Blower Door Test

What is a Blower Door Test?

Perhaps you’ve come across the term “blower door” or “blower door test” on our website or elsewhere during the course of your research on energy efficiency and homes. You understand it’s an important part of the process for testing the energy efficiency of buildings, but what is it exactly, and how does it work? 

How Weathertight is Your Home?

One of the biggest factors for energy efficiency in buildings— if not the single largest factor— is how weathertight your home is. For our purposes this means how much air can get into or escape your home from and to the outside. 

The more air able to enter your home the less weathertight your home is, and consequently, the less energy efficient. This inefficiency adds up to money lost over time for your family due to increased heating and cooling bills, in some cases thousands of dollars.  

Think of your home like a boat in the ocean. If there is a leak in the boat, even if it’s a small one, over time the boat will fill up with water and the sailors will have to expend energy bailing out the ship. 

Your house is the same. Over time, if outside air enters your home slowly but consistently your furnace, boiler, or air conditioner must work harder to keep your home at the temperature you want it. The harder your heating and cooling appliances have to work, the more money it costs you. 

A blower door test is the best tool in our toolbox to gauge how much air is entering and exiting your home, down to square inches. 

The Blower Door Test

At the most basic level, the blower door test uses a large fan attached to an exterior door opening to create an area of low pressure in the home, which then allows us to see where and how much outside air is getting inside. 

In practical terms, during the course of one of our free home energy audits, a technician may place a specialized curtain with a fan attached to a computer over your front or back door. 

By using a fan to blow air from inside the home to outside, pressure drops inside the home. As the universe is constantly trying to even itself out, air from ambient atmospheric pressure on the outside will rush into the house any place it can. 

These are gaps we’re looking for. By walking through the house and using an infrared scope, the technician can then determine where this outside air is getting inside.  

In addition, with a specialized computer attached to the fan, we can also determine exactly how much air is entering the home and can then cross check this with local building codes and national guidelines to see where your house falls on a scale of energy efficiency and if improvement is required. 

In some cases the results are stunning. This test is measured in square inches, so for example a house that is allowing 40 square inches of air into the home— not uncommon— is like having a 10” by 4” inch window open all winter long. 

You wouldn’t keep a window open like this, so why suffer many smaller openings that add up to the exact same thing?  

The Results

The test is 100 percent safe for your home, is in no way dirty or particularly disruptive, and will not cause any marks or scuffs on any place in your house. Our technicians are highly trained, experienced and friendly.  

Once the blower door test is complete, along with the rest of our energy efficiency tests, the technician will show you the results. Based on the results we can make suggestions for areas of improvement and where to spend your home improvement dollars for maximum effectiveness. 

Improvement areas can include things like adding insulation, getting new air-tight and efficient windows and doors, or adding weather sealing like foam and other products. Please see our website for a detailed overview of our offerings. 

Our tests are always 100 percent free, contain no obligations to buy anything, and are no pressure. We perform these tests in the hopes you’ll choose us when it’s time to add efficiency to your home. 

Give us a call today to schedule your free home test and be on your way to saving money through energy efficiency.