Choose the Right Ventilation Strategy




When buildings become personal: Ventilation plays a key role in transforming a house into a home. Panasonic exhaust fans can help


Think of your building's envelope as the foundation for a successful ventilation strategy.

A tight enclosure that minimizes moisture and air leakage lays the groundwork for a good ventilation system also provides better energy performance overall.

This creates a healthy, durable, energy-conscious space.

However, a tight envelope also means that providing fresh air exchange is even more important. Codes and standards, building materials, climate zone, aesthetics, and occupant behavior all place demands on ventilation.

Competing with these demands are your customers' goals for indoor air quality, energy performance, and durability. 

Mechanical ventilation draws out pollutants and draws in make up air in a controlled manner. Controlled ventilation strategies divide into three main categories: exhaust, supply, and balanced ventilation systems.


Exhaust ventilation removes pollutants at the source

An inexpensive and simple approach to ventilating a home, exhaust-only ventilation works by forcing air out of the home to depressurize the interior and gain make up air through passive vents. Because this ventilation system only actively exhausts air, it is not recommended in hot or humid climates.

Since any make up air is gained passively, that air may be very humid, contain pollutants, or be too cold, leading to energy penalties for the home.

Powerful exhaust systems, such as commercial-capacity range hoods, should be used cautiously with combustion appliances, as they can cause back drafting.


Supply ventilation dilutes pollutants

Supply ventilation, another simple and inexpensive approach, uses a fan to pressurize a home, actively bringing outdoor air inside while squeezing out indoor air.

Supply systems offer better control over incoming pollutants, as they only obtain outdoor air through specified vents. Pressurizing the house more readily forces out combustion gases and other pollutants.

However, supply systems struggle with conditioning or removing moisture from incoming air, and can raise heating or cooling costs.


Balanced ventilation is best

Balanced ventilation works by both actively exhausting polluted indoor air and actively drawing in fresh, outdoor air in a balanced, controlled ratio. Because the system uses more fans and ducts than either the supply or exhaust approaches, it is more costly.

However, balanced ventilation is appropriate for all climate zones. By coupling a balanced approach with an energy recovery or heat recovery ventilator (ERV or HRV), incoming air can be conditioned and dehumidified, saving on heating and cooling expenses for the home. A tight enclosure guards the interior of the home and guarantees that air is properly enclosed and controlled.

Mechanical ventilation can take the benefits of a healthy home one step further by providing a controlled source of treated fresh air that balances indoor air quality with energy savings.


Panasonic Solution Center:

WhisperGreen Select 

A customizable all-in-one fan or fan/light combination that gives you more than 250 possible configurations. Variable flow rates, plug 'n play modules (with multispeed operation options), motion sensor, condensation sensor, automatic LED night light allow the possibilities to add up..

Pick-A-Flow speed selector boosts options more by letting you to choose the proper CFM (50-80-110 or 110-130-150 CFM) to ventilate whatever size room you need. 



The only supply fan that cleans the air as it comes in

The WhisperSupply filters outside air through a Merv 8 filter to a deflector that pushes air up and around the walls to avoid drafts and improve comfort.

The result is clean air circulated comfortably around the room.


Whisper Comfort ERV 

A balanced solution that replaces the air it exhausts while exchanging the heat between incoming and outgoing air.

In winter, heat is transferred from the warm outgoing air to the cooler incoming air.

In summer, heat is extracted from the warm incoming air and transferred to the cool outgoing air.

The result is better indoor air quality and low energy bills. 



— This article is by PanasonicIAQ, one of ProTradeCraft's advertisers. #PanasonicIAQ is the premier manufacturer of powerful, energy-efficient ventilation fans that quietly exhaust unhealthy, unpleasant or moist air from home or business. See all of PanasonicIAQ's content here.



I know there are lots of variables, temperature differentials, relative humidity, but are there levels at which ERVs use more energy than they save?

Daniel Morrison's picture

Hello Richard, we forwarded your question to Panasonic and they reached out to a couple of engineers for input. Here's what we got back:

"I believe it would depend on the operation of the ERV and the conditions of the indoor and outdoor environments.  

For instance, during the swing seasons with good outdoor conditions there may not be much to gain from the ERV other than fresh air which may or may not be available via active controls.

The moderate seasons will have different lengths depending on climate/region.

If you make the building or house sufficiently tight then you need fresh air, which means you should use an ERV/HRV all the time (or close to it) unless you can ventilate with outdoor air without an air-to-air heat exchanging, however this is very climate dependent and you still have to bring in actively controlled air movement and the energy that it takes to drive it.
Even in the high-achieving, low EUI, passive-house standard,  active mechanical ‘balanced’ ventilation is required - to provide fresh air while minimizing the additional heat load.  
Finally, there are ways to ventilate a building in a truly passive fashion but most buildings are not designed to facilitate stack effect, open floor plans, etc.
Hope that helps ... "

—James Sweeny, Acting Laboratory Manager Texas A&M Engineering Experiment Station


Another expert added this:


"The alternate question is what would it cost the home owner to add heat and moisture in the winter or remove heat and moisture in the summer by simply opening a window.

An ERV can add moisture in the winter, thus reducing a need or strain for a humidifier and removes moisture in the summer thus reducing the strain on the central Air Conditioning system. The added bonus to an ERV is that it also adds heat in the winter and removes heat in the summer while improving indoor air quality.

To put a cost savings on that can be done, however it is to emphasize that an ERV is constantly in operation in both outdoor conditions, saving money and improve the indoor air quality in the home.  My belief is,  it will never use more energy than you save."

—Don Giannini, Technical Project Manager in the Building Performance Centre (BPC) at Exova Lab in Mississauga, Ontario


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