Storing frozen goods in a garage presents unique challenges that many standard appliances simply aren’t built to handle. Unlike the stable climate of your kitchen, garages experience extreme temperature swings – plummeting below freezing in winter and soaring into sweltering heat during summer months. Humidity levels fluctuate wildly, pests might find their way in, and the space often lacks the insulation and electrical stability of your main living areas. This environment can wreak havoc on a typical upright freezer, leading to inefficient operation, premature failure, or even complete breakdown when you need it most. Choosing the wrong model means risking spoiled food, wasted money, and the frustration of constant maintenance or replacement.
Understanding these specific demands is crucial before investing in a freezer for your garage. It’s not just about finding a large, upright unit; it’s about identifying the critical engineering features that allow an appliance to thrive in an uncontrolled, often harsh environment. The right freezer for your garage will operate reliably year-round, maintain safe freezing temperatures regardless of the weather outside the door, and do so efficiently to keep energy costs manageable. This guide cuts through the marketing noise to focus on the essential technical specifications and design elements you must evaluate to ensure your frozen goods stay perfectly preserved, protecting your investment and your peace of mind for years to come.
Top 10 Upright Freezers for Garage
Detailed Product Reviews
1. Frigidaire Upright Freezer, 6.5 cu. ft., Deep Freeze, Vinyl Coated Metal with Wire Shelving, Compact for Kitchen, RV, Dorm, Cabin, and Trailer, Platinum Design Series, Silver - 21D x 23W x 56H
Overview: This Frigidaire 6.5 cu. ft. upright freezer delivers essential frozen storage in a remarkably compact footprint, ideal for space-constrained environments like RVs, dorms, or small kitchens. Its platinum silver vinyl-coated metal finish offers durability and a clean aesthetic. What Makes It Stand Out: The standout feature is its space-saving flush-back design and recessed handle, enabling tight corner placement impossible for many competitors. The inclusion of six adjustable wire shelves provides superior organization over basic chest freezers, while the reversible door offers crucial installation flexibility in cramped quarters. Value for Money: Positioned as a budget-friendly compact solution, it offers excellent value for those needing dedicated, accessible frozen storage without excess capacity. While larger units cost more, this freezer’s price reflects its targeted small-space utility, avoiding the premium of convertible models. Strengths and Weaknesses: Strengths: Exceptional compactness for tight spaces; reversible door; well-organized shelving; easy-to-clean finish; quiet operation. Weaknesses: Vinyl coating may show scratches over time; wire shelves lack drawers for messy items; 6.5 cu. ft. capacity suits individuals/small households but not large families. Bottom Line: Highly recommended for RVers, dorm students, or anyone needing reliable, organized frozen storage in minimal space; its smart design and practical features justify the price for its intended niche.
2. BLACK+DECKER 14 Cu. Ft. Convertible Freezer Refrigerator, Upright Freezer with Glass Shelves, ENERGY STAR rated, Frost Free, BUC1400XW, White
Overview: This versatile BLACK+DECKER unit functions as both a 14 cu. ft. upright freezer and a full refrigerator, adapting to seasonal or changing household storage needs. ENERGY STAR certification and frost-free operation enhance its practicality for garages or basements. What Makes It Stand Out: The seamless convertible functionality is its major differentiator, eliminating the need for two separate appliances. Electronic temperature control via LED display ensures precision, while frost-free technology removes manual defrosting hassles. Glass shelves provide sturdy, clear visibility. Value for Money: Despite a higher initial cost than single-mode freezers, its dual functionality offers significant long-term value. The ENERGY STAR rating reduces operating costs, and the large 14 cu. ft. capacity justifies the price for families needing flexible bulk storage year-round. Strengths and Weaknesses: Strengths: True convertible capability; spacious capacity; energy-efficient; frost-free convenience; sturdy glass shelves. Weaknesses: Bulkier size requires substantial floor space; electronic controls may be complex for some users; conversion process takes time and planning. Bottom Line: An outstanding investment for families or those with fluctuating storage demands; the flexibility, efficiency, and capacity make it worth the premium over basic freezers for adaptable long-term use.
3. BANGSON Upright Freezer, 7.0 Cu.ft Stand Up Freezer, Convertible Upright Freezer/Refrigerator, Single Door for Kitchen,Garage, Office, Apartment, Silver
Overview: The Bangson 7.0 cu. ft. unit is a compact convertible freezer/refrigerator designed for apartments, offices, or auxiliary spaces. It transitions between freezing and refrigeration modes, offering adaptable storage in a modest footprint. What Makes It Stand Out: Its core appeal lies in the straightforward conversion between freezer (-7.6°F to 6.8°F) and refrigerator (38°F to 47°F) modes. Unique features include three freshness drawer boxes for produce and pulleys for easy mobility – rare in this size class. The removable door seal simplifies cleaning. Value for Money: Priced competitively for a convertible model, it delivers solid value for renters or those needing secondary cooling. While slightly smaller than some competitors, the included ice tray, defrost tool, and organizational drawers enhance utility without inflating cost significantly. Strengths and Weaknesses: Strengths: Easy mode conversion; mobility pulleys; dedicated freshness drawers; reversible door; user-friendly cleaning features. Weaknesses: Temperature range in fridge mode is narrow (may not cool sufficiently in hot garages); plastic drawers feel less durable than glass; 7 cu. ft. limits bulk storage. Bottom Line: A smart choice for urban dwellers or secondary-space users wanting flexibility; its thoughtful design and conversion capability offer strong utility within its size constraints, recommended for targeted needs.
4. Hamilton Beach Upright Freezer, Deep Freeze, Stainless Steel Freezer with Drawer Compartments, 11 cu. ft. Freezer – 25”D x 23.6”W x 66.5”H
Overview: This 11 cu. ft. Hamilton Beach upright freezer combines generous capacity with exceptional organization, targeting larger households and serious meal preppers. Its sleek stainless steel exterior elevates it beyond utilitarian freezer appliances. What Makes It Stand Out: The seven clear plastic drawer compartments are revolutionary for upright freezers, enabling instant visibility and categorization of frozen items – a massive upgrade over wire shelves. The stainless steel finish resists dents and integrates seamlessly into modern kitchens. Value for Money: It commands a moderate premium over basic wire-shelf models, but the organizational benefits and durable finish justify the cost for families. The 11 cu. ft. capacity avoids the expense of larger commercial units while providing ample space, enhancing long-term value through usability. Strengths and Weaknesses: Strengths: Unmatched drawer organization; premium stainless steel build; spacious yet manageable footprint; flush-back design for tight spaces; easy upright access. Weaknesses: Drawers reduce total usable depth for very tall items; stainless finish shows fingerprints; no convertible functionality. Bottom Line: Highly recommended for organized households needing substantial freezer space; the drawer system transforms usability, making this a top-tier choice for home use where neatness and accessibility are priorities.
5. Commercial Cool Upright Freezer, Stand Up Freezer 6 Cu Ft with Reversible Door, Black
Overview: This 6 cu. ft. Commercial Cool freezer prioritizes rugged reliability and space efficiency in a compact, black-finish package. Designed for practical backup storage in garages, workshops, or tight home corners, it emphasizes core functionality. What Makes It Stand Out: Its commercial-grade durability and ETL certification stand out, signaling robust construction for demanding environments. The flat-back design and recessed handle maximize space efficiency, while adjustable leveling legs ensure stability on uneven floors – ideal for garages. Value for Money: Offering excellent value as a no-frills workhorse, it’s priced accessibly for its certified build quality. The energy-efficient R600a refrigerant lowers operating costs, making it a cost-effective long-term solution compared to less efficient compact models. Strengths and Weaknesses: Strengths: Commercial-grade durability; exceptional space-saving design; energy-efficient; reversible door; sturdy wire shelves; affordable. Weaknesses: Basic black finish lacks kitchen integration; wire shelves hinder organization; minimal features beyond core freezing; small capacity. Bottom Line: A top recommendation for dependable, budget-friendly auxiliary storage in garages or utility areas; its ruggedness, efficiency, and compact footprint deliver outstanding utility for its price point where aesthetics are secondary.
6. BLACK+DECKER 14 Cu. Ft. Convertible Freezer Refrigerator, Upright Freezer with Glass Shelves, ENERGY STAR rated, Frost Free, BUC1400XB, Black
Overview: This versatile 14 cubic foot appliance seamlessly transitions between refrigerator and freezer modes, designed for garages or utility spaces. Its frost-free operation and ENERGY STAR certification target households needing flexible, large-scale cold storage without manual defrosting hassles.
What Makes It Stand Out: The standout feature is its effortless convertible design, allowing users to switch between full fridge or freezer functionality via electronic controls. Combined with spacious glass shelves, frost-free technology, and ENERGY STAR efficiency, it offers rare adaptability for bulk storage in fluctuating seasonal needs.
Value for Money: Priced competitively for its class, it justifies cost through dual functionality—eliminating the need for separate units. Energy savings from its efficient compressor offset long-term electricity costs, making it economical versus buying dedicated appliances, especially for growing families or preppers.
Strengths and Weaknesses: Strengths: Massive 14 cu. ft. capacity; intuitive electronic temperature control; zero maintenance frost-free system; energy-efficient operation. Weaknesses: Bulky size suits only larger spaces; glass shelves may feel less durable than wire alternatives; conversion process isn’t instant, requiring cooldown periods.
Bottom Line: An exceptional investment for households needing adaptable, high-capacity storage. Its energy efficiency and convertible design deliver long-term savings and flexibility, though space constraints may limit smaller homes. Highly recommended for garages or basements.
7. Kismile Small Freezer Upright, 3.0 Cu.ft Mini Freezer with Adjustable Thermostat, Removable Shelves, Reversible Single Door, Stand Up Freezer for Bedroom/Home/Dorms/Apartment (Stainless Steel)
Overview: This compact 3.0 cu. ft. upright freezer targets dorms, bedrooms, or small apartments, offering quiet, energy-efficient freezing in a space-saving footprint. Its reversible door and bedroom-safe noise levels cater to personal-use scenarios where traditional freezers are impractical.
What Makes It Stand Out: The ultra-quiet operation (under 40 dB) and front-mounted 7-speed thermostat make it uniquely suited for bedrooms or offices. Reversible doors, adjustable feet, and a top-mounted handle enhance adaptability in tight spaces, while the compact size doesn’t sacrifice removable shelves for organization.
Value for Money: At its price point, it excels for solo users or couples needing supplemental freezing. Low daily energy use (0.6 kWh) and versatile placement options provide tangible savings versus larger units, though capacity limits bulk storage value for families.
Strengths and Weaknesses: Strengths: Whisper-quiet for bedroom use; reversible door and adjustable feet; energy-sipping operation; intuitive front thermostat. Weaknesses: 3.0 cu. ft. too small for family bulk storage; limited temperature range (-7.6°F to 6.8°F) restricts fridge conversion; stainless finish shows fingerprints.
Bottom Line: Ideal for students, singles, or as a secondary unit in small living spaces. Its quietness and adaptability justify the cost for targeted use cases, but avoid if you need substantial storage. A top pick for dorms or offices.
8. Kenmore Upright freezer - Convertible Refrigerator/Freezer, 5 Shelves, Garage Ready, Meat Storage,Auto Defrost, Congelador For Home, Apartment, Cottage, Basement, Dorm, 7.0 Cubic Feet Capacity White
Overview: This 7.0 cu. ft. convertible unit blends garage-ready durability with flexible storage, featuring five glass shelves and a dedicated pizza compartment. Designed for apartments, cottages, or basements, it shifts between fridge and freezer modes to accommodate changing household needs.
What Makes It Stand Out: The unique pizza compartment optimizes flat-item storage, while the simple dial conversion (no electronics) ensures reliability in unconditioned spaces. Auto-defrost and a wide temperature range (-24°C to 10°C) cater specifically to meat hunters or seasonal bulk shoppers.
Value for Money: Mid-priced for its size, it delivers strong value through dual functionality and garage suitability. The absence of complex electronics reduces long-term repair risks, making it cost-effective versus pricier frost-free models for utility-space use.
Strengths and Weaknesses: Strengths: Specialized pizza storage; robust garage-ready build; easy mechanical temperature control; five adjustable shelves. Weaknesses: Manual defrost in freezer mode (less convenient); white finish shows grime; no energy certification for efficiency claims.
Bottom Line: A practical, no-frills choice for garages or seasonal cabins. Its meat-storage focus and conversion ease shine, though frost-free tech would elevate it. Recommended for hunters or secondary-space use.
9. Upstreman 7.0 Cu.Ft Upright Freezer, Large Capacity Stand Up Freezer with 5 Adjustable Shelves, Convertible Refrigerator/Freezer, Reversible Door for Home, Basement, Apartment (White)
Overview: This 7.0 cu. ft. convertible freezer-refrigerator offers customizable storage via five glass shelves and a crisper drawer, targeting apartments or home offices. Its reversible door and compact dimensions suit cramped spaces while supporting dual-mode temperature control.
What Makes It Stand Out: The inclusion of a crisper drawer—rare in compact freezers—enhances fresh produce storage in fridge mode. Combined with a precise convertible thermostat (-7.6°F to 46.9°F) and recessed handle for tight fits, it bridges the gap between mini-fridges and full freezers.
Value for Money: Priced accessibly, it maximizes value through dual functionality and organizational features like the crisper drawer. Low annual operating cost ($36) and energy efficiency (0.89 kWh/day) offer savings over time, especially as a primary unit in small households.
Strengths and Weaknesses: Strengths: Crisper drawer for fresh food; detailed temperature control; quiet operation; space-saving flush-back design. Weaknesses: Crisper reduces freezer capacity; white finish stains easily; defrost tool inclusion hints at frost buildup issues.
Bottom Line: Excellent for studios or small families needing versatile cooling. The crisper drawer and conversion ease set it apart, though frost management requires attention. A smart buy for space-constrained homes.
10. Commercial Cool Upright Freezer, Stand Up Freezer 5 Cu Ft with Reversible Door, White
Overview: This no-nonsense 5 cu. ft. commercial-grade upright freezer prioritizes reliability for home emergency storage or party prep. Featuring steel wire shelves and ETL-certified efficiency, it targets users needing basic, durable freezing without frills.
What Makes It Stand Out: Its “commercial” build quality—flat back, recessed handle, and steel shelves—ensures durability in high-traffic areas. Reversible doors and adjustable legs provide unmatched placement flexibility in corners or tight nooks, ideal for workshops or kitchens.
Value for Money: Budget-friendly upfront, it excels in cost-per-cubic-foot value for emergency storage. Energy-saving R600a refrigerant lowers utility bills, but the lack of conversion or frost-free tech limits versatility versus pricier models.
Strengths and Weaknesses: Strengths: Rugged, easy-clean steel shelves; exceptional space efficiency; reversible door; ETL energy certification. Weaknesses: No fridge conversion; manual defrost required; basic wire shelves limit organization; minimal temperature precision.
Bottom Line: A dependable workhorse for supplemental freezing or emergency stockpiling. Skip if you need fridge functionality, but ideal for pure freezer duties in constrained budgets or spaces. Best for garages or as a backup unit.
Understanding Garage Environment Challenges
Temperature Extremes and Their Impact
Garages are notorious for experiencing temperatures far outside the standard operating range of typical household freezers. During winter, temperatures can plunge well below 0°F (-18°C), while summer heat can push them above 110°F (43°C). Standard freezers often shut down or malfunction in these conditions, failing to maintain the critical 0°F (-18°C) or lower temperature needed for safe, long-term food storage. Understanding the specific low and high temperature limits your freezer must withstand in your geographic location is the absolute starting point for selection.
Humidity and Condensation Concerns
The lack of climate control in garages leads to significant humidity fluctuations. High humidity, especially during seasonal transitions or hot summers, causes excessive frost and ice buildup inside the freezer. This isn’t just an inconvenience; it insulates the evaporator coils, drastically reducing efficiency, increasing energy consumption, and forcing the compressor to work harder, shortening its lifespan. Models designed for garage use incorporate specific features to combat this persistent issue.
Electrical Stability Considerations
Garage circuits may not be as stable or dedicated as those inside the home. Voltage fluctuations are more common, particularly if the garage shares a circuit with power tools or other heavy machinery. A freezer intended for garage use should have robust electrical components and potentially built-in voltage protection to handle these inconsistencies without sustaining damage or losing cooling capacity.
Essential Technical Specifications
Critical Operating Temperature Range
The single most vital specification is the freezer’s certified operating ambient temperature range. Look for models explicitly rated for operation in ambient temperatures as low as -20°F (-29°C) and as high as 110°F (43°C). Don’t settle for units that only claim “garage ready” without publishing verified low and high ambient temp limits – this is a major red flag. This range guarantees the compressor and refrigerant can function correctly regardless of the garage’s seasonal extremes.
Insulation Thickness and Quality
Thicker, higher-quality insulation (measured in inches) in the walls, door, and lid is non-negotiable for garage performance. It acts as a thermal barrier, minimizing the impact of external temperature swings. This reduces the workload on the compressor, improves energy efficiency significantly in volatile environments, and helps maintain consistent internal temperatures. Look for units specifying insulation thickness, ideally exceeding standard kitchen models.
Compressor Type and Performance
The compressor is the heart of the freezer. For garage use, a high-quality, full-size compressor designed for continuous operation under stress is essential. Avoid units with undersized or basic compressors. Look for features like “low ambient” capability specifically engineered to handle cold starts in freezing garage temperatures, which standard compressors often struggle with, leading to failure.
Key Design Features for Reliability
Automatic Defrost Systems Explained
While manual defrost freezers are often more energy-efficient inside the home, they are generally impractical for garages due to extreme humidity causing rapid, excessive frost buildup. An automatic or frost-free system is highly recommended for garage use. It periodically melts frost off the evaporator coils, preventing insulation and maintaining efficiency. Understand the defrost cycle frequency and how it manages meltwater in cold conditions.
Door Seal Integrity and Design
A robust, multi-layer magnetic door gasket is crucial. It must create an airtight seal even when the door is slightly ajar or as the door frame experiences minor warping from temperature changes. Weak seals allow warm, moist air to infiltrate, accelerating frost formation and forcing the unit to work harder. Check for seals that are thick, flexible across a wide temperature range, and easy to clean and maintain.
Interior Layout and Accessibility
Consider how you’ll use the freezer. Adjustable wire shelves offer flexibility for different sized items but can be harder to clean frost from. Solid freezer drawers provide easier access and better organization but may have slightly less usable space. Ensure the layout allows you to see and reach items easily without excessive door-open time, which impacts efficiency in a challenging environment.
Energy Efficiency in Variable Conditions
ENERGY STAR Certification Nuances
While ENERGY STAR certification indicates good efficiency under standard test conditions (around 70°F/21°C), it doesn’t reflect performance in extreme garage temperatures. A certified unit is still a good baseline, but prioritize the certified operating temperature range first. Efficiency will drop in extreme cold or heat, but a well-insulated unit with a capable compressor will fare significantly better than a basic model.
Inverter Technology Benefits
Freezers equipped with inverter compressors offer a major advantage in garages. Instead of cycling on and off at full power (which is inefficient and stressful on components), they modulate their speed to precisely match the cooling demand. This results in smoother temperature control, quieter operation, significantly lower energy consumption during partial-load conditions (common in variable ambient temps), and reduced wear and tear on the compressor.
Realistic Energy Consumption Expectations
Be prepared for higher energy usage compared to the same freezer operating in a climate-controlled room. The extreme ambient temperatures force the unit to work much harder. Use the estimated annual kWh consumption on the EnergyGuide label as a starting point, but understand actual usage in a garage will likely be 20-40% higher, depending on local climate severity. Factor this into long-term cost calculations.
Durability and Construction Quality
Exterior Material Resilience
The freezer’s outer cabinet must withstand temperature extremes, potential moisture, dust, and minor impacts common in a garage. Look for durable, corrosion-resistant materials like powder-coated steel rather than thin plastic laminates that can crack or warp. Avoid units with excessive plastic components on the exterior or hinges that feel flimsy.
Internal Component Protection
Critical components like the compressor, condenser coils, and electronic controls need protection from the garage environment. Some models feature shielded compartments or elevated mounting to guard against dust, moisture splashes, or accidental bumps from stored items or vehicles. Check if the condenser coils are accessible for cleaning but also reasonably protected.
Vibration and Noise Levels
Compressors working hard in extreme conditions can generate more vibration and noise. Ensure the unit has adequate vibration dampening mounts. Excessive vibration can loosen components over time and is particularly noticeable in a quieter garage space. While some noise is inevitable, a well-built unit minimizes disruptive rattling or humming.
Practical Usage and Installation Factors
Adequate Clearance Requirements
Proper airflow around the freezer is critical for散热 (heat dissipation), especially in hot garage summers. Most manufacturers require several inches of clearance on all sides, top, and back. Ignoring this drastically reduces efficiency and can cause overheating and premature failure. Measure your intended space carefully, including potential obstructions like stored items or walls.
Leveling and Stability
Garage floors are often uneven. A freezer must be perfectly level for the door gasket to seal correctly and for internal mechanisms to function optimally. Look for models with sturdy, adjustable leveling legs that can compensate for minor floor irregularities. An unstable unit stresses components and compromises the seal.
Pre-Installation Acclimatization
Moving a freezer from a warm environment (like a delivery truck) directly into a cold garage, or vice-versa, can cause condensation inside the unit before it even powers on. Always allow the freezer to sit upright in its final location for several hours (consult manual, often 4-24 hours) before plugging it in. This lets internal components adjust to the ambient temperature and prevents potential damage or oil migration in the compressor.
Maintenance for Longevity
Defrost Cycle Management
If you choose an automatic defrost model, understand how the meltwater is handled. In very cold garages, the drain line can freeze, causing water to pool inside. Some units have heated drain lines or require specific positioning. Know the maintenance steps to prevent drain freezes, such as ensuring the drain hole is clear and potentially using a small heater near the drain pan in extreme cold.
Coil Cleaning Frequency
Condenser coils (usually on the back or bottom) get coated in dust and garage grime much faster than in a clean kitchen. Dirty coils drastically reduce efficiency and strain the compressor. Establish a routine (at least twice a year, more often in dusty garages) to unplug the unit and carefully vacuum the coils using a brush attachment. Never use compressed air, which can damage fins.
Gasket Inspection and Care
Regularly inspect the door gasket for cracks, tears, or loss of flexibility, especially after winter. Clean it gently with mild soap and water to remove debris that prevents a tight seal. Apply a thin coat of petroleum jelly occasionally to keep the rubber supple in cold weather. A compromised seal is a major source of frost buildup and energy waste.
Frequently Asked Questions
Frequently Asked Questions
Can a standard kitchen upright freezer be used in an unheated garage? No, standard kitchen freezers are typically only rated for ambient temperatures between 55°F and 110°F. Below 55°F, the thermostat may not activate the compressor, causing the interior to warm above safe freezing levels. Above 110°F, the compressor can overheat and fail.
What is the lowest ambient temperature a garage-ready freezer should handle? Look for freezers explicitly rated for operation down to at least 0°F (-18°C), but ideally -10°F (-23°C) or lower for true reliability in harsh winter climates. Units claiming “garage ready” without stating a specific low temp limit are often insufficient.
Will a garage freezer use significantly more electricity than one indoors? Yes, energy consumption will typically be 20-40% higher due to the extreme ambient temperatures forcing the compressor to work harder and longer, especially during severe cold snaps or heat waves.
Is automatic defrost necessary for a garage freezer? It is highly recommended. The high humidity in most garages causes rapid, excessive frost buildup in manual defrost models, making them impractical and inefficient. Automatic defrost manages this internally.
How do I prevent the defrost drain from freezing in winter? Ensure the drain hole is clear of debris. Position the unit so the drain tube has a slight downward slope. In extremely cold garages, placing a small, safe space heater near the drain pan (not touching the freezer) during the coldest periods can prevent freezing.
What clearance is absolutely essential around a garage freezer? Always follow the manufacturer’s specific instructions, but a minimum of 3-4 inches on the sides and top, and 5-6 inches at the back for airflow is common. Never place it flush against walls or under shelves.
Can I plug my garage freezer into a standard garage outlet? Generally, yes, but ensure the circuit isn’t shared with high-draw tools (like saws or welders) that cause voltage drops. Use a dedicated circuit if possible, and always plug into a GFCI outlet required by modern electrical codes for garages.
How long should I wait before plugging in a new garage freezer? Always allow the freezer to sit upright in its final location for at least 4 hours, and up to 24 hours if it was transported horizontally or exposed to very cold/warm temperatures, to let the compressor oil settle.
What’s the biggest sign my garage freezer is struggling? Excessive frost buildup inside the cabinet (beyond normal levels), the compressor running constantly without reaching/maintaining 0°F, unusually high energy bills, or warm spots on the exterior cabinet are key warning signs.
How often should I clean the condenser coils on a garage freezer? At minimum, twice a year (spring and fall). In dusty or dirty garage environments, inspect them quarterly and clean as needed. Dirty coils are a primary cause of reduced efficiency and overheating.