Description of different tests:

1) How air tight is my house? 

    (Basic blower door test)

 

 

 

 

 

 

 

 

• Basic air leakage (CFM50)  This is a measurement of how many cubic feet per minute (cfm) of air is leaking into a house when the house is depressurized at 50 Pa.
• Air leakage goal (ASHRAE 62-89)  This is the next step beyond the basic pressure test. This test is a way to compare one house with another using .35 air changes per hour to guarantee good indoor air quality.  This is the test that determines the answer to the question, "Is my house too tight?"
  

 

 

 

 

 

 

 

 

2) Why are some of my rooms colder than others?

    (Register and Room pressure testing)   

Rooms are cold for two basic reasons: 1) there isn't enough heat being delivered to the room or 2) the room cannot hold the heat.  The first is a mechanical distribution issue.  The second is an air sealing/insulation issue.  The blower door tests listed on this page help identify why a problem occurs.   

Any home using forced air for heating or cooling relies on the conditioned air to be blown through ductwork to rooms.  In all cases air must return to the heater completing a loop.  If air is not allowed to flow to the return registers, then some rooms stay over-pressurized while other rooms will be depressurized. Room pressure testing is done with rooms closed and with the furnace or air conditioning blower turned on.

 

 

 

 

 

 

 

 

3) Are the heating/cooling ducts connected to the outside?  (Pressure pan test)
Most modern homes are built with ductwork.  Unfortunately, ducts are usually not air sealed and lose air (supply duct) to the outside as well as suck air (return ducts) from the outside.  Pressure testing in each room can quickly show which ducts are connected more to the outside than the inside.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

4) Is the house connected to adjoining spaces? 
    (Zonal testing - advanced test) 
Unheated spaces such as garages, attics, and enclosed porches are often built directly next to the conditioned (heated and cooled) home.  These zones often leak air back and forth through gaps in the framing.  These gaps vary in size from tiny cracks to holes large enough to walk through.  Pressure can be tested across the house boundary to any of these spaces.  The accepted pressure limit across the boundary is 5% to 10% of the 50 Pa depressurization or 2.5 - 5 Pa.  This is also true of the duct zone testing listed above.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

5) Will my heater back draft poisonous gases? 

    (Heater zone testing  - part of heater work)
Modern high-efficiency heating equipment no longer uses air from the house to feed the combustion air going up the chimney.  This "closed" combustion equipment draws the combustion air from the outside. All other equipment draws air from the house.   This is potentially a problem in tighter homes, because negative pressure inside the house from exhaust fans such as the clothes dryer, plus the kitchen, and bathroom fans can literally suck air down the chimney and poison the occupants.  Pressure testing the zone around the heater and hot water heater compares the draft of the chimney to any negative pressure created in the house.

 

 

 

 

 

 

 

 

 

 

 

Infrared camera (below) is an excellent tool that can be used with the blower door fan to identify air leakage and breaks in insulation.

Health and Safety Problems:

Energy Auditing routinely finds health and safety as well as energy and durability issues.  Here is one example:

Photo #1 shows a typical ranch-styled home that has a garage tucked under as part of the basement.  Great, except for the fact that the heating ducts travel through the garage to get to two bedrooms. 



The heating problem is heat loss into the garage.  The safety issue is the potential of pulling deadly carbon monoxide from the car (not to mention pesticides, oil, gasoline, etc.) into the house through the return duct system.  The solution was to air seal and insulate both the supply and return ducts.

 

Photo #2 shows the "pressure pan" instrument that works with the pressure guage to determine which ducts are leaking air to or drawing air from the garage. This creates both a heating and safety issue. 

More Problems

 

Photo at Right - It’s good to understand the "total moisture picture" before spending a lot on basement drainage or other moisture remediation systems. 

Where is the water coming from and can you effectively change it?  While we can point you in the right direction, US Green Home recommends a moisture inspection that uses state-of-the-art testing meters to create a moisture “profile” to pin point the source of your problem.  Only then can you consider what the best remediation steps are.

 

 

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