BlowerDoor Homemade

todd anderson · 02-20-2009, 01:50 PM

Has anyone ever made a blower door ?or
has seen any plans to makes one.?

They really dont look like much for what they cost

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**Scott Patterson** · 02-20-2009, 05:06 PM

Originally Posted by todd anderson

Has anyone ever made a blower door ?or
has seen any plans to makes one.?

They really dont look like much for what they cost

Not to pick on you, but somethings you will just need to purchase for this profession!

The Krawller I could understand, sort of..

todd anderson · 02-20-2009, 07:28 PM

No Problem,
I am new, but i like to make things
Thanks for your reply

Originally Posted by Scott Patterson

Not to pick on you, but somethings you will just need to purchase for this profession!

The Krawller I could understand, sort of..

**Dana Bostick** · 03-20-2009, 03:50 PM

The devil is in the details. It's not the door but the calibrated, hi-tech equipment that goes with it that is expensive. Sure, you (or I) could knock one together, it ain't rocket science. The variable speed fan and the monitoring guages is where it gets to be rocket science. Everything must be calibrated to work together and it must be consistant, repeatable and verifyable, every time. Good luck with that!

Jason Kaylor · 04-18-2009, 08:10 AM

Even if you wanted to rig one up, you would be in for about the same price as you can buy one on the open market. A really good manometer is 2-3k by itself. The manufactures buy their stuff in bulk and get extremly good pricing. Whereas you would be buying one piece at a time. The manometer is only one piece. By the time you throw in the fan (6300cfm minimum) the frame, and door, I would expect you to be around 5k anyway.

If you just want the airflow aspect of the blower door to enhance an infrared inspection, you could just buy one of the bigger fans at HD and set it up in a doorway or any other opening. It would not be difficult to tarp that off or whatever. This is not going to work for a "certified" energy audit, but it will increase/decrease air pressure in the structure to assist an infrared inspection.

andy88 · 06-09-2010, 10:58 PM

search the google about it, you will find many designs
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wooden doors

**Bruce Breedlove** · 06-10-2010, 05:30 AM

Originally Posted by todd anderson

Has anyone ever made a blower door ?or
has seen any plans to makes one.?

Originally Posted by Dana Bostick

The devil is in the details.

True. Your biggest hurdle will be in getting an accurate measurement of air flow through the fan. The standard design has a tube with small holes around the center of the fan that measure the pressure drop of the air across the fan. That pressure drop is then converted to CFM (or whatever units of air flow you care to use) and is dependant on the size of the opening (which is specially shaped so as to not impede the flow of air through it).

Don't forget that you will need a set of rings with different size openings for use in houses of different volumes and leakiness. (The faster the fan runs the more accurate your measurements. For a small, tight house you need to restrict air flow by inserting a small ring so your fan runs at a fast enough speed to get a meaningful measurement.)

Good luck with getting everything calibrated. (You will need to calibrate the fan for every ring.)

**Markus Keller** · 06-10-2010, 06:01 AM

It is amazing how simple a blower door kit looks. Once you use one and look at the details, it isn't a simple or cheap thing at all. If you need one, buy it. I'm more than willing to build and improvise but this wouldn't be one of those items.
Another concern would be if there were ever any questions about the validity of your test. "So Mr. Inspector by what approved testing agency has your homemade unit be tested and accredited for accuracy'?

Richard Fuselier · 06-14-2010, 04:30 AM

What's the typical cost for a blower door test?

Thanks, R

Dan J. Payne · 06-14-2010, 06:44 AM

Richard,
There are some variables for pricing as to what is trying to be accomplished.
Blower door testing can be as simple as to determine the air change rate (ACH) of the home or to use the BD to do zonal pressure testing or used in conjunction with a duct blaster to determine the HVAC duct leakage to the outside of the thermal envelope. I any case when performing an audit other considerations such as Combustion Appliance Zone (CAZ) testing are required if appliciable.
If all that is trying to be accomplished is ACH and to locate air leaks and thermal deficiences, and with or without CAZ testing, usually in the $300-400 range which will include a detailed report prioritizing recommended retrofits (with experience) as to ROI.
Your market should be looked at individually!