To add attic insulation or not to add...?

[2HOTinPHX]

So our home was built in 98 so it seems time to add some blow in insulation? Went to a home show this past weekend and talked to a few people regarding this. One company will come out and blow in more and with SRP rebate applied going to be less than 500.00. Others say you first should seal your attic. Its alot more money as they suck out the existing insulation then seal around everything then replace insulation. is it worthwhile to do this additional process? Or is it another money grab?

 

[REWahoo]

We also have a 98 built home and after having our central AC repaired a few years ago, the repair guy suggested I consider adding more insulation. I hadn't paid much attention to the condition of the blown in insulation installed when we built, but it had definitely compacted/shrunk by about 4 inches (started with 12).

I shopped around and had an additional 14 inches blown in at a cost of $1,000 (2,700 SF). I think there was also some type of fed tax break at the time that may have saved me another couple of hundred.

None of the companies I called mentioned sucking out the old insulation and sealing the attic. Your "it's a lot more money" comment leads me to believe there would be a very long payback period.

 

[2HOTinPHX]

We also have a 98 built home and after having our central AC repaired a few years ago, the repair guy suggested I consider adding more insulation. I hadn't paid much attention to the condition of the blown in insulation installed when we built, but it had definitely compacted/shrunk by about 4 inches (started with 12).

I shopped around and had an additional 14 inches blown in at a cost of $1,000 (2,700 SF). I think there was some type of fed tax break at the time that may have saved me a couple of hundred.

None of the companies I called mentioned sucking out the old insulation and sealing the attic. Your "it's a lot more money" comment leads me to believe there would be a very long payback period.

Thanks for the reply. I forgot to think about the pay back period. Just watching some YouTube videos on attic insulation and a lot of them point you in the direction of this sealing the attic idea. If I remember correctly it was about 10k.....waaay more than just blowing in additional insulation.

 

[REWahoo]

If I remember correctly it was about 10k.....

Yikes!

 

[Qs Laptop]

So our home was built in 98 so it seems time to add some blow in insulation? Went to a home show this past weekend and talked to a few people regarding this. One company will come out and blow in more and with SRP rebate applied going to be less than 500.00. Others say you first should seal your attic. Its alot more money as they suck out the existing insulation then seal around everything then replace insulation. is it worthwhile to do this additional process? Or is it another money grab?

I am in a similar situation but in freezing cold Minnesota. Here we have to contend with high humidity house air getting into the attic, forming frost, then melting and dripping water on the underside of the ceilings. For this reason, sealing the attic is recommended.

A couple of years ago I had two insulation companies come out and both touted the whole attic sealing job before blowing in more insulation. However, one of the estimators said that merely sealing around all openings to the attic, like light bulb fixtures, water heater flues/chimneys, ceiling fan fixtures, pipes passing through, etc. is almost as good. Typically that is sheet metal and/or spray-in foam insulation in a can. You might consider this budget approach instead of the full-on attic sealing job, if it makes sense in your part of the country.

 

[retire to nature]

I did two house dec 2021 and jan 2022. I did my house (800sqft) by a company with blowing fiberglass insulation. I had 3 estimate, $1200, 900, and 700. so i went with 700. So I asked the company to estimate for my airbnb house. and the number went more than double and they couldnt provide how the number came out. So I rented a blowing machine thru homedepot and I did with paper kind insulation(forgot the name, i didnt like to do fiberglass for myself doing)for the airbnb house by myself. Actually, it ended up I just spread it by myself thru many days. I knew the sealing technic thru youtube too, but yes it was expensive and thought would be theorical way to charge the many times of cost. Since I spread it by myself with awareness of the leaking issue, I tried to seal possible. Anyway, I was so glad I did before the heatwave and winter storm in the mid-west in 2022. It definitely helps. in my opinion, my house with the company is much looser and less sealed but it still helps. And I learned the rate of insulation. My house was lower than requirement but I did more than requirement for my airbnb house because it was much cheaper doing by myself(even though excluding my labor). airbnb house bill got much lower too. I definitely recommend adding insulation with or without seal.

 

[TripleLindy]

Our house was built in ‘97, so your post reminded me that I probably need to add insulation. It’s been years ago, but I talked to an insulation guy that told me the sealing stuff wasn’t good in the Texas climate, as lots of heat gets trapped in the attic. Ventilation is needed and roof vents alone probably aren’t enough. That feedback plus the high pricing that probably wouldn’t result in an ROI in my lifetime will have me skip it.

One other thing you may want to look into if you haven’t already - replacement windows. We had a couple that had fogged panes and we ended up replacing them all. We went to a much more energy efficient window over the builder’s grade aluminum. Our summer electric bills dropped dramatically and the noise from passing airplanes from DFW airport was also greatly reduced.

 

[Palmtree]

Adding attic insulation is definitely the best bang for your buck as far as insulating goes. If you're handy, it's not too hard to do a pretty good job air sealing it yourself. Rake back the insulation around where any wires or ducts enter the attic space from below and seal with canned spray foam. If you have recessed lights in your ceiling you can insulate around them too with spray foam if they are IC rated (Insulation contact rated). If they are not, then I would use fire block spray foam (spray foam rated for extreme heat) around them. Both are available at Home Depot, Lowes, etc. If you have leaky ducts in the attic, you can seal them easily with mastic. It's cheap and available at the same places.

 

[Music Lover]

It's impossible to answer the question (although people have) unless we know how much insulation is in your attic now, what climate you live in, and what your energy costs are. Generally speaking, more insulation is better but at a certain point the returns diminish.

Also, depending on access, it shouldn't cost $10k to seal a few holes in the attic. It might only take someone an hour. Or, access may be more difficult. But I can't envision a scenario where it takes $10k of work.

 

[Aerides]

A lot depends on your geography, and your overall cooling efficiency. You're in AZ, so your needs are greater than most.

My attic in S Fla is about 145f in the summer. In August, the air leaving my AC heats up by 4 degrees by the time it comes out in the vent across the house.

Roof insulation sealing is an option, but only on a newer roof, not one you plan to replace in <10 years. You also probably don't have humidity to deal with, which is another selling point.

Unless you have specific needs and plan to stay in your house a long time, just go with new blow in.

 

[REWahoo]

It's impossible to answer the question (although people have)...

Ditch the scissors logo and dryer sheet motto, the new byline for E-R.org is "Where we do the impossible!"

 

[Sunset]

OP - Just do as others suggested, seal the obvious big leaks, access panel to attic, ceiling lights, ceiling fan, bathroom fan. Then insulate.

That is the big bang for the buck, spending an additional 10K will probably save maybe $100 more per year, so only a 100yr payback.

 

[2HOTinPHX]

Thanks for the replies. Yeah I am thinking as most advised here to go with some blow in insulation. With our energy company rebate it will be less than 500.00 to someone who knows what they are doing verse doing it myself. At 59 getting up in the attic and trying to get to close enough to the other end of the house is a no go.

One thing I did notice is there is no insulation over the garage. Seems like since I can see all the way from the garage thru the house in the attic that there should be?

 

[hopefullyoneday]

I have spray foam throughout the walls and under the roof. It is called envelope sealing. My attic is within 10 degrees of the inside of my house. My house is 2300 sq ft and in texas. My electric bill averages under $100 per month. More of a up front cost but compared to my neighbors paying around $400 a month sometimes i feel as though it was worth it. It also doesnt work your a/c and heat as hard. So maybe you can just spray the attic roof.

 

[2HOTinPHX]

I have spray foam throughout the walls and under the roof. It is called envelope sealing. My attic is within 10 degrees of the inside of my house. My house is 2300 sq ft and in texas. My electric bill averages under $100 per month. More of a up front cost but compared to my neighbors paying around $400 a month sometimes i feel as though it was worth it. It also doesnt work your a/c and heat as hard. So maybe you can just spray the attic roof.

My understanding is they can do attic sealing with foam when you have an electric unit installed but can't do or trickier to do with a gas model. Something to do with has model needing outside air for combustion I think.

 

[hopefullyoneday]

My understanding is they can do attic sealing with foam when you have an electric unit installed but can't do or trickier to do with a gas model. Something to do with has model needing outside air for combustion I think.

Maybe, my gas fireplace has a double wall pipe going through the attic. The inner pipe is the hot and the outer pipe is the cooler fresh air.

 

[REWahoo]

One thing I did notice is there is no insulation over the garage. Seems like since I can see all the way from the garage thru the house in the attic that there should be?

Unless you have a heated/cooled garage I think there is almost no benefit to insulating the attic above it. Never seen that area insulated in any of the 7 homes I've owned in TX over the past 52 years.

 

[REWahoo]

My house is 2300 sq ft and in texas. My electric bill averages under $100 per month. More of a up front cost but compared to my neighbors paying around $400 a month sometimes i feel as though it was worth it.

That's impressive for TX! I cringe when I hear about people with $400 or more electric bills, winter or summer.

We haven't reached your level of savings but I'm pretty happy that we managed to average under $150/mo the past two years for our 2,700 SF all electric (heat pump) house.

Our electric Co-Op is offering great deals on upgrading insulation and I took a look at the spray foam on the underside of the roof. For those of us in our mid-70's, the payback stretches well beyond what we can reasonably expect for an expiration date.

 

[2HOTinPHX]

Unless you have a heated/cooled garage I think there is almost no benefit to insulating the attic above it. Never seen that area insulated in any of the 7 homes I've owned in TX over the past 52 years.

That makes sense but then should the attic above the garage be sectioned off from the rest of the house? Or I guess that the air above the insulation is what it is in the whole attic and then the insulation is the barrier for heat and cold above the living area then?

 

[REWahoo]

That makes sense but then should the attic above the garage be sectioned off from the rest of the house? Or I guess that the air above the insulation is what it is in the whole attic and then the insulation is the barrier for heat and cold above the living area then?

That's how I see it.

The garage attic has not been sectioned off from the other areas of the house in any of the homes I've owned. I don't see where there would be any benefit.

 

[2HOTinPHX]

Our house was built in ‘97, so your post reminded me that I probably need to add insulation. It’s been years ago, but I talked to an insulation guy that told me the sealing stuff wasn’t good in the Texas climate, as lots of heat gets trapped in the attic. Ventilation is needed and roof vents alone probably aren’t enough. That feedback plus the high pricing that probably wouldn’t result in an ROI in my lifetime will have me skip it.

One other thing you may want to look into if you haven’t already - replacement windows. We had a couple that had fogged panes and we ended up replacing them all. We went to a much more energy efficient window over the builder’s grade aluminum. Our summer electric bills dropped dramatically and the noise from passing airplanes from DFW airport was also greatly reduced.

New windows on order hopefully installed by March. The current windows are looking a little tired. We selected Anlin windows, a little pricey but lots of nice features and good reviews. Hope to get some noticeable noise reduction along with some energy savings.

 

[Sunset]

That makes sense but then should the attic above the garage be sectioned off from the rest of the house? Or I guess that the air above the insulation is what it is in the whole attic and then the insulation is the barrier for heat and cold above the living area then?

That's how I see it.

The garage attic has not been sectioned off from the other areas of the house in any of the homes I've owned. I don't see where there would be any benefit.

I think it should, as that is all I've ever seen, so it's code in some places. The reason is it's a fire separation wall so that if a fire starts in the garage it will take longer to start burning the house.
Without this wall, imagine a fire in the garage, it would rapidly flow over the wall and along the roof underside of the house.

The diagram on the left shows the wall separating house from garage going from floor to ceiling (when no rooms above the garage), if the garage has rooms above, it has a gypsum ceiling to act as fire separation.

 

[Palmtree]

One thing I did notice is there is no insulation over the garage. Seems like since I can see all the way from the garage thru the house in the attic that there should be?

Think of your home as a envelope. There's an inside and outside. The areas that you live in are heated and cooled and therefore are inside the conditioned envelope. The other areas in your home like the garage and attic may be under your roof but not heated and cooled. They are outside the conditioned envelope. The insulation in the attic is to keep the conditioned (heat/ac/air) from leaking away into the unconditioned. Since the garage is unconditioned and the attic is also unconditioned, no insulation barrier is needed.

 

[REWahoo]

...if the garage has rooms above, it has a gypsum ceiling to act as fire separation.

That makes sense.

I'm not familiar with building codes but garages here are drywalled. I always thought it was for slightly improved appearance but it is probably for fire separation. My guess is it is less expensive than building a fire separation wall in the attic.

 

[Mark1]

Think of your home as a envelope. There's an inside and outside. The areas that you live in are heated and cooled and therefore are inside the conditioned envelope. The other areas in your home like the garage and attic may be under your roof but not heated and cooled. They are outside the conditioned envelope. The insulation in the attic is to keep the conditioned (heat/ac/air) from leaking away into the unconditioned. Since the garage is unconditioned and the attic is also unconditioned, no insulation barrier is needed.

I don't disagree with the envelope analogy, but I will say that my attached 3 car garage has insulation within the ceiling area (I also believe insulation is within the exterior walls). My garage essentially has no heating source other than 2 hot water heaters and the furnace and furnace duct work which sit within the garage, but yet the garage only runs about 5 degree cooler than the house itself. Without insulation I have to assume that garage would have a temperature differential much greater than 5 degrees so I believe it does help with my energy conservation. My garage does have its own Reznor gas heater, but it never runs (even during a CO winter) as I have the set point at 55 Degrees.

If it was me, I would probably price blowing in insulation above the garage when I "topped off" the house (even without insulated garage walls), as I have to believe it would help some. If the additonal cost was great since your starting with no insulation, I might change my mind (?).