All about ventilation and more…
We love houses, and so do our friends at Redfin – the very cool and informative real estate website. They just published this article , which has some great tips on keeping your house cool this summer.
Keeping you cool, while saving energy – that’s a core part of our business, so we’re happy to see our partner at AirScape’s tip mentioned. And what do you know ? They suggested whole house fans.
In case you were wondering why we should wear a mask in public and filter the air around us, check out this demonstration of suspended micro droplets.
Micro droplets suspending in air from MixonK on Vimeo.
Our CFB HEPA Filters are currently being used by a number of hospitals to create negative pressure isolation rooms for COVID-19 patients. They are typically paired with an inline fan to exhaust the contaminated air from those areas, filter and then discharge it safely outside. Discharging the air without any filtration is considered risky since you are spreading/distributing the virus particles extracted from the patient areas. If you have questions on how to build negative pressure isolation rooms give us a call.
What is a HEPA?
HEPA stands for high-efficiency particulate arrestance. To be classified as a HEPA, the air filter must remove at least 99.97% of particles whose diameter is equal to 0.3 μm. Classification at 0.3 μm is important because this is the weakest point in the filter’s performance – typical HEPA filtration efficiency increases for particle diameters both less than and greater than 0.3 μm.
Image courtesy of the National Institute for Occupational Safety and Health (NIOSH)
Virus particles, due to their small size, typically fall in the diffusion regime of HEPA collection efficiency. Specifically, the virus that causes COVID-19 is approximately 0.125 μm in diameter. That diameter is perfectly within the particle-size range that HEPA filters capture with great efficiency: 0.01 μm and bigger (see the NIOSH diagram above).
Want to ready more about HEPA and how they filter particles the size of viruses? We found the Submicron and Nanoparticulate Matter Removal by HEPA-Rated Media Filters by NASA study is a great source of reliable technical info. Page 7 of the paper has an excellent illustration of filter efficiency as a function of particle diameter for sizes 0.01 μm and above.
Another great addition to our lineup: The Ostberg CK series inline hydroponics fans.
Keep the temperature down and prevent stress on your plants through proper ventilation. These puppies are designed for tough high static pressure applications such as carbon filters and humid grow room environments. The tough baked epoxy coating and a 10 year warranty are icing on the cake.
http://www.hvacquick.com/products/residential/Fans/Hydroponics-Fans/Ostberg-Inline-Hydroponics-Fans
Recommendations for bathroom ventilation sizing can vary considerably between manufacturers and competing standards. Some of the newer recommendations allow for low ventilation rates over long periods of time as opposed to the typical 8 air changes per hour.
We prefer 8 air changes per hour as A MINUMUM and here is why:
When moisture is introduced into the bathroom it has an annoying tendency to get diluted into the entire air content of the space. With low CFM (background) ventilation that moisture will eventually be exhausted, but in the meantime it will linger in the air and potentially condense on colder objects such as walls and fixtures. Once it’s in liquid form on your walls it takes A LONG TIME to evaporate it again, not to mention the potential long term damage to the bathroom.
So what do WE recommend?
– minimum of 8 air changes per hour (more is better since the extra CFM typically comes at very little cost; nothing wrong with 10 or 12 air changes per hour)
– 100 CFM minimum per bathroom, no matter how small it is
– multiple grilles in larger bathrooms to pickup the moisture/smells close to the source
– keep the system quiet (inline fans!!) so that you will use it
– install a timer and leave the fan running for at least 20 minutes after leaving the bathroom
And remember, the standards are there for the builders and not necessarily for you. Keep the moisture off your walls with adequate CFM and you will avoid mold issues.
The Kitchen…a place of interest for those of us who like to eat.
Most of us are familiar with the noisy, rattling, ineffective range vents usually installed in a home. These units typically have some form of fan and motor right above the range, causing all sorts of racket, and struggle to pull all the smoke from the fish that my wife I burned last night.
Is there a better way? You bet. Fantech Component Kitchen Exhaust systems. These have the a powerful fan located in the attic, coupled with a Silencer (muffler for the automotively inclined) that is able to pull massive amounts of air and do it without driving you from the kitchen with noise.
The ideal setup would have some sort of Hood Liner, a Backdraft Damper to prevent air from coming down the pipe when the Fan is off, the Silencer, The Fan and some sort of discharge hood in that order. All that is left is some hard wall galvanized pipe and you have a vent system that is unparalleled in terms of performance and quiet operation.
Sizing the system can be done by using our handy System Builder or a few simple rules of thumb:
ASHRAE 62.2 “Ventilation and Acceptable Indoor Air Quality in Low-Rise Residential Buildings” is the U.S. national minimum ventilation standard. Note that not all states require it or may apply it differently so check with your local building codes to see what they require.
The standard requires low-level, continuous ventilation in a home using a whole-building fan or other ventilation system. Intermittent whole-building ventilation can be used as an alternative. Note that the standard uses the term “whole-building ventilation fan”, not to be confused with the term “whole-house fan” which is a different product (see AirScape whole-house fans on hvacquick.com.
To calculate the required flow for continuous ventilation, count 1 cfm (cubic foot per minute) per 100 square feet of floor area of the house. Next, multiply the number of bedrooms plus one by 7.5 cfm (cubic feet per minute). Then add those results together. For example, a 2,000-square-foot house with three bedrooms would require 50 cfm (20 cfm for the building area plus 30 cfm for the 3+1 bedrooms).
Typically HRVs or ERVs are used to meet the standard, but bath fans are acceptable as well. There are additional sound and minimum cfm criteria that bath fans must meet in order to be allowable. Fantech and S&P inline fans are a good option due to their low sound levels and available 62.2 control options:
http://www.hvacquick.com/products/residential/Ventilation-Accessories/ASHRAE-62-2-Controls
An online version of the standard is available at the ASHRAE website (www.ashrae.org).
Back in the old days, laundry rooms were put on an exterior wall, almost exclusively to provide a short vent run for the dryer. As our houses grew, somehow function trailed form and the unsightly laundry room was relegated to some hidden corner deep inside the house.
Works out for space usage, opening exterior walls for windows and the like…for the dryer, not so much.
Dryers need to shed heat and moisture to operate efficiently. More than 6 feet or so and they are over matched. Well…what now?
Dryer booster fans! These fans have pressure switches or current sensors to know when the dryer is running and turn on and off all by themselves. These fans have enough strength to keep the heat and moisture moving, allowing your dryer to dry clothes in the time it should.
How Do I Know If I Need One?
Tjernlund, Fantech, Soler Palau and others make great ones. Give a call to find out which one will work best for you…
Older leaky buildings permitted sufficient air change (fresh air infiltration) to remove pollutants (such as carbon dioxide, moisture, mold spores, formaldehyde from building products) by the natural forces of wind and stack effect. Newer, tightly built homes do not allow this air exchange.
The best way to introduce fresh air into a home is through the use of an HRV or ERV. These products allow for balanced ventilation, same amount of air is exhausted as brought into the house, and the majority of the heat/cool is recovered from the exhaust stream into the incoming air. You get the best of both worlds — good air quality and low operating cost.
Heat Recovery (HRV) and Energy Recovery (ERV) units:
http://www.hvacquick.com/products/residential/Indoor-Air-Quality/Residential-HRV-ERV
The average family can dump 10,000 gallons or more down the drain every year waiting for hot water. That’s half a swimming pool wasted! If only there was a way to save all that water… hmmmm…
Luckily there is! A recirculation pump (retrofit or dedicated return line) can save water from being wasted and the corresponding money.
How do the retrofit systems work you ask? The problem of course is that water heated by your water heater sits in the line between the heater and the tap(s) where it cools off. Let’s call this “previously hot” water. When you turn on the tap you need to flush out this previously hot water to get to the fresh hot stuff. With low-flow faucets and long plumbing runs, this can take a long time – and waste a lot of water. An instant hot water system – or hot water recirculation system – flushes the previously hot water back into the hot water tank (rather than you running it down the drain) through the cold water line, so you have freshly heated water waiting for you when you turn on the faucet – instant hot water.
Metlund and Laing pumps:
http://www.hvacquick.com/products/residential/Instant-Hot-Water/Hot-Water-Recirculation-Pumps-NON-TANKLESS
Those of you living in High Rises or older homes have come up with a great way to beautify the interior of your home…covering up that unsightly steam radiator.
As you can see, there are a multitude of methods to do this. One of the most common ways we have seen is to surround it with a cabinet. The one problem is that heat wants to rise, and generally there is controls that need accessing from time to time…
HVACQuick has you covered! (Nice play on words, huh)
Behold!! The Bar Linear Diffuser! We can make these in very long lengths to cover any Radiator. Also, we can put operable doors on one or both sides to facilitate control access…