Home Energy Assessment

Pass The Blower Door Test First Time

If you are constructing a home, Section 402.4.1.2 of the Florida Building Code 5th Edition 2014 Energy Conservation Now requires the property to undergo – and pass – blower door testing. This test seeks to ascertain the air infiltration of a building, a key contributor to energy efficiency. To pass the blower door test the first time, it is important to ascertain what the test is actually for.

What is a blower door test?

A blower door test involves:

  • A powerful fan is mounted at an exterior door to the property.
  • This fan is used to withdraw the air from the property.
  • This lowers the air internal air pressure significantly.
  • The external air pressure then flows through cracks, holes, and other openings in the home.
  • A measurement of the air infiltration of the building is then taken by a manometer.
  • If this measurement is satisfactory, the test is passed.
  • If not, leaks must be identified and rectified. A smoke pencil is sometimes used to assist in the identification of gaps and openings that are contributing to air infiltration issues.

What constitutes a ‘pass’ on the blower door test?

The 2015 International Energy Conservation Code (IECC) advises the following:

  • Residential buildings: a maximum of 3 ACH50 (air changes per hour at -50 Pascal) .
  • Commercial buildings: a maximum .40 CFM/square foot of envelope are at -75 Pascal.

When can a blower door test take place?

A blower door test should take place before construction is finalized, but when the following elements are installed:

  • Doors and windows (including hardware and weatherstripping).
  • Door thresholds.
  • Hatches to unconditioned attics.
  • Hatches to unconditioned crawl spaces.
  • Dampers.
  • Fireplace doors.
  • Light fixtures.Plate covers.

It is also advisable to conduct a blower door test when:

  • Hatches to unconditioned attics and/or crawl spaces have been gasketed.
  • Plumbing traps have been filled.
  • Conduits that lead outside have been sealed.
  • Work is complete on air handlers and all ductwork.

It may also be beneficial to inspect the property and fix any holes, gaps, cracks, or openings that are visible to the naked eye. Managing these issues should help you to ensure you pass the blower door test first time.

How should a property be configured during the test?

There is a specific section of the IECC that dictates how a house should be set up for the blower door test. This includes:

  • Exterior windows and doors should be closed.
  • Fireplace and stove doors should be closed.
  • Exhaust, intake, backdraft, and flue dampers should be closed.
  • Interior doors are left open.
  • Exterior openings for ventilation systems should be closed and sealed.
  • Heating and cooling systems should not be operational during the test.
  • HVAC supply and return registers cannot be sealed.

The professional conducting the test will usually check these elements prior to commencing.

How can you pass the blower door test the first time?

  • Only work with qualified, experienced builders that are aware of the need to work to the standards required to pass the test.
  • Conduct the blower door test at the right time, when the elements mentioned in section two are in place.
  • Perform both an internal and external inspection of the property to identify any gaps or openings, and fill anything you find.

In conclusion

Passing the door blower test first time is not an exact science, but with diligence during construction and careful inspection for gaps and openings, you will give yourself the best possible chance.

Blower door test

Does Your Home Need A Blower Door Test? Let’s Find Out

It’s well known that as homes age, and settle drafts and leaks can start to grow. These will typically cost you a lot of money. You’ll need to spend more to keep your home heated, particularly if warm air is escaping and cold air is blowing through. This issue can also occur if a construction project alters the envelope of a property.

The good news is that there is a solution. You can think about getting a blower door test. What is a blower door test exactly? A blower door test will find the leaks causing those drafts. Once you have located, them, you can seal them up, reduce the costs and generally improve your home.

What Does A Blow Door Test Involve?

Well, the process is quite clever. Using a box in front of your door, you change the air pressure of the home. It simulates a windy atmosphere that highlights air blowing through your home caused by leaks.

You shouldn’t try and find the leaks yourself. Instead, an expert will find them for you by checking out your home. Usually, they’ll be looking for tiny cracks that air will be blowing through to fill the vacuum caused by the test.

Why Do You Need One?

By sealing the drafts, you can tighten the home envelope. That allows you to trap more heat inside the property. It can also provide some info on the level of air quality in your home. You’ll be able to find out how much ventilation you need to keep air quality levels high.

Of course, these drafts can trigger more issues than just heat loss. Through a blower air test, you might discover that you have issues with moisture. Problems like this can be harmful to your health.

Owners with homes that are ten years old or more should definitely have a blower door test. These homes are the most likely to have the drafts we’re talking about.

Signs And Common Places To Search

There is a range of different places around the home where leaks are commonly found. These include:

  • Old windows
  • Old doors and frames
  • Areas where you have completed construction work
  • Switchplates

It can be difficult to tell if your home has leaked. But there are signs.

Cobwebs and pests are common with leaks because insects and beasties can enter through them into your home. Of course, you’ll also notice a drop in the temperature around these areas and maybe even a light breeze.

Is There Any Reason I Can’t Have A Blower Door Test?

There are three main reasons why you can’t have a blower door test:

  • Asbestos or mold – A blower door test will literally blow this into the air of your home and could cause health problems
  • Recently Used Fireplaces – Fireplaces cannot be used twenty-four hours before the blower door test in case a spark is pulled into the air causing danger of a fire.
  • Open Construction – This will impact the results of the test, mainly if the project is unsealed.


With a blower door test, you can save money, improve your home and get rid of some nasty problems. It’s a highly recommended solution, particularly for older homes.


air blower door test

What is a Air Blower Test

An air blower door test is conducted by an energy auditor to see how airtight a home is. The test is performed for several reasons, which are listed below.

  • Reducing air leakage to improve energy usage
  • Eliminating condensation buildup
  • Determining the location of drafts
  • Seeing how much more ventilation is needed for higher interior air quality

How It Works

To perform the test, the auditor will install a fan in an exterior door frame. The fan will draw air outside the house, which lowers the interior air pressure. The outside air will then enter the home through all openings and cracks. A tool called a smoke pencil is used by the auditor to find those leaks and discover how air infiltrates the home or building.

A blower door is a panel and frame designed to fit inside of a doorway flexibly. The fan runs at several different speeds, and a special gauge measures the pressure differential of the home. There are also hoses and an airflow manometer.

Blower doors come in two types, uncalibrated and calibrated. The uncalibrated type is largely ineffective because it can only help find leaks. It does not provide any data on how airtight structure is. An auditor should always use a calibrated blower door because it will accurately determine the amount of air that the fan is removing. This information will help the auditor see the leakage amount and how well air-sealing solutions are working.

Blower Test Preparation

The following steps should be taken prior to an air blower test:

  • All wood-fueled fires should be put out, including the coals, before the test can be conducted. All ash should be removed from each fireplace.
  • The homeowner should be prepared to walk through the house and show the auditor all of the locations that have drafts or are difficult to heat and cool effectively.
  • The homeowner should be prepared to grant access to the entire home, including empty rooms, attics, closets and crawl spaces.
  • Before the test, the auditor will close exterior windows and shut all of the exterior doors. The interior doors will be opened and all woodstove inlets and fireplace dampers will put in the closed position.
  • The auditor will set all thermostats to ensure that furnaces and other appliances that rely on fossil fuels do not come on while the test is being run. When testing ends, they should be returned to their original settings.
  • The test will take at least one hour. Larger and more complex homes could take longer.