What Is A Makeup Air Unit
Musings of an Energy Nerd
All Nigh Makeup Air
If your house is very tight, yous may need to provide a source of makeup air for your frazzle appliances
Almost homes have several appliances or fans that expel air from the home: one or more than bathroom frazzle fans, a clothes dryer, a range hood fan, a gas furnace, or a forest stove. The rate at which these appliances expel air is ordinarily expressed in cubic feet per minute. What are typical air flow rates for exhaust appliances? Hither's a guide:
- Gas furnace (atmospherically vented, 72,000 Btu/h): 30 cfm
- Forest stove: Less than 50 cfm
- Power-vented h2o heater: 50 cfm
- Bathroom exhaust fan: 50 to 150 cfm
- Central vacuum cleaner: 100 to 200 cfm
- Clothes dryer: 100 to 225 cfm
- Range hood exhaust fan: 100 cfm to ane,400 cfm
Common sense tells us that if a fan is expelling 100 cubic feet of air per minute from your house, then an equal volume of air ("makeup air") must exist leaking into your house at the same fourth dimension to replace the exhausted air. If your house is erstwhile and leaky, the makeup air enters through random cracks in your dwelling house's thermal envelope. But if your business firm is relatively tight, you lot may need to provide a deliberate source of makeup air whenever high-cfm exhaust appliances are operating. (For more than data on this topic, see "Makeup Air for Range Hoods.")
Some builders use the following basic (but imperfect) rule of pollex: "Well-nigh houses don't have to supply makeup air for exhaust appliances rated at 400 cfm or less."
This rule of thumb is actually enshrined in the building code. It can be found in the 2009 IRC, department M1503.4, which states: "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 charge per unit. Such makeup air systems shall be equipped with a means of closure and shall be automatically controlled to start and operate simultaneously with the frazzle organization."
(Note…
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Source: https://www.greenbuildingadvisor.com/article/all-about-makeup-air
Posted by: linseymarban.blogspot.com
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