Second Heater or More Insulation?

[Joey-D]

Yes, another HVAC question. I have a 17x23 attached garage on my home. Insulated on all four sides with a insulated door. Ceiling height is 10' at walls and 13-14' at ridge. The ceiling is not insulated. I purchased 2 Emerson Electric wall heaters off Craigslist yesterday. They are 208/240 - 3000/4000 watt units that are 14"x18" 15 amp heaters. My plan was to install one and sell the other, (As I gave $225 for the pair, new). Well the one ran over night and the garage is sitting at 45* compared to 16* outside. I don't want the electric bill to go super high so should I....

A: Sell second heater and insulate ceiling with R-19 for $90 or R-30 for $150?
B: Install second heater and not insulate the ceiling?
C: Insulate the ceiling and install second heater?
D: Stop whining as it is almost 45* in the garage!

I'm just afraid this heater is gonna run full blast all the the time. At a rate of $.0412 per KwH that means $89 a month I think.
.0412(rate) x 3(kw) x 24(hrs day) x 30(days a month) = $88.992 or do I multiply the by 2 since its 220v?

 

[tdkkart]

Heat rises, insulate the ceiling.

 

[Joey-D]

What r-value are ceiling normally?

 

[sjt78]

A) Insulate the ceiling and put on a sweatshirt and gloves Seriously, is the temp it is at now ok to work in? If so you the insulation will help for very little money. 16 degrees is cold, and no matter what you do to the garage, you will still have heat loss due to the garage door. If I can get my garage in the 40's when it is that cold outside I feel good.

 

[buddyboy]

my 35'x24' attached garaged is unheated, but very well insulated (doors, walls, ceiling and floors). it stays in the 40's all winter long. except on very cold days it'll drop to around 32. I'm in northeast ohio.

so I would recommend insulate

 

[njfl]

Insulate the ceiling. That one-time cost of $90.00 will be less than your recurring heating bills. Also, get a ceiling fan or small wall mount fan high up to blow the warm air down (since it will rise to the ceiling). As you have it now, your cold, non-insulated ceiling is just "sinking" the heat that's generated.

 

[mikeyr]

I am in S. Calif. if it gets down to the low 40's outside we consider it freezing and I still put in R13 in the walls and R30 in the ceilings. I wanted more insulation ! It makes no sense to me under insulate no matter where you are in the country, I keep my garage a cool 55 at all times and punch it up when I in there, but the insulation also keeps it nice and cool in the summer time.

I agree with the ceiling fan too, it will really help.

 

[Joey-D]

I am insulating the ceiling now. I will have to insulate directly to the sheeting. If I can't find insulation with a plastic wrap, do I plastic the ceiling and then insulate or used face insulation and then plastic over it or put insulation in reversed with the face to the sheeting or?

 

[jklingel]

Joey: There is absolutely no doubt about your needing insulation in the lid. It is a Period, End of Story deal, IMO. If you could describe the construction of the ceiling, we could maybe offer some suggestions. Why can't you access the ceiling about the sheetrock or plywood you have up there? Normally, you would have sheathing of some kind, then a vapor retarder, then insulation, in that order, from the garage side out to the outside. If you absolutely can not get above the ceiling sheathing, then perhaps consider rigid foam insulation (EPS should do fine) screwed into whatever is in the ceiling that would support it. Get the edges tight, foam any gaps, and install a vapor retarder on the room side of the foam insulation IF there is not already a vapor barrier/retarder installed under the sheathing. I know you don't want to hear this, but it may be best to start over; take the ceiling sheathing down, insulate, vapor retard, then re-sheath. In the long run, you'd be way, way ahead. Good luck w/ the project. j

 

[Joey-D]

I don't have a "ceiling". I have the underside of the sheeting as my "ceiling". The rafters are 2x6. I am doing 2 layers. It was by far the most cost efficient route. The first layer closest to the sheeting is R-13 that is fully wrapped in plastic. The second layer is R-13 with only a facing on it. This will give me an R Value of 26 or 7" of insulation. A little will be lost as I will be stapling it 2x6 and compressing it some. Doing it this was, it was $.524 a square foot. (actually cheaper as the gal at lowes charged me for 20 bags of the faced stuff compared to 10 of wrapped and 10 of faced.) $12.48 a 40 sq ft bag of R-13 fully wrapped and $8.48 for 40 sq of the faced. It cost $210 to insluate 400 sq ft. Or because of the check out error, $169.60. Also if you get in the movers packet at the post office, there is normally a 10% coupon to Lowes there.

 

[jklingel]

Uh oh.... this explains a lot, and I think you are going to hear some comments about this. If I understand you now, you are putting insulation right against your ROOF sheathing. No???? IF SO, big, big mistake. Tell me I am misunderstanding. If you are putting insulation right against your ROOF sheathing, you are going to have, eventually, massive rotting there. Water vapor will escape, hit the cold/cool roof sheathing, and either form water or ice, depending on temp. Your insulation will also be getting wet, and therefore the R value will go south real fast. This is called a hot roof; real hot. I assumed you were talking about insulating in the CEILING, which is a whole different can of worms. Never, ever insulate right against a roof. Period. I think we need to re-plan what you are doing here, again, if I understand correctly. john

 

[jklingel]

PS: I am not a saint, but the comment about the Lowe's error should be corrected, and you are the guy in the driver's seat on that deal. Don't you agree?

 

[Joey-D]

I was planning on insulating against the roof sheeting, thats why I bought the plastic wrapped stuff. Fully wrapped.

As far as lowes thing, they mark up stuff so much that when I get a break like this, I jump on it.

 

[Joey-D]

http://www.thisoldhouse.com/toh/asktoh/question/0,,452954,00.html
Says that 2 inches is needed between the insulation and sheeting. If I staple 3 1/2" insulation on a 2x6 it will give me what I need. So I need to staple the faced stuff first and then the plastic wrapped backwards it will give me what I need.

 

[Crzydmnd72]

is there ever an acceptable way to insulate right against the roof? I have the same scenario in my garage and thought I would have it foamed someday.

 

[Joey-D]

 

[nate379]

Somewhere between R-40 to R-50 would be decent insulation for a ceiling.

What r-value are ceiling normally?

 

[jklingel]

Yes, 2" is the minimum clearance for venting, and with that little a ridge vent is also very helpful. I'm glad you aren't stuffing against the roof sheathing, like I thought your above post indicated. Be sure that the odd batt does not **** out and block off your venting. They make paper-type stand-off "brackets", if you will, just for that reason. As for the R-value needed, it depends on where you live. Contact a local city/county official for their recommendation. As I am sure you realize, your overall R value will be about 3 or 4 digits below the sum of the two batts, as the second layer will be essentially nothing where you staple it to the 2x6. That is not necessarily a bad thing; depends on how much R your area needs. The 2x6 has an R of about 5, if I recall. What that system leaves you with is called thermal bridging, and you may get condensation on the 2x6s. Be sure to use a vapor retarder, keep an eye on it, and good luck. Another option would have been to use rigid foam for the second layer; that may have been a tad neater and a more uniform R, but not necessarily significantly better. j

 

[jklingel]

"As far as lowes thing, they mark up stuff so much that when I get a break like this, I jump on it." Everybody needs to make a profit; that is neither illegal nor immoral. Businesses are not philanthropic organizations. You can rationalize things in a multitude of ways, but we need not debate that here. What would Jesus or Abe Lincoln do? Whatever. Best. j

 

[Joey-D]

I was planning on putting it directly against the sheeting until you chimed in, then I decided to do a little research and came across the 2" rule.

 

[bucs012]

my 35'x24' attached garaged is unheated, but very well insulated (doors, walls, ceiling and floors). it stays in the 40's all winter long. except on very cold days it'll drop to around 32. I'm in northeast ohio.

so I would recommend insulate

Agree. I have a 50x30 garage in Iowa. Mine has gotten down to 25 but it was minus 10 temp outside. Most the time during normal weather conditions 20 to 35 degrees, my garage is 30 to 40 degrees on the inside. Makes it nice to only have to bump the heater to 50-55 to work out there all day.

 

[jklingel]

Sounds like you've got it now. I personally hate hot ceilings, just because they are too "iffy", IMO. But, sometimes you gotta do it, or folks like cathedral ceilings for the feel. Whatever works! j

 

[6768rogues]

Watts = Amps X Volts. If you have a 4000 Watt heater, you do not need to reconsider the voltage when calculating power consumption. 15 Amps of 208 Volt is 3120 Watts. 15 Amps of 240 Volts is 3600 Watts. Single phase electricity will give you 240 Volts and three phase will give you 208 Volts. To get 4000 Watts you would need 267 Volts, not a common Voltage. One leg of a 480 three phase is 277 Volts, but if you had 480 three phase you would not need a single phase heater. In a residential installation, you probably have single phase.
All that said, I would insulate the **** out of the ceiling.

 

[Joey-D]

I insulated the ceiling today. Had to run out and sell a car and didn't get to finish. There is about 20 Sq Ft I need to finish. Holy Moly did that make a difference. With the the 20 feet still open it is 67* in there now and only 25* outside. That was using only R-13 insulation.

 

[Joey-D]

After finishing insulating the ceiling with only one layer of R-13 I am very impressed. I have one 3000/4000 watt electric wall heater and I only need to run it at about medium to keep the garage at 70*. Still have to fine tune it, as I think 60-65 degrees would be better.

 

[director_gtr]

After finishing insulating the ceiling with only one layer of R-13 I am very impressed. I have one 3000/4000 watt electric wall heater and I only need to run it at about medium to keep the garage at 70*. Still have to fine tune it, as I think 60-65 degrees would be better.

Thats really good! I think I would want it around 60 as well... not to mention cheaper

 

[jklingel]

I have one 3000/4000 watt electric wall heater and I only need to run it at about medium to keep the garage at 70*.

Ain't fiberglass just the greatest stuff... once you get past the itching. Glad you are tickled. j

 

[Joey-D]

Used John Mansville kraft faced. No inch or raspy throat. No sweatshirt or respirator either.