels of certain pollutants can be two to five times higher indoors than outdoors. They can get even higher when you are doing high-pollution activities, such as cooking, cleaning, or painting. Your HVAC system helps solve this problem by bringing in fresh air from outside, circulating it around your home and forcing out stale, polluted indoor air.
As an extra air quality bonus, your HVAC system should also have filters that help remove dust, pollen and other particulate matter from the air that it brings in from the outside. However, depending on the type of filters you have installed, your HVAC may have a limited ability to remove small particles from the air (and no ability to remove gaseous pollutants before they enter your home).
Mold concerns with HVAC systems
It is common for homes to have mold. In fact, according to the EPA, completely eliminating mold growth in your home is impossible. However, you still want to control mold growth and keep it from reaching levels that can be harmful to your health. One of the main ways to do this is by controlling moisture levels and decreasing indoor humidity.
To decrease mold growth, you should keep the relative humidity in your home between 30 and 60%. You can do this by:
- Venting your bathrooms, dryers, and other sources of moisture to the outside;
- Using air conditioners and dehumidifiers;
- Increasing the ventilation in your home;
- Using exhaust fans whenever you cook, wash dishes or clean.
While your HVAC system can play a role in maintaining an ideal level of relative humidity in your home, it also has the potential to contribute to airborne mold. The purpose of this system is to spread cool or warm air throughout your home. If there is mold growth in your air conditioner, it can get into the ducts and be distributed throughout your entire home.
To keep your HVAC system clean and prevent mold growth, you can:
- Make sure all window units are fitted tightly to prevent moisture from getting indoors on rainy or humid days;
- Check your HVAC’s drainage system regularly to avoid clogs and prevent flooding;
- Replace HVAC filters regularly to keep clogged filters from blocking airflow;
- Keep all grates and air returns clean and open;
- Only clean your HVAC system with dry vacuuming or wiping (never water).
How do air purifiers work with HVAC systems?
Like your HVAC system, an air purifier can help increase the air circulation in your home. Your air conditioning system deals with indoor air pollution by bringing in fresh air and pushing old air outside. An air purifier, on the other hand, handles airborne pollutants by filtering them from the air in your home.
Unlike your air conditioner, which probably is not on throughout the day, air purifiers do not need to be turned off. In fact, it is better to leave your air purifier on all day so that it is continuously turning over the air in your home, removing pollutants as the air passes through the filter. Yes, it is even a good idea to sleep with your air purifier on.
For the most significant impact on your indoor air quality, look for an air purifier that can handle both particle pollution — such as dust, pollen, and pet dander — and gaseous pollution, including volatile organic compounds (VOCs). Molekule air purifiers accomplish this using Photo Electrochemical Oxidation (PECO) technology. This technology can capture and destroy many different types of pollutants found in indoor air, including viruses, bacteria, gases and particulate matter.
Your air purifier may not be able to relieve you from the summer heat, but it can give you a break from the harmful effects of airborne pollutants. When paired up, air purification and air conditioning can be a winning combination, working together to reduce the buildup of air pollution in your home.