Oil to Gas Heating Conversion: Is It Worth Making the Switch?

Your old oil furnace has made a good run of it and is on its last legs, so it’s time to consider getting a new furnace.  You know there are other options out on the market, but you aren’t exactly sure if it’s worth the cost.  If this describes your situation, this is the article for you. 

You should convert from oil to gas if you want to pay lower costs in energy use over the life of your furnace unit. Gas heating offers some of the best advantages of all furnace types. Before you convert, including efficiency and cost-effectiveness. However, it can be damaging to the environment. Average cost of installation is $4,688.

The best decisions are made when all information is considered.  If you are unfamiliar with gas furnaces or simply need a refresher on the advantages it offers, we will talk about what a gas furnace is and its pros and cons, compare it to your oil furnace and give you a final overview that will help you decide.

What is a Gas Furnace? 

A gas furnace uses combustible gasses as a source of fuel to heat your home.  The type of gas varies – gas furnaces can use natural gas, propane, butane, methane, or ethane, though natural gas and propane are the most common.

A gas furnace is connected to a gas line or a tank of propane.  The thermostat will turn the burner on when it reaches the set desired temperature in your home.  The burner ignites the gas and warms the air, which is then blown throughout your home for warmth.

Depending on the type of gas that your furnace runs on, a gas furnace uses a resource that is widely available as part of the local infrastructure.  You can enjoy the use of a gas furnace simply by hooking it up to the gas line and calling up your local gas company.

The gasses used in a gas furnace are greenhouse gasses.  However, burning these is more environmentally friendly than fossil fuels or oils, producing byproducts such as water vapor, nitrogen, and a low amount of carbon dioxide.  

However, burning gas also produces carbon monoxide which is poisonous, necessitating regular inspections.  A gas furnace can also generate heat more efficiently than an electric unit and produces that heat at a quicker rate.

Types of Gas Furnaces 

There are two types of gas furnaces: natural gas and propane gas furnaces.  While they function similarly, they have their own advantages and disadvantages over the other.  Let’s break down the two and compare them so you get a better idea of the differences between the two.

Natural Gas Furnace

Natural gas furnaces use a mixture of gasses rather than relying on a single gas.  As this is the most common type of gas used in households, getting access to it is relatively easy.  

Most areas have gas lines that provide natural gas, so providing your house with natural gas can be as simple as making a quick phone call.  And since the natural gas connection is using existing infrastructure, there is no cost of installation.

Natural Gas Furnace

Another advantage is that natural gas is cheap.  When compared to other fuel sources, natural gas is always the king of per-gallon cost.

On the downside, natural gas is odorless and colorless, which means that when a leak occurs, it may be hard to detect.  Natural gas is usually combined with sulfur so that leaks are easier to detect, but natural gas exposure can still be hazardous.  While explosions from natural gas leaks are rare, they can occur if leaks are not identified.

Propane Gas Furnace

Propane comes in canisters or tanks and is a popular alternative to natural gas.  You probably have seen or used propane in barbeque grills or as a fuel source for a camper.  It is also a popular choice for low-emission vehicles as a fuel source.

As you can see, propane is a common fuel.  It is more efficient than natural gas in creating heat, producing more BTUs (British Thermal Units or the way heat is measured in most appliances) while only burning half as much as natural gas.  So while propane is more expensive than natural gas up front, it is more cost-effective overall.

Propane Gas Furnace

The main downside of propane is installation and refueling – there is more work involved, and you have to keep an eye on your propane levels. But its portability means that you are also energy-independent.

Natural GasUses existing infrastructure
Cheaper per gallon
Difficult to trace leaks
PropaneEnergy Independent
Must be refueled periodically

Pros and Cons of a Gas Furnace 

Gas furnaces are one of the most efficient types of furnaces, offer many modern features, and are cheaper than electricity and oil in terms of cost to run.  However, while environmentally friendly to burn, it is not always the most environmentally friendly to gather.  Let’s examine these pros and cons one by one.

More Efficient

On average, electric furnaces are more energy efficient than gas furnaces – there is no denying this fact.  However, gas is far cheaper than electricity, which means that if you are running a high-efficiency furnace, the cost savings will be far more significant overall.  

A high-efficiency gas furnace can get an annual fuel-utilization-efficiency rating as high as 98%.  Electric furnaces can do better than this, but even a 2% difference will not save you as much money as running that high-efficiency gas furnace.

Gas will also burn hotter than electric systems, which means that your home will get warmer faster and stay warmer longer.  This means that you are using less energy to achieve the same effect. This makes gas furnaces the hands-down winner in terms of efficiency.

More Modern Features 

Gas furnaces are one of the most popular choices for newer furnaces in homes.  This means that companies producing gas furnaces are keeping up with the times and giving consumers more modern features.  

Gas furnaces are programable, and not only set your temperature but also monitor humidity levels, system performance, and outdoor temperature.  They also use electric ignition (yes, modern gas furnaces still use some electricity), which means that your system only comes on when it needs to come on, saving you money.

Modern gas furnaces also have adjustable blower speeds.  This allows you to control the airflow in your home and makes for more efficient performance from your system.

Cheaper than Electricity

On average, a gas furnace may cost you almost twice as much to install than an electric furnace.  But upfront costs aren’t the whole story.

The Energy Information Administration (EIA) forecasts that over the winter of 2022 – 2023, homeowners using natural gas will pay $931, compared to electricity, which will cost the homeowner $1,359.  And that is just this year, which is seeing higher than normal energy costs.

Gas is cheaper than electricity, and gas furnaces only need half the energy to create twice the heat.  These factors combine to make gas furnaces a much cheaper source of warmth for your home in the long run. 

Cheaper Than Oil 

Oil furnaces are another alternative to electric and gas that are more common in the north.  The installation costs are slightly comparable to gas – the unit price tends to be cheaper, but the installation costs wind up being about the same. 

However, gas furnaces are still cheaper than oil to run. Again, quoting the EIA, this winter, homeowners using oil furnaces are expected to pay $2,354 to heat their homes.  This is more than double the cost of gas, and almost double the cost of electricity. 

Oil prices are dependent on where you live, so the price may be more comparable in certain parts of the country.  However, oil furnaces are still not as efficient as gas furnaces, offering on average 8% lower efficiency rating.  

Causes Fracking 

Using gas as your fuel source for your furnace may be more environmentally friendly than other types of fuel, but that isn’t the whole story.  Some amounts of natural gas come from fracking, which can damage the environment.

Hydraulic fracking uses high-pressure water, sand, and chemicals to blast away at shale rock.  This technique helps extract oil and natural gas.

However, fracking causes seismic events which are usually minor but can still have an impact on the local area. More seriously, it causes air and water pollution, negating the benefits of the cleaner burn that the gas provides.

What is an Oil Furnace

Oil furnaces are an alternative to electric and gas furnaces that burn oil for fuel to generate your home’s heat.  They are whisper-quiet and have long unit lives.

The way an oil furnace works is similar to other furnaces, except that in the combustion chamber, oil is ignited.  Depending on the system, gas or water will be warmed by the heat exchanger, and then a fan will bring in air to be warmed before it is sent out to the rest of your home by a blower.

Oil burns hotter than gas or electricity, which means that your home will warm up faster and stay warmer longer than either of the other two units can.

It is also a great alternative for homeowners that are nowhere near gas supplies.  However, it is subject to fluctuations in market price – oil can get very expensive, especially in the winter when it is most needed.

Oil furnace unit prices are generally cheaper than gas furnace unit prices, but the installation of the two types of systems makes them comparable. So if you are thinking about getting an oil furnace, here are some pros and cons of this type of system for your consideration.

Pros and Cons of an Oil Furnace 

Oil Furnaces are generally safer than gas furnaces and last longer than any other type of furnace on the market.  On the other hand, they end up being more expensive in the long run and need more maintenance than other types of furnaces. Let’s take a look at these pros and cons individually.

Generally Safer 

Oil has the benefit of not emitting toxic gasses, which is a disadvantage that gas furnaces have.  Oil can still burn the same dangerous byproducts, but as a fuel, it is less prone to leaking. You can store oil in your home in oil tanks without having to worry about leaks.

This is a benefit over natural gas – remember, a gas leak is odorless and colorless, and even if sulfur was added, it can still be difficult to detect at times.  This difficulty in detection means that it may pose hazards to your health, or a leak left alone long enough will explode. 

Longer Lasting 

Furnaces are costly to replace, setting back a homeowner at least a couple thousand dollars for the furnace unit alone.  That is why so many owners consider the life of the system that they are installing.  They want to know that when they purchase a system it will last and they will not be forced to ‘upgrade’ thanks to a faulty system.

Oil furnaces are known for lasting a long time.  They are estimated to last a homeowner about 20 years on average.  This is between five to ten years longer than gas furnaces, making them a long-lived investment.

More Maintenance Involved 

Even though an oil furnace is generally a longer-lived unit, there will still be maintenance costs associated with it.  Since oil furnaces are not as common as electric or gas furnaces, you may find that you are having to pay more to find a technician that knows how to service your unit. 

Using an oil furnace means that you will also need to use oil filters.  This is a small part of the maintenance that adds up quickly.   Oil filters are another component that must be kept up with and maintained or risk a more expensive breakdown in your unit.

More Expensive

One of the big costs of oil is transportation costs.  Unlike electricity and gas, there is no infrastructure in place to pipe oil directly into your home, which means that you will have to purchase it and arrange for it to be brought to your home for storage and use. 

The oil has to come from somewhere.  Unfortunately, much of it is coming from overseas sources which add to the transportation costs, which are then rolled into the price of the oil.  You can expect to spend more than two times more on oil than you might on gas or electricity.

Which Type of Heating Should You Choose? 

A gas furnace is one of the best options for heating that a homeowner can consider, though your final purchase should take all your factors into account.  Remember that if you are replacing another system and considering switching between types, the installation costs may rise due to different furnace needs.  A gas furnace, for example, will need a flue, whereas an electrical system does not.  

Whatever your choice, it’s good to weigh all the angles. Below is a chart to help you make a final decision.

Cost of New  Installation (Average)ProsCons
Gas$4,688Long Life Span
Environmentally friendly burn
Energy independence options
Unsafe byproducts
Unsafe leaksFracking
Oil$5,700Longest Life span
Energy independent
Most Expensive
More maintenance
Electrical$3,750Longer life spans
Uses existing infrastructure
Not cost-effective
Infrastructure dependant


Gas furnaces have some drawbacks, but many other great benefits make a gas furnace worth the purchase.  Still, with a higher upfront installation cost, you must ask yourself if you are going to stay in your home long enough for the cost benefits to break even. If you intend to sell your home soon, it may make more sense to simply replace your old furnace with one of a similar type.