Central forced air heating (furnace) and air conditioning systems operate by pushing conditioned air to each room in a house.  To return the “stale” house air back to the furnace return registers have to be installed throughout the house, pressure balancing each room.

In a typical house these return registers exist only in common areas (1 or 2 per level) and not in individual bedrooms. To help the stale air get back to these central returns, builders will often undercut doors. These undercuts can be inadequate for providing enough air flow, especially when plush carpet and under-padding are installed or for large bedrooms with multiple supply grilles. Inadequate return air pathways can result in pressure imbalances, which can cause drafts and temperature differences between rooms or floors, leading to comfort complaints.

The typical recommendation is to provide 1 square inch of free area opening per 1 CFM of conditioned air being pushed into the room.

If building return air ducts into each room is not possible, one common option is installing jump ducts or transfer grilles in the rooms that are often closed. A jumper duct is a short piece of insulated flex duct installed in the attic and attached to ceiling grilles in the closed room and a common space.  This provides a return air pathway between the two areas.

Typical jump duct.  Note the sealant around the grilles.

Jump duct installed in new construction.

 Images courtesy of DOE’s Office of Energy Efficiency and Renewable Energy.

The New York Times recently published findings that a huge source of pollution we breathe is actually caused by our kitchens. As it turns out, the heating of fat, oils and carbohydrates makes organic compounds that are indeed considered contaminants. Perhaps more worrying is that since these smells are generally acceptable to us, we are unaware of the inherent dangers and less likely to act upon them.

Our recommendation is to have (and Use!) a good kitchen vent set up that goes all the way outside the building envelope. Additionally, an air to air exchanger to bring in fresh air to these tighter built homes can do wonders.

I have attached the link to the NY Times article below, give it a read, there is some interesting information in there…

well.blogs.nytimes.com/2013/07/22/the-kitchen-as-a-pollution-hazard/?_r=0

As we have discussed before, the use of a Recirculation Pump in your water system can be of dual benefit…It gets there quicker and you do not waste a precious resource. We have always had two of the more popular lines, the ACT D’mand and the Laing Autocirc…
Luckily, these units have benefitted from newer technologies and we are happy to discuss those changes here!

Both systems have been changed to Stainless Steel or No Lead Bronze housings to comply with recent changes to the drinking water standards, which will prevent any bad materials from leaching into your water supply. The Laing has also received an ECM (electrically commuated) motor which allows for greater speed control as well as superior energy efficiency for low cost operation. Those that have Laing Pumps currently can retrofit to the new motor when it comes time for replacement as the castings have not physically changed.

The Biggest news would be the introduction of the Laing E3 and E10 Series pumps!

These new pumps are much more robust and give great performance for the larger home, or homes with sophisticated plumbing systems. We still have the same two configurations, the E3 for Dedicated Return Lines and the E10 Autocirc for Retrofits where the pump is located at the furthest plumbing fixture and uses the cold water as the return.

By now, you likely have heard of Radon…an odorless colorless gas that causes cancer. But, exactly what is it, and more importantly, how can we get rid of it?

Radon is a gas that is caused by the natural breakdown of uranium in the soil. It appears to be located in areas of high granite content most often. As it happens Iowa is one of the higher reading locations, due to the glacial activities that exposed the Canadian Shield bedrock formation and tumbled the rock down to the plains of the Mid West US. Radon can also be found in higher readings across Ohio and Pennsylvania, glacial activity is likely the cause here as well, due to the proximity to the Canadian Shield, but the rich mining veins also contain Radium and Uranium which is released when the ore that contains them is broken down to smaller size. Radon is measured in Pico-Curies per liter of air, similar to the more popular PPM (parts per million). Guidelines state that nothing need be done if the level is under 4 pico curies, but it certainly couldn’t hurt to mitigate even that little amount.

The ill effects of Radon are caused not by the gas itself, but the by products of its decay. These particles are small enough to be inhaled and lodge themselves in the body and continue to decay, all the while releasing radioactive isotopes that can harm the vital cell structures of the lungs. While cancer is certainly the one we all hear about, the breakdown of cellular tissue is likely causing other health problems.

Enough doom and gloom…what can be done about this? Radon is everywhere in small doses, the ground is constantly releasing it to the atmosphere, but in such dilution that it poses little to no threat. With our homes however, we have taken a large area of dirt and covered it with a slab of concrete which traps the Radon trying to vent out of the dirt; now we have a build up of higher levels that still want to off gas, so they rise up into the houses…

Ideally, we would stop the Radon from rising up by sealing the bottom of the house with a vapor barrier and/or by de-pressurizing the area beneath the slab. What we hope to accomplish in doing that is to not allow the Radon into the house, but rather collect it and disperse it up into the atmosphere. Let’s go over some popular methods to do this:

• Sealing – If you have a crawlspace you can cover the earth floor with a non permeable vapor barrier, this could be considered enough in certain areas or depending on your Radon level. If this is not possible, or if you have a Basement, begin by sealing the cracks and joints, and even where utilities and other services enter the home.
• Sub Slab Depressurization – This consists of having an active fan pulling air from under the slab (or vapor barrier) through a piping system and releasing it into the atmosphere. This is probably the most common way Radon is eliminated, and really the only way to go if you have elevated readings. Typically, there is a hole drilled through the slab down into the gravel bed; a connection made to the perimeter drainage system; or a perforated pipe in laid under the vapor barrier. This is then connected to a fan mounted to some PVC pipe, which is run up above the eaves of the roof to discharge the effluent air.
• A less common way of battling Radon if the alternate methods aren’t achievable is to run positive pressure in the house. This is as simple as it sounds, there is a fan pulling air in from outside which creates an envelope of air pressure that keeps the Radon from flowing in.This Is Not the preferred way of doing this, and in todays tightly built homes, probably not a good idea in any case. It is far preferable to remove the Radon from the general area than to swat it away as it were.

Fan sizes – There are many fans you cam purchase for Radon Mitigation, which one you need can only be determined correctly on site. If we have enough cohesive information a recommendation can be made, but you will need to have some specifics regarding your property. The whole idea of sub slab depressurization is not to purchase the highest CFM you can (like you would for a kitchen) but enough to lower the pressure under the slab to allow the Radon to be evacuated. In fact, too much can be a bad thing, with too much fan you run the risk of actually elevating your Radon level by bringing more to you.

Domestic water supply to our homes tops out at around 60 PSI. So, that’s a lot, right?

What we forget is that the more automated our lives have become, the more auxiliary devices we have to take care of us. Such as sprinkler systems, dishwashers, clothes washers, well you get the idea… The downside to that is the water pressure can only do so much before things start to not be what they should. There are few things worse than having to take a shower in water that barely comes out of the showerhead.

The best way to maintain pressure to the house is with a Davey BT Pressure Boosting Pump. What these pumps do is sense the amount of water being drawn into the house and begin pressurizing the water supply to keep all those fixtures pouring as they should. They can provide a set amount of water at a set pressure increase indefinitely, so that new Rain Forest showerhead or whatever they are calling it today will in fact provide enough rain to cause you to believe you are on an Amazon trek.

Davey pumps are installed near the water supply line to the house, so are out of the way…and better yet, they operate all on their own. Once installed, the Torrium module operates the pump as necessary to keep the pressure even. There is no maintenance, adjustments or otherwise to this pump, you install it and let it work for you.

Caveat – Please consult us to get the right one for you, you cannot get the most powerful one simply because of the impressive performance numbers, it must be sized properly to the system it is going on. We are more than happy to discuss this with you. We always would like to spend the time necessary than sell you something inappropriate.

Back in the old days, ventilation typically stood for fans that extracted stale, odiferous, and otherwise disagreeable air from the kitchen and bath. In these days of energy consciousness, we have become aware of how wasteful pumping out freshly filtered and conditioned air actually is. The furnace or AC unit must work overtime to compensate for this loss, costing precious dollars and resources. Couple this with new construction technologies that make for better insulated and sealed homes and a perfect storm is arising, as now depressurization and backdrafting appliances become possible by extracting air without replacing it.

For the kitchen, due to the volume of air needed to remove smoke and other particles, at this time there is no good answer other than what we currently use. Make-up Air Provisions are becoming more prevalent in Building Departments around the country for Kitchen Fans drawing more than 300 CFM. But that is a whole ‘nother kettle of tea we will examine in a later post.

Bath Fans, however,  can benefit from some newer and energy saving ideas. We have been seeing more and more folks use Heat Recovery Ventilators (HRVs) for venting the bath, as these remove air as well as replace air due to an air to air exchanger that can capture up to 90+ percent of energy from the outgoing air. They can utilize the same grilles as our traditional bath kits and operate just as quietly, as an added bonus, they are adding a small amount of fresh air to the home improving indoor air quality.

As illustrated above, the HRV can really make for a comfortable environment in the whole house. The economics of installing one are not as bad as one would think. Once you are looking at a bath fan or two, the jump to the HRV is not large, especially given the benefits of the unit. For those that are sensitive to allergens, an inline filter box can be added to the fresh air intake to cleanse the incoming air.

For sizing, we like to stick with the tried and true method of 1 CFM per square foot of area in the bath, which gives us roughly 8 air changes per hour. Therefore, the VH704 for instance could be used on a traditional “Hall Bath” of fair size given its’ 70 CFM. Most will fall into the SHR1505 and its’ 147 CFM, although this could do a good size bath or two and perform general ventilation of a laundry room as well.

We here at HVACQuick.com happily announce that we will be Stocking a number of Setra Pressure Transducers and Room Pressure Monitors here on the West Coast. Those of you that know what I just said are likely rejoicing, as these types of things are not readily available, and worse, when you need it, you need it bad. Clients will be able to call and speak to one of our skilled technicians to ask questions, and if you absolutely, positively have to have it we will walk it out to shipping to ensure Next Day Delivery (at an additional charge).

The models we will be carrying will cover most models, and be “adjustable range” so you are certain to find a model that will work in your application to get things up and running.

Room Pressure Monitor

The SRPM Room Pressure Monitor is designed for critical low differential pressure applications that require stringent pressure monitoring and alarming. True differential pressure is measured and displayed with a resolution 0.0001″ W.C. The SRPM is a complete system that includes a convenient backlit RGB LCD display with an intuitive graphical user interface for pressure, security, calibration and alarm setup.

Now that spring has sprung, many of us are experiencing allergies and assorted maladies relating to pollen in the air. Getting rid of those irritants is important, specifically inside the home, as there is no hiding from them outside.

The low hanging fruit to rectify this are fairly simple: Replace the Filters in your HVAC system, clean the registers, and even vacuum the duct near the opening. When selecting your filter, look for a high MERV rating, above MERV8 if possible. These filters will catch very fine items to help improve and maintain indoor air. You may dust less to boot!

Since we are also coming to a time of heavier HVAC usage, you would be well advised to inspect your duct work as well. I recently wondered why my Furnace wasn’t working well, so I climbed into the attic and found the duct feeding the area in question had become detached from the trunk line! I was heating the attic in sub-freezing weather. Not good (or cheap!). A roll of our foil backed butyl tape fixed that and some other questionable joints in no time.

There are some more available options that are a bit more advanced, but will pay dividends over and over. Included in this level would be installing a powered HEPA filter on the main HVAC system, a passive inline filter box,  or even an HRV (heat recovery ventilator).

If you watch the DIY channels, the term “Trick of the Trade” comes up in speech or by implication. Certainly tricks are learned (usually the hard way) over time, especially with repetition. How can the average DIYer do a job easier, saving time and frustration? Simple…the right tools.

We have found a great line of HVAC tools from Malco Products to help pros and DIYers do a better job. These tools help cut the cumbersome flex duct, tighten cable ties effectively or even cut sheetmetal. From my years in the field, I know having a strong, comfortable tool that is made for the job matters. I mean, sure, a vise grip will work as a hammer…but not well.

There’s nothing more satisfying than a job well done…with our Malco Tools that will be easier than ever before.