How Does Oil Heat Work and Is It Efficient?
Only about 6% of Americans use fuel oil for heating, according to the U.S. Dept. of Energy. In comparison, 49% of Americans heat and cool with natural gas, and 34% use electricity.
And heating your home is one of your biggest expenses, eating up 42% of your utility bill. The low-cost of natural gas right now and the ease of connecting to the electrical grid make these popular heating options. Still, there are many good reasons to choose oil heat.
So how does oil heat work? In the following post, we’ll try to answer that question and discuss the pros and cons of fuel oil heating.
The most popular way to heat a home is through a furnace or a boiler. A furnace heats air and circulates it through your home through ducts and vents.
Boilers heat water and distribute the hot water or steam through pipes. The heat from the hot water is then distributed either through radiant coils or baseboard radiators. Steam boilers run hotter than hot water boilers.
Furnaces are generally less expensive than boilers, but boilers are easier to practice zone heating. Also, boilers need to maintain a minimum temperature to stop the pipes of the heating system from freezing. One annoyance with gas furnaces is that their exhaust fans are noisy.
AFUE, or annual fuel efficiency, is the label for determining how efficient a boiler or furnace’s efficiency is in your home. The. AFUE standard rating system is a measurement of how efficient the heating unit is over a year.
- 56% to 70%: Considered a low-efficiency furnace or boiler, likely old or out-of-date with a natural draft unit with a continuous pilot light.
- 80% to 83%: Considered a mid-efficiency furnace or boiler. These units are smaller in size and have an electronic ignition.
- 90% to 98.5%: A high-efficiency unit. These boilers and furnaces feature sealed combustion and a second heat exchanger to condense flue gases.
How Does Oil Heat Work?
Oil is still prevalent in the Northeast, where there’s not as much access to natural gas systems. A truck delivers the oil to homes and places it in a tank for storage. The fuel oil is then used to feed a furnace or boiler.
So how does an oil heater work?
In a boiler, a thermostat sends a signal to the boiler to start the burner. The burner then uses the oil as fuel to heat water. This process is part of a pressure induction system. That means that the oil is under pressure until ignited in a part of the furnace called the combustion chamber.
The water then flows to different parts of the house, also called zones. The hot water runs through baseboard registers, radiators, or radiant coils. The now-cold water then flows back to the boiler, is collected, and the process starts over. Boilers are a closed system, meaning there’s little water loss.
The process is similar for stream boilers except that a chimney is needed to vent any leftover gases.
With furnaces, the unit heats air. That air is pushed through the house through ductwork. After the heat is exhausted, fans are used to feed a heat exchanger, and the process starts again.
Pros and Cons
Oil furnaces have several advantages over gas or electric heat. The first and foremost is cost. An oil furnace is generally cheaper than a gas one, and the AFUE rating comparable. Unfortunately, gas prices seem to fluctuate more than natural gas since a significant quantity of the American supply is an import.
That stated, oil furnaces work well in cold climates where you’re dealing with temperatures at or below zero. Oil furnaces and boilers heat large areas with ease and don’t need a chimney for venting.
Gas furnaces, on the other hand, need chimney venting for a number of reasons, not least of which is to avoid carbon monoxide poisoning. These types of furnaces need to be monitored carefully, not only due to the threat of carbon monoxide but also because natural gas is explosive.
Fuel oil is safe, and there’s little threat of explosion or combustion when stored properly. You can read more here about popular misconceptions concerning oil heat.
While new oil furnaces can produce fewer emissions than their gas counterparts, many consider natural gas furnaces the cleanest fossil-based heating fuel.
A Word on Electric Heat
There are electric forced-air furnaces and radiant floors, but the most common form of electric heat is conveyed by a heating element in a baseboard unit.
The obvious upside with electric baseboard heat is that there’s no venting necessary, And with no furnace needed, you’ll save space. Electric baseboards are also considered a form of zone heating, so in that respect, they have some efficiency.
It’s also encouraging to note that most of the new electricity supply added to the current electrical grid in the United States is green in nature and generated from wind and solar. But a major source of the world’s electricity is still created through the combustion of fossil fuels like coal.
Also, electric heat depends on a steady supply of energy from the grid — something to consider as violent storms rise in number across the country — and some of their efficiency is lost over transmission lines. Lastly, electric baseboard heat is a dry heat source, and some people dislike the effect electric heat has on their skin.
Oil Heat’s Long Life
Maybe a more interesting question than “How does oil heat work?” is “How long does it last?”
In general, oil furnaces and boilers can last 5 to 15 years longer than natural gas. Also, since a lot of oil fuel today is mixed with additives similar to biodiesel, fuel oil can have almost no level of smoke or harmful gases released into the environment.
You wouldn’t think that fuel oil wouldn’t contain carcinogens, but that’s true. So when properly stored and maintained, an oil-fueled home heating source can be a plus for your family’s health and pocketbook.
Want to learn more about home heating or fuel oil? Check out other articles on our website.