Natural gas advantages

Is natural gas really the best alternative?

Natural gas advantages over electrical heating are assumed to include speed of heating, lower cost, and improved energy efficiency. If all you’re looking for is saving money, then natural gas will win out in some cases. But behind the friendly-sounding adjective “natural” lurks the fact that methane, the primary gas in natural gas, is a major contributor to climate change – both in its production of CO2 upon combustion, and in the release of uncombusted methane in the extraction and distribution of natural gas. Let’s look at the pros and cons of natural gas generally, and in each of their three major household applications: space heating, hot water, and cooking.

But first, let’s consider the general pros and cons. General advantages of natural gas include its availability and ease of transport.

Most municipalities of more than a few thousand people in most developed countries have natural gas available to their residents. Once you have a gas line running to your house, it’s a lot easier to heat with gas than with oil or wood. Of course, electric heat is just as convenient as natural gas heat – more so, in homes where there isn’t already a gas line.

One might argue that natural gas produces more heat, for a given amount of CO2 (greenhouse gas) emitted, than electricity produced from fossil fuels. For example, a typical power plant running on natural gas can achieve up to 60% efficiency in terms of conversion of the energy in the natural gas to electricity. Factor in power losses in transmission, and only about 57% of the energy in the natural gas will reach your home. So if you heat with electric resistance heat, your maximim efficiencly level will be around 57% (since electric resistance heaters are 100% efficient at converting electricity into heat). A typical natural gas furnace has an efficiency of 80%+, while a high efficiency natural gas furnace can reach efficiencies of 95% or more. So heating with natural gas in a high efficiency furnace is up to 1.5 times more efficient than heating with electricity generated from natural gas.

If your electricity is partly generated from dirtier sources like coal, then the electricity has an even higher CO2 footprint than natural gas, so the natural gas advantage for home heating is better in this case.

On the other hand, if you are considering replacing an existing heating system, heat pumps tilt the equation much more towards electric heat. I installed a heat pump in my home; it serves as both a heat source in cooler months, and an air conditioner in the summer. A heat pump can produce 3 to 4 times more heat for a given amount of electricity than electrical resistance heating (this is because heat pumps don’t turn electricity into heat; instead they use electricity to pump heat from a cooler space to a warmer space). From the perspective of reducing your climate impact, you’re better off using a heat pump with electricity produced from natural gas, or even from coal, than using a natural gas furnace. Again looking at the 57% figure cited above, if we are able to extract 3x the heat from outdoors for each unit of energy we get from the electricity, a heat pump would produce up to 1.71 units of heat in your home per unit of energy extracted at the power plant.

One of the other natural gas advantages is that natural gas furnaces, water heaters, and stoves typically heat the living space, water, or food more quickly than electrical heat. In theory electrical heating can deliver heat fast as well (after all, we do have arc welders) but in practice it becomes cost prohibitive to build resistance-heat stoves or electrical baseboards that heat super fast.

Space heating with natural gas

Photo by Jez Atkinson, via FLICKR

If we’re going to talk about natural gas advantages we need to start with what heat sources we’re comparing natural gas with.

The main heat sources for homes are: natural gas, oil, electric heat, wood, geothermal, and solar.

Natural gas has an advantage over most of the others in that it is relatively inexpensive to install a natural gas heating system in a new house or replace an existing heating system with a natural gas system, and the total cost of ownership including both installation and operation is relatively low.

However, when compared to renewable sources like geothermal and solar the total cost of ownership is probably higher, especially when you consider that energy prices keep rising (but energy from the sun and from geothermal heat is always free!).

Let’s look at natural gas advantages and disadvantages compared to each of these other sources:

Oil:

• Natural gas heating is typically cheaper than oil heating, as fuel oil is more subject to the peaks and lows of the cost of oil. However, there have been periods (sometimes of several years) when fuel oil is cheaper, so this is one of the natural gas advantages that varies with time. People tend to install oil furnaces at times of relatively low oil prices, but they often regret it later as fuel oil prices rise.
• Natural gas does not require on-site storage. Oil tanks can spring leaks and can run dry if you don’t keep an eye on the gauge or remember to have them filled on schedule. Storing oil inside your home can result in unpleasant odors in the home (I still remember the ugly smell that hit me every time I stepped into my grandparents’ oil-heated house in the 1960’s and 1970’s) and if there’s a major spill you could have a very expensive clean-up on your hands.
• Because of the health, environmental, and fire risks associated with oil tanks, many home insurers will not insure a house heated with oil or even one that contains an empty, unused heating oil tank.

Natural gas advantages over oil seem to far outweigh any savings you might occasionally get from oil prices being low. However, as demand for natural gas seems to keep growing for uses such as generating electricity and firing up the boilers in the Alberta tar sands (an environmental disaster on a massive scale, which, ironically, produces oil), and as supplies especially in North America are becoming more constrained, we could see a dramatic rise in the long-term price of natural gas, which may make oil a more attractive alternative from a cost perspective.

Electric heat:

• Electric heating is considerably more expensive than natural gas heating, in most places.
• Electricity generated from coal results in about three units of energy being consumed at the power plant, for every unit of energy that comes into your home. That means heating with electricity from coal is only about 30% efficient. My own natural gas furnace, purchased in 1997, is 94% efficient – more than three times as efficient as a typical electric heat system.
• Electricity generated from a modern natural gas plant is, as previously mentioned, about 60% efficient. So a high efficiency natural gas furnace will be more efficient than resistance-heating with electricity (electric furnace or baseboards).
• If your electric heat comes from an air source heat pump, the equation tilts much more away from natural gas advantages. Electric heat pumps are very efficient.

The main advantage of electric resistance heat over natural gas heat is that it’s very easy to heat a small space in a large house, without heating the whole house. But unless you’re letting the temperature in most of your house fall to very close to the outdoor temperature and just heating one or two rooms with electric heat, you will probably spend more on heating with electricity than heating with natural gas.

There are exceptions to natural gas heat being cheaper than electric heat for a whole house. For example, in the province of Quebec, Canada, electric heating has historically been cheaper. But there’s a price to pay: Quebec sells its electricity very cheap to its own residents, because it is generated almost entirely from hydro-electric sources, and once you’ve built the dams, the electricity is ‘free’ (if you don’t factor in costs such as the environmental devastation caused by flooding of massive reservoirs, and the displacement of First Nations communities).

Wood: Heating with natural gas is certainly more convenient than heating with wood, as you don’t have to keep loading the woodstove, and you don’t have any wood to cut (or purchase), and you don’t need a place to stack the wood. Wood heat also causes more ground-level pollution in terms of particulate matter, and contributes more to smog, if the wood heating unit does not have proper pollution controls on it.

Wood heating is often not energy efficient. Heating your house partly with an open fireplace and partly with a gas furnace usually means the fireplace is actually sucking heat up your chimney – it is a net drain on the heat in your house. In fact even just the presence of an open fireplace in your home can cause considerable heat loss, as the chimney acts like a giant straw, sucking up hot air, which naturally rises, and drawing cold air in through air leaks elsewhere in the house such as poorly sealed windows and doors, attic hatches, or cracked walls. You can solve this problem with a draft stop plug balloon, such as the one shown at right. You simply push it up the chimney from the fireplace until just below the damper; you then inflate it. It can be easily removed as well, and reused later. It provides a proper seal and may significantly cut your heating bills.

Wood heating tends not to distribute heat effectively through a house with several rooms, as typically wood heating is done from a woodstove or fireplace insert that burns in just one room.

However, if you have an energy efficient woodstove or fireplace insert, that has the proper pollution controls installed, and you have an effective way of distributing the heat through your home, wood is a more environmentally friendly heat source.

People often argue that burning wood or other biofuels is carbon neutral – that the CO2 you release when burning wood, was CO2 the tree withdrew from the atmosphere only a few decades earlier. And the CO2 would have been released anyhow if you let the tree fall in the forest and rot.

There’s some truth to this argument. But of course if we all rushed out and switched to heating our homes with wood, we’d have to chop down so many trees there wouldn’t be any forest left to continue the process of sequestering carbon in new trees! And even if we replanted everywhere we cut (and many foresters argue that second growth forests sequester a lot more carbon in their trees than old growth forests) there would be severe ecological consequences.

Geothermal heating: Geothermal heat is free – it’s right underneath us, in the ground. See my article on Energy saving geothermal, which contains extensive information on the topic of geothermal heating and cooling. The main natural gas advantages for heating over geothermal heating are installation expense and site disturbance. A geothermal heating and cooling system is very expensive to install, so if you’re short on cash or short on credit, you may find it easier to scrape together the cash for a new gas furnace. Geothermal systems also involve considerable disruption to the land around your home – the installation involves either drilling one or more very deep holes (for a vertical loop) or digging a large trench (for a horizontal loop).

In terms of life cycle costs, geothermal is almost always cheaper than natural gas heating, because once the system is installed, the heat energy comes to you free from the ground – though you’ll use electricity to drive the heat pump. Overall, geothermal heating is supposed to require only about 25% of the input energy that heating with electricity requires. Natural gas advantages over geothermal are short-term – in the long run, you’ll save more money by installing a geothermal system.

Another advantage of geothermal systems is that they can not only heat your home, they can both cool it in hot weather, and heat your hot water.

See my Advantages and disadvantages of geothermal energy page for more information.

Solar heat: The main problems with solar heating are related to site suitability, location, retrofitting, and installation cost.

• If your home is located in the shadow of another building, trees, a hill, etc. for part of the day, you’ll get less sunlight, which means it’s harder to heat your home with solar energy.
• If you live in a northern climate or one with a lot of cloud cover, you won’t get as much heat from the sun.
• Solar heating systems don’t necessarily integrate easily into an existing forced air or radiator based heating system.
• As solar heating systems in most climates are only part of the solution (you still need to heat on cloudy days), you will still need another source of heat – typically natural gas, wood, or electric. So you’re faced with paying for the installation of two different heating sources.

However, with proper design of a new house, a solar heating system can provide most of your heating needs, and will save you money in the long term. See Solar power pros and cons for a more thorough discussion of the advantages of solar heating over natural gas heating.

For a general discussion of heating sources, see my Most efficient home heating page, which discusses each heating source in gory detail.

Hot water

Photo by Marco Wessel, via FLICKR

Heating hot water with natural gas is typically faster than heating with an electric tank heater or electric tankless water heater. This is because in an electric hot water heater, in order to heat water at the same speed as a typical gas water heater, the electric heater would have to draw such a high level of current (in amps) that the demand could overwhelm a typical home power supply, and would cause spikes in demand on the grid.

As with all other comparisons of heating with natural gas versus electricity, when electricity is produced via a heat engine (i.e. a turbine at a heat-powered power plant such as a coal, natural gas, nuclear, or geothermal electric plant), about two thirds of the energy in the heat source are lost – so the electricity gets only one third of the total input energy. So one of the natural gas advantages is that more of the original energy goes into heating your water – heating your water with electricity produced from coal or natural gas means only about 30% of the heat goes into the hot water, the other 70% escapes into the atmosphere.

Natural gas tanks are also typically much smaller than their electric hot water tank counterparts. That’s because an electric hot water tank takes so long to reheat the water to the desired temperature. To compensate for this, electric hot water tanks are typically built with much higher capacity than gas hot water tanks, so that when a bathtub is filled, the water still in the tank, which consists partly of previously heated water, and partly of cold water that comes in as the hot water leaves, isn’t freezing cold by the time the tub is full.

Cooking with gas

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Many people prefer to cook with gas than with electricity. I can understand this – natural gas advantages for cooking include the fact that gas stoves heat food much more quickly than an electric stove, and that better quality gas stoves can also simmer more precisely. However, more of the heat energy is wasted in a natural gas stove than in an electric stove, because so much of it rises as hot gas around the outside of the pot that is over the burner.

You are also more likely to burn yourself with a natural gas stove. I find, for example, that the handles on my pots get very hot on my natural gas stove – which never happened when I cooked on an electric range top. Again, the heat rising with the natural gas exhaust fumes heats the sides of the pot including the handles.

Cooking with gas also burns oxygen in your house and releases carbon dioxide, traces of carbon monoxide, and water vapor. If you have humidity problems in winter and you cook with natural gas, the natural gas cooking is only making the problem worse. If you have a very well sealed, energy efficient home, cooking with natural gas means you’re depleting your home oxygen supply. Make sure you run the range vent when cooking. This will help draw moisture and cooking smells out of your house, but more importantly, it will suck in fresh air to replace the oxygen consumed by the cooking.

For a more detailed discussion of the relative merits of different cooking heat sources, at least for stovetop use, see Energy saving induction cooking. Induction cooking stovetops combine the speed and fine control of natural gas cooking, with the safety of electrical cooking, and with energy efficiency and convenience that beats both traditional sources.