Important Code Information

Energy codes and associated building tightness requirements vary across the country. Building tightness is measured in ACH50, or Air Changes per Hour at 50 pascals of pressure. Depending on your state, the requirements could be as low at 3 ACH50 or as high as 7 ACH50, the latter allowing for a leakier home. When creating tighter energy efficient homes, it's also very important to consult your HVAC contractor about introducing fresh air to your system.

Additional State Specific IECC Code Information:

Blower Door Test

Blower door testing is a way to determine the "leakiness" of your home by depressurizing the building and measuring the rate at which air infiltrates through imperfections in the building envelope.

As part of this process, the house can be inspected further with additional tools to pinpoint potentially hidden air leaks (making it much easier to address them when the time comes to get to work). A blower door can also be used to test the effectiveness of improvements that have been made to a home, and to provide homeowners and contractors with a roadmap to further improve a home's efficiency. The blower door is also a key component of the AeroBarrier process.

Duct Blast Test

Duct leakage testing can determine exactly how much energy your home or building is losing through leaky ducts, and how much money you could save by sealing those ducts.

A duct blaster is a sophisticated piece of diagnostic equipment which connects to your home's duct system and measures the rate at which ducts leak air. The duct blaster looks much like a blower door, and is essentially a high-powered fan that connects to a computer, where diagnostic software measures rates of air infiltration. Using the results of the duct blaster test can help determine whether a home or building would benefit from a duct sealing upgrade, and to what extent.

Thermal Imaging

We offer infrared thermal imaging throughout the region, both as part of our comprehensive home energy audit and as a stand-alone service designed to pinpoint energy waste and other building science issues.

Having your home evaluated with an infrared scanner sheds valuable light on the effectiveness of your home's thermal envelope. An infrared scanner reveals hidden air leaks and areas where insulation isn't performing, and can also yield some interesting surprises -- such as where an uninsulated hot water pipe or recessed lights may be contributing to an ice dam, for an example. It's a valuable part of any good home energy audit, and a step that we guarantee to take with thoroughness and precision.

Energy Testing FAQs

What is a blower door used for?

According to, "A blower door is a powerful fan that a trained energy professional temporarily mounts into the frame of an exterior doorway in your home. After calibrating the device, the fan pulls air out of the house, lowering the air pressure inside. The higher outside air pressure then flows in through all unsealed gaps, cracks and openings such as gaps, cracks, or wiring penetrations. If conditions do not allow for lowering the pressure in the home, the fan may also be operated in reverse, with air pressure increased inside the home." For more, click here.

How can I test my home for air tightness?

The Blower Door diagnostics tool is used throughout the building and construction industry to measure the air tightness of a building. This system includes a calibrated fan that provides either positive or negative pressure on the building. A manometer is connected to the fan and provides a pressure readout that is converted to you ACH50 (Air changes per hour at 50 pascals.)

What is ACH50, and What is a good ACH50?

ACH50 is the abbreviation for air changes per hour at 50 pascals (Pa) pressure differential. This is the most common metric used to determine the air tightness and energy efficiency of a home. It represents that total number of times the full volume of air inside a building can be sucked out (or pushed out) of the house at 50 pascals of pressure. In most climates zones where we install AeroBarrier, a decent ACH50 is between 3.0 and 5.0 with the lower number representing a tighter envelope. We often seal below 3.0 for our customers that want greatly improved efficiency. Once you get to 0.6 ACH50, you have reached Passive House certification levels that represent truly remarkable energy efficiency.

How much does a Blower Door cost?

A Blower Door test can be as little as $165 and up to $1,000 or more. It all depends on how much sealing is required to hit the target ACH50. At Green South Energy Solutions, we offer several options to achieve low ACH50 numbers. This can include manual sealing measures with can foam and caulk. We also offer AeroBarrier air seal technology services. AeroBarrier is a computer controlled air sealing process that can achieve any desired ACH50, even Passive House standards below .06 ACH50.

What is a duct blaster?

According to the Energy Conservatory, "A Duct Blaster is used to directly pressure test the duct system for air leaks, much the same way a plumber pressure tests water pipes for leaks. The Duct Blaster fan is first connected to the duct system at the air handler cabinet, or a return grill. After temporarily sealing all remaining registers and grills, the Duct Blaster fan is turned on to force air through all. Two different types of performance testing systems are used to measure duct leakage; a Duct Blaster® and a Blower Door.holes and cracks in the ductwork. The fan speed is increased until a standard test pressure is achieved in the duct system. A precise leakage measurement is then made using an airflow and pressure gauge connected to the Duct Blaster system. Estimates of efficiency losses from duct leakage can then be made from the leakage measurements. A theatrical fog machine can be used along with the Duct Blaster to inject a non-toxic fog into the duct system to visually demonstrate the location and extent of leakage in the ductwork. For more from the Energy Conservatory click here.

How much does a duct blaster pressure test cost?

When duct blast testing a home, each HVAC system must be tested independently. You can expect to pay between $200 and $300 for your first HVAC system, with additional systems on the same property costing a bit less when tested during the same mobilization.