HVAC Repair Threshold
Instead of comparing one specific repair quote against one specific replacement quote, this tool works backward: given the replacement's cost and expected savings, what electricity rate would need to be true for that replacement to hit your target payback period.
At your inputs, the electricity rate that hits a 10-year payback is $0.133/kWh.
| Required electricity rate | $0.133/kWh |
|---|---|
| Payback at your actual entered rate | 7.4 years |
- This uses planning estimates you entered, not a contractor quote or guaranteed savings.
- It solves for the electricity rate that meets your target payback; it does not predict future rates.
What this also tells you: Your actual entered rate gives a payback of 7.4 years; the rate above is only the threshold for your stated target, not a forecast.
This is a planning estimate based on your entries. It does not size equipment, determine electrical or building-code compliance, verify incentive eligibility, or replace a contractor quote or professional energy audit.
Why this decision comes up
A repair-versus-replace decision usually gets framed around one repair quote and one replacement quote, both fixed in time. This tool reframes it around the one number in that comparison that actually moves over the years you own the system: your electricity rate.
How this is calculated
Given a net replacement cost, an expected annual kWh savings, and your target payback period, this solves for the electricity rate at which those three numbers produce exactly that payback. It also shows your actual payback at the real rate you enter, so you can see both the threshold and where you currently stand relative to it.
A worked example
With the defaults ($8,000 net cost, 6,000 kWh/year savings, 10-year target payback), the required rate is $0.133/kWh. If your actual rate is $0.18/kWh, well above that threshold, your real payback is faster than 10 years, meaning the replacement clears your target comfortably at current prices.
Common mistakes
A common mistake is treating the breakeven rate as a prediction of future prices rather than a threshold to compare against your current rate. This tool does not forecast electricity prices; it only tells you how your current rate compares to what the decision requires.
Limitations
This assumes your annual kWh savings estimate is accurate and constant across the ownership horizon. If you expect usage or savings to change meaningfully over time, treat the result as a starting point rather than a final answer.
Common questions
Why solve for a rate instead of just comparing two quotes directly?
Solving for the required rate tells you how sensitive the decision is to something that genuinely varies and can change, your electricity rate, rather than locking the comparison to one moment's numbers. If your actual rate is well above or below the threshold, you can be confident in the decision either way.
What if my actual rate is close to the breakeven rate?
That means the decision is genuinely close, and other factors, like the replacement's reliability, comfort, or remaining life of the current system, should carry more weight than the cost math alone.
Where do I get my annual kWh savings estimate?
A contractor's load calculation is the most reliable source. If you only have a dollar savings estimate at a specific rate, divide it by that rate to get an approximate kWh figure.
How is this different from the heating fuel switch breakeven tool?
Both solve for a breakeven rate, but this one is scoped to a straight HVAC repair-versus-replace decision within the same fuel type. The fuel switch tool is for a bigger decision, changing your home's primary heating fuel entirely. Use whichever matches your actual decision.
What if my utility bills me on a tiered or time-of-use rate instead of one flat number?
Enter your effective blended rate for your relevant usage pattern. The utility-rates cluster's tools break out tiered and time-of-use pricing in more detail if you want a more precise blended figure.