Blower Door - Air tight test
NORDICA-VILLAN - GENERAL DISTRIBUTOR FOR POLAND
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.
How long does it take to do a blower door test?
It takes about 15 minutes to set up the blower door, and about 5 minutes to run a simple blower door test. So you can see that driving back and forth to the house will generally take much longer than the actual test. It takes only seconds to bring up the pressure in the house. Most tests take longer because the tester generally explains the test to the occupant. (It takes a LOT longer if the occupant is an engineer!) And after the test, you can spend a lot of time investigating just where the leaks are in the house.
Can a blower door test damage a house?
It is very unlikely that the pressures from a blower door test will damage a house. The typical test pressure is about 50 Pascals in metric pressure units, or 0.20 inches of water in US units. This is the pressure you feel when you are under a swimming pool by only 0.20 inches. It is the same pressure you feel when a 20 mile per hour wind is blowing in your face. So you can compare a blower door test to having a 20 mph wind blowing on all sides of the building. If the building is fragile enough to be damaged by this pressure it would already have been damaged by the last high wind. The most common type of damage caused by blower door tests is pulling ashes out of a fireplace or stove. ALWAYS check to see if ashes are present before a test, and place a weighted newspaper over them if they are present. In the winter it is VERY IMPORTANT turn off any combustion fired furnaces or fireplaces during the test. It is very rare to have the blower door tests blow out pilot lights in furnaces or water heaters so we do not generally worry about them.
What is the difference between the blower door models?
There are 4 models: