How to Perform a Blower Door Test on a Home


The blower door is the main tool used by residential energy efficiency professionals to identify air leaks in a home and to quantify the amount of energy lost by those leaks. Since 2009 nearly all jurisdictions have incorporated blower door testing into their residential energy code so this diagnostic test will become a regular part of the residential construction process. These instructions are for a depressurization test using a Model 3 Minneapolis Blower Door and a DG-700 manometer.

Part 1
Setting Up the House

Setting Up the House on How to Perform a Blower Door Test on a Home

1
  The house must be put under "winter conditions". Make sure any attic or crawlspace accesses are closed.

Setting Up the House on How to Perform a Blower Door Test on a Home

2
  The entire inside of the house must have all areas communicating fully with each other so when the fan is turned on, it pulls air from the entire house.

Setting Up the House on How to Perform a Blower Door Test on a Home

3
  This includes bath exhaust fans, kitchen fans, whole house fans and clothes dryers.  During the blower door test, the blower door fan should be the only fan exhausting air from the home.  Ceiling fans do not affect the test but should be turned off to help the blower door operator better identify drafts during the test.

Setting Up the House on How to Perform a Blower Door Test on a Home

4
  Turn down water heater and furnace thermostats.  These must not turn on during the blower door test.

Setting Up the House on How to Perform a Blower Door Test on a Home

5
  Clean out any ashes or cover them with wet newspaper to avoid pulling ash into the home.

Setting Up the House on How to Perform a Blower Door Test on a Home

6
The front door is the preferred location to set up the blower door.  Be sure to have a clear spot around the door so it can be fully opened.

Part 2
Setting Up the Blower Door Shroud

Setting Up the Blower Door Shroud on How to Perform a Blower Door Test on a Home

1
  Arrange four outside aluminum frame pieces with cam levers facing up on shroud.

Setting Up the Blower Door Shroud on How to Perform a Blower Door Test on a Home

2
This will make a rectangle. Be sure that all four aluminum pieces are fully collapsed.

Setting Up the Blower Door Shroud on How to Perform a Blower Door Test on a Home

3
  Raise the aluminum frame so the top horizontal frame is touching the top of the door casing, while the vertical frame piece maintains contact against the hinge side and door stop. Once it’s tight in place, finger tighten the cam and engage the lever.  The frame should now be snug in the door frame with the vertical frame fully elongated along the hinge side of the door.

Setting Up the Blower Door Shroud on How to Perform a Blower Door Test on a Home

4
  Be sure to extend the vertical frame piece so the top frame piece stays in contact with the casing across the top.  Finger tighten the three remaining cams so the frame is snug along the entire inside door frame and the frame pieces are firm.  Disengage the lever on the cam lever along the hinge side and remove the frame from the door.

Setting Up the Blower Door Shroud on How to Perform a Blower Door Test on a Home

5
  Draw the remaining flaps over the frame and secure the shroud with the velcro straps.

Setting Up the Blower Door Shroud on How to Perform a Blower Door Test on a Home

6
  Extend the hose so the end of the hose is at least 4 feet to the left or right of the door opening.  Replace the aluminum frame in the door casing, snug along four sides and against the door stop.  Engage all four levers to ensure the frame is tightly installed

Setting Up the Blower Door Shroud on How to Perform a Blower Door Test on a Home

7
  Finger tighten the cam and engage the lever.  Make sure the velcro loop strap is in place.

Part 3
Installing the Fan and Setting Up the Manometer

Installing the Fan and Setting Up the Manometer on How to Perform a Blower Door Test on a Home

1
  Be sure that the hose exterior end stays at least 4 feet to the left or right of the door opening.

Installing the Fan and Setting Up the Manometer on How to Perform a Blower Door Test on a Home

2
Be sure to keep the fan side with the ring covers to the inside. Pull the velcro loop through the fan handle and tighten to raise the bottom of the fan off the ground.

Installing the Fan and Setting Up the Manometer on How to Perform a Blower Door Test on a Home

3
Attach the manometer to the velcro. 

Installing the Fan and Setting Up the Manometer on How to Perform a Blower Door Test on a Home

4
This is the channel A reference port. Connect the red hose to top right hose port labeled "Input".  This is the Channel B reference port.

Installing the Fan and Setting Up the Manometer on How to Perform a Blower Door Test on a Home

5
Connect the power to the fan.

Part 4
Setting up Manometer

Setting up Manometer on How to Perform a Blower Door Test on a Home

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Setting up Manometer on How to Perform a Blower Door Test on a Home

2

Setting up Manometer on How to Perform a Blower Door Test on a Home

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Setting up Manometer on How to Perform a Blower Door Test on a Home

4

Setting up Manometer on How to Perform a Blower Door Test on a Home

5
  Let the timer run for a minimum of 30 seconds before pushing "Enter".

Part 5
Performing the Depressurization Test

Performing the Depressurization Test on How to Perform a Blower Door Test on a Home

1

Performing the Depressurization Test on How to Perform a Blower Door Test on a Home

2
  Increase the flow until the number in channel A reads around -25pa.

Performing the Depressurization Test on How to Perform a Blower Door Test on a Home

3
  Also, any windows that may have been missed will be more easily noticed since air will be coming in. If all exterior openings are still closed, increase the fan speed until number in channel A (left channel) reads -50pa.  Depending on the outside conditions, this number may not be steady.  Any fan speed that fluctuates between -48pa and -52pa is acceptable.

Performing the Depressurization Test on How to Perform a Blower Door Test on a Home

4
This is the amount of air that must be continuously removed from the house to maintain a negative (vacuum) pressure in the house of 50 pascals (metric unit of pressure).

Performing the Depressurization Test on How to Perform a Blower Door Test on a Home

5
The test is complete.  The fan can be shut. The blower door equipment can be disassembled.

Performing the Depressurization Test on How to Perform a Blower Door Test on a Home

6
Multiply the [email protected] number read from the manometer during the test by 60. Divide that product by the volume of the home’s conditioned space to determine the ACH50.