I have a building in which I am going to replace 9 3ton units. There is 3 phase in now but my tech suggests single phase. My clients pay for their own electricity. These machines have been in service since 1989. The cost of the single phase is about 700.00 a unit less. With today's efficient single phase will the client notice a drop in their electric bill with same use? Also will the longevity be the same? My tech also says that repairs down the road will be cheaper with single phase. Both machines are for commercial use.

  • 1
    The commercial nature of this question may make it off-topic for this DIY/home improvement site. The efficiency should be easy to compare with SEER ratings, right? Also, do all the tenants have 3-phase service? – Hank Apr 2 '14 at 23:20
  • How often have you had to replace motors in the last 25 years? Three-phase motors are much cheaper to buy than their equivalent single-phase motors because they're simpler to build and a bit more universal (any three-phase motor can be run either direction by swapping two wires). I'm a little confused, though - at first you talk about 9 units, then later you say "both machines". – TDHofstetter Aug 31 '14 at 4:29

3-phase is slightly more efficient, but not nearly that much for units like this.

3 ton is a very small unit for central air. It is HIGHLY doubtful you (or a tenant) will see any noticeable difference in their bills.

Considering the dramatic difference in cost ($700 less), it's a no-brainer to go with the single phase units.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.