Monday, July 3, 2017

Why Is My Exhaust Fan Always Running – Explaining Continuous Operation

You hear it across the country – Who left the light on? Who left the door open? Maybe even Who left the bathroom exhaust fan on? While there are no good reasons for leaving lights on and doors open and the guilty party should be identified and properly reprimanded for their crime, leaving the bathroom exhaust fan on might not be as straight an answer as you think.

In recent years homes have been built to tighter standards that reduce the energy usage of the homes. These tighter standards allow the home to maintain a comfortable living environment using the least amount of energy possible. Unfortunately a side effect of these tighter standards is that the indoor air quality can suffer. This is where a continuously operating exhaust fan comes in (also known as Mechanical Ventilation). A continuously operating exhaust fan provides a way to exhaust the stale air that builds up inside a home. The fans airflow rate is set to achieve the number of air exchanges needed for your specific home.

There are many options for continuous operation exhaust fans but there are basically three locations for them:
A dual speed exhaust fan in the bathroom: This will operate continuously at a low speed then have a high speed for when the bathroom is in use.

A centrally located exhaust fan: This might be in a main living area open to the rest of the house.

A kitchen range hood: This operates much like the dual speed exhaust fan in the bathroom. A low speed provides the continuous operation while the higher speeds provide the needed ventilation when the kitchen is in use.

A prerequisite for a continuously operating exhaust fan is that it is quiet. With it always on, it is very important that the sound level does not interfere with everyday life. Most continuously operating exhaust fans will have a sound level that is barely noticeable.

It makes sense – bad air out, good air in, but there are still some questions that arise:
How much energy and money is this going to cost me? A very valid question. Energy costs and usage are definitely hot topics, but when you do the math, the exhaust fan is using very little of each. There are a few factors that go into calculating the costs. The two big ones are what type of exhaust fan you have installed and what your actual electric rate is. Using the average United States electric rate with an ENERGY STAR® certified exhaust fan, the cost will be approximately $.60 to $1.50 per month. Overall, a very small price to pay to ensure the quality of the air you breath.

That cant be good for the fan if it is running all the time?
Not to worry, fans that are meant for continuous operation have been tested and certified for this type of usage.

Can I turn the fan off?
The effectiveness of the system to provide proper Indoor Air Quality is based on it operating continuously so it is recommended that the fan stay on. However, there may be times when the fan needs to be turned off for servicing. Some units will be installed with an override switch while other units will need to be turned off at the service panel. You should contact your builder/installer for the specific details of your installation.

So the next time you are tempted to blame someone for not turning the exhaust fan off, stop and think that you might actually want to thank them for keeping it running and ensuring the quality of the air you are breathing. To learn more about Indoor Air Quality, ASHRAE 62.2 standards and Air King products that comply, visit

Thursday, June 1, 2017

The Weather is Warming Up – Air Circulators to the Rescue

Summer is just around the corner and the temperatures across the country have already started to rise. For many of us, it is a welcomed change from the long cold winter. It also means that expensive cooling bills are coming or worse – the dreaded fight over the thermostat in your home or workplace.

When it comes to temperature control, even very small adjustments can have significant impact. For each degree you adjust your thermostat, it is about a 3% cost savings. If your cooling bill is $200 during the summer months, that translates into about $6 per degree per month. Great, so I will turn my thermostat up 15 degrees, save $90 per month and have my house or office feel like a sauna! Yeah, we agree that doesn’t sound all that pleasant. The key to adjusting your thermostat is to still keep the space feeling comfortable. This is where air circulating fans come in.

We first must address a myth that is out there. Standard air circulating fans do not cool the air. The only way air can be cooled is if some type of refrigerant is added to the mix. What air circulators do is make your body feel like it is being cooled. Think of it this way. If you are outside on a hot day with no breeze at all it feels very hot. Now as soon as a slight breeze comes along, it immediately feels cooler. The air has not changed temperature but the introduction of moving air across your skin gives your body the sensation that it is cooler. There are complicated heat transfer and thermodynamic reasons for this but we will leave that to the scientists to explain. For our purposes we just need to agree that when air blows across our bodies, it feels cooler. By creating air movement in your home or workplace, you can have the temperature set higher but still be comfortable.

Another benefit of using air circulating fans are they distribute the cool air from an air conditioner evenly. Almost all homes or workplaces have an area that is always warmer than the others. Using an air circulating fan will distribute the cool air evenly from room to room. This can take stress off your HVAC unit in that you will not have to run it longer than it needs to just to get that one area cool enough to be comfortable.

Wait a minute, dont air circulating fans use electricity, so how much am I really saving? Air circulating fans do use some energy. However the amount of energy it takes to operate an air circulating fan compared to an air conditioner is significantly less. A typical air circulating fan uses between 40 watts for a typical office fan to about 350 watts for a large industrial fan that would be used in warehouses or manufacturing facilities. A typical household air conditioner will use between 1000 watts for a single window unit that can cool 1 or 2 rooms to 3500 watts for a central air unit. If using an air circulating fan allows you to raise the thermostat 3, 4 or more degrees that could mean your air conditioning units operates an hour or so less a day which can really add up over the course of a month or summer – especially in commercial and industrial setting.

For more information about air circulating fans visit

Monday, May 1, 2017

Spring Cleaning Ventilation Checklist

The birds are chirping, its staying light a little longer, the temperature is climbing.... It can only mean one thing - Spring is here!

Spring marks the traditional time of the year to open the windows, air out the house and take care of those once a year cleaning projects. Most people have their standard checklists that probably include items such as cleaning windows, gutters and other items around the house that couldnt be done during the winter months.

Those are all great and need to be done, but there are a few other things around the house that could use a little attention. When is the last time you did any maintenance to your ventilation systems? You exhaust fans provide a crucial function to the indoor air quality (IAQ) of your home. That is why it is important to keep them running properly. Here are a few tips to consider:
  1. Clean your fans. ALWAYS FOLLOW THE MANUFACTURERS RECOMMENDATIONS FOR CLEANING AND TURN OFF THE POWER TO THE UNIT BEFORE STARTING. Most exhausts fans have grills that can be removed and washed with soap and water (As long as there are no electronics in the grill). The interior of the fan can either be wiped with a dry cloth or vacuumed. You might be a little surprised how much dust and dirt can build up in your fan. The good news is that means the fan is working. All that dust is going up into the fan instead of being breathed in by you.
  2. Actually make sure your exhaust fans are working. Do a walk-through of your home and make sure the fans are operation correctly. Do they turn on? Are they making loud noises? Does it seem to be moving air?
  3. Is anything stuck in your ductwork? Inspect the wall or roof cap where the air is exhausted out of for build up of dirt, debris, birds nests or anything else that would cause the air not to flow freely. Always use caution and take the proper safety steps when using a ladder or when up on a roof.
  4. For range hoods, make sure the grease filters are clean and in good repair. This should actually be done 3 or 4 times a year. If you havent been doing it, now is a great time to start that cleaning schedule.

For more information about cleaning, maintaining and troubleshooting your exhaust fans and range hoods visit the FAQ section at

Monday, April 3, 2017

Getting Particular About Particulate Matter

If you have done any research into indoor air quality, you might have come upon the term Particulate Matter (PM). No it is not the stuff that runs the hyper drive of the spaceship in the latest sci-fi thriller. It is defined as the sum of all solid and liquid particles suspended in air, many of which are hazardous. This complex mixture contains for instance dust, pollen, soot, smoke, and liquid droplets.¹ With that definition, we might prefer the spaceship thing.

Unfortunately our living environment is filled with particulate matter but there are a few things we can do to reduce its impact on us. Basically there are two types of Particulate Matter  naturally occurring (pollen for instance) and man made (like smoke from cooking). Particulate Matter is measured in microns. One micron is one millionth of a meter. A human hair is about 60 microns. A good strategy against Particulate Matter is Identify, Avoid, and Reduce.

The first thing you need to do is identify where the Particulate Matter is coming from. Some are simple to identify such as smoking. Without having to make a public health announcement, I think we can all agree that smoking is not good for our health. Some other sources are not as noticeable. Did you know that your kitchen is one of the larges sources for Particulate Matter in you home? During the cooking process, Particulate Matter is released in the form of smoke, grease, and gas (for gas cook tops). If not contained, these pollutants can go right into the air you are breathing.

Once you can identify the sources, avoid them as much as you can. Now we are not suggesting that you should lock yourself in an airtight chamber from spring until fall because there might be pollen in the air, just look for some things you might be able to avoid in your everyday life. When we cant avoid them, we should look to reduce them.

A big way to reduce Particulate Matter is through filtration. Going back to the kitchen, the easiest and most effective way to reduce Particulate Matter in the home is through a range hood that exhausts to the outside. This takes the Particulate Matter directly out of the living environment before it can be breathed in. Another way is to filter air coming into the home. Many new homes now have some type of outdoor air device installed that brings fresh air from the outside into the home to exchange with the stale air in the home (like the Air King QFAM). These devices can be fitted with air filters (like on your HVAC system) that can filter out microns down to 2.5.

To learn more about kitchen range hoods, fresh air filtration and the codes that are currently in place for reducing Particulate Matter visit

¹ source:

Wednesday, March 1, 2017

Over The Range Microwaves, Are They a Good Option?

Oh that rectangular masterpiece of modern convenience that has made its way into almost every kitchen across the United States – the microwave. Microwaves have become a kitchen staple and for many people, they couldn’t live without them. Now available in almost any color under the sun, with more features than a new car, how could you possibly not have one?

A popular location for the microwave is over the cooktop or range. They even have a nifty acronym for them – OTR (over the range). While on the surface it might sound like a good idea, lets take a little closer look. The number one reason people place the microwave over the range is to save space. There is no denying it, by placing the microwave there, you do not take up counter space, but at what cost?

By placing the microwave over the range, you need to have a unit capable of ventilating the area. The issue with microwaves is they are designed to be a microwave first with the ventilation system added onto them. The kitchen is one, if not the largest source of air contamination in the home. If not properly ventilated, the indoor air quality of your home will be compromised. A range hood is deigned to do one thing and do that one thing extremely well – ventilate. Often times the microwave is installed to re-circulate the air through a charcoal filter. If you ask anyone who deals with indoor air quality, they will tell you that this is not an acceptable way to “ventilate” the kitchen. In some locations across the United States it is against the building code to install a recirculating unit – it must vent to the outside (this includes recirculating microwaves as well as recirculating range hoods).

The perception of OTR microwaves is that they are more convenient from a space savings perspective, but are they? Consider the installed high of the unit. The top of the range is typically 36” (3 feet), the unit is installed 24” to 30” above the range. That brings the bottom of the microwave to a height of a minimum of 5”. That means that for most people, they will be reaching up to get items out of the oven. For anyone under 5.5 feet, they will probably need a step stool to get items in and out. This can provide a convenience and safety issue. Think about children trying to reach up to get something hot out of the oven or do you really want a cup of hot tea being pulled out of the oven and held over your head?

Back to the effectiveness of the ventilation, another issue with OTR microwaves is the depth of the ovens. Typically they are about 15” deep. This allows them to basically match up to the front of the cabinets or just stick out a little bit. While this might be nice from a visually pleasing standpoint, it decreases the capture area of the hood. Most cooktops are 24” deep, so with an OTR microwave there is typically about a 9” difference is depth. Range hoods are typically 18” to 24” deep allowing them to capture considerably more contaminants coming off the cooking surface.

As with any larger purchase in the home, especially one that will be installed, there is always a need to weigh the pros and cons and make the best decision for your particular need. To learn more about Air King’s range hoods and indoor air quality solutions, visit

Wednesday, February 1, 2017

Is your ventilation under pressure it can’t handle? Static Pressure Explained

While it might not be the pressure of needing to hit the game winning shot with 0 seconds left in the championship game, our exhaust fans are under a different pressure to perform – Static Pressure.

The dictionary defines it as: The force per unit area that is exerted by a fluid upon a surface at rest relative to the fluid. If you are like most people, that doesnt really clear it up – especially when it comes to ventilation. I thought we are moving air not fluid? The very basic definition is how much pressure is exerted to move a given amount of fluid a defined distance. For airflow (ventilation measured in Cubic Feet per Minute – CFM) that means how much CFM is needed. For instance a fan might move 100 CFM at 0 of static pressure. When the static pressure is increased to 0.1 the same fan might only move 90 CFM.

Okay, the advanced physics lesson is over, lets take a look at what all this means. It can be summed up as, the higher the static pressure, the harder the fan needs to work. When it comes to exhaust fans, there are many contributing factors that can negatively affect the static pressure of the system. As you are determining what type/size exhaust fan you will need, these are some of the factors that need to be taken into account:

Duct size: This is a case of bigger is better. The wider the duct, the easier it is for air to flow through it. Think of one of those small coffee-stirring straws. Try to blow as much air as you can through it. Have you turned red yet? Now take one of those large milkshake straws and exert the same amount of energy blowing air through it. Not even a comparison. This is exactly what is happening in your system when you use smaller diameter ducting. The smaller the duct size, the more force you will need to overcome the static pressure created. This is multiplied if you are reducing the size of the duct coming from the fan to match the rest of the system. For instance going from 6 to 4 will have a big impact.

Duct Length: Lets stay with our straw illustration. Take 20 straws and put them together. You will notice you can still get some air through them, but once again, it takes a lot more effort. A shorter duct length will create less static pressure.

Twists and Turns: Each time you add an elbow or turn in the ductwork, you add more static pressure. Its been working so far, so lets stay with the straw. Now take the straw and bend it into 10 different twists and turns and try to blow air trough it. Each time you add a twist, it will get harder to move air through it.

Great, we now know about Static Pressure, but what’s the big deal. As we learn more about indoor air quality and the benefits of proper ventilation, it is vital that the systems are working as expected. As we saw in the above example if the home calls for 100 CFM of ventilation but because of the static pressure in the system, we are only getting 90 CFM or worse, we have an issue. In extreme cases you might only be getting a fraction of the airflow you thought. This can lead to moisture issues like mold and mildew.

To learn more about ventilation, visit

Monday, January 16, 2017

Bad air out, fresh air in – bringing fresh air into your home

When you hear the term Fresh Air, it might invoke thoughts of a warm summer breeze, a walk on the beach, or that first smell of spring after a long winter.

When it comes to your home, it is much more than that. Fresh air is a vital part of maintaining Indoor Air Quality (IAQ). Bringing fresh air into the home can be as simple as opening doors and windows and letting it happen naturally. The challenge is that opening doors and windows is not always practical. That is where other solutions come into play.

Lets first take a look at why it is important to have fresh air coming into the home. Not to try and scare you, but your home is full of pollutants that are negatively affecting the air you are breathing. Something as simple as you breathing is producing CO2 gas. Add in cooking (especially on a gas range), cleaning or using almost any appliance and the air quality can quickly deteriorate. Brining fresh air in is as simple as exchanging the stale (bad) air in the home with new (fresh) air from outside the home.

Now back to how to do this. We already talked about windows and doors and the limitations they have. Another option is using what is known as a mechanical solution. With a mechanical solution such as the Air King model QFAM, fresh air is brought into the home with a fan. There are a large variety of mechanical solutions on the market and they all have their pros and cons. HRV and ERV units are good, but expensive to purchase, install and maintain. Simpler solutions such as small fans that bring air in can work, but the air is not conditioned or filtered. Depending on the location or day, sometimes the air coming in might be worse than the air inside (high pollution areas or days). It is best to look for a solution that provides air filtration (filters that can be easily accessed and changed) as well as some type of humidity and temperature control that doesnt allow extreme cold, warm, or humid air into your home.

From a homeowner standpoint, do the simple things – open doors and windows when you can, utilize your exhaust fans and range hood. Consult a HVAC expert to walk through the best solutions for your specific home. To learn more about fresh air solutions from Air King visit