Envelope-Driven vs. Occupant-Driven Loads

Challenge

Some energy consumption in a home is heavily influenced by the way homes are designed and constructed – or by the “building envelope” of the home – while other energy use is dictated by occupant use and habits. While some costs can be controlled by the building design, homeowners must also be educated on how to efficiently use their homes. For example, a tight, well-insulated home will require less energy to heat and cool than a comparable house with more air leakage and less insulation; the envelope drives energy needed to heat and cool. By contrast, plug loads, or energy use from items plugged into outlets (televisions, computers, hair dryers, etc.) is driven by the occupant.

Opportunity & Response

Rural Studio clearly differentiates what we can control through design and construction and what we can control through homeowner education and awareness. Energy modeling during the home design process can help housing providers and their clients understand the expected energy use – and, therefore, predicted costs – for envelope-driven systems such as heating, cooling, and ventilation. Post-occupancy monitoring ensures that these systems are operating as modeled. Additionally, post-occupancy monitoring allows Rural Studio to continue to actively engage with the housing provider and homeowner, and to provide the ongoing education necessary to help occupants understand how to use their homes more efficiently and reduce energy use and maintenance costs.

Response

Front Porch Initiative continues to collect ongoing energy use data on two houses constructed to beyond-code standards with Auburn-Opelika Habitat for Humanity (AOHFH). As energy to condition and ventilate the house decreases with more efficient systems, the share of energy devoted to plug loads becomes a larger share of overall energy use.

Implementation

Stevens Street

Renewable Energy

Challenge

Incentives for on-site power generation vary from location to location, often dictated by the local energy provider.

Opportunity & Response

Advocating for policies that incentivize on-site energy generation can greatly decrease the cost for installing energy generation systems. For example, excess energy generated by photovoltaic (PV) panels, also known as solar panels, can either be sent back to the energy grid, or stored in batteries. Energy providers that offer bi-directional meters, which allows excess power to flow to the grid, greatly reduce system costs to the homeowner.

Implementation

Stevens Street

Embodied Decarbonization

Challenge

Increasingly, decarbonization is understood to be the path toward a sustainable future. We know 40% of greenhouse gas emissions are controlled by “operational carbon” or rather by things we do in our households through our active human comfort systems and appliances. However, “embodied carbon” emissions can account for up to 75% of a building’s total emissions over its whole lifespan. Consider all the materials utilized in a home’s construction, from concrete foundations to wood framing, to roof shingles. Embodied carbon is the sum of all the greenhouse gas emissions resulting from the mining, logging, harvesting, and processing of these materials. Plus, the transportation to the job site and the method of construction used. Embodied carbon is all the carbon that is emitted before the building is even occupied. Today, the embodied carbon emissions in constructing a new home are equal to approximately 20 years of operating emissions. And as homes increasingly get more energy efficient, the AIA estimates that 80% of emissions will come from embodied emissions, so lowering embodied carbon emissions is potentially more urgent now than lowering operating emissions.

Opportunity & Response

There are several complimentary approaches to reducing embodied carbon in new home construction. These include:

1) Utilization of low-carbon materials – Architects already use energy modeling software to estimate the energy use (and subsequent carbon emissions) of building operations. But the industry has lacked a standardized system to track the carbon embedded in construction materials. Recently however, the development of open-source tools such as the Athena Impact Estimator, and the Embodied Carbon in Construction Calculator (EC3), are beginning to make it easier. While these tools are currently optimized for commercial building analysis, another approach in residential construction is to utilize “red lists” developed by organizations like HBN. While red lists are focused primarily on health impacts of material specification, research shows that red list materials map closely to high-carbon materials as well.

2) Reducing total materials in the design of the home – simplify systems, reduce redundancy, and insure means and methods during construction to ensure building performance is optimized

3) Design for longevity – consider issues of both durability and resilience in developing building assemblies

4) Repurpose resources – utilize reclaimed and recycled materials, and leverage all “sunk investments” in site development.

Implementation

Protection of Occupant

Challenge

For homeowners unable to seek shelter during natural disasters, special accommodation may need to be integrated into the home to allow the resident to shelter in place. For example, a person with limited mobility in a rural area may have more trouble accessing a community tornado shelter.

Opportunity & Response

Federal entities such as FEMA offer guidance for constructing in-home shelters. Though these shelters can add cost and complication to construction, they may be particularly important for certain homeowners. There are also multiple assistance programs that provide loans and grants to assist in purchasing or building shelters in high-risk areas.

Implementation

Protection of Asset

Challenge

Even in areas not directly hit by storms or other natural disasters, home damage can occur, displacing residents from homes. For example, high winds from a tornado may not destroy a home but may damage roofing and cause water infiltration into the home.

Opportunity & Response

The insurance industry provides incentives for mitigation from storm events. For example, certification from the FORTIFIED Home program by the Insurance Institute for Business and Home Safety (IBHS) can lower insurance premiums. These reductions in monthly premiums can decrease or offset the increased cost of construction.

Implementation

Jean Lafitte

Chipola Street

Preserving Neighborhoods Post-Disaster

Challenge

Following natural disasters such as hurricanes or tornadoes, the character of neighborhoods can change as developers come in and buy up properties. This can be particularly treacherous in minority and low-income neighborhoods, as residents are displaced from their communities, jobs, schools, and services.

Opportunity & Response

Building back more durable homes after a storm event will strengthen the resilience of the neighborhood and cut down on recovery time after future weather events.

Implementation

Jean Lafitte

Health and Cost Burden

Challenge

Contemporary research reveals that financial burdens related to housing affordability directly undermine the health outcomes of occupants. In order to reduce the cost burden of homeownership, many low-wealth homeowners choose to live in older, low-cost, substandard housing in order to make ends meet. Unfortunately, poor in-unit conditions of substandard housing also contribute directly to both acute and chronic health conditions like respiratory infections, asthma, toxic poisoning, and other mental and physical health conditions.

Opportunity & Response

As a collateral benefit of energy and durability performance strategies that better manage thermal variation, ventilation, air infiltration, and moisture control, energy efficient and resilient home construction is increasingly understood to provide a positive correlation in the improved overall health of occupants. By intentionally integrating a material health assessment directly into our actual building performance design process, Rural Studio seeks to better understand and improve the potential health impact of our design decisions that heretofore could only be assumed in the provisioning of energy efficient, resilient, and affordable envelope solutions.

Implementation

Madison County

Local/Regional vs. National Standards

Challenge

Some regions, states, and municipalities have begun to develop their own performance standards, which are able to address the specific conditions in their area. For example, Florida Green Building Coalition FGBC) has developed a series of certification that particularly address Florida’s climate and the natural disaster risks from hurricanes and blowing winds. However, these localized programs may not be recognized by financial institutions when considering a project for an efficient or green mortgage product.

Opportunity & Response

Front Porch Initiative is exploring a partnership with SBP to develop a better understanding of which energy efficiency & resilience standards work best together (considering both logistics and cost); develop recommendations on the optimal resilient/energy efficient building techniques in the Gulf Coast region; and to provide recommendations on changes to existing building standards to better achieve energy efficient, resilient homes at affordable price points

Implementation

Chipola

Integrating Multiple Standards

Challenge

Home performance encompasses more than energy efficiency. Some beyond-code certifications are beginning to address intersections between efficiency, resilience, and health but many focus only on one aspect of performance. Integration of more than one third-party standard into a house can be a challenge when the standards conflict. 

Opportunity & Response

Front Porch Initiative works with housing providers to determine which third-party standards are appropriate and beneficial for their project and helps them integrate said standards into their projects. Planning ahead is key to minimizing added costs and construction delays when integrating multiple standards. As the Front Porch team learns to work with a variety of different standards, that knowledge can be shared with other partners. 

Implementation

Chipola

Combining Grants, Loans, and Down Payment Assistance 

Challenge

For low-income borrowers, there is frequently a gap between the amount of financing an individual qualifies for and the cost to construct a home. These gaps can often be closed by combining or otherwise leveraging multiple sources of additional funding and/or subsidy. However, this type of “stacking” requires a significant amount of knowledge and savvy on the part of a housing provider, which is often lacking in underserved rural markets.

Opportunity & Response

Many lenders and nonprofit organizations offer assistance in the forms of programs such as downpayment assistance which help low-income borrowers purchase homes. There are also potential opportunities to leverage multiple funding sources from organizations. For example, USDA Housing Preservation Grant (HPG) funds are typically used for repairing homes of very-low income homeowners through small grants up to $15,000. However, these funds can also be used for replacement housing. When used for replacement housing, there may be a possibility to combine the HPG funds with other types of grants or subsidies, offering greater flexibility to housing providers. Additionally, it is important for providers to work across boundaries to best maximize and leverage all existing opportunities. Rural Studio is working with our partners to provide technical assistance and capacity building opportunities to our housing providers to do just that. For instance, by utilizing Fannie Mae’s sweat equity provisions in the Home Ready program to provide a necessary down payment, a lending partner can then shift their down payment assistance resources to cover other costs related to loan origination and closing.

Implementation

Chipola Street

Unaka