Hope someone can advise me.
I’m getting ready to install a Tamarack HV1000 whoe house fan in my currently unvented attic. I plan to install gable vents (maybe 3+ sq ft. on each each end) on both sides of the attic as high as possible in the gable. We get heavy winds. I’ve got a few questions.
1. Will the gable vents and fan move around the loose blown cellulose insulation? Do I need to make any precautions?
2. The house is a 1885 victorian. Anyone have any sources for well made wood gable vents. One of the gables has a chimney in the middle and I’ll need to put two vents on that side.
3. The best place due to rafter and joist locations is directly over the stairwell. Will this be fine when trying to exchange the air on the second floor?
Thanks!
Seth
John Cage
Replies
1. Will the gable vents and fan move around the loose blown cellulose insulation? Do I need to make any precautions?
Usually not, sometimes yes. If it mopves the insulayion around, build a curb around it.
3. The best place due to rafter and joist locations is directly over the stairwell. Will this be fine when trying to exchange the air on the second floor?
You'll get cooling where you open windows to allow cooler (night/early morning) air in.
_______________________
"I may have said the same thing before... But my explanation, I am sure, will always be different." Oscar Wilde
Where the whole house fan comes through to the attic you may find that the "bernoli" effect may cause cellulose to be sucked into the updraft from the sides of the fan box. as the air flow speeds into the attic.
To reduce this effect place fiberglass screen over the cellulose for a three foot area around the whole attic fan assemble on the attic side to hold the cellulose in position.
With your "windy" conditions you may find the screen on top of the cellulose at the exterior vents will hold it against the gusts. Also an oversized formed metal storm pan at the base of the wooden exterior vents should be used to move any blown in precipitation back outside.
By the way.....born and raised with a whole house fan, put one in my house, my kids put them in their houses.....fresh air...lower utility bills!!!!
Put several in client's homes also!!
........................Iron Helix
FWIW, in most cases I see there's no apparent effect, sometimes there is._______________________
"I may have said the same thing before... But my explanation, I am sure, will always be different." Oscar Wilde
By all means do not use the screen unless there is insulation movement.....of the 10 installs that I remember only one had a insulation movement problem. That was due to the placement of rafters in a valley intersect directly above the fan unit.
Bob's dead on with FWIW......seldom seen circumstance....thanks!
..........................Iron Helix
Thanks for the tip about the metal pan for moving moisture back outside. I'll make sure to build that in.
I'm prepared to build the vents from scratch, but was wondering if there are any mail order vendors that make high quality vents in a variety of sizes. Any suggestions?
Thanks again.
Seth"Nothing is a
mistake. There is no win
and there is no fail . . . there is only
make."
John Cage
Approach the vent construction as if it were a window. Side jambs, head Jamb, sill, parting stop, and exterior trim mould to match the house. Install the window frame in the GE framing.
Then install the metal drain pan over the sill of the window. Inside the attic attach an 18"deep shelf where the window stool would be installed. Tilt the shelf toward the exterior to allow the oversized pan to drain. The width of the pan will also be wider than the louvers.
Construct a simple louvered insert for the window frame to fit where the sash would be. Two flat side stiles that have been dadoed out at 45 deg at the width of the slats that have been cut at the leading edge to a 45. Add the head to the stiles, but leave the bottom of the insert to sit upon the pan.
Cover the inside of the louvered assembly with some 8x8 harware cloth. The louvered insert can be set into the window frame against the parting stop from inside the attic. Secure with stainless or brass screws.
Double check the actual "free flow" area of your vents w/screen to make sure that there is enough real opening to match your fans capacity.
I do not know of a mfg co for custom sized louvers in wood.....plenty of mfgs for aluminim tackies. Check out a book on window construction......preferably copyrighted around 1920-1950 when windows were hand assembled at the local lumberyard for each job.
A local custom woodworking shop maybe your best source! A HVAC shop can fabricate the pan for you....just take a cardboard template.
...........................Iron Helix.
Thank you. I appreciate you're advice and detailed descriptions.
Seth"Nothing is a
mistake. There is no win
and there is no fail . . . there is only
make."
John Cage
Just a couple more thoughts.........
Some of the architectural salvage yards may have old style window units...and since you need no balances or sash then you might find a real deal. Flea Markets, too!
Check with a local lumberyard about the availability of new "old style" window units....they are still available in my locale. Order one "open"...it will come with no sash, and the salesman will give you a strange look.
Salb Sash & Door.......Chicago, Il............all sorts of custom stuff.
If your attic is readily accessable, you might want to consider a storm sash for the inside to close the attic for the winter season.
Regards...........................Iron Helix
One another forum somebody reccomended a place in IA or NE that all they made was wooden vents. Had a bunch of standard sizes and shaps and did custom.
Sorry, but I don't remember the name, but try a google for thigns like WOOD GABLE END VENTS.