Once an EV buyer, always an EV buyer? Maybe not.

A report from car buying service Edmunds says that in the first three months of 2015, there was a noticeable uptick in electric and hybrid car owners trading in their high-efficiency vehicles for traditional, fossil fuel SUVs. The number stands at 22 percent, Edmunds claims, up from about 18.8 percent during the same period last year and 12 percent three years ago. In other words, just because you buy a fuel-efficient vehicle once doesn't mean you've necessarily bought into the Prius and Tesla lifestyle forever — and that loyalty is actually falling over time.

Many drivers buy electrics and hybrids for the environmental benefit, but for others, it's a simple, cold calculation: taking into account the difference in cost between a hybrid model and its non-hybrid stablemate, how long will it take to start saving money? As Edmunds notes in its report, pricy hybrids made for a more compelling case when gas was over $4 a gallon, because heavy drivers could realistically recoup their money within a few years. At today's average — under $2.50 a gallon, according to AAA's tracker — it would take far longer.

This trend probably isn't hurting Tesla

Edmunds reports that sales of EVs and hybrids are generally down, representing 2.7 percent of total new car sales this year versus 3.3 percent the year prior, which can probably also be attributed to the lower price of gasoline. The report doesn't break down loyalty by specific model, but it's likely that Tesla — where the premium price of the Model S precludes buyers who are primarily concerned with saving on fuel costs — isn't being hurt by the trend. Hybrids are likely the biggest victims, followed by inexpensive, lower-range EVs that compete with commuter cars (Nissan's Leaf and Ford's Focus Electric, for instance). The decision to move all the way up to an SUV, though, is a little puzzling.

Assuming the gasoline market is due for an inevitable course correction as drills and refineries idle, many of these SUV buyers may quickly start to regret their decision — if not for the environment, for their wallets.