Can I install a variable-speed pump on an old pool?

Yes, assuming your electrical can handle it. Check your existing pump’s voltage—if it’s 115V, you may need a new 230V circuit or a 115V variable-speed pump. Older 1.5" plumbing is fine if you run the pump at low speed. You might also need to bypass old timers that don’t work with variable-speed pumps. It’s a solid upgrade that saves electricity and runs quieter.