The most common reason a good short-term rental becomes a bad investment is not a bad property. It is a reserve sized against an annual average in a market whose revenue arrives in four months. Cash flow timing kills more deals than cash flow totals.
Annual averages hide the shape
Two properties both produce $110,000 of annual revenue. The first earns roughly $9,000 every month. The second earns $22,000 in each of four peak months and $3,000 in each of the other eight.
They have identical annual revenue and completely different risk profiles. The second property has eight months where revenue does not cover a mortgage, insurance, utilities, and management. That gap is funded out of the peak season surplus, which means the owner must not spend it, and that is exactly what inexperienced owners do in July.
This is why we model monthly rather than annually. See why the shape of occupancy matters more than the average.
Sizing the reserve
Four components, and most owners budget only the first:
- Operating shortfall reserve. The cumulative gap between fixed costs and revenue across the trough months, calculated from the monthly model rather than a rule of thumb.
- Maintenance and replacement reserve. Short-term rentals wear faster than long term rentals. Mattresses, linens, and furniture on a heavily booked property are three to five year items, not ten year items.
- Vacancy shock reserve. A ninety day outage from a burst pipe or an insurance claim in peak season. Business income coverage may respond, and claims take time to pay. See the insurance guide.
- Capital expenditure reserve. Roof, HVAC, hot tub replacement, and pool equipment. Known items with known lifespans, so they can be scheduled rather than absorbed as surprises.
The first year is the hardest
Year one has no review history, no ranking, and no repeat guests, which means it typically underperforms the stabilized model by a meaningful margin. A reserve sized for a stabilized year is undersized for the year you actually have to survive first.
Reserves are an underwriting input, not an afterthought
We size reserves against the trough month in a specific submarket rather than against an annual average, because that is what actually gets tested.
Apply NowSeasonality by market type
- Beach markets: strong March through August, sharp fall decline, thin winter. Reserve for a long trough.
- Mountain and cabin markets: more even, with fall foliage frequently the strongest period and a genuine winter holiday season. The most forgiving profile.
- Desert markets: inverted, with a January through April peak and a severe summer trough. Reserve for summer, not winter.
- Ski markets: concentrated in a short winter window with an increasingly viable summer season. High amplitude.
- Urban and event markets: flatter with sharp spikes on specific dates. Lower reserve requirements but less predictable.
Protecting the reserve
Two practical rules that keep owners out of trouble.
First, hold the reserve in a separate account from the operating account. Money that is visible in the operating balance gets spent, and the psychology here is stronger than the discipline.
Second, take distributions on a schedule rather than opportunistically. Owners who sweep cash monthly in peak season are the ones who discover in February that the mortgage is due and the account is empty. A quarterly distribution taken after the trough is fully funded is the version that survives a slow year. See how much money you need to start.
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Frequently asked questions
How much should I keep in reserve for a short-term rental?
It should be calculated from a monthly model rather than a rule of thumb, and it has four components: the cumulative operating shortfall across trough months, a maintenance and replacement reserve, a vacancy shock reserve for an outage in peak season, and a capital expenditure reserve for known items like roof, HVAC, and hot tub replacement.
Why do annual revenue averages mislead short-term rental investors?
Because two properties with identical annual revenue can have completely different risk profiles. A property earning evenly across twelve months and one earning most of its revenue in four peak months require very different reserves, since the second must fund eight months of fixed costs out of a surplus the owner must not spend.
Does the first year underperform?
Typically yes. Year one has no review history, no search ranking, and no repeat guests, so it usually falls short of the stabilized model. A reserve sized for a stabilized year is undersized for the year you actually have to survive first.
How do I keep from spending my reserve?
Hold it in a separate account from the operating account, because visible balances get spent, and take owner distributions on a schedule after the trough is fully funded rather than sweeping cash monthly during peak season.