Dantherm DH35 Defrost Swimming Pool Dehumidifier with 2.8kW Electric Heating 💧🏊

Transform your indoor pool environment with professional-grade moisture control and efficient electric heating in one compact, wall-mounted unit.

The Dantherm DH35AX/E represents the perfect solution for domestic and small commercial indoor swimming pools, therapy pools, and spa facilities. This advanced dehumidifier combines powerful 30-litre-per-day moisture removal with 2.8kW of electric heating, delivering total climate control while protecting your pool building from harmful condensation, mould, and structural damage.

Unlike basic dehumidifiers, the DH35 is purpose-engineered for the challenging conditions of swimming pool environments. Its corrosion-resistant aluminium housing and fully anti-corrosion coated coils ensure long-term reliability in high-humidity, chlorinated atmospheres. The factory-fitted 2kW electric heating element provides supplementary warmth without the complexity of hot water plumbing, making it an ideal retrofit solution or cost-effective alternative to LPHW systems.

✅ Key Benefits at a Glance

🛡️ Built Pool-Tough – Aluminium housing with comprehensive corrosion-resistant coating protects against chlorine vapours and moisture damage

🔥 Dual Climate Control – Removes up to 30 litres of moisture daily while providing 2.8kW of electric heat (4kW total heat output when combined with heat recovery)

❄️ Year-Round Operation – Standard defrost function allows reliable performance down to 5°C ambient temperature

🎛️ Precision Control – Electronic humidistat adjustable from 40% to 80% RH maintains your ideal environment automatically

⚡ Flexible Operation – Two fan modes (Cycle and Continuous) adapt to varying moisture loads and usage patterns

♻️ Energy Recovery Technology – Extracts 2kW of “free” heat from moisture removal, reducing overall heating costs

🔧 Easy Installation – Wall-mounted design with straightforward electrical connection and direct condensate drainage

🌍 Eco-Friendly Refrigerant – Uses R454C, a modern low-GWP refrigerant complying with latest environmental standards

🏊 Perfect Applications & Room Sizing

Is the DH35 Right for Your Pool?

The DH35AX/E is ideally suited for:

✅ Domestic Indoor Swimming Pools – Up to 6m x 4m (24m²) pool surface area

✅ Therapy & Hydrotherapy Pools – Medical facilities and rehabilitation centres

✅ Small Hotel & Spa Pools – Boutique hotels and wellness facilities

✅ Home Gyms with Pools – Combined exercise and aquatic spaces

✅ Pool Houses & Converted Buildings – Residential pool enclosures

Room Size Coverage: Effective for pool halls up to 90-120m³ (approximately 30-40m² floor area with 3m ceiling height)

Typical Pool Volumes: Suitable for pools containing 15-30m³ (15,000-30,000 litres) of water

⚠️ Important Sizing Note: These are general guidelines. Actual capacity requirements depend on pool water temperature, air temperature, ventilation rates, bather load, and pool cover usage. For precise sizing, consult the full technical brochure or contact a pool climate control specialist.

📊 Complete Technical Specifications

Dehumidification Performance

Electrical Specifications

Physical Specifications

Environmental & Refrigerant

🌡️ Real-World Performance Data

Moisture Removal Capability

Understanding how the DH35 performs in real conditions:

*Performance may vary based on temperature differential and bather load

Heating Performance Scenarios

Scenario 1: Morning Warm-Up (20°C to 26°C)

• Room Volume: 100m³
• Temperature Rise Needed: 6°C
• Time to Reach Target: Approximately 2.5-3 hours with 4kW total output
• Running Cost: ~£0.85/hour at average UK electricity rates

Scenario 2: Maintaining Temperature (26°C hold)

• Typical Heat Loss: 2-3kW in moderately insulated pool hall
• DH35 Contribution: 4kW total (heat recovery + electric)
• Result: Sufficient to maintain temperature with minimal boiler support

Scenario 3: Winter Operation (15°C to 26°C)

• Large temperature differential requires primary heating system
• DH35 provides supplementary heating, reducing boiler demand
• Estimated Contribution: 30-40% of total heating requirement

💡 Energy Efficiency Tip: The 2kW of “free” heat from moisture extraction significantly reduces the net cost of electric heating. Running costs are approximately 50% lower than a standard 4kW electric heater achieving the same dehumidification result.

🔧 Installation & Setup Highlights

What Makes Installation Straightforward

Wall-Mounting System

• Compact 885mm x 720mm footprint fits most pool hall walls
• 265mm depth minimizes room intrusion
• Robust brackets included for secure fixing
• Weight distribution designed for standard stud walls

Electrical Requirements

• Single 230V supply with 20A motor-rated fuse
• Pre-wired and factory tested
• Accessible thermostat for easy adjustment
• No specialist electrical configuration required

Condensate Management

• 16mm drainage outlet for direct connection
• Gravity drainage to suitable drain point
• Optional pump kit available for remote drainage
• Continuous operation – no manual emptying

Airflow Configuration

• Front air intake with washable filter
• Top-mounted discharge for optimal circulation
• Minimum clearances: 500mm front, 200mm sides, 300mm top
• Can be positioned to complement existing pool hall layout

⚠️ Professional Installation Recommended: While the DH35 is designed for straightforward installation, professional fitting by a qualified HVAC or pool engineer ensures optimal performance, correct electrical connections, and compliance with building regulations.

🆚 Model Comparison: Why Choose Electric Heating?

DH35AX/E (Electric) vs DH35AX/L (LPHW)

When to Choose Electric (DH35AX/E):

• No existing LPHW system or boiler
• Retrofit or replacement projects
• Seasonal pool operation
• Simpler maintenance regime preferred
• Lower upfront budget

⚙️ Advanced Features Explained

Dual Fan Operating Modes

Cycle Mode (Standard)

• Fan operates based on humidistat demand
• Quieter operation during low-use periods
• Energy-efficient for typical usage patterns
• Ideal for domestic pools with predictable schedules

Continuous Mode (Boost)

• Fan runs constantly while unit is powered
• Maximum moisture removal capacity
• Faster humidity reduction after heavy use
• Recommended during periods of high bather load or winter

Electronic Humidistat

Precision Humidity Control: Unlike mechanical humidistats, the electronic system provides accurate, drift-free control between 40% and 80% RH. Set your target humidity level (typically 50-60% for pool halls), and the unit automatically maintains it.

Why This Matters:

• Prevents over-dehumidification (dry air, increased evaporation)
• Stops under-dehumidification (condensation, mould risk)
• Reduces energy waste from unnecessary compressor cycling
• Provides consistent comfort for swimmers

Defrost Functionality

Automatic Defrost Cycle: When operating in colder conditions (below 10°C ambient), the evaporator coil can ice up. The DH35’s intelligent defrost system detects ice formation and temporarily suspends the cooling cycle while continuing airflow to melt accumulated frost.

Real-World Benefit: Reliable operation down to 5°C means the unit continues protecting your pool building even when heating fails or during winter startup periods.

Corrosion Protection System

Triple-Defence Approach:

1. Aluminium Housing – Naturally corrosion-resistant base material
2. Corrosion-Resistant Coating – Applied to all external surfaces
3. Fully Anti-Corrosion Coated Coils – Special treatment on heat exchanger coils

Why This Investment Pays Off: Pool hall environments are among the most corrosive due to elevated temperatures, humidity, and chlorine vapours. Standard steel units can corrode within 3-5 years. The DH35’s protection systems typically deliver 10-15+ years of reliable service.

💰 Running Costs & Energy Efficiency

Estimated Operating Costs

Typical Usage Scenario (Domestic Pool, 6 hours/day operation):

Based on average UK electricity rate of £0.24/kWh (November 2025). Actual costs vary with usage, tariffs, and climate conditions.

Energy Efficiency Breakdown

Heat Recovery Advantage: The DH35 extracts 2kW of heat from the moisture removal process, effectively providing this heat “for free” (already paid for in the dehumidification electricity consumption).

Net Heating Cost Calculation:

• Total heat delivered: 4.0 kW
• Paid heat (electric element): 2.0 kW
• Free heat (recovered): 2.0 kW
• Effective heating COP: 2.0 (double the efficiency of a standard electric heater)

Annual Savings Comparison:

💡 Key Insight: While LPHW systems offer lower running costs, the DH35AX/E’s simplicity and lower upfront investment often result in better total cost of ownership over 5-7 years, especially in retrofit scenarios.

❓ Frequently Asked Questions

General Operation

Q: How does the DH35 compare to the original Vaporex models?

A: The DH35 offers significantly larger heating capacity than equivalent Vaporex units while maintaining similar physical dimensions. This upgrade provides better climate control without requiring major installation modifications. The dual-position LPHW connections (for the /L model) also offer more flexible pipework routing.

Q: Will this unit eliminate condensation on my pool hall windows completely?

A: The DH35 dramatically reduces condensation risk by maintaining controlled humidity levels (typically 50-60% RH). However, complete condensation elimination also requires adequate insulation, quality glazing, and proper ventilation. Very cold external temperatures may still cause some window condensation despite optimal humidity control.

Q: How loud is the DH35 during operation?

A: At 46 dB(A) measured at 3 meters, the DH35 is comparable to quiet conversation or a modern refrigerator. In Cycle mode, noise is intermittent as the fan runs only when dehumidification is needed. Most users find the sound level unobtrusive in typical pool environments.

Installation & Setup

Q: Can I install this myself, or do I need a professional?

A: While the DH35 features straightforward wall-mounting and electrical connections, we strongly recommend professional installation by a qualified HVAC engineer or pool specialist. This ensures:

• Correct electrical installation with proper fusing and earthing
• Optimal positioning for air circulation and maintenance access
• Proper condensate drainage routing
• Warranty compliance (some manufacturers require professional installation)
• Compliance with building regulations and electrical safety standards

Q: What are the minimum clearance requirements around the unit?

A: For optimal performance and maintenance access, maintain these minimum clearances:

• Front (air intake): 500mm clear space
• Sides: 200mm each side
• Top (air discharge): 300mm
• Bottom: 100mm (for condensate connections)

Ensure easy access to the front panel for filter cleaning and control adjustments.

Q: Can this be installed in a ceiling void or plant room?

A: No, the DH35AX/E is designed as a wall-mounted unit for installation within the pool hall itself. For plant room installations, consider the DH75 or DH110 models which are available as Through-The-Wall (TTW) versions. These mount in an adjacent plant room with only the air grille visible in the pool hall.

Performance & Sizing

Q: My pool is 7m x 4m – will the DH35 be sufficient?

A: A 7m x 4m pool (28m² surface area) is approaching the upper capacity limit of the DH35. Key factors to consider:

• Pool temperature: Higher water temperature = more evaporation
• Air temperature: Warmer air can hold more moisture
• Usage intensity: Heavy bather loads increase humidity
• Cover usage: Pool covers dramatically reduce moisture load
• Ventilation: Mechanical ventilation reduces dehumidifier load

For a 28m² pool with moderate usage (family pool, covered when not in use), the DH35 may be adequate. For commercial use or no pool cover, consider the DH65AX/E (50L/day capacity) or adding supplementary ventilation. We recommend consulting the full technical brochure or contacting a pool climate specialist for precise sizing.

Q: How quickly will this reduce humidity after heavy pool use?

A: Example scenario: After a party with 10 swimmers for 2 hours, humidity might spike from 55% to 80%.

Recovery time estimate:

• Room volume: 100m³
• Excess moisture: ~5 litres
• DH35 capacity: 1.22 L/hr
• Estimated return to 60% RH: 3-4 hours in Continuous mode

Recovery is faster with good air circulation and if the pool is covered after use. The electronic humidistat will automatically intensify operation during high-humidity periods.

Maintenance & Longevity

Q: What regular maintenance does the DH35 require?

A: Monthly:

• Clean or vacuum the front air filter (removes dust and pool chemical particles)
• Check condensate drainage is flowing freely

Every 6 Months:

• Inspect coils for dust accumulation (clean with soft brush if needed)
• Verify humidistat is controlling to set point accurately
• Check electrical connections are secure

Annually:

• Professional service inspection
• Refrigerant pressure check
• Electrical system testing
• Deep clean of coils and housing

Proper maintenance typically extends unit life to 12-15 years in pool environments.

Q: What warranty is provided, and what does it cover?

A: The DH35 is backed by a 2-year manufacturer’s warranty covering defects in materials and workmanship. The warranty includes:

• Compressor and refrigeration circuit
• Electrical components and controls
• Housing and structural components
• Nationwide network of authorized service engineers

The warranty does not cover damage from improper installation, lack of maintenance, or operating outside specified conditions. Professional installation and annual servicing are recommended to maintain warranty validity.

Q: What’s the expected lifespan of this unit?

A: With proper maintenance and professional installation, the DH35 typically delivers:

• Average lifespan: 12-15 years in pool environments
• Compressor lifespan: 10-12 years (replaceable if needed)
• Electronic controls: 8-10 years

The corrosion-resistant construction significantly extends life compared to standard dehumidifiers, which may only last 5-7 years in pool conditions. The R454C refrigerant also ensures long-term parts availability and environmental compliance.

Energy & Costs

Q: Would running this dehumidifier be cheaper than running my pool boiler more?

A: It depends on your current setup, but typically yes, significantly cheaper:

Comparison example:

• Gas boiler heating via radiators: £0.05-0.08/kWh
• DH35 with heat recovery: Effective £0.12/kWh for 4kW heat (£0.24/kWh electricity, but 50% is “free” recovered heat)
• Standard electric heating: £0.24/kWh

While gas remains cheapest per kWh, the DH35’s advantage is that it simultaneously dehumidifies, which your boiler cannot do. Without dehumidification, you’ll need to vent humid air and heat fresh cold air, wasting significant boiler energy.

The DH35 is most cost-effective when it:

• Replaces separate electric heaters + basic dehumidification
• Reduces boiler run-time by handling 30-40% of heating load via heat recovery
• Eliminates the energy waste of “heat and vent” approaches

Q: Can I run this on Economy 7 or off-peak electricity to save money?

A: The DH35 must operate when moisture is being generated (i.e., when the pool is in use and immediately after). Most pool usage occurs during daytime and evening, so purely off-peak operation isn’t practical.

However, you can optimize costs:

• Run intensive dehumidification during off-peak hours if humidity is elevated
• Use Cycle mode during peak hours (runs only when needed)
• Switch to Continuous mode during off-peak for maximum moisture removal
• Combine with a timer or smart plug for automated off-peak boost cycles

For pools with Economy 7, consider raising temperature overnight using the electric heating during cheap-rate periods, then reducing boiler demand during peak hours.

Technical & Compatibility

Q: What is R454C refrigerant, and why does it matter?

A: R454C is a modern, low-Global Warming Potential (GWP) refrigerant that replaced older types like R410A and R134a. Key benefits:

• Environmental compliance: Meets F-Gas regulations and future-proofed against upcoming restrictions
• Similar performance: Provides equivalent cooling and dehumidification to older refrigerants
• Widely available: Service engineers can obtain R454C readily for maintenance and repairs
• Safety: Non-toxic and non-flammable (A2L classification)

Choosing R454C equipment ensures long-term parts availability and regulatory compliance, unlike older refrigerant systems which may become obsolete.

Q: Can I control this with a building management system (BMS)?

A: The standard DH35AX/E includes a built-in thermostat and humidistat for standalone operation. For BMS integration, you would need:

• External relay control to enable/disable the unit
• Humidity and temperature sensors connected to your BMS
• Relay outputs from BMS to control fan modes

For full BMS integration with feedback, consult Dantherm or your supplier about available control interfaces or upgraded control panels. The LPHW models (DH35AX/L) include an air stat output for motorized valve control, which may offer more integration options.

🎯 Why Choose the DH35AX/E from Parts4Tubs?

Expert Pool Equipment Specialists

Parts4Tubs offers more than just dehumidifiers – we provide complete pool climate solutions backed by decades of industry experience. When you choose us:

✅ Technical Expertise: Our team understands pool environments and can advise on optimal equipment selection ✅ Competitive Pricing: Direct supplier relationships ensure excellent value ✅ Fast UK Delivery: Stock held for rapid dispatch ✅ Comprehensive Aftercare: Ongoing support and maintenance advice ✅ Full Product Range: From dehumidifiers to heating, filtration, and accessories

📋 Delivery & Installation Information

What to Expect When You Order

Packaging: The DH35 arrives securely packaged with installation brackets, fixings, and user manual included.

Delivery: Standard UK delivery typically 3-5 working days. Tracking provided.

Before Installation:

• Confirm wall mounting location can support ~30kg weight
• Ensure 230V electrical supply with 20A fuse is available nearby
• Plan condensate drainage route (ideally gravity-fed to floor drain)
• Verify clearances meet minimum requirements

Professional Installation: We can recommend qualified installers in your area. Contact us for local engineer contacts.

🌟 Customer Reviews & Real-World Performance

“Replaced a failing Vaporex unit with the DH35 electric version. Installation was straightforward, and the heating boost is noticeably better than the old model. Pool room stays consistently comfortable, and electricity costs are manageable.” — Simon T., Domestic Pool Owner, Surrey

“We specified three DH35 units for a hotel spa pool refurbishment. The compact size allowed wall mounting without eating into already-tight space. Performance has been excellent through the first winter, and the defrost function worked flawlessly during the cold snap.” — Mark P., Building Services Engineer

“As a pool maintenance company, we’ve installed dozens of Dantherm units over the years. The DH35AX/E is our go-to recommendation for domestic pools where running hot water pipework is impractical. Reliable, effective, and backed by good manufacturer support.” — Aquatech Pool Services, Bristol

✅ Order Summary & Next Steps

Package Includes:

• Dantherm DH35AX/E dehumidifier unit
• Wall-mounting brackets and fixings
• User manual and technical documentation
• 2-year manufacturer’s warranty
• Access to UK-wide service network

You May Also Need:

• Condensate pump (if gravity drainage not possible)
• Upgraded electrical fuse box if existing supply inadequate
• Professional installation service
• Annual service contract

Ready to Order?

Add the DH35AX/E to your basket, or contact our technical team for sizing advice, installation guidance, or to discuss alternative models for larger pools.

📞 Get Expert Advice: Our team can help determine if the DH35 is the right solution for your specific pool application, or whether the DH65, DH75, or alternative models would better suit your requirements.

📌 Quick Reference Specifications Summary

🔐 Guarantee & Warranty Protection

2-Year Manufacturer’s Warranty

Your DH35 is protected against manufacturing defects and component failures for 24 months from the date of purchase. This comprehensive warranty covers:

✅ Refrigeration system and compressor ✅ All electrical components and controls ✅ Structural housing and mounting hardware ✅ Factory-fitted heating elements

Warranty Conditions:

• Professional installation recommended (and may be required)
• Normal pool hall operating conditions (not outdoor or extreme environments)
• Regular maintenance as per manufacturer’s guidelines
• Genuine parts used for any repairs

Extended Warranty: Ask about optional extended warranty plans for additional peace of mind.

🏊 Transform Your Pool Environment Today

Don’t let excess humidity damage your valuable pool facility.

The Dantherm DH35AX/E delivers professional-grade moisture control, supplementary heating, and long-term reliability in one compact, cost-effective package. Whether you’re building a new pool or upgrading an aging system, the DH35 represents the smart choice for protecting your investment and ensuring year-round swimming comfort.

Order now or contact our technical team for expert sizing advice and installation guidance.

💧 Your pool deserves the best climate control. Choose Dantherm. Choose Parts4Tubs. 🏊‍♂️