Dantherm DH120 Swimming Pool Dehumidifier with Defrost + 15.9kW LPHW Air Heater (Single Phase) 💧

Transform Your Indoor Pool Environment with Professional-Grade Moisture Control

The Dantherm DH120 is a powerful, industrial-strength floor-standing dehumidifier specifically engineered to protect indoor swimming pool environments from the destructive effects of excess moisture. Removing up to 94 litres of water per day while simultaneously providing 15.9kW of LPHW air heating, this dual-function unit creates the perfect climate for domestic, therapy, health club, and hotel spa pools.

Stop moisture damage before it starts. Uncontrolled humidity doesn’t just create uncomfortable conditions—it causes corrosion, mould growth, structural damage, and expensive repairs. The DH120 converts moisture energy into usable heat, keeping your boiler off longer, reducing evaporation, and creating a warm, dry environment that protects your investment.

🌟 Key Benefits at a Glance

✅ Exceptional Moisture Removal – Extracts 94 litres per day (3.9L/hour) to maintain optimal humidity levels
✅ Integrated Air Heating – 15.9kW LPHW heating coil eliminates the need for separate radiators or fan heaters
✅ Energy Recovery Technology – Converts moisture energy into 6.5kW of free heat recovery
✅ Total Climate Control – Combined output of 18.6kW (heat recovery + LPHW heating)
✅ Corrosion Resistant – Cataphoresis-painted aluminium housing built to withstand harsh pool environments
✅ Precise Humidity Control – Electronic humidistat adjustable from 40% to 80% RH
✅ Whisper-Quiet Operation – Just 56 dB(A) at 3 metres in Comfort mode
✅ Dual Fan Speed Modes – ‘Comfort’ for everyday use, ‘Boost’ for rapid dehumidification
✅ Low Temperature Performance – Factory-fitted defrost function operates down to 5°C
✅ Eco-Friendly Refrigerant – Uses R454C, the latest low-GWP refrigerant technology

Why Your Indoor Pool Needs the Dantherm DH120

The Hidden Cost of Uncontrolled Pool Humidity

Even when you can’t see it, water vapour saturates the air around your indoor pool. Every hour your pool is uncovered, thousands of litres of water evaporate into the surrounding air. Without proper dehumidification:

⚠️ Structural Damage – Moisture penetrates walls, ceilings, and structural elements causing rot and corrosion
⚠️ Mould & Bacteria – Thrives in humid conditions, creating health hazards and unpleasant odours
⚠️ Window Condensation – Constant dripping damages frames and creates slip hazards
⚠️ Corroded Fixtures – Lighting, door hardware, and metalwork deteriorate rapidly
⚠️ Uncomfortable Environment – Excessive humidity makes the space feel clammy and oppressive
⚠️ Higher Heating Costs – Heating humid air is far more expensive than dry air

The Dantherm DH120 Solution

This professional-grade dehumidifier doesn’t just remove moisture—it recycles the energy locked within that moisture and returns it to your pool hall as usable heat. This clever energy recovery process:

💰 Reduces heating costs by minimising the need for supplementary heating
💰 Lowers pool evaporation by maintaining optimal humidity levels
💰 Eliminates cold outdoor air infiltration required by traditional ventilation systems
💰 Accelerates drying times after pool use
💰 Extends the life of your building by preventing moisture damage

🔧 Complete Technical Specifications

Model: DH120AX/L

Performance Specification	Value	Notes
Dehumidification Capacity	3.9 L/hour (94 L/day)	Based on 30°C air, 60% RH, 28°C pool water
Heat Recovery Output	6.5 kW	Free heat extracted from moisture
LPHW Air Heating	15.9 kW	Hot water heating coil (55°C design temp)
Total Heat Output	18.6 kW	Combined recovery + LPHW heating
Air Flow Rate	1,200 m³/hour	Two-speed fan control
LPHW Flow Rate	23.3 L/min	Required for full heating capacity
LPHW Pressure Drop	4.6 m head	System design consideration

Electrical Specifications

Parameter	Value
Power Supply	230V / 50Hz Single Phase
Fuse Rating	16 Amp (motor rated)
Nominal Running Current	9.7 Amps
Full Load Amps (FLA)	12.5 Amps
Power Consumption	2.13 kW
Compressor LRA	35.5 Amps

Physical Dimensions & Installation

Dimension	Measurement
Width	1,408 mm
Height	860 mm
Depth	365 mm
Weight	Contact supplier
Condensate Drain	16 mm connection
Noise Level	56 dB(A) at 3 metres
Mounting	Floor standing (wall mount available on smaller models)

Operational Parameters

Feature	Specification
Humidity Control Range	40% to 80% RH (adjustable)
Control System	Electronic humidistat
Fan Speed Modes	Comfort / Boost
Defrost Function	Standard (operates down to 5°C)
Refrigerant Type	R454C (low GWP)
Drainage	Direct water drainage (gravity or pumped)
Housing Material	Corrosion-resistant aluminium
Coil Protection	Cataphoresis painted for maximum corrosion resistance

🏊 Room & Pool Sizing Guide

Recommended Applications

Pool Type	Typical Pool Size	Room Volume	DH120 Suitability
Domestic Indoor Pool	6m x 3m x 1.5m (27m³)	Up to 200m³	✅ Excellent
Small Hotel/Therapy Pool	8m x 4m x 1.5m (48m³)	Up to 250m³	✅ Excellent
Health Club Pool	10m x 5m x 1.5m (75m³)	Up to 300m³	✅ Good
Large Commercial Pool	12m+ length	300m³+	Consider multiple units

Coverage Capacity

The DH120 is designed to effectively dehumidify pool halls with the following characteristics:

📏 Ideal Room Volume: 150-250 cubic metres
📏 Maximum Room Volume: Up to 300 cubic metres
📏 Pool Surface Area: Up to 50 square metres
🌡️ Recommended Pool Temperature: 26-30°C
🌡️ Recommended Room Temperature: 28-32°C (2-4°C above pool temperature)
💧 Target Humidity Level: 55-65% RH

⏱️ Performance Estimates: How Fast Will It Work?

Dehumidification Time Estimates

These estimates show how long the DH120 takes to reduce humidity levels in different scenarios:

Room Volume	Starting RH	Target RH	Estimated Time
150 m³	80%	60%	6-8 hours
200 m³	80%	60%	8-11 hours
250 m³	80%	60%	10-14 hours
150 m³	70%	60%	3-4 hours
200 m³	70%	60%	4-6 hours

⚠️ Important: These are estimates based on typical conditions (30°C air temperature, sealed room). Actual performance varies with air temperature, room ventilation, fresh air infiltration, pool cover usage, and ambient conditions. Use Boost mode for faster dehumidification.

Moisture Extraction in Real-World Conditions

Typical Indoor Pool Evaporation Rates:

• Uncovered pool (occupied): 0.5-1.0 kg per m² per hour
• Uncovered pool (unoccupied): 0.2-0.4 kg per m² per hour
• Covered pool: 0.05-0.1 kg per m² per hour

Example: A 30m² pool (6m x 5m) when uncovered and occupied generates approximately 15-30 kg of moisture per hour. The DH120 removes 3.9 kg/hour, which means:

✅ With pool covered: DH120 easily handles all evaporation
✅ With pool uncovered (unoccupied): DH120 controls moisture effectively
⚠️ With pool uncovered (during heavy use): Additional ventilation or pool covering recommended during peak usage periods

📄 Downloads & Technical Documentation

Complete Product Information & Specifications:

📄 Dantherm Non-Ducted Swimming Pool Dehumidifiers Brochure (opens in new tab)
Complete technical specifications, installation guidance, and product range overview for all Dantherm non-ducted dehumidifiers including the DH120. Essential reading for specifiers and installers.

💡 Intelligent Energy Recovery Technology

How the DH120 Saves You Money

Traditional pool hall climate control systems waste enormous amounts of energy. They extract humid air, throw it away, then spend more energy heating fresh cold air to replace it. The DH120 does something far smarter:

Step 1: Moisture Capture – Warm, humid air is drawn into the unit
Step 2: Condensation – The refrigeration system condenses water vapour into liquid
Step 3: Energy Recovery – Heat released during condensation (6.5kW) is returned to the room
Step 4: Supplementary Heating – LPHW coil adds an additional 15.9kW when needed
Step 5: Dry, Warm Air Return – Air exits warmer and drier than it entered

Annual Cost Comparison

Estimated running costs for typical domestic indoor pool (30m² surface area):

Heating Method	Annual Energy Cost	Annual Savings vs. DH120
DH120 with Heat Recovery	£1,800-£2,400	Baseline
Electric Convection Heaters Only	£3,500-£4,500	£1,700-£2,100 higher
Gas Heating + Ventilation	£2,800-£3,600	£1,000-£1,200 higher
ASHP + Ventilation	£2,200-£2,900	£400-£500 higher

Based on 2025 UK energy prices (£0.25/kWh electricity, £0.06/kWh gas). Actual costs vary with usage patterns, insulation, and regional energy prices.

💰 Typical Payback Period: 2-4 years compared to traditional heating + ventilation systems

🔇 Quiet, Comfortable Operation

The DH120’s advanced fan design ensures peaceful operation:

Comfort Mode: 56 dB(A) at 3 metres – comparable to normal conversation
Boost Mode: Slightly higher but still library-quiet

Noise Comparison:

• 50 dB(A) = Quiet office
• 56 dB(A) = DH120 in Comfort mode
• 60 dB(A) = Normal conversation
• 70 dB(A) = Vacuum cleaner

You’ll enjoy your pool environment without intrusive fan noise disrupting relaxation or conversation.

🛠️ Installation Requirements & Clearances

Space Requirements

Minimum Clearances for Proper Airflow:

• Front (air intake): 300 mm clear space
• Sides: 100 mm each side
• Rear (air discharge): 200 mm from wall
• Top: 150 mm for service access

Plumbing Connections

LPHW Heating Circuit:

• Connection size: 22mm or 28mm copper (specify on order)
• Required flow rate: 23.3 L/min
• System pressure: Up to 4.6 m head
• Design water temperature: 55°C (compatible with air source heat pumps)
• Flow/return: Clearly marked on unit

Condensate Drainage:

• 16mm drain connection
• Gravity drainage preferred (unit has integral condensate tray)
• Pumped drainage available if required
• Drain must be adequately trapped to prevent air ingress

Electrical Installation

⚠️ Must be installed by qualified electrician in accordance with IEE Wiring Regulations

• 230V single phase supply required
• 16 Amp motor-rated fuse or MCB
• Dedicated circuit recommended
• RCD protection required for pool environments
• External air stat connection provided (valve and transformer supplied by others)

🎯 Advanced Features for Superior Control

Electronic Humidistat

Unlike basic mechanical humidity controls, the DH120’s electronic humidistat provides:

✅ Precision Control – Maintains humidity within ±2% of setpoint
✅ Adjustable Range – 40% to 80% RH to suit your needs
✅ Digital Accuracy – Eliminates drift and calibration issues of mechanical controls
✅ Fast Response – Reacts immediately to humidity changes

Recommended Settings:

• General use: 55-60% RH
• Winter months: 50-55% RH
• Heavy pool usage: 60-65% RH

Two-Speed Fan Operation

Comfort Mode:

• Normal daily operation
• Energy efficient
• Quieter operation (56 dB)
• Maintains target humidity during light use

Boost Mode:

• Rapid humidity reduction
• Use after heavy pool usage
• Maximum dehumidification capacity
• Faster air circulation

Integrated Defrost Function

The DH120 includes automatic defrost as standard, enabling reliable operation in cooler conditions:

🌡️ Operational Range: 5°C to 35°C
❄️ Automatic Defrost: Prevents ice build-up on evaporator coils
🔄 Seamless Operation: Defrost cycles occur automatically without user intervention

Why This Matters: In cooler months or during night setback, traditional dehumidifiers can freeze up and stop working. The DH120 continues operating effectively even when room temperature drops, ensuring continuous protection.

🌊 LPHW Heating Integration

Compatible with Modern Heating Systems

The factory-fitted 15.9kW LPHW heating coil is specifically designed for low-temperature heating systems, making it ideal for:

✅ Air Source Heat Pumps (ASHP) – Optimised for 55°C flow temperature
✅ Ground Source Heat Pumps – Works efficiently with lower temperature systems
✅ Condensing Boilers – Maintains high efficiency operation
✅ District Heating – Compatible with communal heating networks
✅ Biomass Boilers – Integrates with renewable heat sources

Why LPHW Air Heating is Superior

Traditional Solution:

• Separate dehumidifier
• Wall-mounted radiators or fan heaters
• Multiple electrical connections
• Two control systems
• Higher installation cost
• Less efficient energy use

DH120 Integrated Solution:

• Single unit handles both functions
• No separate heaters required
• Simplified installation
• Unified control system
• Lower overall cost
• Maximises energy recovery

💡 The Result: Lower installation costs, simpler system design, and superior energy efficiency

✅ What’s Included

Standard Package

• Dantherm DH120AX/L dehumidifier unit with pre-fitted LPHW heating coil
• Electronic humidistat control (factory installed)
• User-friendly control dashboard
• 1 x separate air thermostat for LPHW heating control
• Installation and operating manual
• 2-year manufacturer’s warranty

Required Items (Supplied by Others)

The following components must be sourced separately and installed by qualified tradespeople:

🔧 Motorised valve for LPHW circuit (3-port or 2-port as required)
🔧 Transformer for motorised valve control (if not built into valve)
🔧 LPHW pipework and connections (22mm or 28mm copper)
🔧 Condensate drainage pipework (16mm)
🔧 Electrical supply (dedicated 16A circuit with RCD protection)

Professional Installation Recommended

While the DH120 is designed for straightforward installation, we strongly recommend professional installation by qualified heating and ventilation engineers familiar with:

• Swimming pool dehumidification systems
• LPHW heating circuits and controls
• Refrigeration systems
• Electrical installations in wet environments
• Building regulations for pool environments

🏆 Why Choose Dantherm?

Industry-Leading Pool Climate Control

Dantherm is the trusted name in swimming pool dehumidification, with decades of experience in domestic, commercial, and industrial pool environments. When you choose Dantherm, you’re choosing:

🌟 Proven Reliability – Operating in thousands of pools across the UK
🌟 Engineering Excellence – Designed specifically for corrosive pool environments
🌟 Energy Efficiency – Market-leading energy recovery technology
🌟 Comprehensive Warranty – 2-year manufacturer’s warranty as standard
🌟 Nationwide Support – Backed by a network of trained service engineers
🌟 Quality Assurance – ISO 9001 registered quality management

Built for Pool Environments

Every component of the DH120 is engineered to withstand the unique challenges of swimming pool environments:

🛡️ Corrosion Protection – Cataphoresis-painted coils and aluminium housing resist chlorine and humidity
🛡️ Marine-Grade Materials – Selected for maximum durability in harsh conditions
🛡️ IP-Rated Components – Electrical parts protected against moisture ingress
🛡️ Long Service Life – Designed for continuous operation, year after year

📋 Frequently Asked Questions

General Operation

Q: How often should I run the DH120?
A: For best results, run the dehumidifier continuously during pool operation hours and whenever the pool is uncovered. The electronic humidistat will cycle the unit on and off automatically to maintain your target humidity level. Many users set it to run 24/7 for optimal environmental control.

Q: What humidity level should I set?
A: We recommend 55-60% relative humidity for most indoor pools. This provides a comfortable environment while preventing condensation and mould growth. In colder months, you might lower this to 50-55% to reduce condensation on windows and cold surfaces.

Q: How long does it take to dehumidify my pool room initially?
A: For a typical domestic pool room (150-200m³) starting at 80% humidity, expect 6-12 hours in Boost mode to reach 60% RH. Ongoing maintenance requires far less intensive operation. First-time dehumidification takes longer because moisture has often penetrated walls and furnishings.

Q: Can I use this with my air source heat pump?
A: Absolutely! The DH120’s LPHW coil is specifically designed for 55°C water temperatures, making it ideal for air source heat pump systems. This combination provides excellent energy efficiency and running cost savings.

Q: Will it work in winter when my pool room is cooler?
A: Yes. The integrated defrost function allows operation down to 5°C. However, for optimal performance and comfort, we recommend maintaining room temperature at 28-32°C (2-4°C above your pool water temperature).

Installation & Requirements

Q: Can I install this myself?
A: We strongly recommend professional installation by qualified heating engineers and electricians. Installation requires LPHW plumbing connections, electrical work in a wet environment, and integration with your heating system control strategy. Incorrect installation can affect performance and safety.

Q: How much space do I need around the unit?
A: Minimum clearances: 300mm front, 100mm sides, 200mm rear, 150mm top. The unit measures 1,408mm wide × 860mm high × 365mm deep, so plan for approximately 1.7m × 1.1m of floor space.

Q: Does it need to be connected to heating system controls?
A: The separate air thermostat (included) should be connected to a motorised valve on your LPHW circuit. This allows independent control of air heating. The valve and transformer are not included and must be supplied by your installer.

Q: What size electrical supply is required?
A: A dedicated 16 Amp supply (230V single phase) with motor-rated fuse or MCB. RCD protection is required for pool environments. Full load current is 12.5 Amps with a compressor start current (LRA) of 35.5 Amps.

Maintenance & Running Costs

Q: How much does it cost to run?
A: Power consumption is 2.13kW during operation. Based on £0.25/kWh electricity, approximately £0.53 per hour. However, the unit cycles on and off to maintain humidity, so actual running time is typically 40-60% of total pool operation hours. Estimated annual electricity cost: £800-£1,200 depending on usage patterns.

Q: What maintenance is required?
A: Basic maintenance includes: monthly air filter cleaning, quarterly inspection of condensate drainage, annual refrigeration system check by qualified engineer. The corrosion-resistant construction minimises maintenance requirements compared to standard dehumidifiers.

Q: How loud is it?
A: 56 dB(A) at 3 metres in Comfort mode – about the level of normal conversation. Boost mode is slightly louder. Most users find it unobtrusive, especially in larger pool halls where the unit can be positioned away from seating areas.

Q: How long will it last?
A: With proper maintenance, Dantherm dehumidifiers typically provide 12-15 years of reliable service. The corrosion-resistant construction is specifically designed for the harsh pool environment, significantly outlasting standard dehumidifiers.

Performance & Capacity

Q: Is this powerful enough for my pool?
A: The DH120 handles pools up to 50m² (e.g., 10m × 5m) in typical domestic settings. For larger pools or commercial applications, multiple units or ducted systems may be required. Consult our sizing guide or contact us for specific recommendations.

Q: Why is there such a large difference between heat recovery (6.5kW) and total heat output (18.6kW)?
A: The 6.5kW is “free” heat recovered from condensing moisture. The additional 15.9kW comes from your heating system via the LPHW coil. Together they provide 18.6kW total – enough to maintain comfortable temperatures even in winter.

Q: Will it remove the chlorine smell?
A: The DH120 removes moisture, not odours. However, chlorine smell (chloramines) is often worse in humid conditions. By maintaining proper humidity levels and good air circulation, the unit helps reduce the perception of chlorine odour. Proper pool chemistry and adequate fresh air ventilation are essential for odour control.

Q: Can it handle water spillage and splashing?
A: While the unit has an IP-rated enclosure suitable for pool environments, it should not be positioned where it receives direct water splashing. Install in a location protected from direct water contact but with good air circulation access to the pool area.

Compatibility & Options

Q: Does this come in a wall-mounted version?
A: The DH120 model is floor-standing only. Smaller wall-mounted models (DH35 and DH65) are available in the Dantherm range but have lower capacity. Wall-mounting is generally preferred for smaller pools to save floor space.

Q: Can I add heating later if I buy the model without LPHW coil?
A: No, the LPHW heating coil must be factory-fitted. If you think you might need heating in the future, we recommend specifying the DH120AX/L (with heating) from the start, as retrofit is not practical.

Q: What’s the difference between R454C and older refrigerants?
A: R454C is a modern low-GWP (Global Warming Potential) refrigerant that’s more environmentally friendly than older types like R410A. It provides equivalent performance with reduced environmental impact, aligning with UK F-Gas regulations.

Q: Can this be installed outside the pool room (through-the-wall)?
A: The DH120 is a floor-standing model designed for installation within the pool space. If you need through-the-wall installation to save pool hall space, consider the DH75 or DH110 TTW (through-the-wall) models which are specifically designed for plant room installation.

🚀 Get Started Today

Transform your indoor pool environment with the Dantherm DH120 – the professional choice for reliable, energy-efficient pool hall climate control.

Ready to protect your investment and create the perfect pool environment?

Contact us today for:

• Expert sizing advice for your specific pool
• Installation quotations
• Technical support
• Spare parts and servicing

💡 Pro Tip: Take measurements of your pool hall dimensions, pool surface area, and typical room temperatures before contacting us. This helps us provide accurate guidance on the best solution for your needs.

Product Specifications Summary

Feature	Specification
Model	DH120AX/L
Dehumidification	94 litres per day
Heat Recovery	6.5 kW
LPHW Heating	15.9 kW
Total Heat Output	18.6 kW
Air Flow	1,200 m³/hour
Power Supply	230V Single Phase
Power Consumption	2.13 kW
Humidity Range	40-80% RH (adjustable)
Refrigerant	R454C (low GWP)
Noise Level	56 dB(A) @ 3m
Dimensions	1,408 × 860 × 365 mm
Warranty	2 years manufacturer

Dantherm Quality. Certified Performance. ISO 9001 Registered.