All of us in the building energy industry know how essential our equipment is to our jobs. One small mistake can result in incorrect air tightness readings. To help energy raters receive consistent test measurements, here are three tips to ensure your air tightness tests are accurate every time.
Tip 1: Ensure the ring and fan selection matches the ring and fan you’re using for house tests.
When the ring and fan selection indicated on your digital pressure gauge does not match the ring and fan you’re using for a house test, it can result in inconsistent air tightness values for a house. If the flow value you receive is unusually high or low, it is best to look at the space you are testing as a whole, and compare the size of the house to the test you are performing. A rule of thumb is a moderately constructed house will have about 1 cubic feet per minute (CFM) of leakage per square foot. In other words, a house with 1,000 square feet of living space being tested will measure around 1,000 CFM.
Tip 2: Trim tubing each month for an airtight connection between the fan and gauge.
When you repeatedly attach and detach tubing from pressure taps, it can cause tiny tears at the end of the tubing. This results in air leakage at the connection and can lead to issues such as your digital pressure gauge showing Lo on a larger ring, while it can’t reach 50 CFM on a smaller ring. To prevent inaccurate readings, make sure there are no leaks in the tubing leading from the fan to the gauge or from the flow sensor of the fan to the gauge. Check your tubing on a monthly basis for leaks, and if needed, trim the ends of tubing to give it a clean connection. The simplest way to check tubing for leaks is to plug one end of the tube with your finger, and suck on the other end to see whether it sticks to your tongue. If it sticks to your tongue, the tubing is airtight. If it does not stick to your tongue, then it’s time for a trim.
Tip 3: Remember to add a pressure tube when switching from a depressurization test to a pressurization test.
Energy raters who typically perform house depressurization tests are familiar with the equipment this type of test requires. When an energy rater switches to a pressurization test, it is common to forget to add the extra pressure tube needed. Without this additional pressure tube, a pressurization test will show inaccurate readings. To ensure your air tightness tests are accurate, remember to add that additional pressure tube for pressurization tests. Energy raters can get assistance with connecting proper tubing for each type of air tightness test by using an advanced digital pressure gauge that guides them through the steps of a test.
The number one goal of energy raters is consistently accurate test results; however, we understand performing air tightness tests can be a complicated process. Using the three tips in this article will help you avoid the most common, preventable problems we hear from energy raters.
Frank Spevak is the Sales and Marketing Manager for The Energy Conservatory.