Tired of climbing ladders and reaching to find air leaks during blower door test I have a solution!!!

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Permalink Reply by Bob Kretvix on September 27, 2012 at 7:30am

Can you explain how you would use the thermoanemometer and your criteria for air flow to determine excessive leakage?  Besides, doesn't the anemometer measure just velocity (fpm) not volume of air (cfm) unless you know the ft2 area of the opening?  Unless its leakage through a regularly shaped opening, like a wall outlet hole, how do you estimate the area of a crack, for example, to determine cfm?

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Permalink Reply by Cory Chovanec on September 27, 2012 at 6:10pm

You haven't convinced us yet. To my knowledge there is not a replacement for IR, smoke, sight, and good old experience. I use the blower door and IR to find air leaks in record time without using a ladder, but if I want to know how much leakage I am seeing there is no gadget for that. Total path zone leakage testing or measuring the hole are your best bet. If you could elaborate on the gadget you speak of and explain how you get a cfm reading I would be open to changing my opinion.

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Permalink Reply by Damien Herold on September 28, 2012 at 7:08am

Take for instance when you crack open a bedroom door during a blower door depressurization test, the Thermoanemometer will tell you exactly the fpm of airflow which is easily converted to cfm leakage. This information is not obtainable with an IR, smoker or back of your hand. I am having a great time using this tool. I hate smokers etc.

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Permalink Reply by Bob Kretvix on September 28, 2012 at 7:13am

You really didn't answer how you use that cfm number.  Are you just comparing relative cfm values for each room, or do you have a specific cfm number that indicates excessive leakage?  If just a relative number, why not just use your manometer that you're using already instead of bringing another instrument?

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Permalink Reply by Damien Herold on September 28, 2012 at 8:09am

If you have a 300 square foot bedroom, and the cfm is under 400 (roughly) the room becomes a low priority. Also, the Alnor works great around windows especially when the sun is out ( which plays havoc with IR) and windows treatments are present, you simply slide the 40 inch probe behind the curtains and wham, job is done. Last week I was in a home with a fireplace that had a cathedral ceiling, and I could run the probe from the top of the stone fireplace (11 feet high) and found that one side read 450 fpm from top to bottom. (103 cfm leakage). No ladder needed.

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Permalink Reply by David Meiland on September 29, 2012 at 6:49am

It doesn't work like you apparently think it does. Yes, the anemometer head gives you feet per minute of airflow (or some other velocity measurement), but to convert that velocity into a cubic footage measurement you need an exact measurement of the area that ALL of the air is flowing through. You don't have that measurement is you are simply placing the probe next to a piece of trim or a can light or a door gap.

Your method has applicability if you stick the probe into a duct of a known size and find the air velocity. FPM in a duct can be converted into CFM because the area is known. Look up "duct traverse" and look at how the method is presented by various folks. Jim Bergmann has a video or two on this topic using a Testo anemometer.

But, without know the area, you can't get a CFM figure...

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Permalink Reply by Damien Herold on November 23, 2012 at 6:23pm

Along side of a fireplace with an 11 foot ceiling which has a .25 inch opening along the outer edge. Dave, it is simple math. 9 cfm total at 450 fpm.

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Permalink Reply by Tammy Kenworthy on September 28, 2012 at 8:30am

does the device have a read out display that shows the CFM #?

-Tammy    ilovewaterheaters.com

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Permalink Reply by Damien Herold on September 28, 2012 at 9:11am

Hi Tammy,  The device gives you FPM, which is converted to CFM by multipling FPM by the area and dividing by 144.

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Permalink Reply by Bob Kretvix on September 28, 2012 at 9:49am

You can also get types where you plug in the dimensions and it gives readings in cfm. 

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Permalink Reply by Glen Gallo on September 29, 2012 at 5:49am

I don't get how this would work for a BD test. The instrument seems to be designed for using in a duct. As it is testing air flow or realistically pressure and converting that number. How are these numbers relative to a induced pressure in a home in specific areas. Would it not read "leakage" in every corner due to flow whether there is a hole or not?

I could understand it working in a cavity such as a can light, duct or other openings communicating between conditioned and unconditioned space.

I do not understand how it would work along side the fireplace in an open space with charged air flowing and swirling from corners or what it would read behind the curtain.

An explanation would be greatly appreciated.  

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Permalink Reply by Glen Gallo on October 1, 2012 at 8:08am

After looking it up I see that it reads temperature of the probe at a set figure. It reads based on how much it cools down and displays that into data. no flow equals no cool down  It does not read pressure at all. Very cool device.

Still don't get how it works as described

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