Is Adding Attic Insulation Really Worth It? | Results from a Real House
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- เผยแพร่เมื่อ 27 ก.ย. 2024
- We had insulation added to our upstairs attic in Fall 2021, and I thought it would be worthwhile to see what kind of difference it made in terms of our heating bill. Previously, the attic had (maybe) R-28 total, and we had 4"-5" of blown-in cellulose added to bring the total up to around R-46 to R-50. Using thermostat data from our ecobee from the previous winter and comparing to this past winter, I can get an idea of how much more efficient heating the house is.
According to This Old House (www.thisoldhou..., adding insulation to the attic, crawlspace, and around basement rim joists can save up to 15% on heating and cooling costs. I investigate how realistic this number is.
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I love this video because it shows realistic expectation from a realistic scenario. Most people aren't going to spend the time removing old insulation and air sealing. Thank you. I will say I'm hoping to have a little better efficiency as I did take the extra step to remove the old fiberglass batts, and air sealed a few big areas like light fixtures and bathroom vents and added approximately 15 inches of Greenfiber cellulose back. But again, this took a whole lot more time and effort which many people won't do, and I still feel I had several things I could have done better.
Thanks. It's hard for the average homeowner to take the real care and dedication that true air sealing and insulation requires. It's a lot easier to do during house construction than when you're living in it.
Thanks for the tip
Con Ed has a program in New York
But I feel like the contractors get the price high and get money from both sides
I think your water heater gas consumption is absolutely relevant. Presumably, making your house leak less heat would also cause your water heater need to heat less due to lower losses.
And by all means, do a similar comparison for your cooling bill in the summer and then combine the two. I track my water use and energy use month by month, which is how I saw how dramatically we cut our water use ~2005 when we got rid of our top loading washer and got a front loader $400 off at a "scratch and dent" sale. Now I'm comparing our larger house in Kansas to the smaller house we had in California, and what my updates and improvements are doing to our energy use over time.
The water heater use is a small fraction of what the furnace uses, usually less than 10%. Regardless, it's about the same every month because we shower and wash dishes the same amount from month to month, so that factor won't really change.
Unfortunately, I could not retrieve data from the summer before those insulation was installed, so I can't do a comparison.
I just got quoted $15k to insulate my attic with cellulose. Told the sales guy to take a hike. Small 1300sq ft house.
That's excessive. I'd have done the same.
Should be around $1000 or $1500 depending if your just adding a few inches. Way more if starting from scratch with air sealing involved....
Wow that's absurd. We just added probably 10 inches to our attic for about $1000 CAD. It was super low when the house was built, probably only 5-6 inches initially.
Saved alot of money renting a machine and blowing it in ourselves. But still.. I imagine even having someone do the labour would have only added 600 or 700 dollars more. We did it in about 4-5 hours and I'm far from a pro.
I just had the same $12,000,,,, nope. I did myself for under 1000
@@mesalaney7282 idk where these companies get their numbers from. 3 or 4 low skilled workers for a 1 day job. Good idea
wow, you rock for putting in so much work into this video! thanks!
Thanks!
Very cool! Thanks for doing this. You are a great example of why TH-cam is great.
You're quite welcome!
Appreciate it. This is the first I've seen on benefits achieved through insulation. In this case it was an increase in insulation from around R-28 to around R-50. Roughly double. Not a huge benefit and sounds like the break-even point on the cost could be 20 years. Albeit if energy prices skyrocket, as they could, then the break even point would of course be sooner.
Yeah, I think I'm about at the point of diminishing returns.
Note that it's double from an already decent amount of insulation, plenty of older houses are initially worse off and might see more improvement
@@kentaltobelli1840 That and if air sealing was done before the insulation was blown in even more savings could be had.
I added 5" of celluose with vents to my 1060 sq ft house two years ago by a local contractor (Minnesota) for a total of $1,200.
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Well, if an air sealed R-12 stops 92% and R-48 stops 98% of heat transfer it makes sense that you had only a 9% improvement, especially without air sealing. Cellulose is nice because it does stop airflow a bit better and unlike fiberglass, cellulose retains r value as it gets colder.
Valid point. I'm probably at the point of diminishing returns until the air sealing is really ironed out.
@@GlennFrazeeYT You could get a thermal gun and see if you have air leakage. 9-10% is pretty good considering you started with quite a bit. If you did want to do air sealing, vent pipes, j boxes and wire penetrations is a good place to start. Then top plates. The insulation is light enough to move aside. Wipe surfaces w a damp rag and spray foam. Also build boxes over any recessed type lights. I did my house several years back and my energy bill is 1/2 of my neighbors w the same house. But, I did 2" under basement slab, ,basement walls and most walls as well. Wall cavities are 3" foil faced Polyiso and boy does that make a difference! zone 5 as well.
@@jonwikan3986 An energy audit is on the list of things I want to do. Got a Klein thermal imager a couple years ago that will help identify cold air leaks. Though I don't know if I feel like crawling around the whole attic with cans of spray foam...
Awesome work ! thanks for sharing.. How much of an improvement in your comfort while in your home during the winters / summers ?
I can't say I noticed a difference in comfort. Air sealing is probably where you'd notice that difference. The numbers say that the furnace is working less hard afterwards, though.
Based on all the youtube research, that heat seal would save like 20% on total home airloss just from sealing the attic.
It's on the list of things to do...
@@GlennFrazeeYT I agree. I really want to spray from the roofing deck(attic ceiling)
Thanks. Good video. Preparing to add insulation this weekend
Thanks!
Wow great data
Thanks Fergy!
Hi Glenn, I’m in Fl and our home is about 18 yrs old. In our attic, I noticed that there is blown-in insulation mostly around the outer walls/perimeter of the attic with almost nothing on the inner floors of the attic (except around ductwork, there are piles around them.) Do you think I should add insulation? I’m looking to maximize energy efficiency for keeping our home cool! Thank you for the great video!
More insulation is usually a good idea. I'd check with a local contractor first though since I'm not too familiar with how things are done in Florida.
From what it sounded like your R rating is still well below what it should be based on living in zone 4. If you were able to get it up to R-60 you would save even more money month by month.
Undoubtedly. If this house were new construction, I'd totally agree. But I think I'm at the point of diminishing returns given how poorly air sealed everything is.
I was given a price of $2,000 for 960 sq ft home and that includes putting baffles in the attic because mine does not have any.
Seems about right
Did you apply for any tax credits to offset the cost?
Yes, we did take advantage of the tax credit that year
Very helpful, thanks.
Thanks Jerry!
You only insulated half of your house dude. let me know what the numbers are after you have a complete thermal barrier please!
Eh, might be a while...
Debating doing a similar project. Likely won't do much air sealing except around can lights, fans, etc. The economic payoff over 20-30 years is simple to justify. Likely breaks even, with a little savings at best. The kicker is a change in comfort levels upstairs. Especially in the summer. Have y'all felt a difference? Does it make the time/effort worth it?
I can't say I've really felt a difference in comfort. Heat and air seem to be working less though.
@@GlennFrazeeYT Thank you for the reply! Glad to know at least the equipment is getting a break and extended life at least.
Can it be added over fiberglass?
Sure can! 🙂
Which one is better? Cellulose or fibre glass? I live in Canada. I was suggested to use fiberglass as my existing insulation is fiber glass. I am seeing in summer my seconf floor is getting hotter and AC is not able to cool second floor. But my main floor and basement is super cool. Not sure if attick cam help this
Cellulose is cheaper, I think. Fiberglass might have a better R value per inch. Air sealing might do you better though.
@GlennFrazeeYT
Cellulose is R-3.7 per inch
Blown fiberglass is R-2.5-2.7 per inch
Is the cellulose fireproof?
They treat it to make it fire resistant. Doesn't stop it from being useless if it gets wet tho.
I have a 2018 house, 2600 sq feet, I did something similar but I removed the loose fill fiberglass with a dust collector from HF, i blew most of it onto my garage attic ceiling. I air sealed everything with spray foam, get a 36 inch gun off amazon. Then I blew in 225 bags of fiberlite cellulose, cellulose cost me about $3200, $300 in canned foam, and I hired a guy who does blow in insulation but I was the one in the attic doing the dirty part. The greenfiber machine from home depot is TOTAL JUNK.
Nice. I'm surprised you had to redo the insulation on a newer house
@@GlennFrazeeYT previous owner tramped a lot of it from running Ethernet cables got security cameras, and they never air sealed so it was worth the hassle
Hello. Considering doing something similar. Did you use the cellulose machine to blow the existing insulation to your garage ceiling? Thanks.
@@xincai951 no I used the harbor freight dust collector and 4 inch corrugated hose
I was looking for information like what you provided in your video. I have a 106 years old house in the badlands of Alberta, Canada.
I think we would benefit with adding to our existing r30 cellulose capped insulation. Thank you for doing this video.
More insulation is usually better, though you do get diminishing returns at some point. Not sure what they recommend/require for attic insulation where you live, but I'm sure it gets cold there!
Just had closed cell foam insulation put in my crawlspace and sixteen inches of blown fiberglass put in my (almost completely uninsulated) attic.
Zero improvement. House is still freezing and I'm still wearing jackets inside to stay warm. A huge amount of money wasted, I'll never bother with insulation again.
That's a big surprise. Are the walls insulated? You must have some pretty big air leaks somewhere. An energy audit would help pinpoint where you're having issues. You could also buy/rent a thermal imager and look around the house on a cold day for leaks.
@@GlennFrazeeYT I don't know anything about insulation in the walls but given that what I've already done did nothing I can't imagine that even if I added insulation there (which I won't) it would help any. I can feel some minor air leaks around a few windows and I'll look into that. It's not much, I've tested with candles, incense, tissue paper and an IR thermometer and haven't found much of anything. Before work even started the crew set up a large fan to check for airflow and they said that the numbers were good even prior to doing their work so I can't imagine that adding a few pieces of weatherstripping will do all that much. It's not a leak issue, it's an "insulation doesn't always do anything" issue, otherwise there would be some kind of improvement. I just wish that I'd known that before throwing five grand down the toilet.
@@cugamer8862 Did you bump your heat up afterwards? The insulation won't make your house warmer, just lower the rate of heat loss to the outside.
@@GlennFrazeeYT I used to keep the house set at 68-70 and it felt cold but I figured with the low amount of insulation that was to be expected. Now post insulation I set the heat at 75 and it still feels exactly the same.
Comparing
different year weather is not an accurate test because the weather year t year changes.
Also the price of gas changes per year as well
I correct for temperature in the formulas
I'm gonna have to say NOT money well spent for various reasons. First, your attic is not usable with cellulose and dirty and any work that may need done will cost more and then more insulation will need added again. Second, you are still losing tons of energy. Three, a very good spray foam installer could give you real savings and your space then becomes usable for storage or whatever. Lastly adding insulation is a never ending situation and does not terminatedly SOLVE the problem but in fact creates more problems...see above. Great video, good luck.
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How much did you pay?
Can't remember.
Be very careful about adding more blown in insulation into an old home like this. They weren't designed to hold all that insulation up there. Our ceilings collapsed under the weight of all that insulation. Air sealing will get you a better result. And then a common sense approach to insulating your attic. You don't need to blow a ton of that crap up there. I prefer air insulating, batting and decking/plywood. Blown in insulation just ruined our home. What a horrible product that blown in insulation is. It was a very expensive lesson for us. Never again.
That's unfortunate. Good note to ensure your ceiling joists can handle the weight.
Do you work with plc logic? You seem just like the people I work with lol
Nope, structural engineer
Brilliant, thank you. R-22-28’ish to R-48ish resulted in an almost 10% improvement in efficiency (reduced heat transfer). And youecexcel skills are impressive.
Thanks James! Bear in mind that this is a 45 year old house that isn't particularly well air sealed.
@@GlennFrazeeYT have you had a blower door test performed to get a quantitative measure of how elk sealed your home is?
Not yet. I'm sure it's quite leaky.
It must be if a 100% increase in attic r value resulted in 10% increase of energy savings
Ulitmately, the time to air seal would have been before that extra insulation was blown in.
Did this project myself. Took along time to air seal. Cost about $2000, I built an insulated cat walk thru the attic. Saves us about 100gallons of heating the first year.
Very nice. I agree that air sealing is a big pain, especially in an older house
Went to home Depot rented the machine and bought the sacs and did it myself
That works too 👍
How much for the machine rental? What did the whole project cost
@@freewilloutlaw6275 the machine was free rent when buying I believe 7 bags it will all depend on how big your house is. I only used 6 bags and returned one and kept the free rental.
@@freewilloutlaw6275 I’m curious also
@@freewilloutlaw6275 Machine rental is general free once a certain bag count is reached and you will certainly reach it if you are doing your entire attic space.
Great video! As you mentioned air sealing helps a lot in my experience. For crawlspaces too.
Top plates and around vents.
Yep, it's on the list of things to do
@@GlennFrazeeYT I sealed my vents with foam / caulk and on top of that I replaced my outlets on exterior walls and added foam to the back of the outlet plates to seal them. Really helped with both noise and drafts.
Unfortunately air sealing can only be done before the insulation is blown in, because you won't be able to access top plates, ceiling fans, light cans, bathroom exhaust fans, piping, or many other types of holes/intrusions.
Thank you for sharing you findings to the world. I’ve done the same added cellulose and added a perforated radiant barrier over the insulation. Curious to see if theres going to be a difference.
I'm interested too, feel free to post back when you know more
I have previously blown in insulation in the attic about 18 inches tall at the highest points. I'm going to buy 10 bags. I borrowed a quality temperature gun from a friend and and scanned the ceiling inside the house 1ft by 1ft to get areas needing touched up.
It's triple digits here and i keep the temp at 75. Attic temp at 112 during testing.
Living room was 77-79 in most spots and highest was 83 1-2ft from edges of walls. Our dining room was half 77-79 and the other half started at 80 rising all the way to 87 as i get closer to exterior wall!! Most of kitchen 79-81.
Hallway was 78 and hallway attic stair drop was 92 at center and 85 at edges. Spare room was entirely 81. Main bedroom was 79-80. Bathroom was coldest at 72-75.
I will make a map layout of the house and draw everywhere i need to spray in/add. I also blocked off half the Bathroom vent it doesn't need to be that cold so the air will push more out the needed vents.
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I have a bungalow just under 1300 sq feet, had 8" R-20 blown fiberglass in the attic.
I added 10"-11" of cellulose to get the attic around R-50.
I also dense packed cellulose around a couple knee walls inside a frame I built around them.
What I did over a period of two years was compared all of my gas consumption.
Looking at the previous winter, then compared to the winter after.
This showed a 23% drop in natural gas consumption based on gigajoules of natural gas used for each billing period.
Cellulose is definitely better than blown fiberglass, or batts.
I've done all three in different homes, and the cellulose made the most noticeable difference.
Very interesting, thanks for sharing your experience!
Lol okay so im not doing shit about my 4 inches of insulation, $15 difference
Depends where you live. If the winters are cold, more insulation always helps.
Great video but this isn't an excel tutorial. Just show the data!!!
You're welcome to skip that part
Only if you completely airseal the living space from the attic is the insulation effective. Don't need a ten minute video to explain that.
Neglecting to air seal won't negate the benefit of the added insulation, but I agree it's not as effective
@@GlennFrazeeYT it will when you have fiberglass bats, they let air through like crazy.
Great comparison, thank you!
Thanks Kent!
This was really cool. Have you looked at how it affected house temperature during the warm months?
Upcoming. Need to wait a month until things cool down here.
@@GlennFrazeeYTcan you given an update now?
OK we get it. You know how to use excel. I just quit watching because you weren't showing any results.
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I actually came for the excel tutorial, thanks @glennfrazeeYT.