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Another thing about the utility point of view, is usually a cut in residential demand (peak KW) goes hand in hand with a cut in energy (KWH). Since most utility tariffs are based simply on KWH, they...

I also recently bought the Allegiance 15 unit, with matching coil when the old system's coil developed a leak. The unit I have is quiet, without the clunk sounds you mention. At least I have not...

The original paper sure seemed to say 86 CFM was the average duct leakage for the Houston area homes. Houston homes built in the last decade are not small, and it could be reasonably estimated the...

Thank you Genduct, for pointing out how things have evolved.

Best wishes -- Pstu

The attachment is a scanned page from ACCA Manual D. That is a direct answer to your question. Copyright 2002, page 3-6. I believe there is a later version of this book.

It sounds as if your...

If your arithmetic is correct, 1000 fpm is way higher than ACCA Manual D says is acceptable. My copy of Manual D says 700 fpm is maximum.

Not many people get static pressure checked on their...

I am bedazzled by the things you are discussing which are not even in my vocabulary. I have the intuitive hunch you might find something practical in this paper of Lstiburek's, if you have not...

Wish Carnak were still around, he probably would have an example house he worked on, in a comparable climate.

I am a homeowner west of Houston TX. A question was asked about solar screens. Based on personal experience, solar screens can make a big difference in room comfort, so I believe they would be a...

I think your air temperature inside the supply ducts may be a lot different from what you are expecting. AC will typically output air about 20 degrees below the supply air, which implies duct air...

This is twice you have mentioned dew point in the 75-77F area. No pro has said dew point needs to be that high to cause trouble. The temperature mentioned was 60, is it possible your dew point could...

Note that they spend several dense sentences acknowledging the oddity of their result, and then going further to claim duct leakage of 86 CFM25.

There had to have been some actual testing via...

If you look on page 44 of the Adobe document (labelled page 39) there is a paragraph which addresses their statement of duct leakage. I interpret it as consultant bafflegab and wonder if you might...

A company named Tamarack Technologies used to have a paper titled "The Problem of Pressure". While oriented toward product sales, it had some valuable info including answers to your question. It...

Houston is pretty much the "Wild West" of home construction. Only a few Municipalities have rules regarding duct leakage, e.g. Katy which is outside the survey area. In most regions builders...

While they do say what you quoted, the one I was dwelling on said "Building envelope leakage appears to be responsible for about 14 percent of summer/cooling loads while duct leakage only appears to...

The source of the 3% number is from this study:

http://www.advancedenergy.org/buildings/knowledge_library/FINAL_Paper_Houston_Energy_Efficiency_Study.pdf

Right there on page 3 it makes this...

Cherokee reports some very surprising observations. There ought to be a VERY publishable paper that could result from a 3rd party visiting the house, repeating the observation, and making enough...

For construction in the last decade, Houston region, does it seem plausible to professionals that duct leakage would account for 3% of cooling loads? I always thought average duct leakage was higher,...

Thanks for sharing that, it is far more accurate than my memory was.

I think your arithmetic is right, you could get down to approximately that natural ACH if you could halve your leakage area....

We still may not be communicating properly. Your number of 8.4 ACH50 is only about 50% higher than mine, it is an entirely plausible number. I have heard that a crude way to estimate natural ACH is...

My own house was tested at 5.3 ACH50 and it is not an energy hog. 3317 CFM at 50 pascals. Fairly well sealed but not exceptional. The blower door report also told me "estimated annual average air...

It seems to me the proposed T-ed return has many characteristics in common with a jump duct, is that not right?

If the addition is well sealed, I certainly would be interested in learning what the...

It sounds like you believe the lack of clamps caused the problem, and the original company claims the old drain line caused it. Get an expert opinion on that, and you may be closer to settling the...

You are completely not seeing the downside of getting it wrong. "It" refers to a wide variety of possible errors. Try it and you will eventually see what I mean.

This reminds me of a car with a...