Establish a baseline
Keep the model number, condition, recent maintenance history and representative energy readings for the existing unit. Age alone does not tell you its current power use. A measured seasonal total is especially useful, although you should note unusual weather or changes in occupancy.
For the replacement, use comparable information. Do not compare an old unit’s hottest-day measurement with a new unit’s annual label estimate without accounting for the different assumptions.
Calculate the simplest payback
Imagine keeping the current appliance requires no new purchase, while a replacement costs $400. Suppose the new unit would save 300 kWh per cooling season. At $0.20/kWh, annual electricity savings would be $60. Simple energy-only payback is $400 ÷ $60, or about 6.67 years.
If you expect only three years of use before moving, those assumptions do not recover the purchase cost through electricity alone. Comfort, reliability or a different installation need may still justify the decision, but they should be named separately.
Include costs that the simple model leaves out
- Delivery, fitting materials and installation.
- Any credible repair quote for the old unit.
- Removal or disposal arrangements.
- Different maintenance costs.
- Any resale value you can reasonably support.
Our comparison calculator includes purchase and electricity only. For a fuller decision, make a separate list of the other costs and add them to the relevant option. Avoid counting a repair cost unless there is a reason to expect it.
Test a less optimistic scenario
Recalculate using 150 kWh rather than 300 kWh of annual savings. At the same price of electricity, annual savings fall to $30 and payback rises to 13.33 years. No one has predicted that either appliance will last that long.
The FTC notes that EnergyGuide operating costs are estimates based on specified use and an average energy price. Your cost can differ. Treat payback as a scenario to challenge, not a guaranteed return or a product-lifespan estimate.
Choose your next step
Continue with the question that matches your next decision:
Sources & further reading
Numerical examples are illustrative unless explicitly described as measured. This guide does not claim hands-on product testing. Read the methodology and editorial disclosure.