If you use an oil-burning furnace to heat your home during winter, you’ve likely been enjoying the extended slump in crude prices. While lower fill up rates can help your dollars stretch further, you may still find yourself needing refills mid-winter (often during inclement weather) or dealing with clogged vents or dirty filters. Should you include a commercial additive with your home’s heating oil? Read on to learn about some popular additives and the benefits they can provide to your oil-burning furnace. 

What do heating oil additives do?

Although straight crude oil is combustible enough to be used as heating fuel on its own, most oil companies add a number of substances to this oil before sale to prevent it from freezing and otherwise make it more “shelf-stable” and less likely to clog or damage your furnace. However, due to the way modern heating oil is mixed before delivery, even oil with additives mixed in may become unstable and separate during long-term storage.

This process allows sludge and deposits to sink to the bottom of your oil storage tank — and because most oil furnaces draw from the bottom of the tank (to help ensure you’ll have heat even when your fuel tank is growing close to empty), you’ll run the risk of clogging your pipes or harming your furnace if you don’t use additives to prevent this sludge from forming.

Some additives are solvents, designed to neutralize the sludge in oil by thinning it out (much like turpentine can render oil-based paint runny and thin). But because adding large quantities of solvents to your fuel oil supply may not be feasible, many of the most popular additives instead use stabilizers which are designed to prevent the oil from separating and allowing sludge to flow to the bottom of the tank.

Should you add these substances to your heating oil supply? 

In the vast majority of cases, adding stabilizing additives to your fuel oil is a very worthwhile decision. These additives are available at a relatively low cost and can help prevent costly repairs to your furnace or fuel tank that could leave your home without heat for days.

However, there is one exception to this rule. If you’re using home-distilled biodiesel fuel in place of heating oil, you’re unlikely to need any additional stabilizers. Biodiesel contains natural solvents that can burn out any residue remaining in your pipes or furnace and shouldn’t require additional treatment to remain shelf-stable.