pheww! Energy Star testing passed!

Steve Klocke, of Steven Winters came to the site on Friday to test Trout House for our Energy Star certification, and after a very long day, and a very patient Steve, We Passed!  The day entailed blower door testing, kitchen and bathroom exhaust testing, carbon monoxide testing of stoves and boilers, HVAC verification, lighting inspection, and thermal bypass inspection.  Phew. and we flew through with flying colors with a small exception - the bathroom exhaust...which required a little tinkering, but more on that later.

a whole lot of equipment came with Steve to conduct the tests.

A blower door test has to be performed for each individual unit, a requirement for the Energy Star certification.  This is testing the air tightness achieved during construction.  and while we were vigilant throughout the construction process, ensuring our wall assembly, and penetrations met our air sealing requirements, it is still a little nerve-racking waiting to know the results.  The blower door test is conducted using a powerful fan that mounts into the frame of an exterior door, or apartment door. The fan pulls air out of the unit, lowering the air pressure inside. The higher outside air pressure then flows in through all unsealed cracks and openings. A metering device then measures the pressure differential. Blower Door tests are typically performed at a pressure difference of 50 Pa.  Before the testing starting, we taped off the vents, and closed the windows tight.

Steve setting up the blower door test in the door frame to the apartment unit.

this is the fan that de-pressurizes the apartment interior.

air pressure gauge showing a reading of 468.

The gauge above shows a reading of 468CFM at 50Pa, and a target of 756CFM.  Air tightness is typically measured in ACH (air changes per hour). For Energy Star V3.0 the target is 4ACH and V2.5 is 5ACH and Passive Haus is .6ACH.  Trout House units were at about 2.48ACH (calcuate CFM*60/volume).  So we easily beat the Energy Star requirements. (but are 4x above the strict Passive Haus goals)

Next was the vent testing for the kitchens and bathrooms.  The diagnostic testing requires an exhaust fan flow meter - that basically looks like a big plastic tub with a hole in it - to be held up to the fan and test the CFM.  Our kitchen ducts were perfect performing at 300CFM.  But one thing to note - Energy Star V3.0 will require much quieter fans than earlier versions (2 sones).  This is to encourage their use, since loud fans tend to be annoying, but limits the options available.

But the problem arose when we tested the bathroom fans - coming in at a very low 5CFM, when we really needed 40CFM.  With such tight construction, we rely on the mechanical ventilation to bring in fresh air continuously.  The testing helped to reveal that the exhaust fan had been sized too small, and needed to be much larger.  Before the end of the day, the GC was able to install a 600CFM rooftop fan, that then helped us reach our target of xx CFM in each unit. Phew and a big thanks to Jimmy and Tommy. But goes to show that the testing is extremely helpful in revealing what is working and what is not working in the mechanical system - very important when constructing these types of very tight houses.

graph on the exhaust fan flow meter that correlates the flow to pressure

pretty cool that Steven does not need a ladder to reach the ceiling vents.

gas leakage testing

The last test focused on the potential gas leakage of the stoves.  Each stove was fired up for the first time, and tested for gas detection, to ensure that combustion is complete.  Steve places a probe into the stove exhaust after the oven reaches about 450degrees for a stable temperature.  An interesting thing to note - our higher end stoves by Bertrozzoni  actually did not test as well as the less expensive mid-range stoves by Frigidaire.