12/8/2015

How Do You Know How Much Ventilation a Home Needs?

When deciding upon ventilation for your home, it is important to make sure you select a system that is capable of adequately circulating the air. Ventilation systems are built to different specifications and have different capacities. Ventilation needs may also differ depending on the way your home is set up and the standards that you are trying to achieve.

For more open homes, it may make sense to rely on a cascade effect that allows fresh air piped into bedrooms to circulate throughout the home. For more compartmentalized homes, it may be necessary to install spot ventilation systems to ensure adequate air exchange. The placement of the supplies and returns may also make a difference in actual air quality, even when the installed system has the capacity to provide adequate ventilation.

Using HVI Ventilation Standards

The Home Ventilating Institute, or HVI, recommends that an HRV or ERV provide at least 0.35 air changes per hour throughout an entire home. This translates to about five cubic feet per minute (CFM) per 100 feet of floor space. For a 1,000 foot home, this standard requires a continuous ventilation rate of 50 CFM-although this may vary depending on the number of occupants in the home.

For best results, the ventilation system that is chosen should be capable of slightly higher rates of circulation than this minimum. Large gatherings and activities that produce airborne VOCs may create a need for higher air exchange rates to maintain air quality. Bathrooms and kitchens may require higher ventilation rates and may benefit from having returns or fans placed strategically to remove warm, moist air.

Using ASHRAE 62.2 Standards

ASHRAE stands for American Society of Heating, Refrigeration, and Air Conditioning Engineers. The organization creates detailed ventilation standards that dictate what proper air exchange should be in a variety of different settings. These standards are very useful for businesses, as areas like game arcades, lobbies, warehouses, commercial kitchens, and hospital waiting rooms may all benefit from having different levels of air circulation.

ASHRAE standards are also useful for private residences and apartments and can be used by construction companies to ensure a new or renovated building is up to par. ASHRAE standards are highly complex and take occupancy rates and other factors into consideration to determine optimal ventilation. Updated standards are also being released for 2016. In order to use ASHRAE standards to determine your home ventilation needs, it is best to consult a ventilation expert.

Using Passive House Standards

Passive House standards dictate the airtightness level of a home, using an onsite pressure test to gauge the air seal. The home must not exceed 0.6 air changes per hour before ventilation has been installed, in order to ensure that air quality is strictly controlled. Passive house standards dictate energy usage, so heat and energy recovery ventilation is key to meeting all standards. ERVs and HRVs installed in passive homes help to make sure that at least 75 percent of the energy is transferred from outgoing air to incoming air. Ventilation is carefully controlled to reach a rate of about 0.4 air changes per hour.

Consulting Experts

The experts at Zehnder America can help you to figure out exactly what system will best fit your needs based on your home design and any particular standards that you are trying to meet. This can help you to optimize the air quality in your home. Experts may understand factors that you had not considered, helping you to select the best system and installation strategy.