Howdy all. Yes another question about heating! I swore I wouldnt ever ask this question because there are so many archived posts. What I noticed though was that they all seemed to be about what you have or what you like or what you wish you had. What I really want to know is how to compare the cost of heating with various fuels. Really looking at natural gas vs LP vs electric. What factors do I need to be aware of to determine this? Any help would be appreciated….
Chris
Replies
I believe the formula is E=mc².
E being energy cost, m being moderation, and c being comfort. In other words, it's gonna cost way more than the comfort level achieved. ;-)
I'd think there has to be a study available on the Web that compares the efficiency of different heating methods, but actual cost comparisons would vary by regional cost variations, what's available, etc.
Electric will usually be the most expensive. Gas or paraffin (kerosene) should be cheaper but depends on the pricing policy in your part of the world.
You should be able to find calorific values for the fuels you are considering on the web. Then calculate the KWh per unit cost.
1 Watt = 1 Joule/sec. 4.2 Joule = 1 Calorie.
1KWh = 1000 watts * 3600 sec. Divide by 4.2 to get calories.
When looking at burning a fuel remember that if you vent the combustion gases you are not going to get all the heat. A fair amount goes out of the chimmney. On the other hand if you use, say, a domestic gas heater then you get all the CO2 and water in the shop. You need decent ventilation which also loses you heat.
1 Kg of propane will generate 1.3 Kg of water vapour as well as 3.2 Kg of Carbon Dioxide. This may cause problems.
Hope this helps.
(I don't heat my shop. 4 deg C is a record low over here.)
What about good o' BTU's??? They are at least a help in comparing one heat source to another.forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
BTU's? I remember those but haven't used them since 1973. Had to use both Metric and Imperial in Chem Eng in Scotland.I honestly forgot that you still use Inperial in the USA and complicate it further with a different gallon.
The reason I asked about BTUs is because many of the heaters I've looked at in the past (propane, kerosene) had BTUs listed in the specs. The Cornell article linked above shows both BTUs and Kcals, but for wood pellets the unit is tonnes instead of tons. Help from my ME husband gave me the key to converting that info to something relevant to a 40# bag, LOL.
forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
There are a great many factors to consider, some of which have already been mentioned here. What is your shop made of (stick frame or block or metal sided, roofing material, etc.), how well it is insulated and where you are located are also important factors.
Using any kerosene fueled heaters will give you lots of fumes and lots of vapor (water). Similarly, but not to the same extent, gas or propane will produce fumes and vapor as well. Electric heat doesn't have those issues, but some areas of the country have priced electric power through the roof.
An interesting alternative that I don't recall having been mentioned on Knots is the radiant floor system. Although the installation cost may be pricey, it would seem that it would be pretty economical to run.
Although this may appear to be skirting your question, our local electric utility guestimated the cost to heat a fairly sizeable addition, and their figures came up about 50% short of the actual figure--before "energy" costs went from ridiculous to obscene.
So, my two cents worth would be for you to soundly research your options as far as the type of heat that will best meet your expectations in your shop, then see what the local "experts" project as the operating cost and double it. You'll be in the ballpark.
If I may elaborate a bit further. Yes, a very very great many factors. If you are using wood, how do you evaluate the cost of the wood unless you actually buy the stuff. Some of us actually enjoy going out in the woods and cutting wood. One source of heat not mentioned much is used engine oil. Lots of garages and trucking places will actually pay you to take the stuff. There are furnaces specifically designed to burn it. Here again the installation of the furnace is expensive.
We tend to think of kerosene, oil and gas stoves as putting water in the room. Not necessarily so. The stove could be vented to the outside. The best is one is isolated from the room so draws its air from the outside then vents right back out usually inside of the pipe that drew the air in.
Resistance electric heat is the easiest to figure, it is always 100% efficient. You don't get pollution where it is converted to heat but the plant that produced the power pollutes the air if it is fossil fueled. All fossil fueled devices have their efficiency limitations depending on how well they are designed and maintained.
One of the very cheapest sources of heat is the heat pump using geothermal as it's medium. The installation is very expensive so one has to consider the interest on ones money if using that source of heat. The list goes on and on and many things have to be weighted and evaluated.
Edited 1/18/2009 8:54 pm ET by Tinkerer3
I am inclined to think that factors such as insulation and construction type are kind of a wash. As these factors are constant (at least for me), is seems they become irrelevant?! I would think the most important thing is the size of the space that one needs to heat...Chris
The cost to heat a space cannot be readily factored without a few considerations. A 1,000sf shop constructed of 2 x 6, superinsulated walls and a well insulated ceiling with a well insulated wood floor cannot cost as much to heat as the same dimension shop with unilsulated block or 2 x 4 walls due to the excessive heat loss of the latter. Any utility would love for you to heat and cool your back yard with their product, but getting the job accomplished is another matter entirely.
Your correct, but with regards to my shop, the conditions are constant and in the end are a wash. I can't imagine it would take more btu's from gas to heat than it would from electric.Chris
hdgis1,"I am inclined to think that factors such as insulation and construction type are kind of a wash. As these factors are constant (at least for me), is seems they become irrelevant?! I would think the most important thing is the size of the space that one needs to heat..."Yes, your correct, along with the 'Degree Days' for your area. The idea is heat a space to a comfortable level assuming it is uncomfortable if not heated. So you need to know the temperature outside verses the temp inside that you want to achieve. The BTU's required to accomplish the task is a function of Mass, Change in Temp. and a coefficient ( the coefficient recognizes steel is harder to heat up than air). The Mass is the heat loss of your space. The Degree Days are kept by all oil companies to determine when they need to refill your oil tank. To calculate the heat loss is not too difficult. The real issue in selecting an appropriate heating unit (ie. BTU Output)is more about your space and work style....and that has an impact on efficiency. any good Plumbing and Heating Supplier usually has an inhouse expert that can advise you on heat loss, degree days and best options.
I installed radiant heat panels in my shop and love them. I did this some time after I built the shop so I just hung them from the ceiling. On a cold day I will quickly warm the shop with a kerosine space heater and then let the electric panels take over. I like the electric panels for several reasons but one is that there is no open flame. I don't remember where I bought them but if you do some research I'm sure you'll be able to find them. Just a quick search took me to http://www.toolbase.org/Technology-Inventory/Interior-Partitions-Ceilings/radiant-ceiling-panels so might start there.
Good luck.
Erv
It is, as others have pointed out, a complicated business. One source of comparative information on fuel efficiency, etc., is the U.S. Dept of Energy. I've used their site for information on the relative efficiency of transportation modes based on BTU consumption and whatnot. I think they even have info on the use of wood for heating. The site is at http://www.engergy.gov
Verne
If a tree falls in the forest, and no one is there to cut it up and make something with it . . . what a waste!
Here is the best link I have found so far. Not sure if it will work as it is a PDF file.http://74.125.47.132/search?q=cache:YqC_NtrbPX8J:housing.cce.cornell.edu/f-sht-pdf%2520libraries/EE-F-SHTS/comparing%2520heat%2520fuels.pdf+comparing+the+cost+of+using+various+fuels&hl=enct=clnk&cd=1gl=us&client=safariSounds like the math is really rather straight forward. Looks like a good place to start!ChrisI think I have the math correct!Electric (100% efficient) = 9.048 cents per Kilowatt hour (1kwh equals 3,413 btus) need 292.99 kwh to produce 1 million btus
costs to produce 1 million btus = $26.37Natural gas (81% efficient see link for item specifics) = $1.6515 per therm (1 therm equals 100,000 BTUS) need 10 therms to produce 1 million btus
costs to produce 810,000(output) btus = $16.5
http://www.grainger.com/Grainger/items/4LX42propane (83% efficient see link below for item specifics) = averages 2.75 gallon (1 gallon equals 91,600 btus) need 10.91 gallons to produce 1 million btus
costs to produce 830,000 (output) btus = $30
Edited 1/18/2009 10:13 pm ET by hdgis1
Looks like you've done your homework. Can you get figures for wood or geothermal? I guess you would have to set your own price on wood unless you bought it from another party.
Natural Gas Vs. Electric...
For me month to month Electric was way more expensive. However the heater was much cheaper, and the install was cheap as well.
Whatever you do get a proper heater. Many people use the portable construction heaters, but they are not meant for this purpose and could result in fire.
Chris,
What I really want to know is how to compare the cost of heating with various fuels.
Last time I looked, #2 heating oil gave the biggest bang for the buck. Here's something you might consider:
http://www.oilheat.com/facteffcnt.htm
This could just be another hype to get folks to buy oil but I think the facts speak for themselves.
Here's another: http://www.cwlp.com/Energy_services/efficiency_ratings.htm
Regards,
Bob @ Kidderville Acres
A Woodworkers mind should be the sharpest tool in the shop!
Edited 1/19/2009 7:52 am ET by KiddervilleAcres
Chris,
I went through all these calculations a while ago when choosing a heater for my shop. A natural gas, wall-hung direct vent heater proved to be the ticket in my situation (Empire brand).
It's cheaper to heat with natural gas than with electricity almost across the board. Oil might be more or less expensive, depending on where you live. But there's another factor at work here - installation cost.
Electric heaters are cheap to buy and install, but expensive to run. There are oil-fired mobile home furnaces that could be a good deal for you, especially if you can find one used in good shape and have access to oil delivery. A natural gas mobile home furnace might be an option as well.
In my case, a new gas heater was a good compromise between initial cost and running cost over time. About $800 to purchase, and with an 80% efficient burner, it's not too pricy to operate.
Zolton
If you see a possum running around in here, kill it. It's not a pet. - Jackie Moon
Thanks all for your input. I was able to find a used Reznor UDAP 45 for $150 so that pretty much sealed the deal for me.Chris
Well this question really belongs over at breaktime.. the Fine Home Building version of Knots..
However do not rule anything out.. you have to do your own homework here..
I found in my location it is cheaper to heat with electricity than natural gas or oil..
But there is a whole lot more to that answer.. Basically I used in floor radiant heat and a super insulated house to cut my heating bills down from $500 a month to $200 a month in spite of pretty steep increases in fuel costs..
MY location there is an abundance of electrical power either on line or coming on line while supplies of gas and oil are getting more and more expensive..
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