Cost

I’m not going to lie. Figuring out which is the cheaper option of gas vs. oil, is tricky. You can’t compare straight price per gallon of oil vs. gas because heating oil produces about 40,000 more BTUs per gallon than gas. So you need more gas to get the same BTUs as oil. (Ugh, math!) This also means that your 100,000 BTU gas heating system will probably be bigger and more expensive than a 100,000 BTU oil heating system. (More math)

This is complicated by fact that oil and gas prices fluctuate. And which one has historically been “cheaper” depends completely upon who you ask – oil producers or gas producers. Each has compelling evidence that THEY are better/cheaper/the solution to all of the world’s energy problems. This all leads me to believe that which one is cheaper depends heavily on which metric or combination of metrics you use to determine “cost.”

At the end of the day, my conclusion is that it is unwise and maybe even impossible to predict the future cost of decayed dinosaur bones in any useful way, so let’s move onto other issues besides cost.

Safety

Though it doesn’t happen frequently, both oil and gas can leak. Oil is makes a mess but gas can explode. That sounds super scary, but it is VERY uncommon. (Captain Obvious Tip of the Day – If you smell gas, call for service ASAP. It greatly reduces the chance that you will explode.) Equipment using both types of fuels can be dangerous if not maintained properly because combustion produces gases like carbon monoxide that can back up into occupied spaces and create unsafe air for breathing. Both are very safe as long as you follow basic operation and maintenance procedures.

By the way, interesting tidbit…I read on the internet that if you drop a match into heating oil, it will simply go out, same as if you dropped it in water. I’ve never tried, so if you burn down your building Myth Busters-style, don’t blame me. Blame the internet.

Efficiency Options

Both gas and oil options offer standard efficiency equipment in the 80% plus range and high efficiency equipment in the 90% plus range, even as high as 98%. High efficiency gas units have been around a little bit longer and are more common than oil. Because of the difference in efficiency of the fuels themselves (oil produces higher BTUs per gallon than gas), gas equipment tends to be a little bigger and thus higher in price than oil for the same BTUs. Whichever fuel you use in your high efficiency unit, whether gas, oil, propane, donut grease or mermaid tears, it MUST be maintained at least once per year by someone who knows these systems (or has at least read the owner’s manual). High-efficiency systems are more needy, but if you treat them right, they’ll make it up to you.

Maintenance

The biggest factor that I can see differentiating gas and oil is that gas burns cleaner than oil. Your gas equipment will need less intense maintenance making it less expensive to keep up than oil equipment. Oil is thicker and heavier and leaves more residue behind. It requires filtration to keep your oil tank gunk out of your equipment whereas gas does not. Gas systems still require attention for the condensate portion of the system as well as standard maintenance stuff like filter change, clean and test safeties, check gas pressure, make sure fans and flue are working properly, etc. but it generally burns much cleaner than oil, giving you a little break on the “cleaning” part of the maintenance visit.

Conclusion

In our office, we are about split down the middle between gas and oil systems in our homes. Those who have gas available to them have gas systems, those who do not have oil, except for the one wild card who installed a propane-fired system to replace his oil system just a year or two ago.

When asked, most of the folks that I’ve spoken to in the HVAC service industry favor gas over oil because it burns cleaner, doesn’t require a large storage tank and is easier to service. In addition, many utilities are giving heavy incentives for natural gas, so there may be big rebates to help you convert to gas and/or install a high efficiency gas system. So gas appears to be the winner, at least in areas where it’s available. To find out which option is best for you, give your residential contractor a call.