indoor air quality

Duct work is a key to a healthy building. While there is not any one single thing that can be done in a building to achieve healthy indoor air quality, duct work is a critical element in the system. On one of our current projects at a local church, we are in the construction process to mitigate indoor air quality and water intrusion issues. Facilities of this scale are difficult to manage without a full-time building maintenance team. In this case, issues arose which further complicating things; decisions during a construction job 25+ years ago to cut construction costs have ended up causing indoor air quality challenges. The elimination of a fresh air distribution system as a cost cutting factor increased the potential for indoor air quality challenges for instance.

Added complications

At the time, it was acceptable to use fiberglass insulation inside of duct work to control noise from the mechanical system in the sanctuary. This fiberglass insulation captured dust and dirt that flowed through the duct work. The dust and dirt provided food for mold growth, and multiple water leaks throughout the structure have added to the complications in this building. The lack of fresh air ventilation, technology available for HVAC at the time, lack of regular preventive maintenance, no dehumidification systems, and high humidity levels have led to this need for a major renovation.

Duct work storage and protection

During the renovation process, it is critical to protect the HVAC duct work that is being installed. A construction site is messy and dusty on a good day. This one already had indoor air quality issues prior to construction. The mechanical contractor, Excel HVAC is sealing all the duct work that is being installed until it is sealed in place. They are also storing duct work that is not currently needed off site to keep it away from the dust and dirt on site. These simple steps protect the ducts to keep them clean and free of damage.

Installation of Duct Work

Once the duct work is installed, all the joints need to be sealed. The vents should be covered until the system is activated, which only happens after all the dirt and dust of construction has ended. Sealing joints in duct work is done with mastic glue and mastic tape. These strategies are geared towards keeping dust and dirt out of the ducts during construction and operation of the system.

These key elements focused on duct work are only one part of the solution. We are also addressing roofing, flashing, and gutter issues. Materials that are impacted by mold are being removed and replaced. This is a complicated project with many moving parts. Working with an integrated team approach using Suter Engineering to design the appropriate HVAC system, and a qualified general contractor, Herr and Company, to manage all the team members is the best strategy overall to achieve the best final solution for this project. Stay tuned for more information as the project continues.

There are some common things on the wish list for most custom homes. Clients want an open floor plan, lots of light, a beautiful kitchen, luxurious master bathroom, and connection to the outside. However, it is not often asked for – healthy indoor air quality.

Materials, structure, and the heating, ventilation, and cooling systems all contribute to indoor air quality. Making the right selections in all these areas is critical.

Fireplace

There are common elements that impact indoor air quality. A fireplace is a leak in the building envelope. When there is a leak, it will either bring dirty air into the home or pull dirty air through the building envelope into the home. This also happens with restroom ventilation fans, crawl space, and duct work.

Ductwork

If the ductwork is not tight, it will actually spread dirty air around your house. Insulate it right and seal it tight.

Building Envelope

The building envelope is critical in the design of a home with healthy indoor air quality. Keeping the air from moving through the walls will allow you to filter make up air through a filtration system. This will, along with a fresh air system, keep the air flowing through your house healthy and clean.

Moisture

Also, and this one has big impacts to durability and indoor air quality, keep the water out of the wall system. Water infiltration in your home will contribute to indoor air quality faster than anything else.

Finally, the materials used in your home impacts indoor air quality. Do the materials you use have VOC’s? What chemicals will they off gas into your air? Are they easy to clean? What do you use to clean the materials used? All of these questions impact indoor air quality and should be considered.

It is not going to be on the top of your list, but include healthy indoor air quality when building or renovating.

Ask any seasoned carpenter (that does not understand building science) and they are likely to tell you “don’t build too tight, you want your house to breathe.” This is a tried and true “because that is the way we always do it idea.”

Early in the construction industry you did not build a home air-tight so that the walls could dry out. This is a leftover from days before we insulated or conditioned a home and wanted to air them out to keep them healthy inside.

However, now we have added insulation into our walls to increase energy performance.

Now we have heating, cooling, and ventilation systems to control indoor-air-quality and make the house comfortable and healthy.

So if your builder tells you they have done anything less than make your home as air tight as an igloo cooler, ask them if they will help pay your monthly electric bills. Ask them if they will come and dust your home once a week. Ask them why they continue to build as if the house is not insulated or conditioned.

Making your home air tight is key to a healthy, energy-efficient, and durable solution. Of course you do need a heating and cooling system that includes ventilation. This is how you bring fresh air into the house – through a filter – using an energy recovery ventilator. Making your home air tight filters the air reducing the need to dust. It also reduces energy consumption. It also filters the air improving indoor air quality. Making it air tight includes sealing every connection, joint, vent, penetration, window, door, roof, and hole.

Your energy bills depend on having a complete thermal envelope. This home owner added insulation to the attic stair which is a good thing. However, there are still problems. The type of insulation used behind the stair only works when it is not compressed and if it creates an air tight seal. Since it is smashed to fit behind the stairs it is not performing as intended and without other measures it is not air tight. There is no air sealing around the stair opening to prevent air leaks into the attic such as weather-stripping. The access itself does not fit tight to the opening when closed adding to the leak. All of these problems hurt the energy efficiency of your home and it impacts your indoor air quality. Make sure all the gaps and cracks in your thermal envelope are tight, complete, and well insulated for the best performance possible.

I remember as a kid seeing ads for X-Ray goggles on the back of comic books. The idea of being able to see through a wall was a thing of fantasies for young aspiring spy kids. Now today, as a practicing architect, I find that x-ray goggles are not only possible, but a requirement for doing a home renovation the right way.

Every home has secrets behind the drywall that impact indoor air quality, efficiency, and durability. There are pipes and ducts that may not be found until the renovation work has begun – usually adding to the cost of construction. Water issues can exist for years without being seen on the surface of a wall or roof leaving an even bigger mess once uncovered during construction. Having x-ray vision is the only way to reduce these cost impacts and delays during a renovation project.

OK, so it is not exactly x-ray vision, but rather the use of thermal imaging that we use during a renovation project that allows us to “see through” a wall. On a recent project I invited Ivy Tools to show our clients, the builder, and me the power of using a thermal imaging camera to eliminate some of the guess-work during design.

In this project we are removing some existing walls – which the camera was able to identify had pipes and ducts that we otherwise did not know about. This allowed for proper advanced planning to take place eliminating the need for a costly change order during construction. We found thermal breaks in the envelope of the house so we could include those modifications in the initial scope and budget for the renovation of the home. We also found a surprise vent pipe in the attic which was a major thermal leak from the home which was contributing to comfort issues for years. While we cannot eliminate all the unknowns on a renovation project, this technology can identify some of the concealed conditions allowing for a better design before construction begins.

We hear about Volatile Organic Compounds (VOC’s) all the time in marketing of paint. That new paint smell that we have suffered through for years in the construction industry, well it turns out, is not good for you. Who would have thought all those air fresheners we added to our cars in the 90’s to get a new car smell was emulating chemical off gassing that is potentially causing us to get sick. The same off-gassing in cars happens in new homes.

 

When you are selecting building products, you may never find a perfect, green solution. Here are some questions you can ask to make sure you select the best green products:

1. Can I reuse what I already have?
2. Can I donate or recycle what I no longer want?
3. What product can I choose that will last a long time?
4. Can I select a product that is made from recycled materials?
5. Can I choose a product that can be recycled at the end of its lifetime?
6. Does this product come from a sustainable source?
7. How much energy did it take to make and ship this product?
8. How much energy will it take to maintain this product?
9. What impact does this product have on indoor air quality?
10. How much does it cost?

Having green products will keep your environment clean, your wallet happy, and your family healthy. Read more about the effects of harmful household products here.

Talking with any experienced carpenter, you have probably heard the phrase “a house needs to breath, you don’t want to build it too tight.” This is common folklore that has been passed down from generation to generation. Your builder tells you he is doing something that is good for your home by letting it leak a little to get fresh air and allow the building materials to dry out. These concepts need to be addressed, but a leaky house is not the solution. You do want to bring fresh air into your home, but you should do it through a planned ventilation system. You also want to allow materials to dry out so you need to know the permeability of those materials and verify that you are not creating a surface that reaches dew point in the assembly.

1      Plant a shade tree. A tree absorbs carbon dioxide, improves air quality, and controls flooding by minimizing runoff and topsoil loss. If located right it can offer free air conditioning on a sunny day for you and your home.

2      Switch all your light bulbs to LEDs (or at least CFLs) to reduce unnecessary heat gain from lights in your home. The average residential lighting energy usage is about 15% of your total energy use. Conventional light bulbs waste most of that energy as heat. An incandescent bulb gives off 90 percent of its energy as heat, while a compact fluorescent bulb wastes 80 percent as heat. LEDs remain cool. 

3      Insulate your attic. If your attic is like most, it could use an extra blanket. Most homes have fiberglass or blown cellulose insulation with no air sealing. With the simple idea that hot air rises, getting your attic insulated right and air tight will improve your energy efficiency along with improving comfort and energy efficiency.

4      Air-seal your electrical outlets. Since we know that positive pressure always wants to go negative we know air movement is going to happen in your home through gaps and cracks. Sealing up those holes will protect your health and improve your energy efficiency.

5      Exhaust fans. Managing the humidity in your home is difficult at best. Higher humidity in the home pushes us to adjust the thermostat instead of focusing on energy usage to improve comfort. Running the exhaust fan during and for 10 minutes after your morning shower and the exhaust hood while you are cooking is a first line of defense in keeping the humidity low in your home. Better even is to connect the exhaust fan to a humidistat so it runs anytime humidity gets higher than optimal in your home.

6      Fix leaky faucets and toilets. Wasting potable water is a huge problem in our goal of being efficient. It not only hurts us on monthly bills but also costs us a precious resource and burdens our infrastructure. Leaks can account for 10,000 gallons of wasted water in a home every year – or enough to fill a backyard swimming pool.

7      Lower the temperature on your hot water heater. Most water heaters come set at 140 degrees when installed while most households only need them to be set at 120 degrees. Turning back the thermostat on your hot water heater can protect against scalding, cut your energy bill, and lengthen the life of your water heater.

8      Collect Rainwater Rainwater is better for your plants because it is naturally soft and free of chlorine, fluoride, and other chemicals. Reducing runoff also minimizes the amount of water flowing into the sewer system and local waterways – this runoff can contain pesticides and fertilizers which is damaging to the eco-system.

9      Close the curtains Using curtains, shades, and / or shutters can greatly improve your home’s ability to fight off those high summer temperatures and help maintain a comfortable home.

10   Use Solar Energy to reduce your impact on the grid. When building new, plan your home for solar in the future even if you are not going to install it initially. Solar energy is renewable, efficient, and getting more affordable every day.

The thermal envelope is the barrier used to protect your interior environment from heat transfer from inside to outside. It may be portions of the exterior envelope and portions of interior elements. The effectiveness of this barrier is dependent on insulation levels, air tightness, and thermal properties of windows and doors.

Improvements in the thermal envelope can reduce heating and cooling requirements dramatically over code compliant construction practices at little to no added costs. It is the first line of defense in a home or office for comfort, low energy bills, and healthy indoor air quality.

Read more from our “Green Term Defined” series here: Green Term Defined: HVAC