Find out why dehumidification is important for your home? Check out pros and cons of various dehumidifier types. See how dehumidifiers can help you live a comfortable and healthier life.
The humidity level in your home will determine your comfort level and potentially affect your health. It can also affect the condition of your house and its contents. It is an essential factor. In addition, a properly humidified home could save you money on energy bills.
Humidity, or Relative Humidity (RH), as it more accurately called, “is the amount of water vapor present in air expressed as a percentage of the amount needed for saturation at the same temperature.” Phew!
So 100% RH would be fog? Well, according to the scientists, yes and no!
We all know high humidity makes you feel hot and sticky. When it's high, you are unable to cool down by sweating, which is the natural process your body uses to cool off, so you stay wet. The warm, moist air can also help bugs and germs to thrive and spread more quickly, making it a potential hazard to your family’s health.
Mold, mildew, and condensation can form, which can cause health risks and possible damage to the fabric of your home and your furniture.
The higher the RH, the warmer your home will feel, and the more moisture there will be in the air. It’s much harder to cool a humid home because warm air holds moisture much better than cold air does.
If you have a heat pump installed, it does remove moisture from the air as it works and acts like a dehumidifier. However, your heat pump does not run all the time. In some homes, a large heat pump will cycle ‘off’ faster. This leaves you with the correct temperature, but the RH will steadily rise when the heat pump is off.
The outcome is dependent on your local climate. You may need to install a dehumidifier to control your humidity instead of only relying on your heat pump.
A dehumidifier is designed to pull air inside and blows it across a cooled evaporator coil. It's then pushed over a condenser coil, removing moisture from the air. It then returns it into the room with a lower RH content than before. The excess moisture drains away either within the unit where the reservoir will need emptying regularly or via a permanent drain installed.
The cycle doesn’t cool the air but makes it feel cooler as moisture has been removed. Moist air always feels warmer than dry air, so if you remove humidity from the air, it is cheaper to cool or heat your home. Neat!
The main types of dehumidifiers are:
These dehumidifiers pull moist air in and pass it across a cooled evaporator coil. The moisture condenses and drains away. The air re-heats by moving it across a condenser coil before the warm, dry air is passed back into the room.
Desiccant dehumidifiers use fans to pull damp air inside the unit, where the moisture is captured by a desiccant material that sits within in a slowly spinning sealed disc. A section of the disc is heated, causing the moisture to condense on a heat exchanger and drain away, allowing the dried air to flow back into the room.
Damp air passes over a cooled heat sink where the moisture condenses and drains, then the drier air moves back into the room.
Select the unit type and size that suits your particular requirements. These units can be portable, so you can move them to where they are most needed; however, their reservoirs will need to be emptied. They do switch off automatically when they are full.
If humidity is a big problem, then a whole-home solution could be the best choice. These units deliver total humidity control by combining humidification and dehumidification in one unit. This will give you year-round control of the RH levels in your home when the outside conditions change.
If you use a gas furnace, you may believe you need dehumidification. However, modern furnaces often require the opposite – a humidifier.
With old-style gas space heaters, high humidity and condensation were huge issues with dripping walls and ceilings, mold, musty smells, and untold damage to your home and furniture. Dehumidification was necessary but rarely used. Fortunately, these are history, and a modern gas furnace will usually operate in one of two ways.
Atmospheric combustion. If the furnace is atmospheric, it means the gas flames are open to the air. If you install the furnace inside your home, it will draw its combustion air from inside your house. That air is replaced by pulling fresh air in from outside. If it’s cold outside, the humidity of the incoming air will be low, and when it exits the furnace, it will remain low. The combustion process does create a lot of water vapor, but it doesn’t get inside the house; it exhausts or drains away. The result is the same dry air comes out, just warmer than the dry air it pulled in.
Sealed combustion. If you install your furnace in an attic, garage, or crawl space, it won’t affect the humidity inside your home. It pulls combustible air from outdoors, so the air in your home stays the same, apart from being heated by the furnace. A sealed unit also won’t dry out the air. The moisture in the air that goes in is the same as it is coming out.
Whole-home solutions are more expensive to buy, and they do need regular maintenance like your furnace or HVAC system does to remain efficient. Still, they will deliver savings as dryer air is easier to heat and cool than moist air, and that will save you money on your HVAC costs.
You can retrofit a whole-home system to your gas furnace or HVAC system. Once it’s installed and commissioned, you can set it and forget it. The unit will be fitted with a hygrometer to monitor RH constantly. A remote humidistat controller will enable you to monitor and change the humidity levels as often as you choose, just like your thermostat allows you to control temperature. Remember, drier air is easier to heat.
You will notice the temperature levels you used to use before will edge lower as you control the humidity accurately. That’s good news for your power bills. The recommended RH level in winter is 30% - 40% and in summer 30% - 50%.
Of course, like any HVAC system, it relies on your home being leak-checked, so you are not paying for expensive lost cool or hot air. You should avoid letting cold, dry air or warm moist air inside your home, which will only put added pressure on your HVAC system.
It’s a worthwhile exercise to check your home thoroughly for leaks, at doors and windows, but also in your ducting and other areas where there could be leakage.
If the air inside your home is too dry, colder air may be getting inside, especially in winter, so you need to leak-proof your home.
If you are running a heat pump, a dehumidifier will improve the performance of your system overall. With drier air, the heat pump will run more efficiently because, as you know, dry air is easier to heat and cool than warm moist air. A whole-home dehumidifier gives you control of the RH accurately all year round, which will mean your heat pump is always running at peak efficiency.
Of course, running any dehumidifier is going to use electricity. The increased efficiency of your heat pump will offset the costs of running a whole-home dehumidifier. Remember, the temperature settings you currently use for your home will lower as you bring the humidity under control, which is another way you will save money.
If you want to know the RH level in your home, you can purchase a hygrometer for a few dollars and check it out. If it fluctuates, then perhaps you need to consider dehumidification, especially if you are running a heat pump system. You may be able to reduce your power costs substantially by fitting a dehumidifier and getting control of your RH.
Small dehumidifier units are cheap to buy. They do vary in running costs, but they will help you to remove excess moisture from your home. Drier air is easier to heat and cool, and that will save you money and give you a more comfortable and healthier environment.
If you can justify it, a whole-home system will give you ultimate control of your environment all year round; it could be the best solution.