Some background
2004 slab house
The Woodlands
single story
1850 sq ft
3 ton A/C (yes, wish I'd gone 3.5 but contractor only offered 3 or 4)

A/C is struggling (as are everyone else's I know).

Considering getting new insulation blown in the attic. Currently have the yellow stuff from when it was built. Looking for anecdotes from others who have done this.

TIA

I'm in a very similar situation. 2004 slab house. I'm sure the crappy builder-grade windows are a problem as well.

I'm considering new insulation in attic.

I did this almost a year ago (thread).

I've been tracking data pretty closely. We've got 2 real seasons here. Cold winters and hot summers. So far, the winter results have been dramatically more effective at reducing gas consumption for heating (40% reduction), and the electricity usage the summer months were not as dramatic (10% reduction). We've also got more people/activities at the home, which plays into electricity usage, some. I don't think we've seen enough summer data to really call it though.

I like the additional storage in a mostly conditioned space, and it gives me a lot of options for PEX replacement in the future, so we had other motivators. I'd do it again if I had the choice. I also did the vacuuming out myself. I'd complain about it a lot, but I'd do that again to save money, if I had to.

ETA - I assumed spray-foam. Sorry.

What changes did you make to your roofing to go to spray foam?

Did you rent the equipment to vacuum the old stuff out yourself? How did you dispose of it? I bought our house and it had foam sprayed, but they never vacummed out the blown in insulation. I want to get rid of it.

Dill-Ag13 said:

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What changes did you make to your roofing to go to spray foam?

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Honestly, not much to the roof. I had powered vents - I removed the motors and capped the wiring. I add a couple of outlets before the wire got covered up.

The biggest issue was the gas-fired heaters. If you don't have a closed combustion system (which draws air from the outside), you've got to make sure you have enough volume in the space for make-up air. I read through a lot of code and ended up adding some internal vents to meet the volume requirements of the code. There are similar requirements for gas-fired water heaters and other gas appliances.

Sweet Kitten Feet said:

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Did you rent the equipment to vacuum the old stuff out yourself? How did you dispose of it? I bought our house and it had foam sprayed, but they never vacummed out the blown in insulation. I want to get rid of it.

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Yep. I rented it from a local place, but I think sunbelt rentals may carry some as well. They had the bags you need to use (they're perforated for the airflow). I might have used 6-8 bags for mine. I had to take them out to the local dump.

Couple of pro-tips:
- I would have run the vacuum on the trailer so that the bags didn't have to be loaded.
- About halfway through, I duct-taped a broom handle to the end of the vacuum hose, and it was much easier to push it where I needed to go, instead of crawling to the nooks and crannies.
- Be careful about large items getting stuck in the hose. I had a large wood-shake that I had to get out. Overall, the vacuum did really well pulling stuff up though.
- I would have pre-gamed with the Advil.
- I wore a respirator and long sleeve clothes. Was a good call.

Rent a roll away dumpster and cover it with a tarp. Let the insulation just blow into the dumpster. Don't have to mess with the bags.

Make sure your HVAC is right for the changes you are making.

Air sealing the attic is very important as well.

El_duderino said:

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Air sealing the attic is very important as well.

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Yes! After removing the old stuff. Seal around light fixtures, A/C outlets, plumbing pipes, etc. penetrating the ceiling.

Food for Thought:

Why many love mineral wool over other options:

In many ways, mineral wool is a superior insulation product.

It has a higher R-value per inch compared to fiberglass, about a 22-37% higher R-value.

It contains 70% recycled material, making it a greener product than fiberglass at 20-30% recycled material..

With a density over three times that of fiberglass, mineral wool has superior sound-deadening properties.

The stiffer batts don't tend to flop over as easily as fiberglass, making it easier to put in place, and they don't require staples or wire to keep them in place.

It's hydrophobic, so it won't absorb water or encourage the growth of mold and mildew.

Mineral wool is also very fire resistant and can act as a fire stop.

However, like many building materials, mineral wool also has its drawbacks. It tends to be more expensive than fiberglass, often between 25-50% higher in cost . Because it is more unusual, it's not available in as wide a range of sizes as fiberglass and is almost never available in a paper-faced format. Because it's denser, it's also heavier, which can make it more ungainly to handle during ceiling installations. Its dense nature requires the use of a serrated bread knife or wood saw to cut batts down to size, and it's very difficult to find in a loose-fill format.
Here's a quick overview of the R-value you can expect from different depths of mineral wool batting:

• For 24" R13 to R15
• For 26" R21 to R23
• For 28" R30 to R32
• For 210" R38

Source: http://rb.gy/6whty

Thanks all. Looks like there is a 30% federal rebate as well

We had R-30 fiberglass blown in the attic of our 1 story home last month. Immediately noticed a difference in the afternoons to where before we were struggling to stay at 78 during the day and now it's 76 and dropping at 6PM. This leads to less work for the AC since it's actually cycling at night and not running continuously.
Spray foam is great, but much more expensive and requires a lot of work to be done on an existing home. Blowing insulation will help year round and I feel like the money spent can be recovered much quicker.

Do you have attic foil?

I did that in my Houston home and the attic temp dropped 30-deg, making a huge difference in the AC efficiently.

I bought 10 bags of fiberglass insulation at Home Depot and used their blower (free) to get my attic up to about R-35. Immediately noticed a difference. It took about 4 hours for two senior citizens, one on the porch loading the machine and me in the attic. I just added the new material on top of the old, which ranged from zero to about 6" depth. This is the way to go for immediate results in my opinion. I guess the hardest part was making sure those styrofoam soffit vent channel things were in place before we started.

Tell me more. Is this where you're just stapling foil to the rafters to make a radiant barrier?

Link?

https://www.energystar.gov/about/federal_tax_credits/insulation

Thanks

I skimmed while being yelled at by the kids this morning and was thinking you found a rebate from a company

Dummy me didn't even think about the tax credit…..which I should've since I claimed it for windows last year

agracer said:

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Do you have attic foil?

I did that in my Houston home and the attic temp dropped 30-deg, making a huge difference in the AC efficiently.

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I moved to the Little Rock area about a year ago and can't find any contractors who do that up here. I'm too old to want to do it myself.

I have a 1973 house with the original single pane aluminum windows, little insulation in the walls, but I did add the blown fiberglass insulation into the attic 2.5 years ago. I did nothing with the old cellulose insulation. My house is about 1850 sf.

Last Wednesday night, power to my neighborhood was cut when a dead tree took out the power line running to the neighborhood. It took over 16 hours to fix. My house was probably 73 when then power went out and 78 when it came back at 12:30 the next afternoon.

Since adding the insulation, my closets no longer feel like an over when I walk into them and I can put chocolate in the pantry and not worry about it melting during this time of year.

Adding insulation was one of the best things I've done. Also, my electric bills haven't topped $140 this summer. I do work from home, so I like to keep it comfortable during the day.

Was just reading reviews of Attic insulation services via Home Depot (3 in your area)
http://rb.gy/wt48j

Although the website is not more helpful than that, a phone call to the Pro Desk might be fruitful.

EMY92 said:

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I have a 1973 house with the original single pane aluminum windows, little insulation in the walls, but I did add the blown fiberglass insulation into the attic 2.5 years ago. I did nothing with the old cellulose insulation. My house is about 1850 sf.

Last Wednesday night, power to my neighborhood was cut when a dead tree took out the power line running to the neighborhood. It took over 16 hours to fix. My house was probably 73 when then power went out and 78 when it came back at 12:30 the next afternoon.

Since adding the insulation, my closets no longer feel like an over when I walk into them and I can put chocolate in the pantry and not worry about it melting during this time of year.

Adding insulation was one of the best things I've done. Also, my electric bills haven't topped $140 this summer. I do work from home, so I like to keep it comfortable during the day.

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What area of Texas are you in assuming Texas? And what are level or sickness did you install?

Waco area, I added about 18"

MrJonMan said:

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Thanks

I skimmed while being yelled at by the kids this morning and was thinking you found a rebate from a company

Dummy me didn't even think about the tax credit…..which I should've since I claimed it for windows last year

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You may be able to file an amended return for 2022 if it is worth it to you.

We have a 2400 sq ft home in San Antonio. We had insulation R-38 cellulose installed with two attic fans. The cost was $4300 plus minus an $850 rebate with our power company. Our power bills dropped by about 20% this summer so far. However, our system still runs 21 hours a day during the summer. I am about to start another post where I am going to dig deeper into an HVAC audit.

YellAg2004 said:

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Tell me more. Is this where you're just stapling foil to the rafters to make a radiant barrier?

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Yes.

https://atticfoil.com/

I put a thermometer in my attic after I did the foil and it was basically outside temp in there vs being 20+ degrees hotter with no foil. Huge difference.

More insulation and sealing the can lights up there will help also.

One of the concerns I've read about with doing spray foam is the ability to find leaks if there is a roof issue. If the foil is covering your whole roof pitch, it would seem to possibly create the same issues, no?

Or is that over-thinking for an issue that isn't very likely to occur?

tgivaughn said:

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Was just reading reviews of Attic insulation services via Home Depot (3 in your area)
http://rb.gy/wt48j

Although the website is not more helpful than that, a phone call to the Pro Desk might be fruitful.

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When I put my ZIP Code in on that page, it said that those services are not available in my area.

Indeed those AI gremlins at work again?

Use this search to FIND Home Depots near you
https://www.google.com/maps/search/The+Home+Depot/@34.7518245,-92.3846759,11z?entry=ttu

Now you can phone each of them asking for the PRO DESK
where a live person will help you get attic insulation blown in for you.

Thanks, but I am not looking for blown in insulation. I have plenty of that. What I cannot find locally are companies that install radiant barrier.

I misspoke in detail, sorry
Talking to the Pro Desk also gets you to blown in insulation bells/whistles services ala installing the radiant barriers they sell to rafter undersides. This also takes you to services that insure you have adequate ridge/soffit vents.
At least, that's what others in Texas have related to me.