Have you wondered which of three options — heat pumps, natural gas or fuel oil —is best for heating your home or business? You may have heard that it would cost less to use natural gas than fuel oil, and would contribute less to global warming. For many of us, however, a heat pump would cost even less and contribute less to global warming.

Heat pumps, sometimes called mini-split heat pumps, operate much like a refrigerator. Air source heat pumps can both heat and cool your home. Heat pumps take heat energy from outside air, even in winter, and produce three units of heat for each unit of electricity used. Heat pumps are very efficient until outdoor temperatures are very cold. A backup heating system is needed when the outside temperature gets below zero degrees Fahrenheit.

• Which is better for the environment? Natural gas, a fossil fuel, produces less carbon dioxide than fuel oil when burned, but heat pumps create no emissions. Heat pumps, however, do use electricity, and the generation of electricity does produce some greenhouse gas emissions.

In Maine, carbon dioxide emissions are relatively low because much of our electricity comes from hydroelectricity and very little from coal. These climate-warming emissions will diminish further as we use more renewable energy in making electricity.

Natural gas leaks into the air during extraction and processing, and from pipelines. Natural gas consists mainly of methane, a greenhouse gas that causes 20 times more global warming per molecule than carbon dioxide. This leakage prevents gas from being a “green” fuel.

• What about startup costs? A single mini-split heat pump for most well-insulated homes costs between $3,000 and $4,000. Additional heat pumps might be needed for a large house. Some newer oil furnaces can be retrofitted to burn natural gas for less than $1,000. Most existing furnaces cannot be retrofitted to use natural gas and must be replaced for about $6,000. It would be good to check with companies that install heat pumps and natural gas to help you decide. A heat pump can be used for heating businesses as well as homes.

What are the long-term savings? According to Efficiency Maine’s website, “Comparing Heating Options,” converting from oil to an air source heat pump could create annual savings of $2,615 for an average house, while converting to natural gas could save $2,209.

Air source heat pumps may qualify for a $300 federal tax rebate plus a $500 rebate from Efficiency Maine. For more information, go to www.efficiencymaine.com/heat-pump.

A fair comparison of heating systems’ costs also requires us to consider the true cost of each source of energy, not just current market price. Carbon dioxide and methane emissions from burning fossil fuels cause climate change, which results in increased damage from fire, flood, drought and hurricanes. These weather problems already are increasing food prices.

Taxpayers also pay billions of dollars to help victims of these catastrophic events. These costs are not reflected in the simple cost of fossil fuels. Also, fracking for natural gas can pollute soil and groundwater for thousands of years, causing serious health problems.

One additional option is to install solar panels for electricity to operate your heat pump and for other purposes. Once the installation cost is paid, there will be no further cost for heat or air conditioning, because electricity from solar panels is free. In Maine, you also can choose a green energy option for electricity rather than the “standard offer.” For more information, see www.maine.gov/mpuc/greenpower.

There are several advantages to converting from fuel oil to heat pumps, instead of to natural gas. Heat pumps are very economical and also provide air conditioning, which will become important as our climate warms. Also, heat pumps minimize carbon dioxide and methane emissions, which helps reduce climate change, whereas conversion to natural gas will continue to contribute to climate change problems.

Decisions we make now about heating our homes will affect the world we leave our children and grandchildren. What could be more important than that?

This column is from the Climate Change Public Policy Team of Sustain Mid Maine Coalition, a grassroots organization dedicated to improving the quality of life for the people of central Maine.