Gas vs Oil heat for cast iron radiators
Hello everyone after trying to find an unbiased source online I decided to ask the group here in hopes of getting an honest answer. I live in Western Mass in a 1910-1920 Colonial Revival two story house with a full size walkup attic and unfinished brick wall concrete floor basement. We bought this house because of the charm and have no intention of replacing our cast iron radiators or many of the other elements that made this house attractive to us. My oil burner is fairly new ( 5 yrs old) and I have a gas line to my house for heating and cooking. I got a quote from a contractor which included SS lining for $4400 for switching to gas. My concern is if the fact that I have “radiant” heat vice forced convection will make the advantages to switching fuels nil. Is there anyone here who has switched to gas with cast iron radiators who have dramaticly lowered their heating bills.
I also plan on insulating my sill plate in the basement wrapping all my hot water pipes. Adding 2″ of ridgid foam to my attic door and adding the secondary zippered door to minimize heat loss. We don’t intend on switching out the original wooden windows although I will in the next five years add metal weatherstripping and completely rehab each window including putty replacement. I would also like to build new wooden storms out of cypress to replace the ugly triple track aluminum ones we have now.
Any advice would be appreciated.
http://www.pesinc.org/Seal_N_Shield_Attic_Door_Insulator.htm
Replies
A BTU of heat is a BTU of heat. Radiators don't care whether the BTUs come from oil or gas.
Generally gas is cheaper per BTU, but prices can vary considerably.
A BTU is a BTU but how efficient is the fuel at producing that BTU, in the past I've read from some unbiased sources that oil provides more heat per BTU than gas which is also stated at this website. I do understand they have a reason to be biased but they support their claims with links to 3rd party sites with no stake in either fuel. Bottom line I would hate to shell out this money and not get the results I would hope to have because of my cast iron radiators. The company I buy oil from also converts from oil to gas for customers and the guy that worked there told me that gas doesn't heat the old radiators the same way oil does so the savings I was expecting would be unrealistic. This is why im on here trying to get some feedback from people who have made this conversion and can give me an amount they're saving yearly since the switch.
http://www.petro.com/Article/446/petro--the-facts-about-oil-vs-gas-heating.html
Their statements don't make any sense. They say that oil efficiency ranges from 83 to 95%, implying that gas is worse. But that's roughly the efficiency range of gas boilers. They claim that oil produces more heat than gas by using some sort of "gallon equivalent" figure for gas. The only valid comparison is BTU content of the two fuels.
The main thing to beware of is a poor conversion of a boiler from oil to gas. Necessarily, when you convert an oil boiler to gas (vs instaling a new gas boiler) you're getting a design originally optimized for oil, and if the gas retrofit is not done properly you can lose substantial efficiency.
One data point: Lennox has gas boilers ranging from 83.9 to 95%. They carry only one oil boiler -- 85.2%.
Even supposing the existing oil burner is only 85% efficient, paying for a gas boiler that's 95% efficient will mean an increased efficiency of only about 11%.
As an example, assume a yearly heating oil cost of $1200, you would save about $130 per year--a payback would take over 30 years if the gas boiler costs $4400. Of course, any savings in the cost of fuel would help reduce the payback time, but it would have to quite substantial to pay you back before the gas unit would reach the end of its service life.
Your $4400 might be far better spent in making improvements to the air-tightness and insulation of the home. The potential savings could amount to far more than what a new boiler would provide by reducing lost heat--besides which, you will also reduce your cooling costs by air-sealing and insulation. The benefit would be year-round.
BTW, the only fair cost-comparison between fuels is the cost per BTU. Natural gas is usually billed at $___ per "therm", a therm being 100,000 BTU's. A gallon of #2 fuel oil has about 140,000 BTU's, so, depending on the price of the two fuels in your service area, savings from gas could be substantial.
Hope this gives you a little help in your decision without sales hype.