Sustainability Spotlight. Text and interview provided by RenewableFarah:
You, the homeowner, can make decisions that will have HUGE impacts on your home's operation over its lifecycle. These changes can translate into energy and cost savings. Today, we dive deeply into passive design, discussing integrating environmental sustainability with architectural design.
If you want to hear the conversation, check out the supplemental podcast episode recording that accompanies today's read. Otherwise, happy reading!
Farah Ahmad is a licensed architect, LEED-accredited professional in building design and construction, and nationally published journalist specializing in sustainable design and green building standards. Views expressed are her own.
Jack Baldwin is one of the managing partners and founders of the custom home design company Reynard Architectural Designs. Jack also hosts the By Design podcast which tells stories about architecture, design and inspired living.
Jack: We have clients who talk to us about sustainability and how they can get the most out of their homes. They want to know about net zero concepts, saving costs, and construction projects that would result in a home that will last for a long time. They don't want something that will cost them more than to maintain it, so that's what we're going to talk about today.
Farah: I really hope that readers can take this conversation and sort of start to think like an architect. So, today let's focus on passive design because it's a way for you to start thinking more sustainably about your project from the onset. So, we are going to talk through what passive design is- how can you start thinking through the lens of a passive designer to save energy and costs and have this truly beautiful and durable home?
Jack: I love what you said about thinking like an architect because one of our mottoes at our firm is "design with," not "design for." And, it's funny how many clients we talk to that say "I should have been an architect." I love that we're going to go into this with that mindset. We really want people to have that collaborative mindset. That is, "how can we empower our clients and help them think about design?" In that way, they can partner well with whomever they're working with- when designing their own home, they think like an architect. Farah, can you tell us more about the passive design concept?
Farah: So, passive design is a way to work with your local climate to maintain a comfortable temperature in your home. So you're not adding a substantial amount of heating or cooling, and you're not relying on an active mechanical system. Instead, that activity transfers over to the building resident. Instead of a dynamic mechanical system, you depend on an active homeowner to properly manage the systems and loads. And that's what I call a responsible homeowner.
Jack: I have one of our projects designed by James Knight, our lead designer here at Reynard Architectural Designs. This one's on our website homepage. It's called Holly Creek, and people always tell us they would love to design a house just like it. So I'm pretty excited about this because you're going to talk to me about this project in particular and how somebody could get the most energy-efficient solutions possible.
We can understand that if your building is running in the east-west direction (so that the longest dimension is facing south, as shown here), then more of your building will absorb that solar energy.
Jack: This image is the rear of the home. You can see some big, retractable patio doors, a little step down to an outdoor patio, and a lovely, gradual slope to the rear of the home. At this point, we're south-facing; we have a lot of glass and a lot of windows. Looking at the rear of Holly Creek, what are some thoughts you want to get into?
Farah: Passive design can invite nature into the home, and this image is the poster child of that.
Let's talk through some exterior elements you can kick off with to have a passive home.
A Micro-climate Study: Site Assessment
Before you even start building and drafting anything, you have to do some site survey and figure out how you will orient your home to take advantage of the sun and any prevailing winds on that site. So, you're doing a micro-climate study to understand where the sun moves around, where your wind direction is coming from, and then taking that and harnessing it. So, we know that the sun goes from east to west. Therefore, we can understand that if your building is running in the east-west direction (so that the longest dimension is facing south, as shown here), then more of your building will absorb that solar energy.
If you have a rectangular building facing south, think of the sun starting from the east and going out to the west and how that sun will percolate through your spaces. A passive solar building with the long side facing south is how you're going to get a lot of your good heating, especially in a climate that is heating dominated. Because you want to basically maximize your solar gain during the winter and keep your home cool during the summer.
Jack: So what if this home had solar panels on it? Where would you orient? Would you be thoughtful about where you would place those solar panels? Does it matter?
Farah: You always want to have your solar panels facing south as much as possible. And you want to achieve the optimal tilt angle of your panels. In New York City, that tilt angle is between 5 to 10 degrees, always facing true south when possible.
Jack: It's very easy to overlook orientation. When we talk to people, we're often just thinking about how to use the space the best way we can. In North Georgia, which is best known for mountains, it's rare to have a lot that's undeveloped and which doesn't have a lot of slopes and rocky terrain. It can be challenging. So sometimes it's thinking through the necessity of where you can place the home. What you're saying, though, is orientation is a huge part of the starting point- having this home enabled to take advantage of its natural site to passively heat and cool the space.
Farah: Yes, that's right. I also want to bring attention to the overhang over these southern-facing windows. You don't want to overheat your space. In Summer, when the sun is higher,
that overhang blocks excessive heat. But in the winter, your sun is low, so you're still getting a lot of solar gain into your home because it's not being blocked. Having an overhang like this on your southern orientation is actually super practical. And, as this southern elevation shows a ton of glazing, that will be awesome for solar heat gain during winter. This is actually a really well-designed southern facade that we're seeing here.
Neighborhood Restrictions in Development
Jack: A lot of times, it's just so easy to overlook that! It's easy to say, "Well, this will work because the contractor told me he has to move less dirt if we build right here!"
Farah: True. And that's the problem with following the norms and traditions. With many of these cookie-cutter homes and American neighborhood developments, you're just observing how the other homes on the street are oriented without regard to the site design itself. Houses are sited the way they are because all of the homes on that street are facing the road, perhaps to maximize views- but that sun movement isn't necessarily the priority or even a consideration. This might be due to an ordinance imposed by the local township that you have to face a specific direction, but that's something you have to figure out as a client. Can you play around with where you enter your home and how you orient it on your site?
Jack: The only factor that sometimes affects orientation is if you're part of a neighborhood with a building covenant or HOA requirements where those requirements have a lot to do with aesthetics and curb appeal. The community is a significant factor in the marketability of a home. So we've run into instances where there may be an ordinance about what the facade looks like. But you can always work around the facade and the presentation, the curb appeal, and still orient your home in a way that will take advantage of what's going to maximize heating in the cooler months and cooling in the warmer months.
Farah: Yes, and if you find yourself restricted to the orientation on a project site, then something that you can be flexible with is how you program your spaces, siting your particular spaces to take advantage of the light. And we'll get more into that as we go through these images.
With many of these cookie-cutter homes and American neighborhood developments, you're just observing how the other homes on the street are oriented without regard to the site design itself.
Windows: Balancing Day-lighting with Heat Gain and Loss
Jack: You also mentioned the glazing on the windows, and, I'm glad you brought that up because many times when we speak with homeowners, almost everybody I speak with wants a lot of light.
They also want to be able to very quickly get outside and back inside- we as humans want to enjoy our outdoor spaces as much as possible.
The trade-off is that glass lets light and heats out and le's light and heat in. So in the warmer months, you know, heat can enter the home and vice versa in the cooler months. You're losing heat, and you're gaining heat.
Farah: The general rule of thumb is that you want to try and minimize windows on your east and west facade to prevent that overheating. And again, there's always this balance between day-lighting and heat gain and heat loss. So you're always going to try and find some combination, but you can combine strategies to find that balance. For example, low-e coatings on windows are a great way to reflect heat. And also, ramping up, and you may not need this, but going from a single pane to a double pane window (which is actually just standard now) versus a triple pane is another consideration. Basically, you're working through whether that will help with the insulating, heat gain, and heat loss. And, of course, taking advantage of shading devices as has been done here.
Jack: There are also quantifiable metrics, like, R-values and U-factors, and, you know, all windows are not created equally. When doing a window door schedule, you're looking at where you want to place these things. Are you selecting high-energy-rated windows and doors?
Farah: A first step to doing that as a client, if you really want to educate yourself, is looking at your local building energy code. First, you want to identify which climate zone your state is located in and then align that with the tables in the code for U-factor and SHGC values for your windows. You can take that baseline value and go to your architect and say, "Hey, this is what we're required to do. Can we go above and beyond this if it makes sense?: So if you come to your builder or architect with that baseline knowledge, you know that that goes a long way. They're going to know they're paying attention and that you want to do better than the minimum.
Jack: We want our clients to come better prepared and educated. That helps us do our job well when we have people who think carefully about what they're doing.
Jack: This is the front entryway. We have a spacious area for entertainment and lounging here, similar to the rear door, which also has a vast opening. What are your thoughts on this image far?
The general rule of thumb is that you want to try and minimize windows on your east and west facade to prevent that overheating. And again, there's always this balance between day-lighting and heat gain and heat loss.
Daylighting
Farah: Looking at this right now, it's not a very deep footprint, which is excellent. In this case, you can get a lot of cross-ventilation here. So the placement of your windows and openings allows crosswinds to cool your home as needed. And so this really allows for passive cooling because, again, you can have cross winds through your footprint. This elongated narrow footprint allows more of your space to be daylit too. And you can see here that there aren't a ton of obstructions in the footprint. You don't have any partitions really blocking out any of that daylight. You have those upper clerestory windows that allow the daylight to penetrate through. Sunlight can penetrate 10-15' into your space. Keeping that in mind, you don't want to block the space with drywall or furniture- you don't like something obstructing that daylight path. This provides that clearance for your room to be well-lit without relying on your lighting.
Jack: So what you're saying is, if you orient right, and if you think right about it, you can have this ample open space. You can have big windows and doors, let air and light in, and still be energy efficient.
Farah: Yes, and a big reason that that works is that the floor area here is more manageable, you know, it's not this colossal space, so you can take advantage of all those passive elements of the climate in your home. You can allow the sun to penetrate through the entire depth, the daylight, and you're creating a manageable footprint. You don't need to have a ton of space. While there's nothing wrong with wanting a lot of space, but if you build what you can manage, you'll find those savings in your utility bills.
Jack: You'll also see that it is more passive and less mechanical because your building area is compact.
Thermal Mass
Jack: So let's go inside, right into the front entryway. This is probably my favorite image of this home. I think it's a vibrant space, and I love the stone material here. What are your thoughts?
Farah: Something that I want to focus a little bit more on here is the building material that's surrounding the fireplace. Something that really comes into play here is thermal mass.
And that's actually a massive part of passive savings if you get into it. So thermal mass is essentially something that absorbs heat. And so, if you take advantage of thick materials like concrete, brick, etc., and use that material in your flooring as well, then your low sun in the winter heats up your floor, and then that floor radiates that heat. Here, this open plan allows heat to percolate into your space, heat up that thick material, and then release it later when you need it at nighttime. That heat is trapped here, and your fireplace will be a supplemental source of heat if you need it. As a result, you want to also think about your furniture layout. Leaving open space at the perimeter between the glazing and the exposed thermal floor will allow heat to be absorbed. In other words, don't block it with that furniture- an unobstructed perimeter along your glazing is effective.
Jack: So you're saying the actual materials you build with on the inside of the home, the walls, and the flooring have a tremendous impact on retaining heat.
Farah: Yes, especially if you do so on your southern face. Suppose you place your active living spaces or working areas on the south side of the building, where you might spend a lot of your time during the day, and you place your less frequently used spaces. In that case, you're taking advantage of the sun during the day when the occupants spend most of their time inside the home. If we're thinking about this as a southern space, then something else to play here as we're looking at the interior is programming, which we discussed before.
Farah: If you orient your house in the inverse direction, where your home is running with the short end facing the south direction, then you might end up with cool spots and hot spots along the east and west runs of your building- where one side of the house is cold, and the other side is hot. You might not be getting the energy savings that you want. So it would help if you considered how the spaces are oriented to take advantage of that light. On your north side, you're going to get a lot of bright and direct light, so you're still going to get really well daylight spaces. Think about what spaces might need, so you can rely less on your interior lighting.
Jack:. So this is the bedroom on the easternmost wing. So we would step from the main living space into this bedroom.
Farah: Generally, we know that on the east side, you'll get a lot of your morning light, and then in the afternoon, you'll get a lot of your west-facing spaces receiving afternoon sun. You're thinking of a 9:00 AM to 3:00 PM window to take advantage of your solar gains. These are just things to consider when you're figuring out the layout of the space layout of your furniture too. If you want to avoid a lot of solar glare, you'll want to think about shifting your TV or any other equipment from the view of the sun on the south side.
Many pre-set designs do not take into account the very unique features of a site. This is why we have to start thinking more about what is on your site and how you move through space during the day. Where are you spending the most time?
Landscaping for Passive Design
Jack: Now we're stepping out of that bedroom and looking straight into a shared dining room kitchen.
Farah: I'm seeing a lot of landscaping here, and that's a pretty good point to touch upon.
When someone comes onto a site, I think the first inclination is to clear up all the trees and have a bunch of clear lands to plot your house on. But there are so many ways to take advantage of our plantings on-site. You want to locate your obstructions on the site, like your landscaping or, let's say, fences or whatever else, so that the total exposure of your sun is available from that 9:00 AM to 3:00 PM window to maximize your solar gain in winter. You want to be aware of the heights of other obstructions on your site. Something else to also think about is the types of trees on site. There are apps you can download onto your phone that allow you to identify the trees on your property. The type of tree affects how the sun enters your home. Deciduous trees on the south side of your building can help block out the sun in the summer when you don't want all that excessive heat. When they lose their leaves in the winter, you gain solar heat during cold days. Deciduous trees on your south side could be a perfect thing for you. On the other hand, evergreen trees, which don't lose their leaves, might be a great way to block out harsh northern winter wind. You want to determine where you could have a row of those on your site.
Jack: That's such a good point. Like you just said, many people will come onto a new construction project, and they'll see the existing landscape as a problem, standing in the way of their goals for the home. But really, if you're thinking about it, it can maximize heat in the winter, minimize heat exposure in the summer, and even cut down on the wind.
Farah: Exactly; it's a consideration for how to locate your home on the lot too. If you decide from the beginning that solar panels are the way to go, and there's a 50-foot tree over your home, start thinking about orientation and how that's going to play a role in shading your roof and where you're going to have maximum solar access. If you spend the time researching your orientation and siting, then a lot of the program and the design of the spaces will fall right into place.
Jack: Exactly. There are so many little things that add up. If you just come up with a little bit more preparation, you can have a design that will serve you for a long time.
Farah: Unfortunately, I don't think many home builders today take this into account. Unless you go with a custom home builder willing to be more flexible, like Reynard. Many of these pre-set designs do not take into account the very unique features of a site. This is why we have to start thinking more about what is on your site and how you move through space during the day. Where are you spending the most time?
Jack: As we continue our sustainability spotlight series, we'll discuss more specific materials and technologies. I've had clients talk to me about catching rainwater and reusing that water, solar panels, insulation panel types, and more. There are also simple things like orientation, landscape design, and the home layout that don't cost a lot of money. It doesn't cost money to plan your home a certain way.
Farah: Yes, and why they don't cost a lot as traditionally specified is that high-performance features are becoming the standard now. Because the code requires the manufacturers are following it. The trend we're going to see in all sustainable design technologies is that once you create a standard for things, then the economic competition levels out where everyone's pricing it out at the same value range because there are no other means.
Jack: And that's the thing, you don't have to overdo your investment if you think wisely and think long-term about what you want to get out of your home.
Farah: I love that we're kicking off this series with passive design because it's really about reducing your loads first before you add on any supplemental technologies and reduce the load further.
Just create a manageable footprint. The takeaway from today is to be very responsible with your building footprint and be very intentional so that you can reduce your loads from the onset, and then we can manage them later.
Jack: Join us next month for the next topic as we continue our Sustainability Spotlight series.