Below are some notable blended HFC mixtures. There exist many more (see list of refrigerants). All R-400 (R-4xx) and R-500 (R-5xx) hydroflurocarbons are blends, as noted above. 1  R-401A is a HCFC zeotropic blend of R-22, R-152a, and R-124. 2  It is designed as a replacement for R-12. R-401A is a HCFC zeotropic blend of R-22, R-152a, and R-124. 2  It is designed as a replacement for R-12. 3  R-404A is a HFC nearly azeotropic  blend of 52 wt.% R-143a, 44 wt.% R-125, and 4 wt.% R-134a. 4  It is designed as a replacement of R-22 and R-502 CFC.
Diesel vehicles may be making a comeback. Diesel engines are more fuel-efficient and have more low-end torque than similar-sized gasoline engines, and diesel fuel contains roughly 10% to 15% more energy than gasoline. So, diesel vehicles can often go about 20% to 35% farther on a gallon of fuel than their gasoline counterparts. Plus, today's diesel vehicles are much improved over diesels of the past.
Most larger RVs, as well as bus conversion RVs, run on diesel fuel. Diesel engines, designed for longer journeys and to take more stress, are also more fuel-efficient. For a price similar to gasoline, you can get several more miles per gallon as well as spend less on overall maintenance costs. However, for the most fuel-efficient RV, look into smaller models with diesel engines. For example, Winnebago makes a smaller motor home called a Rialta that is built on a Volkswagen diesel chassis. Smaller models plus diesel engines make for a surprisingly fuel-efficient motor home.