A boiler that fails in January on a 12-unit costs more than the whole summer's reserve if you haven't touched it since March.

This is one of the most practical threads in the forum for anyone stepping into their first medium multifamily, so I want to add one layer for people who are still in the preparing stage and have not yet closed on anything.

The reserve math here deserves a concrete anchor. Say you buy a 12-unit and your boiler is twelve years old. A commercial hot-water boiler in that size building has a typical useful life of fifteen to twenty years. That means you may have three to eight years left, or you may have less if it has not been serviced. If replacement runs $12,000 installed (the midpoint of the range in the post above), and you want to be ready in five years, you are setting aside $200 a month into your capital reserve account. A capital reserve is money held specifically for big-ticket replacements like roofs, boilers, and parking lots, separate from your operating account.

The thing a lot of buyers miss at this stage is that the purchase inspection report will say "functional" but will often also give an age estimate and a condition note buried on page eight. Pull that page before you close and build the reserve math from it. If the inspector cannot confirm the install year, the manufacturer plate on the unit usually has it.

One area where I would point you to a professional: if you are trying to figure out how to structure reserves for tax purposes, that is a question for your accountant, not a forum.

What stage are you at right now, still evaluating properties, or have you already closed on something?

My Cleveland 12 has a boiler that was installed in 2003 and I did not know that when I bought it in 2019. The inspection said functional. By January 2020 I had a cracked heat exchanger and a $14,200 invoice and two tenants who knew exactly what their lease said about habitability. One of them had been a renter in the city for twenty years and she had the code section memorized. That was my education.

The line about "functional in May and functional in February" is exactly right and I want to add the part that costs you before the breakdown: deferred service records. When I called three HVAC contractors in December for emergency quotes, every single one asked for the maintenance history first. I had nothing from the previous owner. Two of them added a diagnostic surcharge just for that, because unknown service history on a 21-year-old cast iron boiler means they are pricing in risk. The tune-up in October is not just about avoiding the failure, it is building a paper record that keeps your emergency rate from going up. What I do now: I have a licensed tech out in late September, I get the written report, I photograph it with a timestamp, and I keep it in the same file as my insurance policy. If you are in a city like Cleveland where the housing court is active and tenants are organized, that paper trail is the difference between a habitability complaint that closes in two days and one that drags into a rent escrow situation for six weeks.