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My family recently bought our first home dehumidifier.  I’ve wanted one for years to help our aging air conditioner with keeping the humidity low and and our comfort high.  Read on to see how a home dehumidifier can help keep you comfortable and how it works.

As you may remember from a past article, humidity is an important factor in the comfort level (and health) of a home.  In a residential air conditioning system, the thermostat only reads the dry bulb temperature and cycles the unit on or off to meet the desired setpoint.  While running, the unit will dehumidify the air.  But what happens on a day that isn’t too warm, but still humid?  Take for example a raining day in May that is 80 °F with your air conditioner set to 75 °F.  Your air conditioner may run a few times to keep it 75 °F, but it doesn’t care that the humidity in the home is high.  This is where a home dehumidifer can be helpful.  By setting the dehumidifer to a humidity setpoint (typically 50% relative humidity), it will remove the moisture from the air without considering the temperature.  Without the dehumidifer to remove the moisture, you would have to overcool the space by turning down the A/C in order to get your desired humidity level.  This potentially saves energy by letting you keep your thermostat set at a higher temperature.

A dehumidifer works just like a miniature air conditioner with the exception that the condenser has the cooled air blown over it.  The air enters the dehumidifer and passes over the cold evaporator.  This cools the air causing some of the humidity to condense on the evaporator.  The water falls into the bucket while the cold dry air then passes on to the hot condenser where it is warmed back up.  On large commercial systems, this is called hot gas reheat.  It would be great if the air could leave the dehumifier at the same temperature it entered, but due to the laws of thermodynamics it will actually leave a little warmer.  On the refrigeration side, the system works just like any other simple air conditioner.

There are a few other dehumidification technologies that are very interesting, but have yet to find a major foothold in the market.  Desiccant dehumidifiers use humidity absorbing materials which must be re-charged or replaced when full of water.  Silica packets in boxes are an example of a (very small) desiccant dehumidifer.   Liquid desiccants (sounds like an oxymoron, doesn’t it) are usually reserved for large commercial or industrial applications.  They work by having a solution of water and salt (various chemicals and combinations of salts are used).  When the concentration of the salt is high, the solution will actually absorb water from the air.  The now less concentrated solution is then exposed to outside air and heat which removes some of the water and get the solution nice and concentrated so that the process can be repeated.

Humidity control in a home or business is very important and there are ways that it can be done without breaking the bank. If you are having humidity issues and would be interesting in saving money on your building by saving energy, consider hiring us to complete a Small Business Energy Audit.  We will review your building and provide you with options for saving money. Our goal is to provide an affordable service that a business can use to reduce their energy costs.  We are happy to work with you to find a solution that fits your budget.  If you own or manage a building and are interested in an audit, please contact us today.

My wife and I recently went out to dinner with some friends.  Knowing that I write these posts, one friend commented on the revolving door at the entrance and asked whether it saved energy.  The short answer is yes, and they’ve been doing it for over 100 years.

Originally patented on August 7, 1888 by Theophilus Van Kannel of Philadelpha the door was designed to reduce the entrance of wind, snow, rain or dust.  The patent goes on to say that the door could not be opened by the wind and that people could go in and out at the same time without the possibility of colliding with one another.  Most of these benefits concern the comfort of the building, but they easily translate to energy efficiency in the modern day.  Originally, his main motivation for designing the door was supposedly driven by his dislike for chivalry because he despised walking in and out of a building, encountering others and having to insist that they go first.  But most of all, it is said that he couldn’t stand the expectation of opening doors for women.  Whatever his motivation, he designed a door that is still in use today and is still saving energy.

A revolving door saves energy by ensuring that the inside of the building is never directly open to the exterior.  Doors are built in a way that the path of air is always blocked no matter where the door turns.  When you open a conventional door, air can flow freely in or out due to a variety of factors which causes the building equipment to work harder to heat or cool the newly introduced air.  A lot of buildings will solve this by adding a vestibule (a small room with exterior and interior doors) which also attempts to reduce the amount of time the interior is open to the outdoors.  A revolving door takes up less space than a vestibule and, depending on traffic, would block more air transfer.  Unfortunately revolving doors aren’t usually a good solution for a building with a lot of foot traffic.

Strategies to reduce infiltration, such as vestibules and revolving doors, are a great way to reduce energy usage.  There are also many low to no cost improvements that can be made to most buildings that can start saving you money right away.  If you are interesting in saving money on your building by saving energy, consider hiring us to complete a Small Business Energy Audit.  We will review your building and provide you with options for saving money. Our goal is to provide an affordable service that a business can use to reduce their energy costs.  We are happy to work with you to find a solution that fits your budget.  If you own or manage a building and are interested in an audit, please contact us today.