There is a formula for calculating heating Btu and a formula for calculating cooling Btu. Both of these formulas have three components necessary to complete the calculations. Two of the Btu formula components are field measured while the third is a multiplier that is added at the end of the formula.
A couple of months ago, I addressed the topic of how proper HVAC system design could not guarantee the installed performance of a system. Since that article, I have received a number of emails requesting I go into further detail about the measurements I mentioned and how to verify the installed performance of a system.
Have you ever noticed dirt streaking out of the sides of any of the supply vents on the HVAC systems you service? Dirt streaking on supply vents is a common problem HVAC professionals encounter on a daily basis.
Taking a few minutes to investigate your component selection on the airside can help point out if that default duct design has the potential to work or if it is doomed from the start.
One of the primary measurements customers use to gauge comfort is the room temperature shown on the thermostat. If the number falls within an acceptable temperature range, the individual should be comfortable, right? Not quite. Could there be other factors at play here that are influencing their comfort that you might be missing?
The revelation that many of these rules of thumb can get you into trouble, and also the need to comply with new code revisions, is accelerating the move toward using design software to meet industry standards.
Once the realization is made that the HVAC equipment is a component of the HVAC system and not the HVAC system itself, a contractor and homeowner can start to address the real issues.
These temperature-related issues are often corrected simply by renovating the duct system to cure duct leakage and air-balancing issues, which created pressure-related problems in the building. There are instances, though, when you can have the perfectly designed and installed HVAC system and these temperature complaints still exist.