Our New Healthy Home WishList
Sometimes, after hearing about many customers’ problems with their existing homes (problems with attics, basements, crawlspaces, inadequate ventilation, too much humidity, poor location, etc.), we just want to do a positive post on what our dream house would look like! What if you could build a new home in any location to make it as healthy as possible? Where would it be and how would it be constructed? There are lots of methods and designs to choose from, so don’t get overwhelmed, just relish the possibilities!
Size. Homes have always been a showcase of the owner’s tastes, abilities, and wealth. Most homes are built today with the current owner’s needs and plans in mind: if a couple plans to expand their family, they will try to incorporate extra rooms for more children, for example. Size is therefore a function of meeting current and future needs, budget, and space to build on. There is no “best size” for a healthy home, as long as all spaces are ventilated and properly maintained.
Don’t over-size it! The problem with “oversizing” a home is that unused rooms still need to be conditioned and maintained, using energy. Closing off ventilation registers in unused rooms is not good for the HVAC system or the air quality in the room. Unused rooms should have circulating fans left on and some sort of ventilation connection with the rest of the house (door vent grilles or transom windows are great for this purpose if you want to close the door). This article looks at the ideal house size in which to raise a family.
Once you build a home and love where you live, it’s hard to conceive of moving in the future just because you grow out of space. Look at incorporating expansion into the plans at the beginning. Here are 4 plans that make expansion easier by incorporating it into the plan. This allows you to build “just right” and expand when needed.
Try to find an architect who is known for indoor air quality. It is better to use their skills in design to build a home of the right size, small or large, than to work with an architect who designs beautiful homes but does not design for air quality.
Foundation: We have to protect our homes from moisture coming up from the ground, and without encapsulation, crawlspaces just do not offer the best protection. A properly waterproofed slab or basement affords better protection than a crawlspace. Although it may not look like it, concrete is porous. You’ll need a water barrier below it (slab) and around it (basement). If you build in an area with very moist soil or active springs, it is important to have the proper drainage around and under your basement. Having a finished basement requires no water coming in, so that the air is not becoming humidified. The temperature of basements, because they are in contact with the cool earth, is cooler, and cooler air can hold less moisture (its relative humidity will get higher). Higher relative humidity causes everything in the basement to become more moist, risking mold growth. So, even if you have a properly waterproofed basement, you may need to use a dehumidifier or small heater to keep the relative humidity at the proper level. Remember that a finished basement will need to be included in the ventilation system!
Attic: Unconditioned attics can serve as a thermal “buffer” between your home and the outdoors, but they require proper ventilation, which can be difficult to get right even with the proper products (soffit vents, baffles and ridge vents). For this reason, we recommend no attics (with the rooms’ ceilings extending to the rooflines) or conditioned attics (the thermal envelope still resides at the roofline and the attic space may be finished or unfinished). Conditioned attics are an extension of the home below, and if HVAC equipment or any storage is located there, it is not subjected to extreme heat, cold or moisture as in unconditioned attics. Remember, when planning for a conditioned attic space, ventilation is just as necessary as the rest of the home!
Heating/cooling: In the US, the bulk of heating and cooling new construction is done by forced air systems. That does not mean it is the best system, however. Forced air creates pockets of warmth and cool. Moving forced air through unconditioned spaces like attics and voids also allows for leakages. In contrast, radiant heating creates an even, comfortable environment. Here is a diagram that shows the difference:
According to BobVila.com, the benefits of radiant heating over forced air heating are several:
Radiant heating consists of 50% infrared light, which is an invisible natural light that warms by proximity (ie, in the floors you walk on).
Air is not stratified like in forced heat systems.
Radiant heating eliminates allergy symptoms that are generated when blowing air through the home.
Distribution losses are nearly eliminated.
New products like WarmBoard heat and cool quickly and transfer heat better than traditional techniques of installing radiant heating.
Radiant systems can also be used to cool your home.
Some studies show that radiant heating is up to 30% more efficient than forced air.
Radiant heating will still need a fresh air system to exchange stale air with fresh, conditioned air.
Now, of course you can heat or cool water for radiant heating using any type of heater/cooler. Geothermal energy uses the coolness of the earth about 18-30 feet below the surface, and only requires an electrical pump to circulate the liquid. However, the installation costs for such a system makes payoff distant for most homes. Geothermal and radiant heating and cooling for large buildings such at the University of Southern California has been a cost-saving, long-term investment.
The next best alternative to a radiant and geothermal systems is heat pumps (with high velocity mini duct system for distribution). As with all forced air systems, if you take care of them, including changing filters regularly and caring for the air handler and condenser, they are great for heating, cooling and ventilation.
Ventilation: A good portion of our blog is devoted to ventilation, and we’ve come to the conclusion (as many building health experts have) that intentional, balanced ventilation in a highly sealed home is best. It doesn’t matter whether you live in a pristine area with low humidity and pollution and prefer to open your windows most days; if pollen season or wildfire smoke or just cold winter air sets in, you will want to close your windows and still ventilate effectively! For these reasons, it’s best to start with a tightly sealed home with dedicated, pressure-balanced ventilation installed. Here are the features we would look for:
Stale air is exhausted at the same rate fresh air is introduced into the home. This will be 0.35 air changes per hour, but not less than 15 cfm (cubic feet per minute) fresh air per person (EPA.gov).
Fresh air brought into the house should be filtered and conditioned (humidity removed or added and temperature adjusted) so that it’s not overloading the HVAC system and can be distributed to the home using only the air handler fan without need for the heater or compressor to run.
To be effective, fresh air can be continuous or run on a timed schedule every hour; it shouldn’t rely on a manual switch!
Although there are situations that advocate for having separate ventilation and temperature control systems, in reality this creates redundant duct work. An alternative is mixing conditioned outside air with the return air in the HVAC system in a mixing box.
An HRV (in non-humid climates) or ERV (in humid climates) optimize the exchange of energy between the intake and exhaust air.
In humid climates, a whole-house dehumidifier helps the HVAC system to keep the home at the right humidity without having to over-cool.
Air quality monitoring for temperature, humidity and CO2 are the minimum variables but VOCs, CO and radon can also be added.
Garage: Garages have become an extension of our homes because of their convenience for home access, ability to protect another very important investment (our cars), and for storage and hobby space. However, not many people realize how garages impact the health of our homes. You may know not to allow your car to idle while in the garage, but recent studies show that engines continue to emit benzene even after turning off the ignition. Exposure to high levels of benzene over time can cause cancers like leukemia, and decrease red and white blood cell production. “On average, benzene levels in houses with attached garages are three times higher than of other houses,” according to Deborah Schoen, the head of Health Canada’s indoor air section. Therefore, we recommend that:
homes with attached garages be sealed off from the garage with spray foam in the adjoining wall and ceiling
Use ⅝” type X (fire-rated) gypsum board on the garage side of the walls and ceiling (if there is a room above), and use fire-rated caulk, adhesive, or expanding foam to seal up penetrations
The door between the garage and house needs to be air-tight to avoid allowing hazardous gasses to leak into the home. Install an insulated, metal, fire-rated door with a self-closing feature, so it won’t be left open accidentally. A good weather seal is also imperative. (HGTV.com)
Consider making the garage a negative pressure zone with an exhaust fan.
Always seal up paint cans, chemicals and fertilizer well
Consider a detached garage or 3-sided carport
Wall and roof construction materials: In the US, homes have been built with wood framing since our colonial days because it was cheap and plentiful. Since then, we have been criticized for building with wood because of its weaknesses: fragility in storms and wildfires, its non-insulating properties, and susceptibility to rot and insects and mold. Now, with lumber shortages due to the COVID-19 pandemic, wood prices are high and other products are getting due attention. There are many traditional products that have mold-resistant chemicals added, but in general these chemicals may be as dangerous to those who are chemically-sensitive.
According to Joe Lstibureck, an expert in home construction and insulation, the best place to locate the water, air, vapor, and thermal barriers is on the outside of the structure. A “clever wall” combines all four of these layers in one layer. Here is one way to do it:
If you need some points on building the perfect wall, roof and slab, check out this video and article! Although it was written/filmed in 2010, it still holds true. Building a healthy home requires that these layers are installed in the right order and connected to their counterpart on the wall, roof and slab.
The following are some newer materials and methods for better insulation, weather and pest resistance than traditional wood framing. Notice that any weather-tight cladding can be installed over them, although SCIP homes are typically finished in the concrete integral to the exterior of the panel.
SCIP (structural concrete insulated panels) is a building system that resists earthquake, tornado and fire damage better than traditional wood framing. It was innovated over 45 years in Austria by the EVG Company. The walls are made with a structurally welded steel frame, which holds a layer of foam insulation. The wall is then sprayed with 1.5” of concrete on both sides. This “monolithic” construction is very energy efficient and long-lasting. New homes are constructed with custom-made panels, which reduce labor costs as well. Here is a page showing SCIP construction. RSG-3D panels are a form of SCIP construction.
ICF blocks (insulated concrete form) have the insulation on both sides, and concrete is poured in the middle. With 2 layers of insulation, it can be between 4.8-12.7% more energy efficient than traditionally built homes, according to one study. ICF blocks are made by different manufacturers, Nurdura being a notable one. Nurdura offers several types of ICF which are manufactured to accommodate interior and exterior finishes, radiant heating/cooling, and a variety of wall designs. The outer polystyrene acts as a vapor barrier, while the inner concrete acts as an air barrier.
SIP (structural insulated panels) are also pre-made panels, which have a sandwich of metal, OSB, magnesium-oxide, or plywood, with polystyrene in the middle. They are made to support floor and roof loads. The SIPs are held in place with steel channels at the floor, sides and top, with screws that are common to metal construction.
Steel framing with cold-formed steel (CFS) is now cost-competitive since wood prices are higher. Exterior insulation such as foam board can address the problem of thermal bridging, which is the conduction of heat through the steel frame. This exterior insulation can provide all 4 barriers in one layer.
Flooring options: Flooring can be a major source of VOCs and allergens, thus it’s important to make a healthy choice here. Hard flooring is preferable to carpet because carpet can harbor many allergens, but a HEPA vacuum can go a long way to keeping carpet clean. Here are some materials in order of least VOCs, least allergenic and easy to clean, to more problematic. It is also important to check the underlayment and glues recommended to install your choice of flooring. (source: mychemicalfreehouse.net)
Natural hardwood flooring with zero-VOC finish like tung oil
Tile: marble tile, slate and concrete tile are all very safe options. Ceramic and porcelain tiles should be tested for lead if the manufacturer does not give any warranties about it.
Engineered wood with plywood base and zero-VOC finish
Natural carpets: the best are made of wool or seagrass
Synthetic carpets: PET polyester is very low in odor and off-gassing.
Laminate flooring is generally low-VOC now, but look for GreenGuard Gold certification.
Cork flooring does contain binders but some are certified GreenGuard Gold.
Bamboo flooring can warp, crack or split and contains quite a lot of resins or glues to hold it together.
Vinyl planks and luxury vinyl planks are low-VOC, but do have “plasticizers” that have replaced phthalates.
LOCATION: When moving into a new area, just like finding out how long it will take to get to and from work, it’s important to take time to study about geography, topography, windflows and potential pollution areas to know how they will affect your home. For instance, although California on the whole is a highly desirable state to live in, some pockets of California have terrible air quality because of geography. For example in the San Joaquin valley, smoke from surrounding wildfires can get trapped for extended times, agricultural burning was practiced, and increasingly hot days cause ozone problems (pbs.org). This area feeds many with its rich farms and soil, but the migrant workers who harvest crops are most subject to the dangerous air quality. Likewise, homes in the prevailing wind path of airports experience levels of ultra-fine particles (UFPs) that are several times higher than homes outside these areas. Here are some other critical locations and situations to be aware of:
a busy thoroughfare or bus station
oil wells or refineries
Chicken or cow farm
Stagnant farm pond or standing water (like used tire recycling center)
neighbors who burn trash or wood consistently
farms that crop dust or use aerosolized fertilizers
Areas that employ insecticide spray trucks
Golf courses and other public areas that use copious lawn treatments
Businesses that perform outdoor renovation work like sanding or spray painting
Seasonal issues like wildfires, tree pollen, ragweed, etc.
Neighbors who cook odorous foods, smoke, barbeque meat, have bonfires, etc.
General air flow/floor plan: Traditional home design features defined rooms for living, dining and kitchen space. In contrast, open floor plans have become quite popular in recent decades. Open floor plans can create better cross-ventilation and air circulation, but we understand that life after the COVID-19 pandemic may require more walls, doors and private space in order to accommodate the many functions of working, learning and staying at home. (prnewswire.com) Make sure that whether it’s time to throw open the windows or keep them shut, your floor plan works with natural or mechanical ventilation, instead of against it. Here are some aspects to consider:
The number of house stories depend on style and space available to build. With multiple stories, ventilation becomes more complicated. The “stack effect” of hot rising air is more pronounced with taller home height, and if air circulation from the bottom to top is unimpeded, this channel can provide significant cooling through ventilation. The architect of an antebellum residence Longwood in Natchez, Mississippi, planned on this effect during design of the octagonal house that contains a basement and 7 stories above ground. A center gallery was incorporated into each floor with doors to rooms and verandas on opposites side of the building, so that air flow was unimpeded through the outside doors and windows to the center galleries and up through the cupola of the home. A modern home could incorporate a central courtyard for the same effects: natural light, cross ventilation, separation of spaces, and the psychological and physical benefits of plants and the outdoors. (fraherandfindlay.com)
Layout of the home should not only consider views to the outside, but prevailing winds and penetrations such as doors and windows.
Types of windows are very important to ventilation. Casement windows are one of the top choices, as they can be opened fully for maximum ventilation. Next, awning windows hinge at the top and provide the option of opening windows even when it’s raining. If you live in a pollution-prone area, you may opt for double-hung windows, which can be opened vertically to allow the use of pollution-controlling window screens at the bottom. Plus, you can allow cool air to enter through the bottom and warm air to exit through the top. If your ceilings are tall, this effect is even more pronounced.
Ceiling height: if you have a large open space with high ceilings, it is either prime for a big fan to circulate cool air (see our post “What’s the deal with those big ceiling fans?” or skylights or high windows to exhaust hot air.
Location of the kitchen: The kitchen is still a source of heat and odors, so the placement of the kitchen and its exhaust vent hoods can assist in house ventilation. Balanced exhaust hoods are a new design that pull air from the outside as well as exhausting heat and vapors, so that a strong negative pressure is not created in the home.
Hallways: Going back to past centuries, hallways were important to provide a private buffer for bedrooms, access to common washrooms, and ventilation. The “dogtrot house” had a central hallway that separated rooms on either side, providing a breezeway and common area in the center. Narrow hallways might be considered a waste of space, but with enough room, they can contain useful features like a sink to wash hands, concealed laundry, creative space, art display, etc. (matthewjamestaylor.com)
The use of partial walls and glass can “define” space without limiting ventilation. Where walls and doors are needed, such as bedrooms, consider the old-style use of transoms over doors, or in-door ventilation grilles.
Room use increases air circulation, because body movement and heat naturally causes the air within the room to move too. Traditional homes may include a dining room that rarely gets used when the family eats in the kitchen, but by making such a room multi-purpose, the family gains access to more livable space. For example, you can create a bookshelf wall on one end with comfortable chairs, a large table that can serve as dining, craft or homework space, and mobile carts that can wheel away supplies or serve food when needed.
Furnishings: overcrowding a room with large furniture or using a room for dedicated storage creates air flow problems that can lead to mildew and poor air quality. If possible, maintain spaces between furniture, and never cover an air vent with furniture (you can purchase “vent extenders” though).
Well, those are some of our best suggestions for living comfortably and health-fully…only the sky (and budget) are your limits!