Pool owners face two key tasks to maintain a comfortable microclimate: dehumidification and ventilation. Dehumidification is required to reduce humidity from 80% to a comfortable 50–55%, preventing condensation, mold, and corrosion. Ventilation ensures constant air renewal, removal of CO2 and chlorine vapors, and the supply of fresh oxygen.
A typical dilemma for a pool owner: what to install — a dehumidifier, ventilation, or both systems? The traditional approach involves installing two separate systems: a dehumidifier to combat humidity and a ventilation unit for air renewal. This solution is effective but requires significant capital expenditures for the purchase, installation, and maintenance of both systems.
A modern solution offered by Mycond is the MSHA C dehumidifier with fresh-air mixing, which combines two effects in a single device. This system provides proper dehumidification as well as continuous air renewal, significantly improving the pool microclimate.
Let’s take a closer look at four possible options for solving the pool microclimate challenge and determine the optimal solution.
Comparison of four options
Dehumidifier without mixing plus separate ventilation
This option involves installing two independent systems: a duct dehumidifier without fresh-air mixing and a separate supply ventilation system with heating.
Operating principle: The dehumidifier recirculates indoor air, removing excess moisture. In parallel, the ventilation system supplies fresh outdoor air and exhausts stale air.
Efficiency: Dehumidification — excellent, air quality — excellent. Both functions are performed reliably and independently.
Capital costs: HIGH. You need to purchase two systems and carry out two separate installations, which requires more space and materials.
Operating costs: High. Both systems consume electricity and require regular maintenance.
Conclusion: Works excellently, but expensive in terms of both capital and operating costs.
Dehumidifier only without mixing
The second option is to install only a dehumidifier without a fresh-air mixing function.
Operating principle: The system works solely on recirculation, meaning the same air constantly circulates in a loop, being dehumidified but not renewed.
Efficiency: Dehumidification — excellent, but air quality — problematic. Due to the lack of fresh air supply, CO2 and chlorine vapors accumulate, especially in an enclosed space. The air becomes stuffy even at a normal 50–55% humidity level, and a feeling of stuffiness may occur.
Capital costs: LOW. Only one system and one installation are needed.
Operating costs: Lower. Only one device operates.
Conclusion: Effectively dehumidifies but does not provide good air quality. Suitable only if there is additional natural ventilation (windows) or in a space with good air exchange.
Ventilation only without a dehumidifier
The third option is to use only supply and exhaust ventilation without a dedicated dehumidifier.
Operating principle: The system attempts to dehumidify the room by removing moist air and supplying dry outdoor air.
Drawbacks: Ventilation dehumidifies VERY slowly. In winter, outdoor air is dry and helps dehumidification, but it must be heated. In summer, outdoor air is humid (60–80%) and dehumidification practically doesn’t work. Effective dehumidification requires air exchange volumes 10–20 times above the norm, which creates noise and drafts.
Energy consumption: Huge. The exhaust removes heated air (+28–30°C) outside, and the supply brings in cold air. In winter, powerful heating is required; energy consumption is 5–10 times higher than that of a dehumidifier.
Capital costs: HIGH. A very powerful ventilation system, large ductwork, and powerful heaters are needed.
Conclusion: THE WORST OPTION. Inefficient, expensive, and energy-intensive. Ventilation alone for a pool is not recommended.
MSHA C dehumidifier with fresh-air mixing
The fourth option is to use the MSHA C dehumidifier with a fresh-air mixing function.
Operating principle: The dehumidifier has TWO inlets: the first for recirculated indoor air (60–70% of total volume), the second for outdoor fresh air (30–40% of total volume). The air streams are mixed, dehumidified, heated, and supplied to the room.
Efficiency: Dehumidification — excellent, air quality — excellent. 30–40% of the air is continuously renewed, ensuring removal of CO2 and chlorine vapors and the supply of fresh oxygen.
Capital costs: LOWER than with two separate systems. Only one device, one installation, less space, one control system.
Operating costs: Low. Fresh air is mixed with warm recirculated air, and heating is provided by the dehumidifier’s condenser.
Conclusion: THE BEST OPTION. Works as effectively as a combination of a dehumidifier and ventilation, but with lower capital and operating costs.
Comparison table of options
| Criterion | Dehumidifier + ventilation | Dehumidifier only | Ventilation only | MSHA C with mixing |
|---|---|---|---|---|
| Dehumidification | Excellent | Excellent | Problem | Excellent |
| Air quality | Excellent | Problem | Good | Excellent |
| Capital costs | High | Low | High | Medium |
| Energy consumption | High | Low | Very high | Medium |
| Maintenance | Complex | Simple | Complex | Simple |
| Space required | Large | Small | Large | Medium |
| Recommendation | Good, but expensive | Only with natural ventilation | Not recommended | Optimal choice |
How fresh-air mixing works in the MSHA C
Airflows in the system
There are three main airflows in the MSHA C dehumidifier:
Recirculated air: Drawn from the pool room, has high humidity (70–80%) and temperature (28–30°C). Accounts for 60–70% of the total processed air volume. Contains elevated humidity, CO2, and chlorine vapors.
Fresh air: Drawn from outdoors, usually drier (especially in winter) but colder. Accounts for 30–40% of the total volume. Contains oxygen and lacks indoor pollutants.
Mixed supply stream: The result of mixing and processing the first two streams. Has optimal humidity (50–55%), a comfortable temperature (28–30°C), and a renewed air composition.
Air treatment process
Air treatment in the MSHA C takes place in five steps:
1. Mixing: Recirculated (70%) and fresh (30%) air are mixed. The temperature of the mixed stream is approximately 20–25°C.
2. Filtration: The mixed stream passes through G4 and F7 filters, and HEPA H13 if required (optional).
3. Dehumidification: In the evaporator, the air is cooled to the dew point, causing moisture to condense and drain away via the condensate system.
4. Heating: In the condenser, the dehumidified air is heated to 28–30°C. It’s important to note that the heating is FREE thanks to the compressor’s operation.
5. Supply to the room: The dehumidified, heated, and renewed air is supplied to the pool area.
Fresh-air damper control
The fresh-air damper in the MSHA C can be adjusted depending on conditions:
- In winter: Outdoor air is very dry; its share can be increased to 40%.
- In summer: Outdoor air is humid; it is advisable to reduce its share to 20–30%.
- At night: When the pool is not in use, the fresh-air share can be reduced to 20%.
- At peak load: When many people are in the pool, fresh-air supply can be increased to 40%.
Control can be performed automatically via the controller or by manual adjustment.
Why fresh air is needed in a pool
Removal of CO2
People constantly exhale CO2, and its concentration can quickly rise in an enclosed space. At CO2 levels above 1000 ppm, headaches, discomfort, and reduced performance may occur. A normal level is considered 400–600 ppm.
In a system without fresh-air mixing, CO2 constantly accumulates. The MSHA C with mixing renews 30–40% of the air, allowing CO2 to be removed and fresh oxygen to be supplied.
Removal of chlorine vapors
Chlorine used for pool water disinfection constantly evaporates into the air. Its vapors can irritate the mucous membranes of the eyes and respiratory tract, creating the characteristic “pool smell.”
In a dehumidifier without mixing, chlorine vapors continue to circulate in the air. The MSHA C removes 30–40% of air with chlorine vapors, replacing it with fresh outdoor air. This significantly improves comfort for the eyes and breathing.
Oxygen supply
In an enclosed space, people consume oxygen, and its concentration gradually decreases. This can lead to a feeling of stuffiness even at normal humidity and temperature.
The MSHA C provides a constant supply of fresh, oxygenated air, creating a feeling of freshness and comfort. Even at the same temperature and humidity, air with fresh-air supply feels lighter and more comfortable.
Pool owners who have replaced a regular dehumidifier with the MSHA C often note that the air has become much fresher and the unpleasant feeling of stuffiness has disappeared.
Economics: capital costs and payback
Comparison of capital costs
Let’s compare the capital costs of different system options (in relative values):
Option 1: Dehumidifier plus ventilation
- Duct dehumidifier without mixing: 100% (base cost)
- Supply ventilation with heating: +80–120%
- Installation of two systems: +50–70%
- TOTAL: approximately 230–290% of the base dehumidifier cost
Option 2: Dehumidifier only without mixing
- Duct dehumidifier without mixing: 100%
- TOTAL: 100%
Option 4: MSHA C with mixing
- MSHA C dehumidifier with built-in mixing: 130–150% (30–50% more than base)
- Installation (one system): +20–30%
- TOTAL: approximately 150–180% of the base dehumidifier cost
Conclusion: The MSHA C is 50–80% more expensive than a simple dehumidifier, but CHEAPER than the combination of a dehumidifier and ventilation by 50–110%, while delivering the same dehumidification and air renewal effect.
Operating costs
Option 1: Dehumidifier plus ventilation
- Dehumidifier: 1–10 kW (depending on model)
- Ventilation: 2–5 kW (fans plus heaters)
- TOTAL: 3–15 kW
Option 2: Dehumidifier only
- Dehumidifier: 1–10 kW
- TOTAL: 1–10 kW
Option 4: MSHA C
- Dehumidifier with mixing: 1–10 kW
- Additional minimal heating of fresh air is provided by the condenser
- TOTAL: approximately 1–11 kW
Conclusion: The MSHA C consumes almost as much energy as a simple dehumidifier but far less than a combination of a dehumidifier and a separate ventilation system.
Payback of the MSHA C
MSHA C vs. Option 1 (dehumidifier + ventilation):
- Capital cost savings: 50–110%
- Pays off immediately, as it is cheaper to purchase and install
MSHA C vs. Option 2 (simple dehumidifier):
- Extra cost: +50–80% in capital expenditure
- Benefit: significantly better air quality, health, and comfort
- Payback: through avoiding health issues, no headaches from CO2, no discomfort from chlorine odor
What fits which facilities
Private pools (small and medium, 20–80 m²)
Recommendation: MSHA C with mixing
Reason: For family use, 30–40% fresh air is sufficient. There’s no point overpaying for two systems, especially when air quality is important for children and their health.
Alternative: With a very limited budget, you can install a simple dehumidifier and regularly air out the room.
Large private pools (over 80 m²)
Recommendation: MSHA C with mixing
Reason: A large water volume requires a powerful dehumidifier. MSHA C models from 250 to 1000 l/day all have mixing, making them an ideal solution for such facilities.
Commercial facilities (hotels, fitness centers)
Recommendation: MSHA C with mixing, essential
Reason: Commercial pools have high load, dozens of people per day; CO2 and chlorine build up quickly. Codes require 80–100 m³/h of fresh air per person. The MSHA C covers a significant portion of these requirements.
Note: Under very high load, you may need the MSHA C plus additional ventilation, but the MSHA C reduces ventilation requirements by 30–40%.
Pools with natural ventilation (with windows, doors)
Recommendation: A simple dehumidifier without mixing can be used
Reason: Fresh air comes through windows. In summer, you can open windows to ensure ventilation.
But: The MSHA C with mixing is still more convenient, since you don’t need to open windows and ventilation works automatically.
Enclosed pools without windows
Recommendation: MSHA C with mixing, essential
Reason: Without natural ventilation, CO2 and chlorine accumulate quickly. Without fresh-air supply, it will be stuffy even at normal humidity.
Alternative: Dehumidifier plus separate ventilation, but this is significantly more expensive.
FAQ: Frequently asked questions
Is ventilation needed if there is a dehumidifier?
If we’re talking about the MSHA C with mixing, then for most private pools additional ventilation is not required. The MSHA C supplies 30–40% fresh air, which is usually enough for family use. For commercial facilities with high load, additional ventilation may sometimes be required, but the MSHA C reduces the need by 30–40%.
Can a dehumidifier fully replace ventilation?
The MSHA C with fresh-air mixing can replace supply ventilation in most cases. It provides fresh-air supply, removal of CO2 and chlorine vapors. For private pools, this is usually entirely sufficient.
How does the MSHA C differ from a conventional duct dehumidifier?
The MSHA C has an additional inlet for outdoor fresh air, thanks to which 30–40% of the air is constantly renewed. Conventional dehumidifiers operate only on recirculation, i.e., they drive the same air in a loop, dehumidifying it but not renewing it.
Why is the air stale in my pool even with a dehumidifier?
Most likely, you have a dehumidifier WITHOUT fresh-air mixing. It handles humidity but doesn’t change the air. CO2 and chlorine vapors circulate in a loop, accumulating in the air. The solution is to periodically open windows for ventilation or install the MSHA C with fresh-air mixing.
How do you get rid of the chlorine smell in a pool?
The chlorine smell is chlorine vapors in the air. Removing them requires a constant supply of fresh air. Options: airing through windows, supply ventilation, or the MSHA C with mixing (the most convenient option, as it automatically supplies fresh air and removes chlorine vapors).
Is the MSHA C more expensive than a regular dehumidifier?
Yes, the MSHA C is 30–50% more expensive than a regular dehumidifier, but significantly cheaper than a combination of a dehumidifier and a separate ventilation system (savings of 50–110%). At the same time, the quality of operation is no worse than that of the two-system combination.
Can the amount of fresh air be adjusted?
Yes, the MSHA C has an adjustable fresh-air damper that allows you to change its share from 20% to 40%. Typically, an optimal figure is around 30%.
Does mixing work in winter when it’s cold outside?
Yes, mixing works all year round. Cold fresh outdoor air first mixes with warm recirculated air (60–70%), and is then additionally heated in the dehumidifier’s condenser. As a result, air at a comfortable temperature of 28–30°C is supplied to the room.
What’s better for a private pool: the MSHA C or a dehumidifier plus ventilation?
The MSHA C with mixing is the optimal choice for most private pools. It provides both dehumidification and sufficient ventilation, yet costs less than two separate systems and takes up less space. If the load is very high (hundreds of people), additional ventilation may be needed, but even then the MSHA C significantly simplifies and reduces the overall solution’s cost.
Conclusion
There are four main options for providing a pool microclimate:
1. Ventilation only: The worst option. Inefficient, expensive, energy-intensive.
2. Dehumidifier only without mixing: Works for dehumidification but does not ensure fresh air.
3. Dehumidifier plus separate ventilation: Works excellently but is expensive due to two systems.
4. MSHA C with mixing: The optimal solution. Provides the same effect as option 3 but is cheaper to install and operate.
The MSHA C dehumidifier with fresh-air mixing from Mycond is a modern, economical, and effective solution for pools of any size. One system provides two effects: dehumidification and ventilation, allowing you to save 50–110% in capital costs compared to installing two separate systems, while ensuring excellent air quality.
Mycond is a leader in its segment, offering comprehensive, modern, and energy-efficient microclimate solutions without overpaying for a global-name brand.
For a free consultation on system selection, calculation of the required MSHA C capacity, and a comparison of capital costs for your facility, call us or fill out the form at the bottom of the page.
