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Product Certification is Vital to Honest Performance Claims
Last Updated: 12/21/2009
"Imitation is the highest form of flattery."
Yes, our mothers told us this statement is true and through the years we’ve seen this in business practices as well. But what happens when that imitation is misleading to the consumer? We think that’s just wrong. There are whole house comfort ventilator manufacturers out there who are making claims using verbiage that closely resembles many of the attributes we have published about our product, the Comfort Stream, despite the fact that there are vast differences in the products. There are a lot of misleading claims about performance including airflow and sound levels and product testing.
To set the record straight, let’s first talk about what the Home Ventilating Institute calls a whole house comfort ventilator or what a whole house fan is and what it isn’t. These are fans that rely on the outside, relatively cooler air (relative to the inside temperature) to reduce the temperature of a home by drawing in the cooler air through open windows. These are not “attic fans” – that’s an entirely different product. There is no cooling mechanism in a whole house comfort ventilator/whole house fan. There is no magic way of reducing the indoor temperature; just mechanical ventilation moving air through the house. Whole house comfort ventilators should NOT be used as the primary ventilation system – to expel pollutants, stale air, or odors from the house. They are simply too powerful. No fan will work without the adequate amount of free opening for air to move in as well as move out of the house. It’s a rule of physics that one cubic foot of air won’t move out of the house unless one cubic foot of air moves in. Air will seek the closest, easiest path and that might be the fireplace or water heater chimney if a window is not open. That’s a formula for disaster. There are excellent products out there such as HRVs or ERVs that are specifically designed for primary ventilation, for moving a continuous, gentle airflow through the house for the occupants and the building. Always make sure you use the right product for the right job.
Ducted – what does THAT mean? We’ve been in the whole house fan/comfort ventilator market for more years than we like to think about. The old school type of fan – a huge propeller in the attic floor sucking up massive amounts of cfm at a deafening sound level rely on convective airflow up through the fan and pushing the air out of the attic through existing vents (soffit, ridge, gable, etc.). Virtually all of the whole house comfort ventilators/fans on the market today also rely on propeller or axial fans to create the convective flow from the house to the attic. Yes, you are blowing the hot air into the attic and relying on the lazy air finding its way out through the designated openings. And most of the time it does okay unless the “designated” openings aren’t big enough to handle the pressure and then air sneaks back into the house through wall cavities, pushing the dust and hot attic smells back into the rooms. And there are instances when it is too risky to blow hot, potentially humid air into your attic without specific channels to get that air completely out of the house. Particularly if your home is tightly sealed – you must direct the air immediately out or you will risk serious damage to the building materials. The Comfort Stream is one of only two fans on the market that are truly ducted whole house comfort ventilator systems. The ducting runs from the grille in the individual room to the fan unit and then additional ducting runs from the fan unit DIRECTLY TO THE OUTSIDE so none of the air goes wayward along the way. Air can’t think and has the tendency to wander if you don’t give it clear directions.
The fan used in the Comfort Stream is a motorized impeller, a “work horse fan” specifically designed to move air through ducting. It is NOT an axial fan, the type of fan used by 99.9% of other manufacturers’ whole house comfort ventilators. Axial fans are great for moving air with no resistance like a box fan in a window. They have to work much harder to move airflow through ducting and will perform at a lower cfm as you add ducting runs from the living space to the fan. (That’s why you won’t find an axial fan in your furnace air handler or in a bathroom fan.) Axial type fans aren’t effective at pulling the air from the living space AND pushing it through additional ducting directly to the outside. They just are not designed to perform that way. So when you see a manufacturer claiming they have a ducted whole house fan/comfort ventilator, what they really are offering you is a panel fan with ducting attached. Make sure that the airflow they are promoting includes the ducting and the grilles and any backflow dampers and is not just the panel fan sitting by itself on somebody’s bench.
Sound levels – sones vs. decibels. Technology has come a long way making whole house comfort ventilators quieter and quieter. Manufacturers continue to come up with clever ways to reduce the sound levels heard in the living space. Being able to sleep with your fan running all night is creating an atmosphere that is idyllic for whole house comfort ventilators due to the fact that it’s the cooler evening/night air that you want to pull into your home. The fan industry standard for measuring the sound level of residential fans is sones, not decibels. Sones are not a subjective rating, in spite of what some manufacturers claim. Sones are a linear measurement; the decibel scale is logarithmic. There is no easy conversion from decibels to sones – the math is extremely complex. Sones take into account sound pressures at 24 different acoustic bands and subtract background noise. Because sones are used to measure the lower end or “quieter” (yes, a subjective term) sounds they can only be accurately measured in specifically constructed sound chambers. The Texas Engineering Experiment Station (TEES) Energy Systems Laboratory (ESL) and AMCA Lab are the two, nationally recognized facilities that are capable of accurate sone testing for fans. If a manufacturer tells you, the consumer, that they have a sone rating, you should ask for their test results from one of these laboratories. Anything else is not independently verifiable and is probably wishful thinking. Accurately measuring in decibels is equally as complicated to get repeatable results and will be more subjective if the measurement is done with a hand held device, which is often the case. One can get verifiable decibel ratings but once again only in sound chambers that have been carefully crafted and calibrated. Also worth noting here is that as we age our ability to hear certain sounds diminishes. This is just a medical fact and one of the “perks” of aging. So a subjective “quiet” to me is different from “quiet” to my 20 something kids. That’s why we go to the trouble of having our sound ratings measured in the respected, recognized lab (TEES) under strict, standardized conditions. Any other approach would be subjective and essentially meaningless.
Test Laboratories: On the subject of respected, recognized labs let’s look at where our whole house comfort ventilator is tested and why we have it certified. The Home Ventilating Institute is considered the industry leader in unbiased, verifiable performance certification of residential ventilation products. Membership in HVI and certification is voluntary. Many state and local codes require HVI testing and/or certification for products used in their jurisdictions. This is because if a product is HVI Certified you, the consumer, have the peace of mind that the numbers it is claiming are accurate and not “tweeked” in any manner, and HVI independently verifies those performance numbers randomly on a regular basis as long as the product is on the market. No game playing; just honest reporting and a watch dog for you, the consumer. Some state programs have mandated fans tested to HVI procedures and standards but allow non-HVI approved labs perform this testing. Although this may be a tremendous savings to the manufacturers using non-HVI approved labs, particularly when their own in-house labs are doing the testing, how much confidence can the consumer have in these numbers if the lab has not been sanctioned or approved by the organization that has spent decades creating an unbiased – free of any one manufacturer’s influence - procedure and testing facilities? We strongly urge anyone buying any home ventilation product to visit the HVI website (www.hvi.org) and learn more about the integrity behind the Certification seal (and what it looks like – we proudly display it on the Comfort Stream).
We hope you’ll agree that going the extra mile and spending the extra time and money to prove our product performance is done for the sensible consumer who values such integrity. Also, don’t be fooled just because a manufacturer is an HVI member – this is a great first step, but it doesn’t mean that the products have been tested and certified. The HVI certified label and listing in their certified products directory - http://www.hvi.org/resourcelibrary/proddirectory.html is the ultimate step for consumer protection and truth in advertising. Whole house comfort ventilator/whole house fans are an excellent way to a natural cooling effect and take advantage of dropping evening temperatures and often meet the needs of people who simply do not want to use costly air conditioning. There are good products on the market and there are some products that may be trying to mislead consumers – often not intentionally, but nonetheless their information is confusing. If you’ve gotten this far in this piece then congratulations! You’re a savvy consumer who wants to know. Naturally we hope you’ll buy our product after reading this, but mostly we hope we’ve helped clear the air of some of the mis-information.

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