Myth #5 Its best to keep my current car, furnace or water heater as long as possible before replacing it.
This myth is based on the true principle that in general it is best to use products for as long as possible before replacing them with new ones. This concept is true for many products, but not for those that consume fossil fuels when operated.
For most of the things we purchase - clothes, furniture, housewares etc. the carbon emissions related to that product stem entirely from the energy consumed to create it and to ship it to you. So the damage has been done so to speak, and the best thing to do is to use that product fully and for as long as possible so that more energy does not have to be consumed to create a new one.
Products that burn fossil fuels for power - cars, water heaters, furnaces, lawn mowers, gas stoves etc. - are a different case altogether. They emit greenhouse gasses each time they are turned on. They are sources of emissions themselves and generally have long useful lifespans. The emissions from their operation are many times greater than the emissions from their manufacture. An automobile for example will produce 8 - 10 times more emissions from operation than were produced to manufacture it. In the chart on the right from an article about lifetime emissions of EV’s, you can clearly see that the emissions from manufacturing are a small fraction of the lifetime emissions for an automobile. Therefore, the sooner that a fossil fuel powered source of emissions is replaced with a clean electric product, the fewer total emissions will be created.
Furnaces and water heaters do not have a robust second hand market, so when they are removed from your household, they stop emitting forever. Replacing a natural gas water heater or furnace with a clean electric heat pump version will avoid tens of tons of lifetime emissions from that device - many times more than the emissions produced from manufacturing the new non-emitting device.
Some products, like cars and lawn mowers, have a robust second hand market. If you sell your gasoline powered car, someone else will continue to drive it. Most cars change hands several times over their 13 - 17 year lifespan. So regardless of whether you own it or someone else does, your car will continue to be driven until it reaches a level of use that reduces its value to below the scrap value of the metal it is made of. So, if your gasoline powered car is going to produce emissions regardless of who owns it, why is it best to sell it and buy an EV?
Imagine that the fleet of cars in this country is like a big pipe. Each year, 17 million new cars are put into one end of the pipe to join the others in the fleet. They will be driven around for about 15 years and then they will come out the other end of the pipe and be turned into scrap metal. Every year new cars enter the pipe and old useless cars exit the pipe. At the moment, the pipe is filled with gasoline burning automobiles which produce enormous amounts of greenhouse gasses. The sooner we fill the pipe with clean EVs and eliminate the gasoline burning cars, the sooner we can reduce our overall emissions and clean up our air. The only way to do this is to put more EVs into the pipe at the front end and to do this as quickly as possible. Each new EV purchased makes the overall fleet cleaner. This is why the best thing you can do is to let someone else drive your gasoline burning car around for the remainder of its lifetime and put a new clean EV into the fleet as soon as you are able. When you buy an EV you are also helping to influence others - your friends and neighbors will notice and it will send a signal that EVs are normal and practical, and this will make it easier for others to do it too.
So, while it is generally a good idea to use products for as long as possible before buying a new one, that is not the case with products that emit greenhouse gasses. The sooner those products are replaced with clean alternatives, the better.