Bathroom Vent Fans - How To Measure

How you can Size a bath room Vent Fan

While the inclination towards larger spa-like bath rooms continues to gain in acceptance, the demand for correct air-flow gets to be much more essential. Even though a number of folks are tired of their loud as well as ineffective bath fan - certainly not many individuals realize how you can properly size a fan with their preferences.

You will discover there are several unique approaches to calculate the amount of Cubic Feet Per Minute (CFM) of air flow needed to correctly ventilate any rest room. Make certain you take a look at the end of the article and learn about static pressure. A prolonged duct run from the fan to the outside could skew the computations.

Technique one

This method works on the supposition that the objective for bath room venting is 8 total air changes each hour. Take your sq footage x ceiling elevation to get the total cubic ft to be vented.

Case in point: Bath room measures 10 ft across along with twelve ft long. It has eight ft . ceilings. Thus 10 by 12 by eight equals 960 cubic ft ..

We then take this number of cubic feet and divide by sixty - which is the number of minutes within an hour. We next take the actual result and multiply by eight (keep in mind, our target will be eight full air changes each hour). The full equation is as follows:

The First Step
ten feet By twelve ft By eight feet = 960 cubic feet.

Step Two
960 is then divided by sixty = 16.

STEP 3
16 by 8 = 128

Therefore - we require 128 CFM of air movement to be able to effectively vent this particular rest room. Supposing there is not an overly long or twisting duct run to the outside - we would select a fan that moves some where around one hundred thirty CFM or greater. Good examples can be the Panasonic FV series as well as Broan QTXE series, each of which are rated at a hundred and fifty CFM. In the event that an inline fan will be preferred - the Fan-tech FR 110 could suffice.

Technique 2

This approach is a simple one - for bath rooms below one hundred square feet. In accordance with rules of HVI (Home Venting Institute) bathrooms one hundred sq . ft . or smaller call for one CFM for every square foot of bath room - with a minimum of 50 CFM.

Therefore - if you have a seven foot by 9 ft . bathroom - you'll need 63 CFM. It doesn't get any easier | more straight forward than this. The majority of standard ceiling insert fans, nonetheless, are usually rated either fifty or eighty CFM - therefore you will need to round up or down (we recommend you round up).

Strategy three

This approach of calculation is designed for bath rooms over 100 square feet and factors in the number of fixtures within the bath (toilets, showers, tubs). The actual rules are:

- Allow 50 CFM for every common lavatory, shower area or tub
- Whirlpool and jetted bathtubs require one hundred CFM

Therefore - if you have one lavatory (50 CFM), one shower (50 CFM) and one whirlpool bathtub (one hundred CFM) - you'll need a two hundred CFM Fan. A Pansonic FV series would likely perform very well in this bath room. An inline fan package that will function effectively in this washroom would be the Fan tech PB series. That system consists of a two hundred CFM fan and allows for 2 exhaust grilles in the ceiling.

A bathroom vent fan should overcome amount of resistance while pushing air from the inlet, through the duct, to the exterior of the structure. This specific resistance is generally known as static pressure. The actual amount of static pressure depends on the duct lengths, form of duct, elbows along with the roofing jack as well as wall cap. Basically, the more elbows and duct length, etc. which you have - the more static pressure will likely be present and less effective CFM you will get out of the fan.