- Air Filtration
- Air Treatment Systems
- Carbon Monoxide
- Dehumidifiers
- Humidifiers
- Thermostats
- Ventilation
Dehumidifiers
Dehumidifiers are designed to remove moisture from spaces where
high humidity is causing problems. Too much moisture (humidity)
in a home can be the result of poor ventilation, water intrusion
through the building envelope, or indoor sources (aquariums, spa’s,
plants, open sump pits, etc.) In order to remove moisture effectively
we need to look at the “The House as a System”. Identify
all sources of moisture production and then determines how to
best address how to remediate the problem.
For years there were commercial dehumidification systems used to control humidity levels in swimming pool and spa areas in large homes. Now, we now have whole-home dehumidifiers that are more affordable and more plug and play than the complicated field fabricated units of the past. The small portable dehumidifiers in some instances remain an option, but when they can't the ducted dehumidifier can step in.
Dehumidifiers are designed to assist in the removal of temporary increases in excess moisture in basements and homes in spring, summer and fall when air conditioning equipment that may be slightly oversized is not providing enough dehumidification. (Never oversize and air conditioner) Another common problem is basements that may be located in areas with high water tables.
Experts all agree that the ideal level of relative humidity in a home should be kept between 30% min. - 60% max. Keeping within this range ensures that your home will be the most comfortable and the effects of unwanted conditions and harmful household contaminants kept at bay.
During the three seasons, if the moisture levels in the home are not kept within the limits occupants will feel the air cool and clammy, and especially stuffy at night. Surfaces can also become sticky.
Excessive humidity also creates an excellent breeding ground for mould and mildew – invaders that can be unhealthy and destructive to a home, its occupants and its furnishings.
Tighter homes (new or renovated) have moisture loads that need to be controlled. Although moisture infiltration is reduced, many normal living activities – such as cooking, showering, dishwashing and laundry – add significant amounts of moisture. And because HVAC systems need to operate less in a tighter home, less of this moisture is removed.
Where is dehumidification needed in Canada?
The need for humidity control in the summer varies in different regions. Any area where dew points average above 50ºF in the warm months is an area where the humidity has the opportunity to rise above recommended levels. This can occur in those regions that have significant moisture content coupled with many hours of air conditioning not operating at peak load conditions. In order to ensure the proper humidity level in the home, those areas require some type of moisture control separate from cooling. Manitoba is an excellent area that could make use of whole-house ducted units because of the high humidity and relatively low number of cooling hours per year.
I heard that higher efficient
air conditioning systems could increase dehumidification needs.
Is this true?
North America wide
Governments have mandated minimum efficiencies, Seasonal Energy
Efficiency Ratio (SEER). These higher SEER systems save energy
by reaching desired temperatures more quickly. The majority of
the higher SEER indoor coils are dedicated to the sensible load
of the home. New tall, thin, coil designs drop a home’s
temperature faster. These changes produce air-conditioning systems
that run less frequently and remove less latent heat. Latent heat
creates the feeling of being damp.
In addition, air conditioning
is sized based in peak load – a condition reached only 2%
- 3% of the year. The other 97% of the time, the air conditioning
system is operating in a part load condition, resulting in less
run time, and further reducing the moisture removal capabilities
of the system. This situation is especially apparent in spring
and fall, when the HVAC system seldom operates. Therefore, a significant
need for moisture removal remains.
Many homeowners try creating optimum humidity conditions by running their air conditioning system longer. They are probably creating a comfort issue by doing so, with their home temperatures consistently dropping below desired comfort levels.
Are there other products available?
There are a number of ways currently being used to address excessive humidity in the home, however, none are a complete solution.
- Portable dehumidifiers are a huge market with over 1.5 million
units sold annually. This in itself is an indication of the
demand for moisture control by homeowners. While portable dehumidifiers
remove moisture in a given area, they seldom address the needs
of an entire home. Also because of their design, they are not
effective in removing moisture at temperatures below 65ºF.
They can be noisy and messy.
- Many HVAC manufacturers have introduced products that address
excessive moisture when used with the air conditioning system.
These advanced thermostats include a humidity control that provides
additional run time of the air conditioner p remove moisture
at the indoor coil. The system operates at lower speeds giving
the air more time at the coil, focusing on latent energy to
remove moisture in the air.
Although this does
remove moisture, it also has drawbacks. The result can be temperatures
in the home that are cooler than expected. Temperatures can drop
below the set point when using this method. In addition, there
will be times when the homeowner does not want additional cooling
introduced into the home - when mild outdoor temperatures exist
during evenings, fall or summer.
Again and we cannot
stress this enough - size does matter - DO NOT OVERSIZE
AN AIR CONDITIONER. When selecting high SEER air conditioning,
look beyond the SEER rating, look at the two-speed and variable
speed compressor models that offer higher latent heat removal
capabilities.
Dehumidifiers are rated
by how many pints a day they can remove from the air at a particular
temperature and humidity. So, look at this information when making
comparisons.
The addition of a dehumidifier
in some cases is simply the difference between a comfortable night's
sleep, or one that feels like your slept on swamp grass.
Whole-home
dehumidifiers can be installed in the following methods:
- Whole - home convertible to basement - in this manner the
dehumidifier can also automatically switching from whole-house
and localized dehumidification, allowing you installation flexibility
in basement and crawlspace applications.
Automatic switching
allows the system to provide dehumidification to the whole-home
when the air conditioning is on and then converts to a specific
location (i.e., basement) when the air conditioning is shut off.
- Whole - home, living space to supply - the dehumidifier can
pull from a primary living space and places the dehumidified
air into the supply air downstream of the cooling coil.
- Whole - home, pulling from the return to supply - the dehumidifier can pull from the return of the HVAC system and places the dehumidified air into the supply air downstream of the cooling coil.
You do not have to sacrifice comfort. As indoor air quality leaders Custom Vac understands proper humidity control and provides the best in comfort and durability of the products that they recommend. The Aprilaire whole-house dehumidifier is one of the many products that Custom Vac offers utilizes to achieve proper humidity control.
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