A comparison of auxiliary locks (crescent lock reinforcement) and security film types, prices, and installation methods for window security in rental housing. Including impacts on restoration to original condition, real estate experts explain window security enhancement strategies available to rental tenants.
Reviewed by: Nobuyuki MoriPresident, M-Assets Co., Ltd. / Licensed Real Estate Transaction Specialist (Miyagi #018212)
When away from your rental apartment for weeks or longer due to travel or family visits, discover practical strategies to prevent security risks and equipment problems that can lurk in a vacant home.
A complete comparison of cost ranges, effectiveness by product type, and restoration risks when securing furniture for earthquake safety in rental apartments. Real estate experts explain the costs of different methods—L-brackets, tension rods, isolation pads—and their impact at move-out.
Noise problems in rental apartments can cause significant stress after moving in. This guide helps you understand the causes of different types of sounds, explains concrete DIY soundproofing solutions, and covers key points to consider when selecting a rental property—all from an expert perspective.
Unattended deaths in rental housing are a risk that both landlords and tenants cannot ignore. Experts explain practical measures covering everything from handling leftover belongings and restoration costs, disclosure requirements for affected properties, insurance options, and welfare check services.
About 60% of burglary entry points are through windows. Compared to owner-occupied condominiums and single-family homes, rental housing windows often have lower standard security performance, requiring tenants to take countermeasures on their own.
This article provides a comprehensive comparison of two major window security strategies available to rental tenants—"window locks (auxiliary locks)" and "security film"—including types, costs, and impacts on restoration to original condition upon move-out.
The crescent locks typically found on rental housing windows have a simple structure—they simply rotate. A technique called "prying open" (inserting a thin tool from outside, rotating the crescent lock to unlock without breaking the glass) can be completed in 5-10 seconds, making crescent locks low in security.
| Measure | Primary Effect | Limitation |
|---|---|---|
| Auxiliary Lock (Window Lock) | Physically blocks window opening | Ineffective against glass breaking |
| Security Film | Makes glass harder to break | Minimal effect if locks are not engaged |
The ideal is a combination of both, but rental properties have constraints on installation methods, costs, and restoration to original condition, so you should prioritize and select accordingly.
A type installed above or below the crescent lock, locked with a key.
Types that pinch into window grooves or frames, or adhere with seals. Installation requires no screws.
A type fixed to the sash rail with a rotary knob for locking.
A type with sensor functionality that triggers an alarm when the window opens.
A type that applies a clear film to existing windows without obstructing visibility.
A multi-purpose type that prevents glass shards from scattering if broken by earthquakes, combining security and disaster prevention.
Security film installed by professional contractors (350–400 μm or thicker).
Most commercial security films are water-applied (using only water to adhere), and can be removed at move-out. However, if left in place for extended periods (5+ years), adhesive residue may remain, so regular condition checks are recommended.
| Budget | Recommended Measure | Estimated Total |
|---|---|---|
| Up to ¥3,000 | Pinch-type auxiliary locks × 2 | ¥1,000–¥4,000 |
| Up to ¥10,000 | Keyed auxiliary lock + clear security film (1 window) | ¥5,000–¥9,000 |
| Up to ¥30,000 | Alarm sensor + security film (all windows, DIY) | ¥10,000–¥25,000 |
| ¥30,000+ | Professional security film (management company confirmation required) | ¥20,000–¥50,000+ |
Window security in rental housing is most practical starting with pinch-type auxiliary locks (requiring no construction) and, if budget permits, combining with clear security film. The two-pronged approach of "preventing opening with auxiliary locks + making glass harder to break with film" is most effective and can be achieved for approximately ¥5,000–¥10,000 total. However, since screw-fixed locks and professionally installed film may affect restoration to original condition, it is essential to confirm with the management company beforehand.
不動産ネットワーク
投資物件・賃貸住宅・テナント・運営会社をつなぐ不動産4サイト連携。
床スラブ厚と上階の足音問題——賃貸で「ドン」という衝撃音が響く構造的な理由と物件選びのポイント
前橋・群馬の賃貸エリアガイド【2026年版】——主要エリア別家賃相場と住みやすさを徹底比較
Making the Most of Protruding Beams and Columns in Rental Apartments — Smart Furniture Placement Strategies
Mito & Ibaraki Rental Area Guide [2026] — Comprehensive Explanation of Rental Rates and Livability by Major Area
Uncovering Property Issues by Asking Previous Tenants About Their Departure—Questions to Ask During Viewings and How to Interpret Answers
