Kitchen Ventilation

Every time an exhaust fan removes air from your house, an equal volume of air must enter. The air that enters cracks in a home’s envelope to replace air that is exhausted is called makeup air. Two existing building practices affecting makeup air are causing increasing problems for homeowners: homes are getting tighter, and trendy multiple burner stoves require more powerful range hoods to exhaust heat and moist. 

So where does a powerful range-hood get its makeup air? If the house doesn’t have enough random air leaks around windows, doors, and mudsills, the makeup air is often pulled backwards through water-heater flues or down wood-burning chimneys — a phenomenon called backdrafting. Since the flue gases of some combustion appliances can include carbon monoxide, backdrafting is dangerous. In some cases, it can be life-threatening.

In newly engineered homes with range hoods over 400 CFM, there is a new code dictating air replenishment. Although this code has been on the books since 2009, inspectors are now enforcing it. 

International Residential Code (IRC) IRC 1503.4 Exhaust Makeup Air in a High-Efficiency Residential Environment reads:

"Exhaust hood systems capable of exhausting in excess of 400 cfm shall be provided with makeup air at a rate approximately equal to the exhaust air rate. Such makeup air systems shall be equipped with a means of closure and shall be automatically controlled to start and operate simultaneously with the exhaust system."

The Fantech LD silencer reduces the "perceived" noise of a kitchen ventilation system by 50–60%. This is particularly important with range-hoods where the airflow rate is generally high (300+ cfm).

If you are in an area that experiences cold weather in the winter time, you will want to have an additional MUAH heater to temper the air coming into your home.

Fantech suggests installing the supply air register as close to the kitchen exhaust range hood as possible.

Yes, you can. However, you should not install the makeup air system and the supply air duct work directly above or closer than 2 feet to any furnace or its supply plenum, boiler, water tank or any heat producing appliances. Remember to insulate the ductwork to the R value required for your area.

You can place the silencer anywhere in line between the hood and the MUAS. However, it is normally mounted as close to the inlet as possible for ease of installation.

Yes, it is possible; however, Fantech has programmed the heater to optimize its performance over a wide range of CFM settings. Remember, for the maximum temperature gain, we recommend lower CFM rates.

At a minimum, Fantech recommends you inspect the filter every 2–3 months. Once you have a better understanding of how the air quality affects the MUAS over a longer period, you may only have to inspect your filter every 6 months. To order a replacement filter, contact one of our Customer Care Representatives at USsupport@fantech.net or by telephone at 800.747.1762, ext. 3.