Renewal profile
Read your own register in this page and see when items fall due for renewal, first with every item on a single life and then with lives spread around it.
The seamThe register the asset team keeps and the renewal bid the finance team submits, built from the same lives used for depreciation and never questioned in between.
A renewal plan is almost always built by adding one life to one installation date, which puts every identical item in the same year. The result is a cliff, and the cliff is a property of that assumption rather than of the estate.
A hundred identical items on a 25 year life give a hundred renewals in year 25 and none in any other year. ASHRAE reports centrifugal chillers replaced at a mean of 25.2 years with a standard deviation of 7.6, so the same hundred items spread across decades: about five in the peak year on a Weibull fitted to those two numbers, five on a normal, four treating every age as equally likely. The point calculation overstates the peak by 19.1, 19.7 or 26.3 times. Those figures depend on the model and are marked as ours; the direction does not, because any dispersion at all divides the peak. You can switch the model below and watch how little the answer moves. One of our standing proposals, with what would show it wrong.
Read in this page and nowhere else. There is no upload and no endpoint; reload and it is gone.
If your register is a workbook, save a sheet as CSV first.
How this is built, if you want it
One thing to notice about your own file. A renewal profile wants three fields and no single register has them: the financial register holds the cost, the useful life and the date available for use, while the technical register holds the date installed and the planned replacement interval and no cost at all. Joining the two on the asset tag is the traceability between the registers that this calculation needs, and the reason the columns above default to the financial register is simply that it is the one file that can be used alone. That is a convenience, not a recommendation, which is what the note beside the result is there to say.
The spread is a model and the page says so. None of these three curves is an assumption ASHRAE makes; what its data supports is that the lives are dispersed, and any dispersion at all divides the peak. The only estate whose renewal profile is a cliff is one where every item fails on the same day. One standard deviation is also applied to every item in your file whatever its class, which assumes dispersion is absolute rather than proportional to the life. Nothing we have found settles which of those is right.
Corrected on 4 September 2026. This page first gave the range as 19 to 35 times, the 35 from treating the lives as flat across ASHRAE's observed 7 to 42. That distribution has a standard deviation of 10.1, not 7.6, so the comparison changed the shape and the dispersion at once and credited all of it to the shape. Held at one deviation the three models give 19.1, 19.7 and 26.3, which is a narrower range and a better argument.
Renewal profile
2026-10-01. projects-advisors.com/tools/renewal
Built on a depreciation life. The life used here is the financial register's useful life, which allocates cost to reporting periods and says nothing about when the item stops working. Every date below inherits that.
0 items, 0 of replacement cost. Point life, no dispersion. Read in the browser from a file that was never uploaded. What each model assumes, and what would show the argument wrong, is at projects-advisors.com/tools/renewal
Computed from
- ASHRAE Service Life and Maintenance Cost Database (live database; read 2026-09-26)https://costdatabase.ashrae.org/service_life.asp
- ISO 55001:2024, asset management system requirements (2024 edition; read 2026-09-26)https://www.iso.org/standard/83054.html