I did the math based on my current energy cost (15 cents per kWh) and estimated tire life (30,000 miles). For each wh/mi increase, the lifetime cost of the tire increases by $5. So if going with a decent tire bumps up my lifetime efficiency from 225wh/mi to 250, that's only $125 more over the lifetime of the tire, meanwhile a set of those tires might cost $250 less than the ION EVO or MXM4.
Obviously this varies greatly on your energy rates, expected tire tread life, tire sales in your area, etc but I was surprised to find that the impacts of tire efficiency are a lot less than I expected. If I were to factor in my solar panels into the calculations, the higher efficiency tires would save me nearly $0 for 9 months of the year
What I'll end up doing is making a list of several tires and just get the one that has the best price at the time of replacement. So far I'm considering the all season variants of the following:
- Hankook ION EVO
- Michelin MXM4
- Michelin Pilot Sport
- Continental DWS 06
- Hankook Kinergy GT
- Goodyear Electric Drive GT
And of course I will only have my tires serviced at Discount Tire. They've always offered the best service and have been willing to match prices with online retailers and discount warehouse clubs like Costco and Sam's Club.