$635. That is a conservative estimate of the fixed monthly operating floor for a Nashville short-term rental townhome — electricity, water, internet, insurance, permit amortization, and the tech stack guests now expect as standard. Not the mortgage. Not the cleaning fee. Not the management cut. Just the nut that hits whether the calendar is full or completely empty.
Most investors who come to us with a Nashville STR they're considering have modeled revenue and mortgage. Almost none have modeled fixed operating expenses line by line before calling us. That gap is where deals go sideways. Our STR advisory work starts here — with the monthly floor — because that number determines your real break-even occupancy rate, which is the only number that actually tells you whether a deal makes sense.
Here is every fixed cost, sourced and current, with what it actually means for your underwriting.
The Electric Bill: $150–$250/Month, Not the Residential Average
Nashville Electric Service runs at approximately 13.47 cents per kilowatt-hour, putting a standard residential household near $119 per month at roughly 886 kWh of monthly usage. That figure is accurate for a primary residence with one set of occupants who pay their own bill and have an incentive to conserve.
An STR property is a different animal. Guests run the HVAC at full tilt, leave lights on, run the dishwasher multiple times per turnover, and do not care about the bill. Nashville summers regularly push properties above 1,500 kWh per month. Residents on the EnergySage Marketplace in Nashville spend an average of $190 monthly on electricity, totaling $2,280 per year. For an STR with high-turnover guest usage, budget $150 to $250 depending on property size and season — not $119.
In Tennessee, heating and cooling often makes electric the largest share of the utility bill. That is especially true in a Germantown rowhouse or a Nations townhome where the HVAC is working hard during July and January. A smart thermostat — which runs roughly $200 to $400 installed — can recover 15–25% of that spend annually, but it still doesn't change the baseline math in peak months.
Water and Sewer: $50–$80/Month, and Climbing
Metro Water Services raised residential and commercial rates by 3% on January 1, 2026, reflected in February bills. That followed a 2.6% increase that took effect January 1, 2025 — the fifth consecutive year of rate increases. Water is not a volatile line item, but it is not flat either. Anyone underwriting a Nashville STR with a static water budget from two or three years ago is already behind.
Average monthly utility costs in Nashville are about $210.21, based on 1,000 kWh of electricity and 5,000 gallons of water, plus sewer and trash fees. For a residential unit, that is the full utilities package. For an STR doing 15 to 20 turnovers per month — each involving multiple showers, toilet cycles, a laundry load, and dishwasher runs — 5,000 gallons is a light estimate. Budget $50 to $80 per month for water, sewer, and stormwater charges combined, and expect that number to drift upward annually per the rate schedule Metro has signaled.
Internet: $60–$80/Month, and It Cannot Go Down
Internet is not optional. It is the number-one amenity guests cite after location and bedrooms. A slow connection generates a bad review faster than a stained towel.
Spectrum leads with plans starting at $30 per month, AT&T Fiber starts at $35 per month, and Xfinity offers plans from $40 per month. Those are promotional entry-level rates. For an STR, you want a mid-tier plan with enough bandwidth to handle multiple simultaneous devices — streaming on the TV, video calls, phones, smart home devices. Internet plans in Nashville range from about $25–$35 per month for entry-level service, while most households will find solid mid-tier plans around 300–500 Mbps priced between $50 and $70 per month.
Budget $60 to $80 per month for a plan that won't generate complaints. That accounts for the real post-promotional rate, not the 12-month teaser. And unlike electricity, you cannot tell guests to keep the Wi-Fi usage down.
STR Insurance: $100–$200/Month, and Non-Negotiable
This is the line item investors most frequently undercount — or skip entirely — in their initial models. Standard homeowners insurance does not cover Airbnb. STR policies run $1,000 to $2,000 per year for most properties, with higher-value homes or those with outdoor amenities running more.
Most Airbnb hosts pay $100–$200 per month for comprehensive STR insurance. Rates depend on property value, location, guest volume, and coverage limits. In Nashville specifically, the stakes are higher than in most markets. Nashville requires an STR permit and proof of liability insurance with a $1 million minimum. That means STR-specific coverage is not a preference — it is a permit requirement.
The Nashville version of the most common insurance gap is a Type 2 non-owner-occupied STR insured on a Type 1 owner-occupied policy form. The carrier will deny the claim. That $1,200 annual savings on insurance can become a six-figure uninsured loss. Budget $125 per month as a floor for a standard Nashville STR, and verify your coverage matches your permit class before the first guest checks in. Our investment advisory process includes this coverage review before we recommend making an offer.
The Permit: $150–$200/Year, Renewed Annually
The new online STR permit application process became effective March 11, 2026. In Nashville and Davidson County, the law requires that anyone wishing to rent a property on STR websites must receive a permit from the Metro Codes Department prior to listing. STR permits must be renewed annually.
Permits are annual and non-transferable — they end on sale or any change of ownership entity. That last point matters enormously for investors buying an existing STR: the permit does not convey with the property. A non-owner-occupied permit in a residential zone cannot be reissued to a new owner under current Metro rules. All traditional residential zones — R, RS, AR2A — cannot obtain new non-owner-occupied permits. If you're buying in The Nations or East Nashville expecting to operate as a Type 2 NOO STR, and the existing permit is tied to the current owner's entity, the deal structure needs to be examined before you close, not after. This is precisely the kind of pre-purchase verification we run on every STR acquisition.
Amortized monthly, the permit fee itself is roughly $13 to $17. The real cost of a permit problem is not the fee — it's the lost revenue while you're trying to fix a zoning or ownership structure issue after closing.
The Tech Stack: $30–$50/Month
Nashville's noise ordinance is not casual. Nashville's noise code sets a hard 70 dB(A) nighttime cap that STR permit holders are personally responsible for under Metro Nashville Code, Title 9. That makes a noise monitor less of an optional gadget and more of a permit protection tool.
Minut, one of the most widely used noise monitors in the STR industry, runs a subscription of approximately $9.90 to $11.90 per month. A smart lock subscription (August, Schlage Encode, or similar) adds another $5 to $15 per month depending on the platform integration. Add a dynamic pricing tool like PriceLabs or Wheelhouse — both of which run $20 to $30 per month — and you're at $35 to $55 per month in recurring software before you've bought a single supply run.
In 2026, smart home technology is closer to a baseline expectation than a premium differentiator. Properties without keyless entry and reliable Wi-Fi increasingly get dinged in reviews for the absence. These are not optional upgrades in Nashville's competitive STR market. They're table stakes.
The Real Monthly Floor: What the Numbers Add Up To
Here is the conservative operating floor for a Nashville STR townhome, built from the verified figures above:
Electricity: $175/month (mid-range, seasonal average)
Water, sewer, stormwater: $65/month
Internet: $70/month
STR insurance: $125/month
Permit (amortized): $15/month
Tech stack (noise monitor, lock, pricing tool): $45/month
Streaming services for guests (Netflix, etc.): $20/month
Total: approximately $515–$635 per month before mortgage, management, cleaning, or supplies.
That is not a worst-case number. It is a realistic baseline for a 2- to 3-bedroom Nashville STR operating with the infrastructure guests expect. A 4-bedroom East Nashville bungalow pulling 18 turnovers per month will run closer to the top of that range. A Gulch studio will sit toward the bottom.
The number that matters most in STR underwriting is not projected revenue — it is break-even occupancy. Take your total monthly fixed costs (operating floor + mortgage) and divide by your realistic average nightly rate. That gives you the occupancy percentage you need just to not lose money. Most pro formas investors bring us are missing $300 to $400 per month in operating expenses, which means their break-even occupancy is materially understated. We've been featured in national media for the approach we take to STR underwriting precisely because it surfaces these gaps before the offer, not after the closing.
The 2026 Costigan Group STR Playbook and Nashville STR Underwriting Calculator are built around this methodology. Revenue is what you earn. The monthly floor is what you owe. The spread between them is the only number that tells you whether a deal actually works.
If you're evaluating a Nashville STR and want the full operating expense model — not a pro forma built around peak-season ADR — reach out before you make an offer. The conversation is free. The mistake of skipping it is not.
