Passive House Rebuild Elements

Now that we have discussed why we are building passive homes in the Marshall Fire community, lets get into the details of what makes a home meet this standard, and how our company’s values have determined what methods we use to achieve it.

Climate, Solar Orientation, and Energy Use

Passive houses take into account site conditions such as orientation of the lot/home in relation to the sun, the local climate, and energy needs of the home. A passive house should use the least amount of external energy inputs as possible, by orienting windows to capture heat during the winter, yet providing sufficient shading in the summer to keep the home cool and comfortable.

Air Sealing and Insulation

Passive House design, with its superior insulation and airtightness, significantly reduces heating and cooling demands in residential buildings. This combination not only reduces energy bills but also enhances indoor comfort and air quality for occupants. Additionally, windows and doors must meet high quality standards, including the use of triple-paned glass, and be designed to have a tight seal when closed. Attention to detail and careful planning are required to meet thermal continuity and air tightness standards.

Passive house modeling for window and wall assembly insulation
Interior Air Quality and Continuous Ventilation

A Passive House will provide a healthier indoor environment when compared to code built new construction by minimizing the use of toxic chemicals and incorporating mechanical ventilation. Each of these homes has a full house ducted ERV ( Energy Recover Ventilator), with intake and/or exhaust vents in each room. The system runs continuously, bringing in fresh filtered air and removing indoor air which may contain VOCs, excess CO2, and other pollutants that are created indoors. The air passes through a central system which exchanges the heat and humidity to maintain the indoor air temperature.

Low Carbon + Passive House

Although the Passive House standard does not currently require it, we are choosing to build with low carbon and carbon sequestering materials as much as we can. In conjunction with implementing Passive House design principles, the choice of building materials plays a crucial role in reducing carbon emissions. Low carbon building materials refer to products that have a lower carbon footprint throughout their lifecycle, from production to disposal. These materials include recycled content, sustainably sourced timber, low-emission concrete, and innovative alternatives like hempcrete.

Building materials that actively sequester carbon dioxide from the atmosphere further enhance the sustainability of residential construction. For instance, products that not only have a lower embodied carbon footprint compared to traditional construction materials but also lock in carbon during their lifespan. Examples of carbon sequestering materials include straw bale construction, which employs straw as a natural insulating material, cellulose insulation, which is made using recycled newsprint, and denim, hemp or sheep’s wool batt insulation.

In our homes, we are building double stud walls to reduce thermal bridging, and filling this entire cavity with cellulose insulation from recycled newspaper. The attic and rafter framed roofs will also be insulated with cellulose. We do have some EPS foam below grade in the basement of one of the homes. This serves in part to reduce the amount of concrete being used by eliminating a concrete slab floor. The other factors going into the decision are cost, and a decision to use the foam to provide an extra barrier between the living space and the cool concrete basement walls, without having to worry about potential condensation and moisture wicking damaging bio-based insulation.

All Electric

In another effort to minimize our contribution to climate change, these homes will be all electric, using heat pumps for heating and cooling and hot water, as well as electric induction stovetops. Colorado is already promoting all electric housing because this will reduce the consumer use of natural gas. Another benefit to all electric home is that they will have the option to add renewable energy directly (rooftop solar), which can reduce energy bills to zero. Also, as we clean up the power grid more and eliminate petroleum based energy sources, these homes will have a reduced impact on air quality and climate change, even without needing a personal solar power array.

Let’s Build More Passive Homes

Residential construction in the United States is undergoing a significant transformation as Passive House design principles and low carbon building materials start gaining more attention. Follow along with our projects on our Instagram page as we build these homes!

About Passive House Design/Build

Residential construction is undergoing a transformative shift towards energy efficiency and carbon reduction. The Passive House design standard, coupled with low carbon building materials, is at the forefront of this revolution.

Living Craft is building two new homes in the Marshall fire burn area in Louisville, CO to the passive house standard. We have partnered with Shape Architecture, a passive house designer and promoter based in Denver, to design the homes.

History and Principles

Passive House originally began in Germany. It has now become an international standard for constructing energy-efficient buildings that prioritize occupant comfort while minimizing energy consumption. The principles include airtight construction, high-quality insulation, high-performance windows, and a mechanical ventilation system with heat recovery. These elements significantly reduce the need for heating and cooling, resulting in up to 90% less energy consumption compared to conventional buildings. Just like LEED or Living Futures certified buildings, a building must meet certain requirements to become Passive House Certified.

Passive House Model Designed by Shape Architecture for construction in Louisville CO
One of two Passive House Marshall Fire Rebuilds, designed by Shape Architecture

Why We Are Building Passive Houses

With so many energy efficient home standards to choose from, we chose passive house for a number of reasons.

Local Incentive Program for Passive House

Incentives in the form of rebates are being offered by our local energy company for homes in this fire area. The rebates will offset any extra cost involved in making the home live up to the passive house standard, and hopefully provide some cash back to the homeowner.

Operational Energy Use and Comfort

Another reason we wanted to build to this standard is because a passive house should provide energy savings over the long term. The reduced heating and cooling costs and needs make monthly energy bills low. It also will be comfortable, quiet, and healthy for the residents.

Resilient Buildings for Climate Change

Additionally, our clients are concerned about climate change. The Marshall Fire that destroyed their homes was worsened by extreme weather patterns brought about by climate change. Because of that, they are hoping to provide an example of how housing and building in general could be involved in mitigating climate change rather than exacerbating it. That means we have to take into account the reduced energy consumption of the house, and also make smart choices about our design and the materials we use.

Also, simple homes that are airtight are actually more resilient in the face of future fires. Because it is so air tight, a passive house is less likely to have smoke damage after fires nearby. There are also fewer points for embers to gather and ignite with simpler roof lines.

It Takes a Village

Of course, the clients need to be excited about and on board with this process. Shape has the expertise in creating the design to meet the energy standards and the clients needs. Living Craft has four Certified Passive House Tradespeople on our team. This will help to ensure proper on-site implementation of the design elements, which requires a lot of attention to detail. Rounding out the team are BldgTyp, the PH Design Consultant and CertiPHIers, a third party certifier who will review the home design and construction process at completion of the project to make sure we have met the goals of the design.

We are excited to be getting building with these two new Passive Homes in Louisville, CO. Stay tuned for more updates.

The Importance of Energy Auditing

An energy audit is sort of like a physical check up for your home. This is especially important in the case of an older home which may have been built before the updated building code called for a certain level of insulation and air tightness. An energy audit is a great way to find out exactly which interventions will have the most impact on lowering your home’s energy usage and reducing heating and cooling losses.

Do you know where your home is losing the most energy?

To make the process even easier, Xcel Energy even has a program available to their customers for home energy audits, including options for rebates to offset the cost of the audit.

An energy audit is often the first step we recommend for our remodel clients. That way, we can be sure to design the project with all the data available. This allows us to meet budgetary needs while making the best choices to craft a more efficient home.

In addition to finding areas that lack insulation or have air leakage, energy auditors can point out aging mechanical systems which may be having a greater than necessary impact on energy bills and carbon emissions. Going all electrical with the mechanical systems in a home is one great way to plan for the future, as our energy grid becomes less dependent on fossil fuels. The auditor will recommend specific practices for sealing leaks and insulating, or suggest which systems to upgrade. We can help you decide which of these options will give you the best and healthiest home.

An example of some of the types of infrared images that the energy auditor will include in their report, tailored to your home.

With the data from an energy audit, together with Living Craft, you can choose which areas of your home to focus on, whether it’s air sealing in the attic, adding cellulose insulation, or upgrading an aging water heater or boiler. Once we’ve set up your home to be more efficient, we can then design interior renovations that will make it more beautiful and healthy.

For example, one client came to us with a bathroom remodel project. Since her bathroom tub was leaky, it had caused damage to the ceiling below, and obviously needed some work. After an energy audit, we were able to find out that the attic also needed air sealing and the bathroom fan wasn’t venting outdoors, but instead bringing humid air out of the bathroom and in to the attic. Since these are not ideal, we were able to reroute the bath fan vent, air seal and add insulation into the attic, and also give her an updated bathroom with a fully water sealed shower. Without the energy audit, she may have only acheived some of these objectives. She not only got a rebate from Xcel, she also saves money every month on her heating and cooling bills, and stays more comfortable year-round in her home.

The finished bathroom, with a bonus whole house efficiency upgrade.

So, if you have an older home that you are planning on upgrading or remodeling, be sure to get that energy audit before you start budgeting for other upgrades, because it is the quickest and simplest way to start saving money on energy bills. Even if the inside of your home doesn’t need any work, an energy audit can let you know where the weak spots in your building envelope are, without being intrusive. And if you need help interpreting the results and deciding which interventions to make, let us know!

Case Study: Healthy Basement

We were approached by a family that was hoping to have their currently unfinished basement built out to include a bedroom, bathroom, storage, living area, and home office/meditation space. This extra space will accommodate a family with up-and-coming teenagers.

Design

Our clients already had a design for the new space and emptied the basement of most things, minus a piano which would be too difficult to move upstairs – so we built the basement around it! The bathroom design was tweaked a little by us and our plumber to make it easy to drain everything and provide required clearances and access for pipe clean-outs.

We also made some modifications to the office/meditation space, which ended up with a very cool and versatile corner of sliding barn doors.

Indoor Air Quality

Basements in older homes are notorious for being moldy, damp, and having stale air. Because we build healthy homes, breaking from the stereotype was necessary. This featured heavily in our materials selection and building method criteria.

This house has luckily not had any problems with bulk moisture in the basement (i.e. flooding). In order to create an air and vapor barrier inside the permeable concrete foundation walls, we used a polyiso foam board (a case of least-bad when it comes to foams). We foil taped all joints and caulked along the bottom. This barrier was completed using spray foam along the rim joist at the top of the wall to seal that area from air infiltration, both from outside and from the garage. Its very important to keep car fumes out of living spaces!

We also installed a small, two unit, balanced ERV, with one unit in the bedroom and the other in the living area, on the other side of the basement. These ceramic-core fans alternate drawing air in and pushing it out. The ceramic is a heat sink, designed to keep the air temperature inside the same and prevent energy loss.

A nearly silent, motion activated bathroom fan keeps excess moisture down. Clay plaster also plays a big role in managing humidity and keeping air quality high.

 

The existing wood-burning fireplace was replaced with a new gas insert. This is cleaner burning, and no more having to sweep dusty ashes.

Finally, we used a paperless drywall in all areas of the basement. This choice is mold resistant, since it’s actually the paper that provides the food for the mold spores. The only place that’s different is the shower, which we fully waterproofed using Schluter Kerdi products. Here, the longevity and mold resistance in the wet environment of a shower is valuable for a long lasting home. It will prevent unnecessary water damage and further remodeling work later on.

Insulation and Sound

Because of the possibility of moisture, we used mineral wool batts within the 2×4 framed walls to insulate the basement further. This insulation is rot-resistant, since it’s basically just rock, turned into fibers. Up in the ceiling, we used cellulose in mesh bags to insulate the top of the outside walls, between each joist, before the drywall went in.

Extra insulation batts went into the interior walls surrounding the bathroom and bedroom. This will allow the family to use the space in multiple ways without disturbing each other if someone is sleeping or showering.

Finishes

As part of a healthy indoor environment, all the surfaces are treated with VOC-free finishes. Custom clay plasters cover all the walls and ceilings except the bathroom. The bathroom has a lime plaster on the walls and ceilings, and a groutless tadelakt shower, which will never have issues with mildew in grout lines.

All trim is custom milled beetle kill pine. Doors are from used building supply stores, and are all solid alder wood. All of the wood in the home is treated with a VOC-free and plant based oil finish.

The floor is the original slab of the basement, polished and tinted and then sealed. This is easy to keep clean, and will also keep air quality higher than if we’d used carpet. Area rugs can be used in places of high traffic or where you might be walking barefoot.

A Healthy, Natural Basement

This family was great to work with and be around, as we worked in their home. We’re excited to see how the space lives up to their needs. We are glad that this basement offers them some extra living space, without having to worry about the problems of unhealthy indoor air quality.

basement before
Before

basement after
After

Check out finished photos of the job over at the projects page.

What is “Building Science”?

We use the term building science a lot. For those who may have never heard the term, or fully explored it, here is a quick debrief.

Building Science

Taking into account experiences of architects, engineers, and builders, building science explores the way that a building responds over time to environmental factors and natural phenomena. Or, a detailed study of a building with the goal of increasing its life span, health, and/or performance, and applying those lessons to new buildings.

Big Topics

Indoor Air Quality/Indoor Environmental Quality

This covers things like sound/acoustics, lighting, indoor air pollutants and how to control them. Ever heard of “sick building syndrome”? In those cases, actually being inside a building will negatively affect a person’s health, whether from stale or toxic air, lack of good ventilation, noise levels, or a number of other factors.

Mechanical Systems

Air conditioning, heating, and ventilation are some of the important mechanical systems. Without proper systems, filtration, and flow, a building will not function well and keep its inhabitants comfortable. We prefer balanced ventilation, like an energy recovery ventilation system that is continuously alternating between bringing fresh air in and venting stale air out, while maintaining the temperature indoors to prevent energy loss.

ENCLOSURES and Air/Moisture Barriers

An enclosure is simply the surfaces of a building that separate indoors and outdoors. Walls, ceilings, windows, and soffits. Not surprisingly, better methods for keeping moisture out of building materials will prolong their life and reduce problems like mold and rot. So, things like air and vapor barriers are very important. They also increase the energy efficiency of buildings, and reduce operating costs from heating and cooling. However, its all connected. Since a home with a “tight envelope” or a continuous air or moisture barrier doesn’t allow air to flow through cracks, it will also need to be closely monitored and have a good, balanced ventilation system in place to circulate fresh air and reduce indoor air pollutants.

Building Sustainability

With the increasing awareness of the pressures that humans are placing on the global environment, we recognize the role that the construction industry needs to take on in reducing our impact. Big changes can be made with a choice of materials that have a low carbon footprint, or by building using carbon rich materials like wood, hemp, and straw that sequester the carbon out of the atmosphere. Things like passive solar design and an integrated landscape and water management plan also help to greatly reduce a building’s need for external energy inputs.

Modern Building Science, Traditional Materials

Hopefully it’s all coming together for you. At Living Craft, we are always trying to educate ourselves on the latest innovations in building science. We are doing the work of researching and picking out the best solutions which honor the traditions of building and respect the environment on all levels. If you have questions, we would love to hear them!

8 Steps to Improve Indoor Air Quality

Arboretum indoor air quality

The EPA considers indoor air quality (IAQ) to be one of the top threats to public health. Today, most people living in industrialized societies will spend up to 90% of their time indoors. Improving indoor air quality is one of the most important things we can do to increase our health and wellness in the built environment. As contractors and designers, there are many things we can do to help with this issue when designing and building new structures or remodeling existing structures.  As a homeowner, there are several things for you to consider as well. Many solutions are available to you right now to improve your health at home and at the office.

When we talk about indoor air quality concerns, we are mainly talking about three main culprits: bioeffluents, volatile organic compounds (VOC’s) and airborne chemicals, and airborne microbes. Bioeffluents are organic contaminants that emanate from the bodies of humans or animals. Our own exhaust is harmful to us and needs to be managed. VOC’s are organic compounds that essentially evaporate at room temperature (off-gas or outgas). These can be natural or synthetic, and many are very harmful to humans – either acutely, or more commonly over a long period of time – which makes research into their effects difficult to examine. VOC’s usually emanate from synthetic building materials inside our homes like glues, paints, and finishes. Airborne microbes include viruses, mold spores, dust, and allergens. These may exist in the outside air or may be a symptom of the humidity levels inside of your home.

Let’s take a look at simple steps we can take to improve our air quality with basic principles and solutions:

1. Limit Exposure.

doormat air qualityHave doormats at all entrances. We track in chemicals, dust, and dirt into our homes every day. The less we bring in, the less we have to worry about. Request people to take off their shoes when they enter your home. If necessary, consider having slippers available for guests. This also applies to dirty clothing. This is especially important for us in the construction industry. If you have been exposed to lots of dirt, grime or dust throughout your day, try not to spread that throughout your home.

2. Vacuum with a HEPA air filter.

Carpet, upholstery, drapes, etc. hold onto dust and chemicals. By vacuuming regularly with a HEPA filter, we can help to safely remove a lot of these irritants from the home. If you are ever remodeling, consider getting rid of wall to wall carpet and just throwing down runners in high traffic areas.

lemon, lemon tree, nature3. Stop using conventional cleaners and air fresheners.

Avoid ingredients listed as just “fragrance”. These are synthetic, proprietary and can contain lots of different types of chemicals including Volatile Organic Compounds and Phthalates. Look for cleaners that don’t have artificial fragrances. Avoid aerosol sprays. Try more natural solutions like citrus for a fresh aroma.

4. Test for Radon.

Radon is known to cause lung cancer and can be found in nearly any type of soil, in any part of the country, in any type of home. Testing is relatively inexpensive and quick. The EPA has a “Consumer’s Guide to Radon Reduction” to help you with this.

5. Use healthy materials. lintel, window, garlic, natural

When you have work done on your house, know what the materials are, and what is contained within them. Many paints, finishes, carpets, engineered and synthetic products contain VOC’s. These can off-gas for hours, days, or years. Know your exposure so you can make educated decisions on how to manage it. There are many no-VOC options out there. No-VOC doesn’t always mean it’s healthy for you, but it’s a good place to start. Consider a contractor who is well-versed in this type of construction and is able and willing to answer your questions on these topics. If you are concerned that you may have toxic materials already in your house that are causing you harm, like lead, have them tested by a professional.

6. Get a humidifier. train station, humidifier

Healthy humidity levels range from 35-65%. In the winter months, the relative humidity is very low, and with active heating systems it is reduced even further. Dry conditions irritate sensitive membranes in the nose and increase susceptibility of airborne microbes, leading to frequent colds, allergic attacks, and asthma. They make both stand alone humidifiers all the way up to whole house humidifiers that may be integrated into your existing HVAC system.

7. Ventilate. modern, art, ventilator

This is a big one, so I’m going to break it down a little.

a. Change your filters often. Even if your HVAC system brings in new air from the outside, it doesn’t mean that the outside air is clean. Consider getting HEPA filters for your HVAC system.

b. Have your ducts cleaned by a professional service. Dust and debris can collect inside your ductwork, causing bad air quality every time it runs.

c. Use Exhaust Fans.ventilation air quality There are so many sources of moisture inside of your building: cooking, bathing, breathing, etc. The most significant being your stovetop and your shower. Humidity in excess of 70% can cause mold and mildew growth within your house, especially within your wall cavity in conventional construction. Many times, you don’t even realize it is there. Trust your nose. Does it smell musty? Recognize symptoms that persist when only at home but not outside like congestion and irritated eyes. Cooking also produces potentially hazardous levels of gasses like nitrogen dioxide and carbon monoxide. Make sure you have a vent hood above your stove that exhausts to the outside of your building, not the kind that re-circulates back into your home or attic. When you shower, run your bath fan and leave it running for 5-10 minutes after you finish. Again, make sure the bath fan exhausts outside of your building and not to your attic. The main problem with exhaust fans is that people don’t use them, mainly because they are too loud. Consider investing in a new one that has a lower decibel level that you can run while carrying on a normal conversation.

d. Upgrade to an ERV (Energy Recovery Ventilator). If you are looking to upgrade your HVAC system, consider looking into continuously running ERV systems. These never turn off, giving you a constant supply of new air, as well as regulating temperature and humidity with up to 90% efficiency.

8. Get Indoor Plants. Green Leaf

NASA has conducted several scientific studies showing the ability of plants to increase humidity, remove bioeffluents and VOC’s, and suppress airborne microbes. The first list was created by ‘The Clean Air Study’ back in 1989. Start with one plant from the list and place it close to where people most often occupy the space, like on a desk, next to the couch, or on the bedside table. You will get the most benefit if the plant is within your personal breathing zone. If you want to go all in, or want something to work up to, the most effective and efficient air cleaning ability will be achieved by growing one plant per 100 square feet of living space. This research doesn’t even take into account the numerous other studies showing the psychological benefits of growing plants, as well as the aesthetic beauty they add to your home.

Most of these solutions are within the budget and experience level of the typical homeowner. When in doubt, consult a professional. Most people feel that they can only control their diet and exercise. Well, now you have some power over your environment too, so use it. Take charge of your space and make it healthier for you and those around you, one small step at a time.

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