Any home inspector that goes along with 40% loss is an acceptable efficiency loss standard and an open air duct connection is okay, is just perpetuating this problem.
Exactly what is your argument?
Your pointing out that this air leakage is a significant energy concern but then say you wouldn’t hang a big red flag on it as it is insignificant or acceptable?
Exactly what direction are you going with this and maybe we’ll have less disagreement.
Your introduction of minimal information from several different viewpoints at the same time is only clouding the conversation. There are no specific facts, just opinions from different sources.
You say that you can’t measure the pressure difference when an open duct system exists. You can measure it, how can you argue this? You can use a micro-manometer to detect air flow through the dirt below a concrete slab sitting underneath a three-story building! If you find that you can’t measure it, it’s because a pressure differential doesn’t exist because of excessive air leakage from an improperly sealed attic space.
Seeing as the air in the attic space is not being properly conditioned due to improper design, “unconditioned air” is being introduced into the living space of the house just as you describe.
Again, we are talking about theory not specific facts (because there are none).
Maybe you’re focusing on the use of the new “conditioned attic space” scenario. Again, it’s being used, it has a standard, but in many cases is employing substandard workmanship and theory in the process.
[size=2]Dumping supply air into the attic, or drawing attic air throughout the return of his not appropriate system design.
I don’t know where this thread is leading because we do not have any specific facts from the initial question.
The laws of thermal dynamics, as you know are quite specific and do not vary under different circumstances. The circumstances may vary, but the laws do not.
I guess that it doesn’t really matter what is actually going on at this house because it is an evaluation way beyond what a home inspector is expected to achieve. However, I think that it is prudent for a home inspector to call out a situation such as this (whether they understand it or not).
I’m not arguing that these conditions do not exist almost everywhere. I am not saying that these conditions adversely affect the building in every case. But to flat out say that it’s unimportant is not appropriate. We don’t know the circumstances or the test conditions and in no way can make this statement.
I pointed out several situations that could be adversely affected from air leakage in the ducts (regardless of where it exists or how it is designed). We don’t know if these situations exist or to what proportion, but to blow it all off because we can’t prove it otherwise is unwise.
Several alleged explanations as to what this connection is was brought up, and under each scenario there is adverse potential.
We don’t have to make the analysis and provide the facts but we should not underestimate the potential.
[/size]