I am getting very close to start finishing the interior of my house and was woundering if anyone had done or heard of someone useing a fan to do a blowerdoor test to find air leaks in the building envelope. I though i could use a smoke pen inf i could create negative presure in my house, maybe even by disconecting my erv fresh air intake. Any thoughts or ideas appreciated. Can you rent those blower door units? Thanks Michael

Blower doors move something like 5,000 - 6,000 cfm and your ERV moves what, 200 cfm?

You might try talking your local energy utility into checking out your new construction for a nominal fee, maybe even free.

You can also rent blower doors for about $450/month. Once you've gone that far, though, you might have been better off paying someone to do an energy audit which might get you some use of the infrared camera and other tools as well.

You can do quite a bit of air leak sleuthing with large window fans or "whole house" type ventilation fans, especially if you have the partition walls and interior doors installed, checking at the bottom of the interior doors finding and fixing the leakiest rooms first, etc. ERVs or bathroom/kitchen fans, not so much.

A large portable fan about 1 meter in diameter plus a smoke pen should work.

I don't have any windows or doors that are a meter wide (does anybody?)

16-20" window fans of this ilk work pretty well:

http://www.marketamerica.com/affiliate-36544114/air-king-9166-na_window_fans_20_3560_cfm_3speed_whole_house_window_fan_9166.htm

http://www.grainger.com/Grainger/AIR-KING-Window-Fan-2EJR6?cm_mmc=GoogleBase-_-HVACR-_-Fans-_-2EJR6&ci_src=14110944&ci_sku=2EJR6

If you want to cheap out, similar sized box fans wedged in the window with corrugated flaps taped for a better air seal can do the trick too. Higher CFM ratings are always better when starting out, but if the place is semi-tight can still find the remainders with even smaller fans.

So where does one buy a "smoke pen"?

There is a nice description of how to use a window fan to perform a "blower door" type test at:
http://www.nlcpr.com/Pressuretesting.php

Lee Dodge
http://www.residentialenergylaboratory.com
in a net-zero energy house

glenfotre-

Do an internet search for "smoke pencil" and you will find a number of suppliers.

Lee Dodge
http://www.residentialenergylaboratory.com
in a net-zero energy house

I just got my smoke pen from CHIMNEYBALLOON.COM. Called a wizard stick and i bought mine with the extra long tip to focus the stream to a small stream. I also ordered an extra 4 oz of smoke fluid. It busted in shipping and made a mess. JUst ordered a 600 board ft diy spray kit. I plan to use a box fan, do a blower test, find weak spots and mark them and come back and seal them as good as i can then do another test and finally spray foam. Thanks again to all of you and i will let you know as soon as i am done what i learn.

Nice website. Is that your house? Can you rent those cameras? Very cool.

You should really skip the box fan and hire an auditor or whoever has a blower door to run their door for even a couple of hours for you. Someone will do it by the hour for you, I would if I lived by you but I dont.

With a box fan you will have no idea exactly how leaky you are, and you will not know the impact you made with your air sealing. You'll have no comparison to other homes, you'll have no idea how much fresh air you may or may not need brought into the house, it likely wont be powerful enough to show you the spots that are your major leaks that would have the most impact to seal in a place you'd never guess.

If money is the issue try this, have them set it up and take a reading, if you did your due dilligence you'll get a good reading, then have them run it at a lower pressure for awhile while you go around with the wizard stick and note the areas you find leakage. Then send them home. This should take less than 2 hours. Even better would be a final reading but the consultant should be able to guess your reduction off your initial reading.

While a little box fan may or may not work, you'll really never know until you get a blower door test. That's my pitch for the morning.

$125/day to rent a camera. Would useful with the +/- pressure method to find leaks.


http://www.thermalcamerarentals.com/rental-camera-pricing.html

Michael-

"Nice website. Is that your house?"  
I assume those comments were directed to me.  Yes, that is my house.  I had a fellow with an IR camera take the pictures, and he set up the blower door to improve the indoor IR pictures.  jonr provided a good link for camera rental.  I have not rented a camera myself.  I payed the guy $100 for the pictures, and feel like I got an excellent deal. 

You can use the fan to check for leaks without quantifying the leakage rate.  If you do want to quantify the leakage rate, you could measure the airflow with a vane aneometer, and you would also need a very sensitive differential pressure gauge.  It is probably cheaper to pay somebody $150 or so to perform those tests rather than spend the several hundred dollars for the equipment, unless you want to play.  I diid buy all the equipment myself, since I want to play.

Lee Dodge
http://www.residentialenergylaboratory.com
in a net-zero energy modified production house

windows or doors that are a meter wide (does anybody?)

Lots of houses around here have 42" main front doors.

As far as the original post query: A couple of old furnace blowers can easily get the average house to 50 Pa (0.007psi) unless the house has a few windows open.
Piece of plywood, furnace blowers (see a few a year at garage sales for $5 or so), couple of pieces of vinyl tubing for manometers and the bodyof an old ball point pen for the pitot tube, and presto, you have your DIY blower door test.

Many utilities will do the job for $20 , if so with your POCO, hardly worth the time to set up your own unless for the eduacation aspect.

I don't think one can easily build a manometer that detects 50 Pa. Come to think of it, I have an ASP1400 that I should sell (because I have two).

http://www.sensirion.com/en/04_differential_pressure_sensors/04_asp1400-differential-pressure-sensor.htm

Lee, nice house!!! I really like those window grids, and your front door is a thing of beauty.

-Rosalinda

Building a manometer

50 Pa is 0.2 in H2O, correct?

11.5 degree slope on a piece of 38" (or big enough for surface tension to be negligible) clear tubing, ruler laid along side. Water runs up the tubing, 0.2 times the reading on the ruler is inches of water pressure . What could be simpler?? Water 1" up the tube, 50 Pa.

did a quick bing search just out of curiousity, first hit was for a GRADE SCHOOL experiment
http://www.ehow.com/how_6643295_make-manometer-measuring-vapor-pressure.html

Point taken.

Rosalinda-

Thanks.  It has been fun building up the web site.  I have been pleased with the performance of the house, with the exception that I would like to try to reduce the leakage rate.  Lots (14) of double-hung windows may make that challenging.  I have all the equipment for doing leakage testing, and just need to get a bum shoulder healed up to crawl around in the crawl space. 

I am planning on adding a bunch of instrumenation to the house so that it can be used for verification of computer models for heat losses from a house.  So far it seems to be following the model predictions closely.

Lee Dodge
http://www.ResidentialEnergyLaboratory.com
in a net-zero source energy modified production house

A lit stick of incense works well for draft detection, and you can buy packages of it in a scent you should be able to tolerate at any dollar store.

-Rosalinda