Healthy Home Building Guidelines
The Asthma-Housing Connection: Buildings emit almost as much air pollution as light duty vehicles and more than electricity generation. Air pollution can cause asthma and is a public health challenge in Boston where 1 in 6 children in K-8th grade have an asthma diagnosis. By reducing air pollution from buildings, Boston can address one of its most pressing public health problems.
Asthma is a respiratory disease that can be provoked by â€œtriggersâ€ in the indoor environment. These triggers can be reduced by good construction and maintenance practices. Common triggers include gas cooking stoves, mold, dust mites, and pests. The Boston Urban Asthma Coalition (BUAC) has prepared the following best practices recommendations for Developers and Contractors who would like to build â€œHealthyâ€ housing. BUAC has identified these practices through literature review and input from members as well as from health and industry experts. Following these recommendations cannot guarantee a healthy indoor environment; however, BUAC believes that they will help to minimize potential health-related problems for people with asthma.
Health and Safety Benefits of Efficient, All Electric Buildings: All-electric buildings are healthier, safer and they reduce harmful greenhouse gases. Buildings whose energy comes from fossil fuels not only release harmful greenhouse gas emissions, they are a significant contributor to indoor and outdoor air pollution. A growing body of evidence indicates that all-electric buildings have better air quality than those built with fossil fuels. All-electric, net-zero-carbon buildings are also safer than those whose energy is supplied by methane gas because they reduce the risk of carbon monoxide poisoning and the risk of explosions. Highly efficient buildings reduce utilities bills and are more resilient in extreme weather and can allow people to shelter in place for longer periods of time.
Climate change is affecting our health in many ways: from more heat-related emergency room visits, vector-borne illnesses, like Lyme disease, to an increase in respiratory illnesses. Building all-electric buildings will help us reach the climate mitigation goals outlined in the Massachusetts Global Warming Solutions Act.
To build healthy housing, steps must be taken beyond what is required in the current building code. The following steps are strongly recommended:
Energy Efficiency & Electrification Recommendations
- Install Energy Star qualified windows. Energy efficient windows have lower condensation potential than less energy efficient windows.
- Where possible at exterior walls, include continuous insulation. Insulation prevents moisture and air from infiltrating the building envelope
- Roof insulation:>R-50 plus with continuous insulation to eliminate thermal bridging
- Wall insulation:> R-36 with continuous insulation to eliminate thermal bridging
- Build all-electric; avoid using natural gas, oil, or propane. If you cannot build an all-electric building, make the building electric-ready. Electric-powered appliances and heating/cooling provide cleaner air quality, are safer, and allow for moving away from reliance on fossil fuels.
- Consider updating an electric panel that will provide enough electricity for an all-electric building. It may be more cost effective to upgrade your electric panel now as electric demands are expected to increase.
- Where reasonable, make building solar-ready with structure and electrical capacity for future solar. If situation is appropriate for solar, roof improvements and electrical capacity improvements can be made with future solar in mind, avoiding more expensive future upgrades.
- Consider installing an all-electric high efficiency heating/cooling system that does not use forced air distribution (cold-climate air-source heat pump, ground source heat pump, or VRF). High-efficiency cooling should be added because the number of dangerously hot days in Boston is expected to rise and extreme indoor heat increases the risk of heat-related emergency room visits and deaths.
- If installing gas, install high efficiency heating equipment with â‰¥95% AFUE (Annual Fuel Utilization Efficiency). Increased efficiency reduces carbon emissions.
- Install Energy Star rated appliances. Energy Star appliances are more energy-efficient.
- Install an electric oven/range and/or cooktop instead of gas. Cooking with gas stoves contributes to household air pollution. Children living in homes with gas cooking stoves have a 42% higher risk of current asthma. A longitudinal study in Massachusetts showed that children with asthma had more severe and frequent asthma symptoms if they lived in homes with gas cooking stoves.
- New lighting is LED. LED lighting consumes less power, produces less heat, and lasts significantly longer than other lighting.
- Include installation of vehicle charging capacity, including bi-directional charging when appropriate, or be vehicle-charging-ready. Electric cars produce lower carbon emissions. Preparing for vehicle charging now can avoid more expensive upgrades in the future. Bi-directional charging involves a battery that can also be available as back-up power to the property or the grid at specific times. The technology is still evolving, but currently there are utility and car manufacturer subsidies available.
- Do not install carpet, except where required for safety or sound-absorbing purposes. Instead, use a smooth, easy to clean surface. Carpets can trap dust and moisture and become a breeding ground for mold and dust mites.
- Maximize wipeable surfaces. Use semi-gloss paint that can withstand cleaning. Install wipeable window shades. Smooth cleanable surfaces are easier to clean and will reduce the amount of dust in the home.
Control Moisture to Prevent Mold Growth
- Insulate all hot water piping. This will reduce condensation.
- Avoid plumbing in exterior walls. It is easier to detect and repair leaks in interior walls.
- Provide adequate storage space. Storage in damp basements can lead to mold growth. If storage space is only available in the basement, provide shelving to keep items off the floor.
- Ensure all exterior claddings and trim are backprimed. Backpriming helps prevent wood clapboard from absorbing moisture and makes sheathing wrap or building paper more effective.
- Install properly lapped sheathing wrap or building paper between the cladding and wall sheathing. Sheathing wrap or building paper provides resistance to water that gets behind cladding and it must be properly lapped to direct water away from the building.
- Provide adequate drainage for the basement and provide positive drainage away from the building. Effective groundwater management is one of the most important factors in controlling moisture and humidity in the building.
- Install gutters/downspouts to move water away from the home.
- For below grade living spaces, follow best practices for waterproofing and site drainage to minimize water infiltration. For healthy indoor environments it is critical that residents not be subject to the hazards of damp basements.
- Install a capillary break on top of footing, between footing and perimeter foundation wall. This helps minimize movement of moisture from the ground to building assemblies.
Ventilate Home to Keep It Free of Combustion Products and Toxins
- Install and use low sone bath and kitchen fans (less than 2 sones) directly vented to the outdoors. Install timers or humidity control sensors on bathroom fans. In addition, provide exhaust venting to the outdoors for other moisture-generating appliances including dryers. Point source exhaust is needed to remove moisture and harmful fumes from known sources such as cooking, washing, and combustion appliances.
- Use interior points, varnishes, caulks, and adhesives with low volatile organic compounds (VOCâ€™s) and complete painting before occupants move in. VOCs are harmful to health and should be minimized.
- Keep bushes and trees at least 3 feet from the home. Bushes and trees near a home provide food, a living place, and sheltered passage for pests such as mice, ants, and roaches.
- Install a walk off system at principal entrances by allowing space for a mat or shared lobby with space for a doormat. 2/3 of indoor dust is tracked in from the outside.
- Use sustainable resources where possible.