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At what point does adding more R-value do little in energy savings?
Consider this situation: New Jersey location. Not too cold in winter but we get snow and occassional 20* days. Summers can get hot but not like Fla or Texas. All air sealing done. R40 cellulose in attic. Will adding another R10 to the attic be noticeable in energy savings?
I know the first R10 has the most benefit and then goes down some for R20 and more so for R30 and R40. Is the extra $$ & effort for R50 worth it or is it soooo minimal it’s not worth doing?
Thanks for any advice
JeffB
Replies
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jeff, there's another problem with the extra R-10.. if wasn't installed with the original.....so it probably will cost you just as much for the additional as for the original...
the best time to make this decision is when you are talking to the insulator.. how much for R-40.. and how much for R-50 ?
if you 're over R30 in NJ, then i'd think twice about more.... and if i had less than R-20 i'd probably go to R-50...but an increase of R-10...marginal.. now ask me again when home heating oil goes to $3 / ga...
*Hi Jeff,I wouldn't do it. The returns are no longer there for you to benefit from in your climatic zone.Look to the rest of the house envelope such as windows and doors.Gabe
*After I read your reply I see how my post isn't totally clear. I'm about to have the attic insulated. I can choose to go R40 or R50. The extra R10 will be about $500 for 1800 sq ft of attic. Jeff Bernard
*i'm looking at a chart for Cellulose..blown , R-50 would be 14.7 inches...and R40 would be 11.7 inches..the difference is about 11 bags per 1000 /sftell him you want R-60 for the $500..my attic has 18 inches..b but hey, whadda i no ?
*Jeff, I don't know where you are in NJ, or how long you've lived there, but I've seen 26 below zero in Warren County. That's exceptional, but on the average, in the 35 years that I lived in the Garden State, I could count on 4 or 5 below-zero nights in a given winter. I'd vote with Mike.Andy
*Jeff, I think one needs to consider the FUTURE costs of energy. As you may be hearing, natural gas prices will be about 50% higher this winter than last year. I expect this trend to continue due to the increasing number of commercial users switching to gas powered staionary power, refrigeration, etc. As demand increases, so does cost. Natural gas demand is definetly increasing. There have been several articles to this effect, the last one I read was in "Energy user news."A local cellulose guy here also tells me about some "fuels parity act" whereby the fuel cost can legally be seasonally varied to make competition fairer. Because heating oil went up, they can raise natural gas prices appropriately. I have not had a chance to confirm this.An over insulated house can also "insulate" (pardon the pun) you from energy price swings.My peak gas bill will go from $80 last winter to maybe $120 this winter. But this winter I will have finally added the R-13 worth of cels in the old rafter bays. That will also cost about $500 and will be dense packed - more work than open blowing..27 psf for the extra 10 is high. Tell him you'll feed the machine and ductape the hose to a rafter. Now you only need to rent his machine for an additional 15 minutes. What does that cost? Sorry to oversimplify, but the blower is merely a conveyance to get the cels into the attic. Gravity does the real work there.-Rob
*my point XACTLY.. but you can often get more for your money than trying to get the price down..kinda face saving for both of you..that's why i was suggesting the R-60..
*Rob et alI just yesterday got a price for R40 of cells in my attic: $736 for 920 sq ft. My location is Long Island NY. There seems to be only 2 guys that install cells on Long island. At least that's all that I've found so far (called, asked around and called manufacturer). Many will do blow-in but just fiberglass. Anyway, this one guys name kept coming up for cells.He actually told me, in his opinion, adding anymore than R40 won't really benefit. He refered to a chart showing after R30, a relatively flat graph line of energy savings. I can't vouch for his opinion nor can I vouch for his chart. He cited that careful airsealing of all penetrations thru the ceiling, walls and floor eliminates the need for more cells. Just another story....Phil
*P.S.That price includes approx 54, four-foot vent chutes and a wad of insulation stuffed in the bays to prevent the cells from falling in the soffits.Phil
*not a bad price - In my area that would be .65 to .70 psf totalling $644. Considering your escalated local economy that price seems great.-Rob
*RobI thought it was a decent price especially considering the following. According to the manufacturer, for R40 one 30# bag will cover 13.64 sq ft including framing. 920 sq ft / 13.64 = almost 68 bags. 68 bags @ $7.25 bag costs $493. That doesn't include the vent chutes, fibreglass batts to roll and stuff in the soffit rafter bays, a blower rental ($75/day), picking up the materials or installing it all.Not bad at all, huh?Phil
*$7.25 per bag!!!!!They're $5 around here. Home Depot had them onsale for $3 a few weeks ago and sold their inventory out in 45 minutes. Commercial places do not stock cels here.-Rob
*Yep $7.25 for a 30# bag. My impression is that cellulose is not very "popular" here on Long Island. Very, very few places to buy it. No competition for sales. Home Depot doesn't sell it here. Many people don't even know what it is. They're all fibreglass-brainwashed!!!To tell ya the truth, I didn't know about it until a few years ago, reading about it on one of these type of online forums. I think it was the original This Old House site and the post was a gigantic tome called WEATHERIZATION. To keep the topic from disappearing from the end of the list (no archive), people would occasionally just post the word "BUMP".When I tell people about what I am using for insulation I get blank stares or comments "doesn't that stuff burn and settle/decompose in the walls?". I start sounding like a salesman when I explain it all. If this area (Long Island) can be educated to the value of cells, the market would be strong. I was told that the only "peak" period for cells on Long Island was back in the energy crisis days of the 1970's. Maybe when oil hits that $3.00 gallon price this fall/winter people may be inclined for retrofitting.Even tho Long Island enjoys a high standard of living, people still will be adverse to paying premiums for a specialist for insulation. Just about anyone can stuff fibreglass in the walls or ceiling. No special training, no special equipment, and easily purchased at all home centers.There is a new development just 400 feet from my house. $400,000.00 and up (yes four hundred THOUSAND) homes that are getting the bare minimum R-value of fibreglass. It seems someone could sell the buyers on the value of cellulose, especially with all those cathedral ceilings. Some of the monster homes are upwards of $700,000.00!! How much extra $$ could using cells actually cost?Just some of my thoughts,Phil
*phil... installing cells should cost less per R-value than installing F'brglas..sounds like you should rent a good quality machine ad go in business..there's a lot of room at $7.25 /bag..around here, i can usually get insulation installed for less than or the same as i can buy it for..mostly because the installers have better price breaks.. it only gets dicey for them when the mfr's start putting them on aqllocation..""Patchogue Phil--Your Insulation Specialist""has a certain ring to it , don't it ?
*All kidding aside, I actually have thought about it. The hard part would be attracting business for a product/service that is not well accepted here. It's a whole paradigm shift in thinking for homeowners and contractors alike.
*my insulator is booked for the next 6 weeks.. he juggled his schedule to give me one day for a small house ...and he does almost no new construction...he sells, his brother and two guys install....cellulose, fiberglass, rigid, vent chutes, and mushroom roof vents..one blower and a hi-cube truck..find out who the local insulation distributor is.. it'll be some guy with a wharehouse full of insulation...selling to installers...
*Mike and Phil,You couldn't pay me enough to be a cellulose insulation specialist. I just spent a week pumping a house full of cells and nearly lost my mind from boredom! I still try and convince people to go with cells, though. I just would hate to do it full time.Steve
*phil.. guess we can forget about hiring steve...hey, steve, i hate doing anything full time... that's why i'm a remodeler... ADD.....and the boredom level is low...
*Phil, et.al.Take a drive over to Cresskill, NJ to a development called rio-vista - it's up[ on the palisades.Here you can see 3 and 4 MILLION dollar houses that have every defect Joe Lstiburek has ever photographed!How about 2x4 walls - probably going to use a "high density" batt, right.I guess the brick veneer on the outside of the house must count for thermal mass.Some of the largest, crappiest "houses" I have ever seen.They even have solid vinyl windows in some of them. "Seal failure? What's a seal failure?" "A seal failure is what you would get in 7 years, if you had any regard for money or quality, when those damn vinyl windows start frosting themselves!"Around here there are 6 guys in the book that do cels - none compete on price, many do lots of new houses. Maybe 2 of them will return your call, and none will ever show to give you a price, unless you know them. I'm friends with one of the best in the area. Cels costs more here because most of the guys doing it have been into the industry and building science for over 20 years. And they are booked solid for ever. The others are riding the veterans coattails and charging similarly.-Rob
*We have a manufacturer of cells about 8 miles from me, in Bohemia called PINACLE. They must export to upstate NY and NJ etc etc.
*I'm new to this site but have sporadically bought the mag and would like to get some insight into the world of insulation. I live on the coast of Maine and have a recently finished (our first house) modified salt-box shell building 30x42 with 2x6 walls and 2x10 rafters. I'm ready for insulation and am looking at several options. Cellulose is sold at Home Depot etc and seems reasonably priced. I've heard the usual settling, insects, etc. Also looked at blown in fiberglass-both Guardian's Ultrafit and Certainteed's Insulsafe IV and the usual glass batts/roles. The blown in glass seems best but has a rather premium price. What is everyones opinion (better yet, experience) with the blown in fiberglass? I hear so many different claims from contractors (depending on what they are trying to sell) and the manufacturers (of course). I'd kind of like to save the coin (about 30 percent of the other systems) and do the traditional fiberglass batts myself. Any thoughts? Thank you, SkippBob.
*Take a peek at http://www.cellulose.orgPhil
*You can do the cellulose yourself too. At higher densities, it does not settle. I have personally had less problems with rodents and insects in cellulose than in fibreglass - they moved out when I blew in cells. Others may have had different experiences.Cellulose will provide a radiant barrier - fibreglass will not - this may or may not be important to you.R values for batts are based on labortory tests with tolerances for the batts fitting in the test wall measured in 1000ths or 10,000ths of an inch. I don't believe you can achieve that on site and thus will have a significantly lower r value. So while they may seem less expensive, you would probably see less return than with a blown in product that always fills every nook and cranny and crack no matter how irregular or out of tolerance.Plus, if you do it yourself, no itch and no potential for adverse health impact with cells.
*The settling myhtology comes from incorrect installation procedures from 40 years ago.Back then they drilled 1 or 2 small holes in each stud bay, insert a rigid nozzle into the hole and pump the stuff in. Due to friction, etc in the pack, the extreme ends of the cavity were filled with "fluff." This caused settling.Nowadays, you snake the house down the cavity and start filling from the far end first. It is difficult to install it wrong in this manner.-Rob
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At what point does adding more R-value do little in energy savings?
Consider this situation: New Jersey location. Not too cold in winter but we get snow and occassional 20* days. Summers can get hot but not like Fla or Texas. All air sealing done. R40 cellulose in attic. Will adding another R10 to the attic be noticeable in energy savings?
I know the first R10 has the most benefit and then goes down some for R20 and more so for R30 and R40. Is the extra $$ & effort for R50 worth it or is it soooo minimal it's not worth doing?
Thanks for any advice
JeffB