Capital Expenditures (CapEx)
Large, infrequent costs to replace or improve major property components — roof, HVAC, water heater. CapEx is excluded from NOI but must be reserved for, because ignoring it overstates a rental's true return.
Capital expenditures (CapEx) are the large, infrequent costs of replacing or improving major components of a property — the roof, HVAC system, water heater, windows, foundation, or a full kitchen. Unlike routine maintenance, CapEx items are big-ticket, long-lived, and don't recur monthly. They're a critical (and often ignored) part of a rental's real economics.
CapEx vs. operating expenses
The distinction matters because it affects NOI:
| Operating expenses | Capital expenditures | |
|---|---|---|
| Frequency | Recurring (monthly/annual) | Infrequent (years apart) |
| Examples | Repairs, taxes, insurance, management | Roof, HVAC, water heater |
| In NOI? | Yes (subtracted) | No (excluded) |
| Nature | Keeps property running | Replaces/upgrades major systems |
Because CapEx is excluded from NOI, a property's NOI and cap rate can look better than the property's true long-run profitability — which is exactly the trap.
Why ignoring CapEx is dangerous
A rental might cash-flow nicely month to month, then a $12,000 roof or $8,000 HVAC replacement wipes out a year or more of profit in one shot. CapEx items are inevitable — every roof and furnace eventually dies — so a deal that doesn't account for them isn't really as profitable as its NOI suggests. New investors who underwrite only operating expenses routinely overstate their returns.
Reserving for CapEx
The disciplined approach is to set aside a CapEx reserve — a monthly amount banked toward future replacements, so the big bill doesn't blindside your cash flow:
- A common rule of thumb is 5–10% of gross rent, or estimating each major component's replacement cost and remaining life and reserving accordingly.
- On a $1,500/month rental, reserving 8% means putting aside $120/month for future CapEx.
This reserve is your discipline — it isn't part of NOI or the lender's DSCR math, but it's essential to honest underwriting of your actual return.
CapEx and the BRRRR / flip connection
On a fix-and-flip or BRRRR rehab, you typically replace major systems up front as part of the scope of work. A benefit of buying and fully rehabbing is that you reset the CapEx clock — new roof, new HVAC — so near-term CapEx on the held rental is low. That's a real, if often unquantified, advantage of the BRRRR model over buying an already-tired rental.
Practical takeaway
When you evaluate a rental's true return, treat CapEx as a real cost even though it's outside NOI: estimate it, reserve for it monthly, and factor the property's age and system condition into your numbers. A deal's honest profitability is its cash flow after a sensible CapEx reserve — not the rosier figure that ignores the roof and furnace you'll inevitably have to replace. Building CapEx into your analysis is what separates investors who keep their cash flow from those who watch it vanish on a single big repair.
Frequently asked questions
What's the difference between CapEx and maintenance?
Maintenance is routine, recurring upkeep — service calls, minor repairs — and is an operating expense subtracted from NOI. Capital expenditures are large, infrequent replacements or improvements of major systems like the roof, HVAC, or water heater. CapEx is excluded from NOI but must be reserved for separately.
How much should I reserve for CapEx?
A common rule of thumb is 5–10% of gross rent, or you can estimate each major component's replacement cost and remaining lifespan and reserve accordingly. On a $1,500/month rental, reserving 8% means setting aside about $120/month toward future big-ticket replacements so they don't blindside your cash flow.
Why isn't CapEx included in NOI?
Because NOI captures recurring operating costs, while CapEx items are infrequent capital replacements that are capitalized rather than expensed. The downside is that NOI and cap rate can overstate a property's true long-run profitability if you don't separately reserve for CapEx — which is why honest underwriting accounts for it.