Kitchen with blue cabinets

Kitchen Ventilation

1. Why do I need an active Makeup Air System (MUAS) for my kitchen?

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 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."

2. What is the purpose of a silencer and when do I need to use one?

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).

3. Can I use the Fantech MUAS with fireplace applications?

No, Fantech designed the MUAS exclusively for residential kitchen cook top ventilation.

4. How much space do I need to install a Makeup Air System?

Maximum length is 9.5 linear feet with the optional heater. Minimum length is 8.5 linear feet without the optional heater.

5. Should I use a heater with a makeup air system from Fantech?

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.

6. Does Fantech sell decorative Range-Hoods?

No, Fantech sells hood liners which can be used inside a wood hood that matches your cabinets or custom-made façade such as mantle style hoods.

7. What is the best location for an interior register to bring fresh air into my home?

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

8. Can I install the Fantech MUAS in my uninsulated attic/basement?

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.

9. Can I install the Fantech MUAS in a vertical position?

Yes. Due to its component-based, field-assembled nature, the Fantech MUAS offers flexibility in the installation process as far as location and point of orientation are concerned. However, Fantech recommends that the installation location be suitable for periodic inspection and maintenance. The MUAS does not require installing the individual system components in a linear (straight line) arrangement. 

10. Can I install the components with a 90-degree bend instead of a straight line to reduce space requirements?

Yes, you can split the components into segments to support tight spaces. Be mindful of the location of the heater when altering the air path through the device. Install the components a minimum of 24 inches before and after the heater to ensure linear air flow across the elements. Non-linear air flow can create pockets of low air that can cause the element to overheat and shorten the elements life.

11. Where should I install the silencer in my Fantech kitchen hood exhaust system?

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

12. Is it possible to change the output temperature of the heater?

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.

13. How often should I change the filter?

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 or by telephone at 800.747.1762, ext. 3.