TIPS

TIP: When you repaint a room, go a little extra to really finish the room!!!

• Sir Fixalot can change your switch plate covers, install new switches or dimmers for less than a can of paint.
• Also, let Sir Fixalot clean the bugs out of your light fixtures, polish them up or possibly replace them. 
• If the ceiling is being repainted let Sir Fixalot remove the ceiling light fixtures while it is being painted. He can clean the fixtures and reinstall them when the painting is done.

Bathroom Exhaust Fan Selection

When you go into the local hardware store, it is slightly overwhelming just how many choices there are in exhaust fans. This article will describe the options available and then describe the parameters associated with the fan.

From a basic functionality standpoint you have between one and four features in a fan unit:

• Exhaust Fan

• Light

• Night Light

• Heater

These features are typically grouped into the following categories:

You will need a separate electrical switch for each feature in order for them to work independently, but it is possible to connect the features together into one switch.

Recently, I replaced a recessed-can-light with an exhaust-fan/light (option 2) as shown below:

Since there was only one existing electrical switch to the can-light, I connected the light and fan together so that they will always be on at the same time. This made sense because the light is over the tub and will only be on when the tub is in use. It was also important to select the quietest fan in the available budget so as not to disturb the peacefulness of the bath. The remainder of this article will describe how to choose the proper fan considering the bathroom size, the fan noise level and the budget.

The exhaust fan air flow required is based on the bathroom size and is measured in Cubic-Feet/Minute (CFM). The noise level of the fan is measured in SONEs. You will see both CFM and SONE on the box of every fan unit. The bathroom dimensions in the picture above were 9.5' X 7' X 8' = 532 cubic feet. The table below shows the calculations used to determine the fan size:

The loudness of a Fan is rated in SONEs and the SONEs go from <1 up to 4. The things to consider are the lower the SONE the higher the price and the greater the CFM the higher the SONE. A bathroom fan that will produce a gentle sound will have a SONE of 1.0 or less. Here is a table explaining these 4 sound levels and the associated approximate pricing:

The prices can vary with additional options like metal trim, night lights and heaters. I prefer the plastic cases since they integrate nicely into the typical white ceiling. In this example, I selected the Broan QTR070L. It has a CFM of 70, a SONE of 1.0 and is very affordable.

*The 7.5 is calculated based on the CFM rating of the fan which represents the airflow required to completely exchange the air in your bathroom 8 times in one hour. CFM is cubic feet per minute therefore we have to convert from hours to minutes as follows:

• Volume represents the total amount of air in the bathroom. 

• Volume=Length x Width x Height

• 60 = Number of minutes in an hour

• Volume/60 = the number of cubic feet which must be recirculated each minute for one complete recirculation in an hour.

• 8 = The number recirculations per hour required for a bathroom

• CFM = 8 * Volume/60 

•                     = Volume / 60 / 8 {multiply numerator and denominator by 1/8}

•                     = Volume / 7.5     {60 / 8 = 7.5}

Bathroom Exhaust Fan Installation

• This turned out to be a rather easy job since the access in the attic was good. Here are the steps involved:

  Step 1) Remove the Can light. 

  • This must be done in the attic but make sure the power is off and put a piece of tape on the switch so that somebody does not turn the power back on while you are in the attic..

  Step 2) Install the Fan housing while in the attic. 

  • Use screws to eliminate future vibrations which can happen if nails back themselves out.

  • Complete the wiring per the instructions.

  Step 3) Verify Operation

  • Go back into the bathroom and use a key hole saw to cut the sheetrock to the same dimensions as the inside of the fan housing. Be sure to put down a drop cloth in the tub to catch the dust.

  • Insert Light bulb in cover and attach the cover to the housing.

  • Flip the switch to verify the fan and light operate.

  Step 4) Connect a vent hose to vent the exhaust, preferably outside, through the roof or soffit.

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Last modified: September 21, 2009