Improved indoor air quality is a result of proper ventilation. Indoor humidity and airborne pollutants, both of which might pose health risks, can be controlled via ventilation.
Indoor Humidity And Ventilation
Mold growth is aided by high indoor humidity. Poor site design that does not adequately manage water, poor construction or restoration, and/or insufficient air exchange can all contribute to high humidity. 30 to 60 percent relative humidity is a reasonable goal. Relative humidity can be determined with a cheap hygrometer, which is accessible at hardware stores. Since everyday activities like cooking, bathing, and breathing produce moisture and there isn’t enough natural or mechanical ventilation (such opening windows or exhaust systems) to remove it, chilly regions are particularly susceptible to excessive moisture and humidity throughout the winter.
The heating, ventilation, and air conditioning (HVAC) system can draw hotter, humid air inside in warmer areas. In this situation, unless the ventilation system also dehumidifies the air, it may contribute to interior humidity issues.
Contaminants In The Air
INDOOR POLLUTANTS. These include substances used in building construction or renovation (e.g., glues, off-gassing from carpets, emissions from particle board, cleaning compounds). Gas-burning appliances can also release carbon monoxide and particles into the air. These appliances (cook stoves, gas furnaces, gas boilers, and gas water heaters) can contribute to indoor pollutants through incomplete combustion and poor ventilation. Fans that exhaust outside should be utilized with gas cooktops. To eliminate the byproducts of incomplete combustion, gas-fired heating appliances should be sealed, and power-vented systems should be fitted. Additionally producing particles, wood-burning stoves need to be vented outside.
EXTERNAL POLLUTANTS. When a home’s heating or cooling system pulls air in, outdoor debris may be brought inside. The outdoor air can contain allergens and particulates that can cause asthma attacks. HVAC systems can effectively remove particles by filtering the incoming air. Although higher MERV levels trap smaller particles and are generally more ideal for people with allergies or where the indoor environment has a high concentration of mold spores, dust particles, or other allergens, experts still advise utilizing filters with a MERV 6-8 rating.
Reducing Health Risks Through Ventilation
Spot ventilation and dilution ventilation are two ventilation types that can assist in reducing dangerous air pollutants and humidity. Spot ventilation exhausts air to the outside by drawing it from a specific area (such as a bathroom or kitchen). Low-level pollution throughout the house is addressed through dilution ventilation.
SPOT VENTILATION. All restrooms and kitchens should have exterior exhaust fans. These fans eliminate carbon monoxide and dampness. The most efficient fans are strong and quiet. Utilize fans that run at one sone or less, and direct their exhaust outside. To make sure the fans run for a long enough period of time, fans with timers or de-humidifier controls are helpful. After taking a shower, it’s a good idea to leave the bathroom fan on for around 45 minutes.
VENTILATION OR DILUTION. The entire living room is ventilated using dilution. The efficiency of dilution is affected by air shifts (exchanging interior air for outside air) and air cleansing. Natural ventilation (infiltration, leaks, and windows) and mechanical (controlled) ventilation work together to modify the air. When particulates are filtered and moisture is removed from the air, air is cleaned. The objective is to make enough adjustments to guarantee a healthy environment. To achieve this, a variety of heating and cooling systems with filtration can be installed. Duct sealing is a component that is common to all systems and is especially important on the return side (the side drawing the air into the duct).
Considerations For HVAC
HVAC System Sizing
It’s crucial to avoid oversizing a system. Oversizing can result in inadequate dehumidification and poor air distribution, which can foster the formation of mold. Oversized heating systems have the potential to “short cycle,” which refers to the system not running long enough to turn on the fan for long enough to disperse new air. While air conditioning systems that short cycle will give chilly air in brief bursts, they may not necessarily dehumidify the air. Mold growth may be encouraged by the consequent chilly, damp environment. To account for duct leaks and reduce customer complaints about the quality of the heating or cooling, some contractors oversize HVAC systems. In their Manual J, the ACCA offers advice on system sizing (Residential Load Calculation).
Air Quality Issues May Be Exacerbated By HVAC Systems
Problems with interior air quality can potentially be made worse by HVAC systems. The HVAC system might be contaminated (due to, for instance, mold in the duct lining or bacteria on the coil or filters), and the system could disperse these pollutants all throughout the house. Second, contaminants may be transferred from one area of the house to another by the HVAC duct distribution system. These issues can be reduced with routine maintenance and duct sealing.