Modcon vs Buderus Oil.. Cost to Operate?

scrook_2

at a price ratio of $3.15/ gal for #2 and ~$4.20 equiv for LP (33% more) it's going to be tough to come out ahead on LP no matter what you install. OTOH if you want (need?) LP for for one or more of the following: cooking, cloths drying, permanent gas grills, gas fired pottery kilns, gas mantle lanterns, etc. too, maybe it's worth the extra fuel cost to switch anyway. For just heat & domestic hot water I'd stay oil.

Saggs

Perhaps this subject has been beaten profusely, not sure? Got a customer in need of a new boiler. Presently has an old oil unit w/ standard baseboard throughout an older home. Needs a approx 60K btu's of heat and a domestic hot water source. I've installed both types of units but have never been able to do the calculations of cost savings of one vs the other. Oil around here is about $3.15/ gal and LP maybe $2.75? Assuming an indirect h2o htr and outdoor reset on both units what would the payoffs be to switching to LP? Would the initial cost of installing say a Prestige or somthing similar make up for the 30% fewer btu's in a gallon of LP? I guess the bottom line is how quickly the cost difference would be overcome by the improved efficiency... Sorry for the long thread. Thx

Darin Cook_5

Buderus G125BE

The new G125BE rated at a 89+% afue would be the boiler to put in there.




Darin

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Saggs

Is that the best efficiency they can get out of those units? I think the Prestige is around 93%?

Don Robertson

Siggys

I get these kinds of questions quite often. I use Siggys HDS program to compute annual fuel costs. http://www.hydronicpros.com/
At this point the G125BE would probably be the best choice however with Oil skyrocketing who knows what the future will bring. LP is climbing as well.

Saggs

I went to the link you suggested but didn't know which software you were referring to? Was it the discs you can buy or the free downloads? Do you have a proper name for the program? Thx

Don Robertson

Hydronics Design Studio

The program is called hydronics design studio. It has a fuel cost analysis program on it.

FeemiaVeque

Over 95% now...

Just like Viessmann...

Uni R_2

GIGO

The math is the simple part. The tough part is knowing with any degree of certainty what the efficiency of a particular setup is on an annualized basis. I don't believe in Santa, the tooth fairy or AFUE. Without having a good idea of what the real efficiencies are it is simply garbage in garbage out.

scrook_2

Oil vs LP

at a price ratio of $3.15/ gal for #2 and ~$4.20 equiv for LP (33% more) it's going to be tough to come out ahead on LP no matter what gas boiler you install.

OTOH if they want (need?) LP for for one or more of the following: cooking, cloths drying, permanent gas grills, gas mantle lanterns, etc. too, maybe it's worth the extra fuel cost to switch anyway. For just heat & domestic hot water I'd stay oil.

Glenn Sossin_2

How many btu's for dollar x efficiency

I believe its a pretty simple mathematical comparison.
You determine how btu's of heat you get for your dollar and then apply the expected efficiency of your system. This lets you see how much heat energy you are buying for your dollar.

Oil - 1 gal No2 contains 140,000 btus of energy. If it costs $3.l5 per gallon then the math would be 140,000/3.15 = 44,444 btu's for the dollar.

LP gas - 1 gal on has 91,502 btu's per gallon. If it costs $4.20 per gallon, the math would be 91,502/4.20 = 21,786 btu's for your dollar.

Now you would apply efficiencies. If your oil boiler was 84% efficient .84 x 44,444 = 37,333 btu's that you got to use for heating.

In this example, even if your LP boiler was a condensing boiler and able to operate at 95% efficiency, you would have .95 x 21,786 = 20,697 btu's for heating - far below the 37,333 of the oil. The efficiency of the condensing boiler is a function of the flue gas/operating temperatures of your system. The lower the operating temps, the higher your efficiency would be.

Hope that clarifies the situation for you.