Replies

1. 
   darrel | Jun 17, 2003 07:18am | #1

   thanks!

2. 
   BossHog | Jun 17, 2003 05:01pm | #2

   O.K, you probably knew I was gonna poke my head in here. It's like a compulsion or something.....................(-:

   I noticed your web page talks about cutting ceiling joists, but makes no mention of trusses. The bottom chords of trusses should NOT be cut out for whole house fans.

   I did a thread a while back about Cutting trusses for skylights that covers this.

   Every time I see two heaps slammin' into each other tonight, I'll think of you [Tim Taylor]

1. 
   jjhamer | Jun 18, 2003 12:55am | #3

   Boss,

   Thanks for the information and the link.  I agree that trusses should never be cut for any reason.  In the case of a whole house fan, I would install on the trusses, and get as thin a louver as possible.  Somewhere there was an article about building a box above the hallway and installing the fan vertically.  This allowed for a door to be closed to weather proof the fan in the winter.

   At the house I have 4 temperature sensors from the basement to the attic.  The attic temperature changes from about 65 in the morning to over 100 in the afternoon.  I'll add a graph when I get time.   Turning on the fan, drops the attic temperature 20 degrees in about 15 minutes.

   If you haven't noticed, I like to crunch numbers and you've been a member for 454 days, that's about 9.33 posts per day for 6 months.  I sure hope you're getting paid for this!

   Anyway thanks for the help.  J.J.

1. 
   BossHog | Jun 18, 2003 02:57am | #4

   "... you've been a member for 454 days, that's about 9.33 posts per day for 6 months. "

   Well, a lot of my posts are short - Some just one liners poking fun at people.

   Also - Piffin has 8329 posts to my 4234. How come you aren't giving HIM a hard time ???.........................9-:Life isn't like a box of chocolates, it's more like a jar of jalapenos.You never know what's going to burn your a$$

1. 
   jjhamer | Jun 18, 2003 08:05pm | #5

   Boss,

   I'm not giving you a hard time, I'm impressed that you have written that many posts.  Thanks for all the information.

   I added an actual temperature link to the page.  It graphs the temperature changes in the basement, 1st floor, outside, and attic from about 10am to 4:30pm.   I turned the fan on at 4:00pm and by 4:30 the temp in the attic dropped 20 degrees.  The basement temperature stays very consistant through the day.    I will try to get over to the house in the evening to see what the temperature changes are, since that is when the fan is most likely to be run.

   Anyway, click on the link below and then click on "actual temperatures" in the upper left corner.   http://hamerconstruction.com/whole_house_fan_installation0612.htm

   Also the hit counter at the bottom of the page is at 253. 

2. 
   dIrishInMe | Jun 20, 2003 10:25pm | #6

   Plus some breaktimers have been around in the days before Taunton migrated to this forum format.  I'm wondering if you are the one who used to refer to yourself as the PE (Pretend Engineer) in the old days?  Was it Ron...?Matt

1. 
   BossHog | Jun 20, 2003 10:43pm | #7

   Yup - You're right.

   I'm a pretend injunear, pretend farmer, and probably a few other things.

   Actually, I think I started on the forums just as the WebX thingy was getting up and running. Been a long time - Don't really remember when it was.

   Are you an old WebX person? Your nickname doesn't look familiar........Mediocrity: It takes a lot less time and most people won't notice the difference until it's too late.

2. 
   dIrishInMe | Jun 20, 2003 11:21pm | #8

   On the old format I just went by Matt G.

   And, there was another format before that. Maybe 2..

   I had been "off line" for quite a while as I had 2 jobs and very little time to play around... 

   The Irish thing is something from another biker type forum that I participate in.  Taunton and the other one used to be tied together via Delphi somehow, but they don't seem to be any more.  Matt

3. 
   Jencar | Jun 21, 2003 08:25am | #9

   Thank you for the link.

   A customer called today and asked about a way to ventilate the attic, and I suggested a whole house fan, but have never installed one.

   Before they got an HVAC system, my dad in MO had an attic fan.Really did a great job cooling the whole house in the summer (on nights when it acually did cool down outside a little!)

   Jen

1. 
   jjhamer | Jun 21, 2003 10:14pm | #14

   Although whole house fans do a great job ventilating an attic, if the customer only wants the attic ventilated, I would first make sure the passive ventilation is adequate, making sure soffit vents, and roof vents are installed correctly, and if needed install a roof or attic fan that sits on top of the shingles. 

   Attic fans are installed in my area on a regular basis for a tenth of a whole house fan, under $300, and run with an automatic temperature switch, typically going on when the attic gets to about 90 to 95 degrees.   The nice thing about attic fans is that they run together with the house Air Conditioning.  They do a good job of helping the house A/C because the A/C is not fighting a hot attic that can be as warm as 150 degrees on a hot day.   

   The only thing I don't like about attic fans is that the motors tend to stop running after about 2 years and never get replaced.  I'm not sure whether the motor needs to be oiled on a regular basis, maybe somebody else knows?

   Whole house fans are for people that do not like air conditioning, but like cool outside air.

1. 
   Jencar | Jun 21, 2003 11:36pm | #15

   Thanks for the additional info. Haven't checked their roof yet for passive venting...would be a good first step for either type of fan...

   They do have AC already, so the attic fan sounds like a good choice.

   Jen

2. 
   wrudiger | Jun 22, 2003 07:10am | #16

   My folks have had a couple of attic fans - in fact I "got" to install the first one ages ago while still living at home.  No AC - usually the natural cooling of the SF bay & ocean do the job.  However, we do get runs of 90's and 100's.  The fan made a huge difference in the old uninsulated, single-pane aluminum window'd house.  As you said, the fans die after a few years.  They did replace it last time they reroofed.  Since then they have added attic insulation and double pane windows.  The new fan recently died and this time they don't plan to replace it as they can no longer feel the difference with and without the attic fan.

4. 
   wrudiger | Jun 21, 2003 10:09am | #10

   There appear to be two approaches to whole house fans.  The common one, that you describe, uses a large diameter high volume fan that typically requires cutting joists.  The big benefit appears to be rapid air replacement in the house and the comfort from all that air moving over the occupants.  Downsides as I understand them are noise and, as you mention, winter heat loss.

   I just purchased the other approach, by Tamarack.  It fits between joists and has motorized insulating doors to address the heat loss problem.  It contains two (relatively) small fans and is supposed to be significantly quiter than the other fans.  It will do 3 to 4 air changes per hour, so you don't get that air-flow cooling feeling, but it's cheaper to operate and the mfg. claims it still gets the job done. 

   Our local utility includes them in their energy rebate program so there must be something to the claims.

   It's sitting in the shop.  As soon as I get it installed and we have another heat wave (been quite rare this year in No. Cal.) I'll let you know how it works.

   Wayne

1. 
   jjhamer | Jun 21, 2003 09:43pm | #13

   wrudiger,

   I have not installed one of the Tamarack fans but I'd be interested in their performance.  They do solve the winter heat loss and the noise problems.

   Please let me know how you like it when you get it installed.   J.J.

5. 
   goodwood | Jun 21, 2003 06:54pm | #11

   Thanks for the site.

   What is considered to be a comfortable ach rate? What would the minimum be?

1. 
   jjhamer | Jun 21, 2003 09:39pm | #12

   Goodwood,

   Most fan manufacturers don't specify Air Changes per hour ACH.  If you look at the whole house fan page at http://hem.dis.anl.gov/eehem/99/990511.html  you'll see they recommend between 15-20 ACH. 

   At our site house with 0.10 status pressure we are at 23 ACH on high speed, and 8 ACH on low speed.    I don't have any way to measure static pressure or actual CFM yet, but I may have my HVAC guy bring an air flow meter to test this fan.

   In any case the air flow is very comfortable on both speeds.   Making sure the attic vents properly is important.    When the outside air temperature gets around 80 degrees whole house fans begin to loose their effectiveness, that's why they are used mainly in the evening and at night.