Why the monthly security fee is not the total home-camera cost
A monitored home-security quote usually leads with a monthly fee, while a DIY camera starts with a device price. Those figures occur at different times and often cover different services, so comparing them directly can be misleading. A service contract may add installation, deposit, cloud storage, connectivity, transfer, early termination, return, or excluded response charges. A DIY plan can add sensors, a hub, local storage, cloud subscriptions, batteries, memory, replacement, and reinstallation.
This calculator lays out both alternatives month by month and discounts each cash flow to the same starting date. It reports three- and five-year present-value TCO, equivalent monthly cost, the first month from which DIY remains no more expensive, and the monthly service base fee that would make the two alternatives equal. The lower number remains locked as a planning result until the view, retention, response requirement, quote, and contract evidence are comparable.
Questions this model can answer
- Which alternative has the lower present-value TCO for the expected residence period?
- How do a move, a contract ending early, or a DIY replacement change the comparison?
- When does the higher DIY upfront cost remain recovered after later replacements and exit costs?
- What monthly monitored-service fee would make its PV equal the DIY plan?
- Are camera count, view, retention, and professional response truly like for like?
Match the protection scope before comparing prices
One indoor camera that sends an app alert is not equivalent to several cameras covering an entrance and yard with professional monitoring and on-site response. Fix the required locations, view, night performance, alert path, retention, and response before entering money. A low-cost result based on fewer functions is a scope gap, not a saving.
View and count
List each required location. Matching camera counts can still leave different blind spots, mounting heights, and night views.
Retention
If the target is 30 days and one plan stores only seven, the prices are not comparable. Enter confirmed service retention and configured DIY retention separately.
Monitoring and response
An app notification differs from professional monitoring and dispatch. If response is essential, include an actual equivalent service and its cost in DIY.
Decision lock: the calculator still displays planning numbers when evidence is missing, but it does not present the numeric leader as a final choice. A written service quote, a matched DIY cart, contract terms, equivalent scope, sufficient retention, and any insurance-discount evidence must be checked first.
Where to find each input
Evidence and inputs for monitored home security and DIY cameras| Area | Inputs to capture | Best evidence |
|---|
| Shared scope | Camera count, locations, retention, residence period, move month, response need | A simple floor-plan note and household requirements |
| Security service | Installation, deposit, recurring fee, cloud, term, exit, transfer, return, excluded response and service | Written quote, contract, and exit estimate |
| DIY cameras | Devices, sensors, hub, storage, installation, cloud, data, power, supplies, replacement, move, residual | Same-date cart, subscription terms, and manufacturer specifications |
| Credits and risk | Confirmed insurance discounts and user-defined residual-loss scenarios | Policy or insurer response and a separately documented user scenario |
The prefilled values are editable synthetic examples, not a 2026 Korean market average for any security provider or camera brand. Use the same VAT basis for both alternatives. If one quote includes tax and another excludes it, the difference is not a real saving.
How the TCO and present value are calculated
1. Separate upfront and recurring cash flows
Service upfront cash equals installation plus the refundable deposit. Its monthly gross cost combines the base fee, extra cloud or connectivity, electricity, one-twelfth of annual excluded costs, and one-twelfth of any user-entered residual-loss scenario. DIY upfront cash equals camera count times unit cost plus sensors, storage, and installation or network setup. DIY recurring cost includes cloud, connectivity, electricity, maintenance, and any separate residual-loss scenario.
2. Put moves, termination, replacement, and credits in the correct month
Transfer or reinstallation costs occur once in the planned move month. The entered early-termination charge applies only when the analysis horizon is shorter than the mandatory service term. DIY replacement occurs at each cycle before the final month. Service deposit recovery and DIY residual value are credits in the final month, while verified insurance discounts are monthly credits.
3. Discount future cash flows to the starting date
Monthly rate = (1 + annual rate)1/12 - 1
PV of month t = nominal net cost in t / (1 + monthly rate)t
PV TCO = upfront cost + sum of all monthly present values
At a zero discount rate, nominal TCO and PV TCO are equal. With a positive rate, a fully refunded deposit can still have a positive present-value cost because the household gives up cash now and receives it later. The model follows the timing principle described in NIST Handbook 135e2025, but it does not import a United States federal discount rate or price index into a Korean household decision.
Step-by-step workflow
- Write the protection requirement. List locations, target retention, alerts, and whether professional response is essential.
- Choose the residence period. Enter the most realistic number of months and one known move month, or zero when no move is planned.
- Transcribe the service contract. Include installation, deposit, recurring fee, cloud, mandatory term, confirmed exit charge, transfer, return, and exclusions.
- Complete the DIY cart. Include every camera, sensor, hub, storage device, subscription, data plan, power cost, supply, replacement, and reinstallation item.
- Resolve the evidence lock. Check comparable view, retention, response, contract terms, and any insurance discount.
- Read both horizons. A short stay can magnify contract exit costs, while a long stay can expose DIY replacement and subscription growth.
- Save the fee threshold. Compare the quoted service base fee with the break-even fee and request a corrected written quote when included services differ.
Worked synthetic example: three years versus five years
The built-in example uses three cameras, 30 days of target and confirmed retention, and a 3% annual discount rate. The monitored plan has KRW 100,000 installation, a KRW 55,000 monthly base fee, KRW 5,000 monthly cloud or connectivity, and KRW 2,000 monthly electricity. The DIY plan has KRW 80,000 per camera, KRW 150,000 sensors and hub, KRW 100,000 storage, KRW 100,000 installation and network setup, KRW 12,000 monthly cloud, KRW 3,000 monthly electricity, and a KRW 250,000 replacement in month 36. These values explain the model; they are not market-price claims.
Three- and five-year present-value TCO for the synthetic example| Horizon | Service PV | DIY PV | PV difference |
|---|
| 36 months | KRW 2,565,756 | KRW 1,279,805 | KRW 1,285,951 |
| 60 months | KRW 4,061,267 | KRW 1,970,328 | KRW 2,090,939 |
How to read the example
At 60 months, the equivalent monthly cost is KRW 72,903 for the service and KRW 35,369 for DIY. DIY becomes persistently no more expensive in month 10. The service base fee that equalizes 60-month PV is about KRW 17,466. Nevertheless, the evidence boxes start unchecked, so the calculator does not convert this synthetic numeric lead into a final recommendation.
Interpret the outputs without overclaiming
Present-value TCO
This is the main financial comparison between a high-upfront DIY plan and a recurring-fee service. If it differs materially from nominal TCO, review the discount rate and the timing of deposits, residual value, replacement, and termination.
Persistent DIY break-even
This is not merely the first month when DIY looks cheaper. It is the earliest month after which DIY cumulative PV stays no higher through replacement, move, and end-of-horizon cash flows. A later replacement can make a simple first crossover misleading.
Break-even service base fee
The calculation changes only the monthly base fee and keeps installation, deposit, cloud, electricity, transfer, exit, and credits unchanged. It is a negotiation and quote-normalization threshold, not a score for response quality or safety.
Move, contract, and replacement scenarios
- Move after 24 months: distinguish a transfer charge from an early-termination charge. Do not add both unless the written service estimate actually does.
- Rental housing: drilling, wiring, restoration, and a view into a common corridor can require separate owner or building-management review.
- Cloud downgrade: verify whether ending a DIY subscription shortens retention or removes alert functions before treating the free tier as equivalent.
- Replacement scope: decide whether the event replaces only cameras or also the hub and storage. Enter the cost for the planned scope.
- Deposit recovery: even a stated full refund may be reduced for damage, missing equipment, or unpaid balances and may arrive later than the last payment.
- Insurance credit: enter only an approved amount and applicable duration. Camera installation does not establish an automatic discount.
Korean privacy-law boundary for home cameras
Korea-based legal checkpoint, verified September 2, 2026
The National Law Information OPEN API returned the current Personal Information Protection Act as law ID 011357, master sequence 270351, effective October 2, 2025. Article 25 addresses fixed visual-data devices in publicly accessible places, including allowed purposes, visible notice, purpose-limited camera direction, disabled audio recording, safeguards, and an operating policy. Article 29 requires technical, administrative, and physical safeguards. The current Enforcement Decree is law ID 011468, master sequence 283503, effective August 20, 2026; Articles 24 and 25 detail notice and operating-policy items.
Check before installation
- Whether the view stays inside a private home or captures a common corridor, road, neighbor entrance, visitor, or worker
- Whether the installer has authority and whether a visible notice is required for the location
- Whether audio recording is truly disabled rather than merely unused in the app
- How household members, visitors, and care workers receive applicable notice and rights information
- Account access, multi-factor authentication, storage location, retention, deletion, and device-disposal controls
Act No. 21445, master sequence 283839, is scheduled to take effect on September 11, 2026. Its Article 25(6) updates safeguard wording, while the core checkpoints used here remain. Recheck the in-force text, any follow-up decree, and current Personal Information Protection Commission guidance after that date. This calculator does not determine installation authority, privacy compliance, infringement, cybersecurity, or suitability.
What the calculator intentionally excludes
No automatic decision
- Crime probability or prevention effect
- Provider response success or product quality
- Legal termination damages or dispute outcome
- Insurance eligibility, discount, or claim approval
- Installation authority or privacy compliance
Separate specialist work
- Bitrate, RAID, bandwidth, and exact storage engineering
- Facial recognition, biometrics, or audio collection
- Network penetration or encryption assessment
- Multi-property monitoring architecture
- Tax, financing, or accounting treatment
Frequently asked questions
Can I enter only the monitored-service monthly fee?
It can show a rough direction, but it is not a complete TCO. Confirm installation, deposit, cloud, connectivity, electricity, term, exit, transfer, return, and any excluded response or service charges.
What DIY replacement cycle should I use?
There is no universal statutory cycle. Use the warranty, actual environment, battery and memory history, and your replacement plan. Enter zero when no replacement is planned within the horizon.
Does Korean law require exactly 30 days of retention?
Do not assume a universal 30-day rule for every home camera. Review purpose-limited minimum processing, the actual contract, any applicable sector rule, and current PIPC guidance, then enter the retention the plan really provides.
Why does the model not calculate a legal early-termination fee?
Home-security offers can combine equipment rental, guard service, communications, and cloud subscriptions. Classification, written terms, and facts can change settlement. The Korea Consumer Agency describes consumer dispute standards as settlement guidance used with the parties’ agreement and other applicable rules. Enter only the amount in a current written exit estimate.
If DIY is cheaper, should I select it immediately?
No. Evaluate response need, blind spots, internet failure, account security, retention and deletion, installation authority, and the household’s ability to maintain the system separately from cost.
Sources and update boundary
- Korean Personal Information Protection Act Article 25 and Article 29, law ID 011357, master sequence 270351
- Enforcement Decree Article 24 and Article 25, law ID 011468, master sequence 283503
- Korea Consumer Agency consumer dispute standards guide, administrative-rule serial 2100000270136
- NIST Handbook 135e2025, DOI 10.6028/NIST.HB.135e2025, for present-value timing methodology only
- Current written provider quotes, contracts, exit estimates, DIY carts, subscription terms, manufacturer specifications, and insurance records remain the primary price evidence.
Official materials were checked on September 2, 2026. Recheck the amendment at master sequence 283839 and any related decree or PIPC guidance after September 11, 2026. Product and contract prices must be refreshed every time the calculator is used.
Recalculate with matched written evidence
Put the required camera locations, retention, and response on one page, then replace every synthetic amount with the service contract and complete DIY cart. Save the three- and five-year TCO and persistent break-even month so the next quote comparison starts from the same scope.