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Energy saving value


JOB's Avatar
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Join Date: May 2007
Posts: 32
NY

03-14-11, 04:41 PM   #1  
Energy saving value

Hello I own a 3100 sq. ft. two floor center hall colonial in upstate NY. The attic has R-30 insulation. I have been to a number of web sites and have determined that I should have between R30 and R60 in the attic.

My question is what kind of energy saving can I expect in the Winter if I upgrade from R30 to R60. I heat the house with propane thru a forced air system.

I can get R-30 in 25' lengths 15" wide at Home Depot, rough guess will cost me about $600 for the material.

Any input would be appreciated
Thanks
JOB

 
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Bud9051's Avatar
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Join Date: Oct 2008
Posts: 9,771
ME

03-14-11, 06:35 PM   #2  
Hi JOB
R-30 is a substantial amount of insulation and your ceiling is only one of 5 major areas of heat loss. Yes, the extra insulation will reduce your heating costs, but there are most likely larger loss areas you should be looking at. Example: Air leakage. First, it is a whole lot easier to seal some leaks before you add all of that extra insulation.

Forced hot air means heat ducts. Where they are located and how well they are sealed may be another big contributor. Returns that use the framing cavity for the air path can often be pulling outside air into the house.

Air seal the house and those ducts, think 25% reduction in heating costs. (a guess)

One quick indicator of excess air leakage is low humidity.

To answer your question, I had to make a lot of assumptions (guesses), but $200 per year if you just add the extra r-30.

More details and we can walk you through the numbers.

Bud

 
fairplay's Avatar
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Join Date: Feb 2011
Posts: 71
CANADA

03-15-11, 05:18 AM   #3  
I live north of Toronto so I know what Cold means. I stuggled with the decision of replacing the large and leaky picture window or adding attic insulation. (lack of funds) Obviously it is important to seal up any leaks, but because heat rises I decided to do the insulation first. I originally had batts up in the attic for a total of r20. So in late December I had blown in cellulose (recommended) installed right on top (took 1/2 hr) bringing up the value to r50. It was the best money I ever spent. I have an electric furnace and since Ontario Hydro as introduced time of use metering system you can go online and track your hydro usage monthly, daily and even hourly. I can see on the graph from the day it was installed the very significant energy savings and it was proven when I received my January bill. I also can bank on lower cooling costs and higher comfort levels this summer. For this winter anyway, the old plastic film on the windows will have to do.

 
resercon's Avatar
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NJ

03-15-11, 01:10 PM   #4  
First and foremost you have to know what the R-values stand for. R-30 stands for 1/30th of a BTU traverses one square foot of this material an hour. R-60 is 1/60th. This rating is done for comparison and is known as a standard. Meaning to say that variables like temperature and pressure are made constant to obtain this rating. What this explicitly implies is that an insulation rated at R-30 will have more than that amount of heat loss(1/30/sq.ft./hr.) when the temperature outside is below the standard testing temperature and less heat loss when the temperature outside is above it.

Take fairplay's reply for example. Because of the average temperature north of Toronto in the winter is below the testing temperature the additional insulation saving was significant. This would not be true if he lived further south where the winters are less severe. Unfortunately fairplay will be disappointed during the summer because his area does not have severe summers as south of him. His savings will probably be insignificant for the summer.

I suggest that you look up the "Law of Diminishing Returns" before deciding to add more insulation. Also look up the "Heating Degree Days" (HDD) for your area. If it's more than 10,000 HDD's go for it, if it's less you might want to consider investing elsewhere in your home.

 
fairplay's Avatar
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CANADA

03-15-11, 02:53 PM   #5  
Resercon, Not to be contrary, but because Toronto is literally across the lake from Upstate New York our climates are quite similar. Yes, we have brief but intense cold snaps, but so do a good deal of the States. The difference in average temperature is within a degree or 2. In fact I think you guys had a worse winter then we did here in Ontario. Plus all new building codes will have a r value of r50. I can't speak about the technicality of the whole thing, but JOB asked for input and that is my experience. BTW I'm a she.

 
resercon's Avatar
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NJ

03-15-11, 05:03 PM   #6  
Forgive me for not being clear and not knowing fairplay is a she.

The temperature used to determine the R-values is 32 degrees Fahrenheit (outside) and 72 degrees Fahrenheit (inside). The barometric pressure is 29.95. So if the outside temperature is 40 degrees Fahrenheit the heat loss is less. The reverse is true. I live in New Jersey where the average winter temperature over the last 20 years is 36 degrees Fahrenheit. Insulation of R-30 would actually lose less heat per hour in my area. If I added more insulation to R-60 the amount of saving would be less than 10%.

Heat loss is defined as the amount of heating measured in BTU's per hour needed to maintain a certain temperature. What influences this is degree difference between the conditioned and unconditioned areas. The greater the degree difference, the greater the heat loss.

Let's say there are two identical home next to each other. One home sets its thermostat at 70 degrees and the other sets it at 72 degrees. Which one will have a higher energy bill? The one with the greater degree difference between the inside and the outside. The same is true for cooling except the home that sets it's thermostat lower would have the higher energy bill.

 
JOB's Avatar
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NY

03-15-11, 06:54 PM   #7  
Energy Saving

Hello, thanks for all the input so quickly. I have a 1000 gallon propane tank that maxs out @800 gallons. I used apx. 600 gallons last heating season (it was mild) and for 2010-11 I have used 700 gallons to date. I have sealed all the drafts including over my sill plate (which I also insulated) and have insulated my heating/ac ducts in the basement. I have a programable thermostat that keep it at 67 when we are home, 63 @ night, 67 when we wake up then 60 when were gone. I even have insulated blinds.

I felt that it wasn't cost effective to replace all the windows and glass doors as the house is only 15 years old. I felt the best bang for the buck was increasing the attic insulation and the encapulated batts look good a DIY project.

The reason I will do this, with the possibility of only a 10% savings on my energy bill is because i want to raise the heat (thinking of retiring soon) but don't want to have to turn off the tv,computer and phone to afford it. When I retire I expect my fuel usage to double.

Love the house just don't know if I can afford to heat it, when we built the house we had an oil furnace (heat exchanger failed) oil was $0.62/gallon in 1996.

Thanks again
JOB

 
Bud9051's Avatar
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ME

03-16-11, 05:58 AM   #8  
JOB, I can certainly relate to higher temps in the house as I spend most of my time home and with the meds the doc has me on (blood pressure and sugar) I seem to have lost my natural insulation, although it doesn't look it. I can no longer be comfortable at the 70 and below numbers and the oil tank has shown the penalty for my comfort. I too am making heat loss changes, but I'm going to the extreme so that my tomorrow costs will still be low with the anticipated tomorrow prices.

One of the pieces of advice I hand out is for home owners to be prepared to take advantage of improvement opportunities when they present themselves. If you decide to replace the siding, add a few inches in rigid insulation in the process. Remodel a room, increase the exterior wall thickness with additional insulation.

You can hire an energy auditor to document all of the opportunities in your home or you can pull up one of the DIY energy audit pages and dig out the needed information yourself. Either way, you are better prepared to jump when one of those opportunities comes along.

Stay warm
Bud

 
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