FAQs

How do I order replacement parts for my HVI fan?
What is a sone?
What is CFM?
How much ventilation do I need?
Can I install an exhaust fan over a tub or shower?
Can insulation go over an exhaust fan in the ceiling or attic?
Why is water dripping from my exhaust fan?
Can I exhaust into the attic?
Can a bath fan be mounted in the wall?
Do range hoods have sone ratings?
At what height should I install my range hood?
How do you clean a range hood?
How often should I change or clean the range hood filters?
Is it better for a range hood to be ducted or ductless?
What type of duct should be used in venting a range hood?
Can I replace a microwave with a range hood over the stove?
What is the difference between an ERV and an HRV?
Some HVI-Certified products are not rated for sound performance. Why is that?

How do I order replacement parts for my HVI fan?

Please contact the fan manufacturer for parts. HVI certifies ventilating fan performance and publishesfan performance ratings based on third-party testing, but HVI as an organization does not manufacture or sell fans, nor has any resource for locating products or parts. It is suggested to look around on the fan for any identifying marks such as model number, serial number and/or manufacturer to help in determining the correct parts for your unit. Often manufacturers post customer service contact information on their websites. Website links to HVI member manufacturers can be found here.

Also, please note that some of today's fans are much more efficient and quieter than older models, so this may be a great opportunity to update your fan. Please check the current listings in the HVI Certified Product Directory, found here.

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What is a sone?

The sone is an internationally recognized unit of loudness. Sones follow a "linear" scale, like inches. Double the sone value is double the loudness. In contrast, decibels follow a "logarithmic" scale. The sones translate laboratory decibel readings into numbers that correspond to the way people sense loudness. A fan rated at 3 sones makes half the sound of one of 6 sones. Sone ratings offer easy, quick and accurate comparisons of product loudness. In technical terms, one sone is equal in loudness to a pure tone of 1,000 cycles per second at 40 decibels above the listener's threshold of hearing. In everyday terms, one sone is equivalent to the sound of a quiet refrigerator. The lowest certifiable sone rating is currently <0.3 sone for residential ventilating products. For more information, watch HVI-Certified Ratings Explained, Part 2: Sones (Sound).

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What is CFM?

CFM is the abbreviation of the words "cubic feet per minute" and references the volume of air that is exhausted or supplied each minute of operation. If an exhaust product like a bath fan is certified at 80 cfm, this means that every minute that the fan is operating, 80 cubic feet of air will be exhausted from the space. HVI-Certified Ratings Explained, Part 1: CFM (Airflow).

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How much ventilation do I need?

This really depends on the area that you are looking to ventilate. We provide more information on the main site that can be found here.

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Can I install an exhaust fan over a tub or shower?

This question is specific to individual products. The installation instructions of the product will provide the information and can be provided by the manufacturer. If the fan is rated for installation over a tub or shower, a ground fault interrupted is also required to control the fan and prevent electric shock.

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Can insulation go over an exhaust fan in the ceiling or attic?

Yes, as long as the product is listed by a safety agency to UL standard 507. For fan/light combination units, UL requires 8.5 inches of insulation on all sides (including top) of the product. Insulation shall be of the loose fill type and should have a thermal resistance per inch between 3.75-3.85 R (declared by the manufacturer) when conditioned to a density of 32.04 - 40.05 kg/m3. This scenario is equivalent to an approximate R value of R32. R40 is the max for Canadian installations. For a fan without light, there is no insulation limitation for fan in Canada where the max value is R40.

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Why is water dripping from my exhaust fan?

If there is water dripping from your exhaust fan, there could be several reasons. The most common reason is because uninsulated duct is used and it is traveling through unconditioned space. When fan is exhausting warm, humid air through a cold attic or exhausting cool, humid air through a hot attic, condensation can form in the duct work. Replacement of the duct with an insulated type should correct the problem. The other possibility is wind-driven rain through a faulty roof or wall jack. Rain can be blown in through the duct and then the water can follow the duct down to the fan.

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Can I exhaust into the attic?

No, you cannot exhaust directly into the attic as this practice is prohibited in building codes.

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Can a bath fan be mounted in the wall?

Some products are permitted to be installed in a side wall, but this will need to be verified by the installation instructions or by contacting the manufacturer directly.

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Do range hoods have sone ratings?

Yes, range hoods do have sone ratings and they can be found here in the certified products directory. If a .pdf document is preferred, click here.

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At what height should I install my range hood?

The hood should be located at the manufacturer-recommended height above the cooking surface. Review of our membership installation instructions show an average range of 20-30". The specific information for your range hood can be found in the product installation instructions or by contacting the manufacturer directly. A list of HVI members can be found here.

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How do you clean a range hood?

Most manufacturers recommend that the range hood is cleaned with a damp cloth and mild soap. The mild soap will help prevent any discoloration or staining of chrome or aluminum finished and will not dull painted surfaces.

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How often should I change or clean the range hood filters?

The aluminum mesh grease filters should be washed in your dishwasher approximately every month depending on the amount of usage. Clean all-metal filters in the dishwasher using a non-phosphate detergent. Discoloration of the filter may occur if using phosphate detergents, or as a result of local water conditions — but this will not affect filter performance. Wash often if your cooking style generates greater grease like frying foods or wok cooking.

Carbon filters that are installed in range hoods that are not ducted to the outside cannot be cleaned and they must be replaced. 3-6 months is the recommended replacement rate depending upon cooking habits.

Baffle filters, which are used in professional style range hood products, are designed to operate longer in high grease conditions without loss of performance. Generally, these need to be cleaned with soap and water whenever the surfaces become unsightly.

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Is it better for a range hood to be ducted or ductless?

Range hoods should be ducted to the outside of the home. While non-ducted filters trap some of the grease and odors from normal cooking, the humidity, smoke and heat will all be re-circulated back into the home. If the non-ducted filters are not regularly replaced, eventually the grease and odor catching effect will no longer protect your home from impurities.

High BTU gas cooking equipment should always be ducted to the outside of the home.

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What type of duct should be used in venting a range hood?

Range hoods must be vented using metal duct. Given a choice between flexible metal duct and smooth metal duct, go with the smooth. The ridges found in flexible metal duct create turbulence and will diminish airflow. To maximize your range hood's performance, match your duct size to the original size of the fan's ducting, use the shortest amount of ducting possible and keep the ducting as straight as possible.

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Can I replace a microwave with a range hood over the stove?

YES. To help make the transition easy, make sure you know if the current unit is ducted or ductless, and if it is ducted, which way the ducting is running and the size. This will help you choose a proper replacement. When replacing a microwave, you will want to consider the height of the microwave compared to the height of the range hood and you might need to make height adjustments to insure proper ventilation.

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What is the difference between an ERV and an HRV?

HRVs and ERVs are similar devices in that both supply air to the home and exhaust stale air while recovering energy from the exhaust air in the process.

The primary difference between the two is that an HRV transfers heat while an ERV transfers both heat and moisture. Both ventilation systems place the control of air quality and air exchange in the hands of the homeowner rather than relying on inherent, often inadequate, leaks in the home to provide necessary ventilation.

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Some HVI-Certified products are not rated for sound performance. Why is that?

As is the case with residential air conditioners, which are also not rated for sound performance, the sound levels of these products are more dependent on installation factors than on the sound power emitted from the product into the ducts and/or emitted through the enclosure of the product to the occupied space. The installation variables are nearly infinite as the location of the installed product (e.g. basement, attic, or closet), the types of duct that is utilized (rigid, flexible, or insulated flexible), the distance from the inlet or outlet in the occupied space to the ventilator, the type of inlet and outlet fittings, the type of material used to construct walls and ceilings, and insulation thicknesses, all significantly influence the sound characteristics. For all of these reasons, HVI determined that a sound rating would add confusion rather than value to the consumer’s decision making process. For more information and for tips on how to reduce the noise level of your installed fans, refer to our position paper here.

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