insulating/heating?

[dlenardu]

HI,

I have a 35x30 garage with 14' ceilings. This is an all block garage with roof trusses. Currently I do not have any insulation in the ceiling but that is going to be changing soon, the two garage doors are fully insulated. My question is, since the walls are block, how much heating am I going to loose through the block? The ceiling will be r30 but nothing on the walls. What size heater do you think I will need, I would like to keep it around 60 if possible. I do not have natural gas. When I was looking at propane it seemed a bit expensive. If I get a large tank 300 gal it is $50 a year for the tank plus $3.00 a gallon with a minium one time fill per year. I pay $.08 per KWhr for electricity, so unless my math is off which wouldn't suprise me, propane would have to be around $1.00 per gallon to come out the same as electricity. So my questions are:

1) how much is the block walls going to hurt me in the heating factor, is there anything I can to for the wall other than build another wall around it and insulate that wall?

2) size of heater needed to stay close to atleast 60 degrees?

3) Is my math wrong, and electricity is cheaper than propane in my case?

Thanks again for all of your help

 

[sneezer41]

If there was some way to get an inch of foam on those walls you would be a happy camper.
concrete block has an R value of about 1, so it is like having a glass building without the view. It does have thermal mass however, so it is not quite as bad.

At a 50 degree delta T you will lose 90 k btus out those walls if they are 14 feet tall.


Can you get heating oil where you are? It has almost 50 percent more btu's than propane, and a regular house style hot air furnace would not be pricey.

 

[HoosierBuddy]

Your building is a lot like the barn I was working in before I built my garage 3-years ago.

You are going to need a bunch of heat to get it up to a reasonable temperature. I like the idea of buying someone's old 80+ house furnace and using it with just a little duct work to direct the air. Check Craig's list.

The key is going to be NOT using any heat the 95% of the time you aren't out there working. Just heat it when you need to use it, or it will eat you alive.

Not having any insulation with concrete block walls is pretty bad. I know there a lot of industrial structures out there that are heated 24X7 with uninsulated block, but it's not the best situation. To heat your building 24X7 in a cold winter environment with propane could cost $600, $700, or more a month.

Just heating it 5% Of the time costs 10 times less. Say $50 to $100 per month.

BTW...a good solution is to use polystyrene on the exterior and use metal or vinyl siding over that. You could also fir it out on the inside. Do it if you are going to heat it all the time. Save your money if you aren't.

Phil

 

[D.J.]

I don't know anywhere that electricity is cheaper than propane. You have to take into consideration the BTU factors of both. I would definately insulate the indoor side of the garage with at least ridgid foam board or fir out and vapor barrier and then fiberglass bats. You could check around with the local fuel dealers and HVAC guys and see if they are installing new furnaces anywhere where you could go in and gut the existing system for them. Also check with the area fire departments and see if they know of any recent canidates of a fire where the structure will be condemed. Lots of options!
________
black girl Cams

 

[pcmeiners]

heating fuel cost comparison....

http://www.eia.doe.gov/neic/experts/heatcalc.xls

 

[dlenardu]

Pcmeiners,

Thanks for that link.

According to that spread sheet fuel oil (at $2.79 a gallon) would be the cheapest at $20.12 per million btu's, electricity would cost me $23.45 per million btu's and propane would cost $32.85 per million btu's

Electricity seems to be the most economical for me at being just over $3 more than fuel oil but then I don't have all of the initial start up costs of having a tank installed, getting that tank filled, running the lines, etc.

If I could get the fuel oil around $2.oo a gallon then I could save some money but still have all of the start up costs. Propan will have to fall to about $2.14 to be the same as electricity.

I wish I could find a rubberized coating that I could apply to the block that would have a r-value, be thin, and look good on it own

 

[jdaallen]

If you fir out the inside walls with 2x4s and R11 fiberglass bats (both cheap) it will pay for itself in about 2 to 3 years plus you'll be a lot more comfortable in the meantime.

 

[Tom McDermott]

Hi,

I assumed a couple of things about your garage in order to run a calculation:
1) Concrete slab on grade, no insulation.
2) All 4 walls exposed (not adjoining a heated house, for example).
3) The two garage doors are 9-ft wide by 7-ft high, insulated, metal.
4) 40-degrees temp differential. IE: keep garage at 60F when outside temp is 20F.
5) 'poor' air infiltration performance, no vapor barriers, no sealing tape aound pipes, joists, etc.
6) No windows.

Based on those assumptions, calculations are:
Total heat loss: 11,950 watts.

Heat loss through uninsulated walls: 6,249 watts
Heat loss through insulated ceiling: 408 watts
Heat loss through slab concrete floor: 1313 watts
Heat loss through doors: 162 watts
Heat loss through air infiltration: 3818 watts

Electric heating would require ~12 kW electric, or about 41,000 BTU.

You can find the Excel spreadsheet calculator I used to compute these numbers at:
http://www.dimplex.com/HEATLOSSCALCULATOR.xls

-- Tom

 

[dlenardu]

Tom,

Thanks for the reply and link,

Two of the walls are underground for about 11 ft high, with 3 ft exposed on those two walls (i'm not sure if that helps with insulation or hurts)

I have two 10'x10' insulated doors, a walk in door (insulated), no windows, I only have one pipe coming into the building and that is where the electricy comes in (the whole was great foamed) No windows. The ceiling will be 5/8" sheet rock with R30 insulation

 

[dlenardu]

If you fir out the inside walls with 2x4s and R11 fiberglass bats (both cheap) it will pay for itself in about 2 to 3 years plus you'll be a lot more comfortable in the meantime.

The problem with doing that is a loose space, have to sheetrock, then I have to redo all the electrical because it currently is conduit running along the walls. (I know it is a tradeoff) but I'm trying it keep as much space as possible in there, I guess I could fur it out with 1x and put foam board in and sheetrock over but I was not really wanting to sheetrock it.

 

[thelatist]

I accept with information:Based on those assumptions, calculations are:
Total heat loss: 11,950 watts.
Heat loss through uninsulated walls: 6,249 watts
Heat loss through insulated ceiling: 408 watts
Heat loss through slab concrete floor: 1313 watts
Heat loss through doors: 162 watts
Heat loss through air infiltration: 3818 watts

 

[Kjbakke2]

The problem with doing that is a loose space, have to sheetrock, then I have to redo all the electrical because it currently is conduit running along the walls. (I know it is a tradeoff) but I'm trying it keep as much space as possible in there, I guess I could fur it out with 1x and put foam board in and sheetrock over but I was not really wanting to sheetrock it.

you could drill holes and do blow in insulation
its pretty cheap and at home depot when you buy blow in they rent you the machine for literally next to nothing (i think the sign said a penny or some **** like that)
just a thought because it sounds like youre trying to not take walls apart
scratch that i didnt see that you had concrete walls

a big massive durr on my part

 

[krooser]

I've seen a TV show where he contractor used a long nozzle to fill the voids in a block building with closed cell foam.. probably expensive but would eliminate the need for any inside insulation.

 

[dlenardu]

I've seen a TV show where he contractor used a long nozzle to fill the voids in a block building with closed cell foam.. probably expensive but would eliminate the need for any inside insulation.

Now that would be pretty interesting, I wonder who could do that and what it would cost?

 

[Duck]

dlenardu, my shop is 30 x 40, 10' ceiling, uninsulated attic, concrete block.
One 10 x 12 roll-up, one personnel door, 3 windows. Overhead is 7/16" OSB.
I put in an old homemade wood stove after I built the shop, but I'm getting tired of the cold days in the shop. I'm looking at building a waste oil heater, and have started gathering up the pieces. The whole rig can be built for under a hundred bucks or less, depending on how much of the fabbing you can do yourself.
I'm lucky to have a small machine shop in mine, so I can do all of the fabbing.
From what I've read, waste oil heat is the way to go. The oil is free, and no electricity is needed.
Check out the following link: http://www.journeytoforever.org/biofuel_library/ethanol_motherearth/me11.html
That site has several other links inside, be sure to scope them all out.
It doesn't get as cold here as where you live, but if it'll keep Roger Sanders' shop warm in his part of the country, it'll work for me.
Good luck in your endeavors.
Duck

 

[bobadame]

For what it's worth, I think you should place the insulation on the outside of the building. I believe that 2 layers of 2" thick pink or blue foam will give you about R-20. Of course you'll have to cover it with siding or stucco to protect it. The advantage of doing it out side vs inside is that with the insulation on the outside, your block structure is a huge thermal mass. Should be nice and cool in the summer too.

 

[nate379]

I don't see it being that bad with a block building.

My friend has a shop out of block, it's about 60x70 with 20ft tall ceilings, 3 bays with doors, maybe 16x18 or so. Runs him around $500 a month to heat in the winter and it's kept at 65 all the time.

To compare my house/garage which is roughly 1/2 the sq footage and only 9ft ceilings costs me ~$150 a month.

 

[Kevin54]

From what I've read, waste oil heat is the way to go. The oil is free, and no electricity is needed.

Waste oil is getting harder and harder to come across. And unless you are doing a huge fleet of trucks yourself in changing oil, you are not going to generate enough oil from the occasional oil change to even come close to justifying a waste oil furnace. At one time you could get it for free, now you have people going around in large trucks buying it up on the cheap. I tried the above link but it did not work so I don't know what type of waste oil burner they are talking about, but to purchase a waste oil furnace, you are looking at a few grand, plus installation, plus trying to find enough oil to run it. My nephew has a diesel repair business and I know he goes through a few hundred gallons in a heating season

 

[Duck]

Link works fine for me.
In a nutshell, the design uses an electric water heater tank, modified for this purpose.
According to the article, if Sanders runs the burner on high, he uses about a gallon an hour, much less on lower settings.
I realize that if you run the heater 12 to 16 hours a day, you may have trouble with getting enough oil. I have about 40 gallons stashed back; I put the word out at work that I would take all the old engine oil I could get my hands on. I have guys bringing it to me fairly often.
I don't know if it's true, but I read somewhere that oil change shops would give you waste oil. I haven't tried that, but it doesn't seem likely, what with the EPA and whatnot.
Duck

 

[armstrr]

For what it's worth, I think you should place the insulation on the outside of the building. I believe that 2 layers of 2" thick pink or blue foam will give you about R-20. Of course you'll have to cover it with siding or stucco to protect it. The advantage of doing it out side vs inside is that with the insulation on the outside, your block structure is a huge thermal mass. Should be nice and cool in the summer too.

agree 100 % IF you plan to keep it warm all the time. that block is a huge thermal mass as mentioned above....if you plan on throwing the heat on for a few hours on saturday....then you are best to insulate the inside. your building will recover much quicker this way. that said, insulating from the outside keeps your interior footprint unchanged and saves square footage and gives you a chance to improve the look of the outside if you sheath it/side it.

the cheapest way to do it from the outside with great results would likely be modified larsen truss and dense pack cellulose.

http://www.greenhomebuilding.com/articles/larsentruss.htm

 

[wickerdave]

As I former foam contractor I would tell you about $1.50 per sq. ft.

 

[kbs2244]

Do some research on the radiant heaters.
They heat things not air.
The concept is the same as feeling warm in the bright sunshine on a 20 degree day.