Tuesday, 22 January 2019

Ventilation and Air Distribution

When it comes to energy efficiency, it is not only related to saving money on the bills, it is also about making use of less energy for protecting health, ensuring comfort, and securing the house from any kind of damage. When air travels around the house, it gets rid of pollutants such as, gases, odors, particles, and even moisture. However, it may also cause uncomfortable indoor temperature, drafty walls and humidity levels. Right kind of air distribution and ventilation plays a very important role in offering a comfortable, safe, and durable home.

Image Courtesy: Pixabay
In basement and ground floors, cool low-pressure air gushes for replacing the rising air for maintaining balance of pressure. This upward natural current is known as the stack effect. Similar principle makes the hot gases and smoke to rise up towards the chimney. In almost all houses, the air that has entered the house increases when it is cold and windy. Times when it is hot outside, the stack effect may reverse.

The fan of the furnace or the “air handler,” will move more cool and warm air than what you would like it to move. One of the primarily reasons for this is because traditional duct installations have leakage. Also, most houses keep the main equipment and leaky return and supply ducts in attics that are uninsulated where they are free to exchange the conditioned air from the air outdoors.

How does the air move in the house?

Basics of ventilation:

In almost all houses indoor air is exchanged with the outdoor air. This is due to two main reasons. Firstly, every house has some leaks (or passages), no matter how small, that tend to join the outside and the inside. Such gaps may include larger ones around pipes, chimneys, vents and small cracks at the window joints. Another reason that causes the air to exchange is that there are numerous pressure and temperature differences between outside and inside — air moves from high pressure regions to areas with low air pressure.

Think of a two-story house with a basement at the time of winters. It is believed that warm air rises towards the top, and the ceiling can be many degrees warmer in comparison to the basement. Buoyant, warm air has greater pressure in comparison to the chilly air outside, and tries to move out from the windows, leaks and ventilation openings, etc.

Distribution of air:

About two-thirds of the houses in the United States, including townhouses and condos that are low-rise, make use of forced-air systems for moving cooling and heating energy from an air conditioner, central furnace, or heat pump around the house through a duct. Forced-air is different from ventilation — this system is supposed to regulate the distribution of air inside a house, not the way the air exits or enters. However, it is also true that the air distribution system may act as the biggest reason for infiltration.

Ideally, a house which is healthy and energy efficient is able to control carefully the air that is coming inside and traveling outside, at the correct rate. The best way to ensure this is to keep the systems working well by getting them checked by HVAC experts.