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Discussion Starter #1
Hi folks,

I got 3 bids for attic insulation on Tuesday. I live in the Chicago area so the R Value is a no-brainer, at least R49. Currently, the attic insulation is only 3 inches high and I have 7 roof vents and no soffit vents. The 1300 sf home was built in 1959. I decided to go with blown-in fiberglass over cellulose.

However, I am struck by the difference in price ($800) as well as the differing opinions of these 2 top-rated companies.

Comparing apples to apples, one says he will NOT do the work unless I have soffit vents installed (he's the expensive bid). The other 2 guys say that soffit vents aren't necessary because I have 7 roof vents and one gable vent on one side.

I am getting a bid for soffit vents on Saturday, just in case.

My questions:


  1. Should I spring for the soffit vents no matter who I use? They seem necessary from what I've researched.
  2. Has anyone heard of the "Jet Fan" attic fan? I would love to get one installed b/c I don't have an attic fan.
Quick FYI: This whole thing with the attic insulation started because I wanted to have 5 new light fixtures installed and one trouble-shooted. The electrician said the neutral is at 40-43 volts and stopped his work. He went into the attic and told me he can't troubleshoot and trace the "whole house" electrical problem until I remove the THREE inches of insulation first because he doesn't want to dig in the insulation. I paid him for what he did and now I'm all about the attic and lights not up. Sheesh!

Moral: Don't install new light fixtures. LOL :laughing:

Thanks for any opinions, jokes, comments,

Mary
 

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1. I would add cellulose as it is what you have existing, it will be cheaper, and it is generally preferred. FG will work, cellulose just seems like the obvious choice for your circumstance.
2. Yes, you do want soffit vent baffles installed. As long as you have sufficient intake and exhaust through the soffit and roof vents, that gable vent can be sealed off and a fan should not be necessary.
3. AIR-SEAL, AIR-SEAL, AIR-SEAL! I dont know if this was mentioned by your potential installers or not, but it is a MUST! Adding ventilation and insulation without air-sealing will not yield the results that you are looking for, and can even decrease efficiency.
4. If at all in doubt, get an energy audit done. This is actually something that I recommend anyway, as you get before and after testing to make sure that the job was done right. In addition, most states have programs where you can get cash back for these improvements, and the audit ($300ish) will be paid for. I'd also recommend looking for an installer that is part of such a program (if you have one?) , or at least works with auditors regularly. He will know what he's doing, and not just collect a check for a "blow and go".
 

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Discussion Starter #3
Thanks HomeSealed, for the reply. I may have worded it wrong. I am choosing fiberglass -over- cellulose, meaning I am choosing that -instead- of cellulose to go over the 3 inches of fg I now have. There, that's better. It's been a long week...wait, it's only Weds!!

Also, since you mentioned Air Sealing, that is what the higher quote person will be doing, checking around pipes, chimney, exhaust vents, etc. The cheaper guy didn't mention it and he also said not to install soffit vents.

Now the higher cost makes sense!!

What are soffit vent baffles? Are those the things that prevent the insulation from clogging the soffit vents? If so, I don't have soffit vents...yet.

So, the question remains, do I need to install soffit vents for proper air circulation in the attic?

And, is anyone familiar with the attic fan called the Jet Fan?

Thanks,

Mary
 

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If you have soffits, installing vents and using those as intake rather than the gable vent(s) would be preferred. The baffles that I speak of allow the air to flow up from the soffit vents into the attic. Insulation dam would be placed around the baffles in cavities with vents, and and block insulation from falling into the soffit in the other cavities. Spray foam is the best in this application... It sounds to me like you got one good quote, and one from someone who is uninformed on best practices of home performance.... Fg over Fg does make sense. Cellulose would still be good in your application, but fg will be good as well.... What makes you think that you need a "jet fan"?
 

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Discussion Starter #5
Hi HomeSealed,

I was told by the electrician that I needed an attic fan. When researching attic fans, I came across the Jet Fan attic fan and it sounds like a good product if I need an attic fan. http://www.atticfans.com/

Thanks for explaining the baffles to me, it seems I wouldn't need that unless I have the soffit vents put in...getting a quote for that on Saturday. I know this is a DIY Chatroom, but I'm not going to be the one cutting into my soffits.:no:

So far, soffit vents-- a Yes.
Attic fan a maybe.
 

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I would not use an attic fan if you are adding soffit vents and have exhaust vents; http://www.airvent.com/homeowner/products/intakeSoffit-specs.shtml

The attic fans can easily pull conditioned air from below, especially without air sealing first, all the way from basement or crawlspace; http://www.advancedenergy.org/build...entilation/Attic Ventilation Case Studies.pdf
I hope he does more than just "checking around pipes"; http://www.google.com/url?sa=t&sour...sg=AFQjCNEV_sFpJPB8DwLjAd-t6PJoO842EQ&cad=rja

Check on the density of the new fiberglass insulation, be careful of 0.5# per cu.ft.= comes with convective loops when it gets cold; http://www.homeenergy.org/archive/hem.dis.anl.gov/eehem/92/920510.html

http://www.diychatroom.com/f98/biggest-loser-fiberglass-insulation-90438/

Gary
 
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Discussion Starter #7
Thanks, GBR in WA for the reply.

I especially liked the link to the PDF Guide to Attic Air Sealing. I saved it and already printed out several pages. VERY informative and good illustrations, just what I needed!

Also, may end up going with cellulose rather than fiberglass after reading one study. You gave me a lot to research so I make the best decision for me.:thumbup:

I may not need an attic fan after all. Shoot, we only have 3 months a year where the temps are in the 80's and up anyway. Rest of year is milder and cold.

Mary
 

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