About Blower Doors.

What is a blower door, how is it used, and what kind of
information is available on the Web? Everything you always
wanted to know. Call (540) 943-2776 weekdays 7AM-4PM EDT for assistance.

What is a blower door?

A blower door is a large calibrated fan that is temporarily mounted in a house door to measure the "leakiness" of the house and to assist in finding the location of the leaks. Modern blower doors have variable speed fans so that the pressure in the house can be adjusted, and they also have door mounting frames so that the fan can be sealed tightly into the door jamb. In order to measure the leakiness of the house, the blower door measures both the air flow through the fan and the pressure difference between the house inside and outside.

What does a blower door look like?

Why should you care about air leakage in houses?

Everyone knows that air leakage can cause uncomfortable drafts in houses, but energy researchers have discovered that sealing air leaks is one of the simplest and least expensive way to save energy in homes. A typical house may lose about 1/3 of its heat through walls and ceilings, 1/3 through windows and doors, and 1/3 through air leakage. A few hours of air sealing with inexpensive sealants can often reduce the air leakage by about 1/4 to 1/2, resulting in a saving of 10% to 20% of the total house heating and cooling bill. Each house has different amounts and types of air leakage, and the most efficient technique is to spend the most time sealing the leakiest houses. Duct leakage is probably the worst type of house air leak. Therefore, you need a tool that can quickly identify the leaky houses and show you where the leaks are.

How can you use a blower door?

Air leaks can be simple and inexpensive to seal if you can just find them, and that is where the blower door comes in. First you use the blower door to measure the air leakage and see how the house rates on a scale of "leaky" to "tight". If it is already tight, then you can forget about air sealing and look at other ways to save energy. But if it is too leaky, then the blower door can tell you how bad it is and then it can help you to find the location of the leaks. After you seal the leaks, the blower door can tell you how well you have done.

rainbow line

Some Articles About Blower Doors on the Web:

-Since these articles are not on the Infiltec pages, you must press BACK to return to the Infiltec pages once you have read the article.

Please send link problems & suggestions to Infiltec

Introduction to Blower Doors by David Keefe from Jan/Feb 1994 Home Energy Magazine. "Now a widely used diagnostic tool, blower doors have revolutionized the way most professionals approach retrofit work. This introduction explains how blower doors work, what can be gained from their use, and what a typical blower door test involves."
When is a house too tight? by George Tsongas from Mar/Apr 1993 Home Energy Magazine. "When it comes to weatherization, what's good in Arkansas may be bad in Maine. New guidelines will help blower door users tailor air tightness levels to the house and its setting--preserving air quality and energy savings."
Infiltration: Just ACH50 Divided by 20? from Jan/Feb 1994 Home Energy Magazine. "This Home Energy classic, originally printed in 1986, explains a simple way to take one air infiltration measurement and determine a home's average air infiltration rate."
Diagnosing Ducts from Sep/Oct 1993 Home Energy Magazine
The History of the Blower Door by Abba Anderson, from the November/December 1995Home Energy Magazine: "Perhaps no piece of equipment has changed the way energy professionals look at buildings more than the blower door. Over the past 15 years, entire diagnostic procedures have evolved around this relatively simple device that can make subtle, but measurable, changes in house pressures.
Air Sealing in Occupied Homes by David Keefe, from the November/December 1995Home Energy Magazine: "Over the last decade, many new techniques have evolved for improving the airtightness of existing homes. With this increased ability has come the responsibility to be comprehensive."
User-Friendly Pressure Diagnostics by Fitzgerald, et al from the Aug/Sept 1994 Home Energy Magazine: "Here is an easy-to-understand explanation of pressure diagnostics. The "user friendly" approach focuses on measuring pressures rather than just leakage to help you quickly determine which weatherization treatments a home needs. Know what you're measuring before you start work."
To Russia With Blower Doors by David Saum et al, from the Sept/Oct 1995 Home Energy Magazine: "Russia may soon be the scene of one of the world's largest building energy retrofit projects, designed by the Russian government with support from the World Bank and other agencies."
Urethane Foams and Air Leakage Control by Bob Braun, et al, from the July/August 1995 Home Energy Magazine: "Urethane foams can be a key component in a continuous, high performing air barrier and have high R-values when used as insulation."
Accuracy of Home Energy Rating Systems by Jeff Ross Stein. An LBL report: Actual residential energy bills were compared to estimated energy use and energy costs for four Home Energy Rating Systems (HERS).
Perry Bigelow: Energy Efficiency Maestro from Mar/Apr 1994 Home Energy Magazine
Evaluating Ventilation in Multi-Family Buildings from Jul/Aug 1994 Home Energy Magazine.
The Use of Blower-Door Data by Max Sherman from Lawrence Berkeley National Laboratory. This is a technical paper.
Creating Quality in New Construction: A Practitioner's Perspective by Michael Uniacke. from Jan 1996 Home Energy Magazine: "Twenty-five years after the first energy crisis, most newly constructed homes still lack the most basic energy conservation details."
Mechanical Ventilation for the Home by Don Stevens from the March/April 1996 Home Energy Magazine: "A ventilation system gives occupants control over a home's air change rate and thermal comfort. This article discusses the options available today for good mechanical ventilation."
Sick Houses: Using Diagnostic Tools to Improve Indoor Air Quality" by Scott Finley from the July 1997 Home Energy Magazine: "Sick building syndrome" is caused by everything from dangerous molds to meteorological occurrences. Improving the indoor air quality of these buildings calls for careful diagnostics and even more careful removal of and repairs to problem areas. Scott Finley of Energy Options Northwest describes how these repairs can be done and how to use diagnostic tools to find the sources of the problems."
Bigger is Not Better: Sizing Air Conditioners Properly by Proctor et al from the May 1995 Home Energy Magazine: "It is generally accepted that "the right way" to specify an air conditioning system is to calculate the loads and select a piece of equipment that will provide comfort to the customer in a wide variety of conditions. Unfortunately this is rarely practiced."
Sizing Air Conditioners: If Bigger Is Not Better, What Is? by John Proctor and Peggy Albright from the Sept/Oct 1996 Home Energy Magazine: "In this follow-up to the original "Bigger Is Not Better" article, Proctor Engineering Group offers ways to improve comfort, reduce noise, and increase efficiency when installing home air conditioners."
Black Stains in Houses: Soot, Dust, or Ghosts? by Frank Vigil from the July 1997 Home Energy Magazine: "Builders are never more surprised than when they walk into one of their newly built model homes and find black stains at wall-to-floor joints and on previously pristine carpeting underneath doorways. What causes these stains and how can builders and homeowners prevent them?"
Combustion Safety Checks: How Not to Kill Your Clients by Rob deKieffer from the March/April 1995 Home Energy Magazine: " People who manage or work within programs that provide any significant service inside a building need to be familiar with the basics of combustion and combustion safety."
Beauty and the Beast Upstairs by David Connelly Legg from the March/April 1995 Home Energy Magazine: "The same features that are often added to the top story of homes to give them distinctive architectural beauty can also make them rather beastly to heat or retrofit. One-and-a-half-story houses, like the Cape Cod-style found in New England, are typical of those that pose tricky insulation and air sealing problems."
Air Sealing in Low-Rise Buildings by Victoria Hayes from the September/October 1995 Home Energy Magazine: "Reinforcing the pressure barrier in low-rise multifamily buildings can increase occupants' comfort and savings."

Other Blower Door Related Information on Infiltec Web Pages:

Infiltec Blower Door Catalog
Infiltec Blower Door FAQ (frequently asked questions).
Large Building Airtightness Testing
About Duct Leakage
Fire Protection Enclosure Integrity Testing
To Russia with Blower Doors (article on Russian energy retrofit project).
Favorite Web and Net Links

For further assistance, call (540) 943-2776 weekdays from 7 AM to 4 PM EDT, or email: Infiltec Factory .
rainbow line

Return to
the Infiltec
Home Page.