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Due to the current situation in North America, many hotels have closed or have opted to close some of their common areas including the pool facilities. As cashflow is a concern in these challenging times, it is wise to find ways to reduce costs as much as possible when facilities are on standby.

Pools certainly consume lots of energy and the good news is there are some ways facility engineers can reduce the cost of keeping hotel pools on standby with a few simple steps.

Lowering Evaporation Rate

The number one topic of interest with reducing pool operating costs while keeping systems on standby is to reduce the evaporation rate from the pool. Unless you drain the basin, the water will not stop evaporating. However, the rate of evaporation can be slowed down a lot with some measures.

If you are able to, cover the pool. This reduces the evaporation rate to an absolute minimum and brings with it some added benefits. The Department of Energy estimates you can lower water heating costs by as much as 70% by covering the pool (for normal use, this number is likely higher when the pool is always covered and at-rest.) When the pool is covered, the minimal evaporation rate means the dehumidifier will not be placing many dehumidification calls throughout the day which saves on compressor runtime.

In addition to using the cover, or if your hotel pool does not have a cover, you can make some other changes to save energy costs.

Changing Water Temperature

Changing setpoints is a tricky subject, because it could backfire if done improperly. One thing you can do is lower the water temperature. You can drop it quite a bit, even down to 60°F if you want. This will drop your water heating demand by a significant amount.

Water has a high specific heat capacity which means pools respond very slowly to temperature changes. For larger pools it could take days for a water temperature setpoint adjustment to fully take effect.

Changing air setpoints take effect very quickly. While it may be tempting to lower the air temperature, keep in mind that lower air temperatures correspond with higher rates of evaporation. As a result, it isn’t recommended to lower the air temperature.

If a facility wishes to lower the air temperature they should ensure it is always at least two degrees warmer than the water temperature to minimize evaporation. Also do not go below 74°F room air as the dehumidifier will not operate well below that temperature. Drop the pool water temperature and then wait until it cools down before lowering the space temperature. Otherwise the RH will spike up and the dehumidifier may be unable to keep up with the moisture load until the pool finishes cooling down and evaporation slows.

Don’t Forget Maintenance

Regular preventative maintenance should continue to be a priority while a facility is on stand-by. If anything, it’s a good opportunity to shut down the unit (following proper safety protocols including cutting power at the breaker) and wash the interior airpath and coils; this is normally recommended to be done twice a year to stave off corrosion.

To clean, get a rag and a water/dish soap solution and scrub the interior airpath. Rinse with fresh water and ensure drainage or dry with a towel. For the coils, start by brushing them with a soft brush in the direction of the fins. Be careful not to bend them. After, use a pressure washer (under 100 psig) to spray a lukewarm soapy water mix into the coil, being cautious to spray the coil in the direction opposite to where the air enters. Spraying them in this counter-airflow direction ensures any foreign objects collected at the front of the coil is pushed out rather than being driven deeper into them.

Other good maintenance practices to keep in mind includes changing of the airside filters, checking the condensate drain pan for blockages, and ensuring the outdoor condenser is functioning properly.

Want to take a deeper dive?

We’d love to discuss your unique pool environment and conditions to provide more detailed expert advice. Leave a comment below or complete the form on the right for a direct response.

Whether big or small, all hotels pools must have robust measures to control humidity and prevent condensation.

Obviously, an indoor pool has the potential to produce an enormous amount of moist air. But that’s not the only reason condensation is a unique concern in pools. Their air temperature is also much higher than a regular room, meaning their dew point is also quite a bit higher than usual. Combined, these factors mean condensation can easily occur in a pool while it wouldn’t normally be an issue in another room.

Dew Point

The dew point is the temperature at which moisture in the air condenses when it comes into contact with a surface that’s colder by 1°F or more.

You only have to enjoy a cold drink on a summer day to experience dew point and condensation firsthand. When you pour a cold beverage into a glass, condensation will begin to form on the outside of the glass almost immediately. This is because the surface temperature on your glass is below the ambient dew point temperature.

This happens at indoor pools across North America every year when outdoor temperatures fall during the winter. Exterior-facing surfaces that have low insulation values, like windows, skylights and fire doors, are very likely to have a surface temperature that is below the room dew point during cold weather. As a result, moisture condenses on them.

The Dangers of Condensation

There are two major concerns for hotels around condensation at their pools:

• It can damage the hotel assets.
• In doing so, the guest experience will be negatively affected; sweaty windows are unsightly, and visible mold or corrosion could drive guests away.

Condensation triggers a destruction process, since it allows mold and mildew to grow on the materials from which a building is constructed. It also frequently foments corrosion on metal surfaces.

In a hotel pool, air will almost always have some degree of corrosiveness due to chemicals that off-gas from the water.

Other than condensation that you can see on surfaces, there is a hidden danger. If allowed to permeate the building walls or roof, condensation will not only instigate mold-induced deterioration, it will also cause additional devastation of the structure in winter. This is because when temperatures drop below freezing point, the moisture that’s soaked into the structural components of the building turns into ice and expands, putting additional stress on the materials and causing fissures and cracks that compromise the integrity and safety of the structure. That is why it’s critical all hotel pool rooms have a properly constructed envelope with a vapor barrier.

Preventing Condensation

The pool room dehumidification system is an essential part of condensation control and preventing. It must maintain the interior conditions (temperature and RH) at the correct, desired setpoints as determined when the hotel pool was constructed. The air ducts must distribute air all around the pool room, taking special care to direct warm airflow against surfaces that are likely to drop below the dew point of the room.

It’s important to ensure the entire surface is covered by warm airflow. Mother nature will tell you on the first cold day how good a job you’ve done — it’s common to find the top of a window condensation-free because it’s near a diffuser, but the bottom is sweaty because the diffuser does not have enough “throw” distance to work the air all the way down.

If your hotel pool room struggles with this aspect to HVAC, then it is a smart idea to have an expert come in and review your dehumidification system. They will have the experience and the knowledge to identify areas that can be improved to better control condensation. In many cases adjustments can be made for little cost. For example, one facility was recommended to rotate their ductwork to improve supply air diffusion.

Want to take a deeper dive?

We’d love to discuss your unique pool environment and conditions to provide more detailed expert advice. Leave a comment below or complete the form on the right for a direct response.

While it’s true indoor pools can be perfectly safe and healthy environments with good air quality, they must also be contained environments. After all, even great-quality air from a pool room is not air you’d want to have mixing into the lobby!

If your guests are being greeted at your hotel by a scent of the pool, rather than a smile from the concierge, then that is a problem with the potential to damage guest perception as well as the hotel property.

Why Can I Smell the Pool Without Being Near the Pool?

Normally, indoor pool rooms should be contained from other areas of the building they are within. This is accomplished through a number of means, including:

• A physical airlock or vestibule to enter the pool room.
• A separate HVAC (dehumidification) system with its own ductwork.
• The pool room is kept at a negative air pressure.
• A vapor barrier ensuring the higher moisture levels in the pool area stay in the pool area

These measures ensure that the environment is a closed system for the comfort of all building occupants, including guests and employees.

Sometimes, however, air can drift out of the room. A common cause is related to the dehumidification system. Indoor pool dehumidification systems commonly include exhaust fans that ensure the environment is at negative pressure. Generally, the exhaust fan is separate from the dehumidifier. In hotels they are located in the pool room and ideally draw in air from above the spa if you have one.

If the exhaust fans are off, or not at the right speed, then they may not be exhausting enough air to the outside to keep the space negative. As a result, the code-required outdoor air that the dehumidifier introduces to the space will be greater and result in a positive-pressure situation that pushes air out to the rest of the hotel.

Additionally, a positive-pressure pool room would worsen the phenomena known as vapor migration. This is particularly acute during cold weather, where high pressure moisture inside the pool room tries to migrate through the building envelope to equalize with the lower pressure moisture levels outdoors. While this is a predictable and normal occurrence, it is vital that it is mitigated by special design of the vapor barrier in the building envelope during construction. Anything but a negative air pressure indoor pool exacerbates moisture trying to migrate by forcing air through the envelope.

If you find that you can smell your pool room without being in it, the doors/vestibule to the room should be checked to ensure it is properly sealed. Then, examine the exhaust system to ensure it is removing enough air from the space for negative pressure. It should be exhausting 10–20% more air in CFM than is being brought in from the outdoors. Because indoor pool environments can be complex, it may be valuable to bring in an experienced expert as they will be familiar with this particular problem and how to resolve it.

Of course, another thing to keep in mind is that your indoor pool should not have a strong acidic or chlorine smell. This is an indicator of a potentially hazardous environment and should be addressed as quickly as possible.

Want to take a deeper dive?

We’d love to discuss your unique pool environment and conditions to provide more detailed expert advice. Leave a comment below or complete the form on the right for a direct response.

Having good indoor air quality (IAQ) at your hotel’s indoor pool isn’t optional. It has a direct impact on equipment and building longevity, as well as the comfort, health and safety of your guests and employees.

Although pool room air will always have a degree of corrosivity, due to the presence of moisture that is usually laced with gases derived from the chlorinated water, the true fact of the matter is that great IAQ is absolutely possible if the right steps are taken.

When a hotel pool possesses good IAQ, guests will want to come back to that facility next time they are in town — even if they didn’t 100% put their finger on why they enjoyed that particular pool so uniquely.

What Causes Poor IAQ in Pools?

There are a number of possible causes for poor air quality in pools. Any one of them on their own will lead to issues.

One of the most basic is air distribution. The best quality air in a pool comes directly out of the dehumidifier. This air needs to be distributed down to where the guests are on the deck and in the water.  Without getting good air in the breathing zone, the IAQ will suffer and exacerbate an unhealthy and potentially hazardous environment.

Note that for the most part, people are breathing anywhere between the water surface — which is much lower than in a regular room — and 7 feet above the deck, approximately the height of a very tall human. Air must circulate at the deck level and across the water surface. In addition, the HVAC system must blend in the correct amount of outdoor air according to codes, plus the grilles/diffusers must have sufficient throw distance to direct air where it needs to go.

You should be able to feel the supply air a little on your head when you stand on the deck, but it’s also important to not create a strong draft as that will chill guests coming out of the water.

Avoiding condensation is critical to asset protection

The air distribution must also address areas of potential condensation, like exterior windows, sky lights and fire doors. They need to have the warm air blanket them fully to avoid condensation. This fact is often missed because designers forget that these surfaces are more likely to create condensation than in a regular room, due to the pool’s heightened dew point condition. Avoiding condensation is critical to asset protection, because the droplets that collect on windows and ledges can be corrosive and will lead to degradation where it occurs.

Another aspect of air distribution is providing ventilation to move harmful gases away from the surface of the water. These are a major cause of poor air quality in pools. The main type is trichloramine.

Trichloramine is a type of combined chlorine created through reactions between chlorine and contaminants in the water that contain ammonia. Many of these contaminants are introduced to the water by swimmers. Some examples are sweat, urine, body oils, makeup, deodorant and dirt. When the introduction of these contaminants outpaces the introduction of free chlorine, the chlorine reacts with them instead of fully oxidizing them. As a result, the chloramine levels in the water increase. Trichloramine rapidly off-gasses from the water and causes that signature “chlorine smell” of pools. A slight smell can water your eyes, while a strong one can drive guests away from your hotel and pool, while also accelerating damage to the building envelope due to their corrosivity.

The Two Keys to Ensuring Good IAQ

There are two key aspects of ensuring good IAQ:

1. The reduction, control, and elimination of chemicals off-gassing. Hotels can reduce contaminants entering the water and resulting trichloramine by encouraging guests to shower before swimming and to avoid urinating in the water. Technologies like UV water treatment and even special exhaust systems are available to minimize the issue as well.
2. Having an air distribution system that supplies sufficient air to the breathing zone, including across the water surface.

Achieving good pool room IAQ isn’t just relevant to new hotels being designed and built; it is also of critical importance to existing facilities. If your existing hotel pool is experiencing IAQ issues, there are likely some cost-effective strategies you can take to improve the air — and along with it, improve the experience you provide your guests while also protecting the hotel investment. There are many potential benefits to having a Dehumidified Air Solutions expert visit your site and review what options are available for improving your facility.

Want to take a deeper dive?

We’d love to discuss your unique pool environment and conditions to provide more detailed expert advice. Leave a comment below or complete the form on the right for a direct response.

Indoor pool spaces are meant to be comfortable places for hotel guests to enjoy recreational swimming. Temperatures are kept warmer than a traditional indoor space for swimmer comfort and energy savings. Additionally, relative humidity (RH) is generally kept between 50% and 60% so that the space humidity is very similar to what it would be like in any other room. When these two measurements (temperature and RH) are where they should be, an indoor pool area is a perfectly enjoyable environment and the hotel investment is protected for years to come.

Yet, pools often operate at different setpoints either because of problems with their dehumidification system or because they don’t fully understand the impact of their choices. Here are some reasons why your indoor pool conditions may not be right:

• Expectations have changed
• Worn down equipment
• Duct work not operational
• Exhaust fan not functioning
• Outdoor air intake blocked
• More outdoor air than required

Different Operating Parameters

A popular setpoint for hotel pools is 84°F water temperature, 82°F air temperature and no more than 60% RH.

Dehumidifiers are designed and selected for a specific air temperature and RH setpoint, also with a specific water temperature in mind. This is important because these three things will influence the water evaporation rate and that has an impact on whether the dehumidifier is going to be able to keep up with the load and maintain the space. Therefore, the dehumidifier works best when these parameters are not changed. A very popular one for hotel pools is 84°F water temperature, 82°F air temperature and no more than 60% RH (the RH typically ranges 50% when less active and up to 60% when busy.) These parameters are popular because hotel guests are kept comfortable whether they are in the water or fully clothed on the deck, just watching.

While 82°F can feel a bit warm when you are fully clothed, some facilities make the mistake of lowering the space temperature. Changing setpoints from the original unit selection criteria will have an impact on system performance and operating costs. if you set the room too cool, you will wind up with increased evaporation and a unit that may no longer properly maintain the space conditions. Conversely increasing the air temperature too much, while rare, would result in oversized unit that constantly hard cycles its compressor on and off for short periods of time, frequently over-cooling and over-dehumidifying the room. Either are not good operating scenarios and lead to guest discomfort, increased operating costs and greater wear and tear on the equipment.

Lowered Equipment Performance

Unless well-maintained, mechanical equipment will experience diminished performance over time. Indoor pool dehumidifiers are especially vulnerable to this because they operate in a typically corrosive environment and their ideal operating parameters are not always understood by people servicing them. While high-quality machines built today can often last 20 years, older models that are less corrosion-protected tend to last a lot less time.

Equipment performance has a direct impact on your bottom line.

Corroded or improperly operating components, such as cooling coils, heaters and condenser coils, lose their effectiveness over time. It is best to have these components be fully-protected with an anticorrosion coating to keep them operating at peak efficiency for the life of the equipment. Older components that have corroded can be replaced, however the hotel operator should consider the ROI of replacing old components versus getting new equipment that is equipped with modern features and better corrosion protection.

Additionally, there is much to be gained with regular maintenance of the equipment by people who understand how they should be operating. Internal cleaning, including washing of all coils (inside the unit and also the outdoor heat exchanger coils), can help stave off corrosion. Plus, coils can get dirty over the years and this also lowers their output. For this reason, it is recommended to regularly change return and outdoor air filters, about once per quarter, as they keep small airborne objects from getting caught in the delicate coil fins.

Other Changes

Besides setpoints, other things may have happened at your hotel pool to change the situation. Consider these as possibilities:

• Are all supply air and return air openings in your duct work operational? Sometimes they get blocked due to objects in the space, like plants or window treatments. Especially with floor-grade supply air openings, sometimes they are covered up because they were blowing air onto guests and causing discomfort. But, covering up grilles can limit effectiveness of the dehumidification system.
• The exhaust fan, which may be remote or inside your dehumidifier, could be non-functioning.
• Was the outdoor air intake blocked off to save money? For public spaces, having outdoor air is a code-requirement and closing it off completely can significantly deteriorate air quality.
• On the flip side, poor air quality in the space has led some facilities to have more than code-required outdoor air blended in. This can cause the dehumidifier to struggle because it must treat additional outdoor air. Keep in mind, more than necessary outdoor air is expensive to treat and does not guarantee better air quality. If your facility is following the code minimum for outdoor air but still struggles with air quality, it may be a good idea to have an expert review your facility because there are likely more cost-effective ways to address the problem than increasing the outdoor air intake.

Want to take a deeper dive?

We’d love to discuss your unique pool environment and conditions to provide more detailed expert advice. Leave a comment below or complete the form on the right for a direct response.