This episode is brought to you by The Cooper
Foundation What if I told you that it’s possible to
build a house that uses up to 90% less energy than your current house? And combining that with solar panels you could
heat, cool, and even charge an EV for just a few hundred dollars a year? Let’s take a closer look and explore Passive
Houses. I'm Matt Ferrell. Welcome to Undecided. Teslas and electric vehicles, solar and wind
production, and energy storage like Powerwalls and Megapacks tend to get all of the attention
when we talk about ways to combat climate change. But it's going to take a wide array of solutions
to make a real dent. And one of those that doesn't get talked about
enough is how we build our homes to make them as energy efficient as possible. In 1996, the Passivhaus Institute in Darmstadt
(darm-schtadt), Germany, set building standards to create low energy consumption houses that
still provide comfort at an affordable price. This demanding, performance-based, energy
efficient construction standard provides heating and cooling savings of up to 90% compared
to conventional homes, and over 75% in relation to average new buildings. That's a pretty big gap, which raises the
question: how? Passive house buildings rely on five main
principles. 1) A Highly Insulated Envelope**
Quality insulation is fundamental to achieving the great performance of a Passive House design. Multiple layers of high-efficiency insulation
materials are used to cover every surface from not just the roof and walls, but the
slab and footing as well. The only exception is obviously the windows
and doors. All of this is to minimize the heat exchange
with the outside environment. Some examples of these layers are rigidur
boards, oriented strand board (OSB), taped sheathing, air barrier tape, and plywood sheathing. Thankfully, several high-performance insulation
materials are also environment-friendly, which increases the benefits, like sheeps wool and
cellulose. 2) Thermal Bridge Free**
Heat likes to escape to where it's colder. So the heat inside a building will always
try to go outside if it's cooler using the easiest path it can find. These are called thermal bridges, which are
specific areas of the building envelope where the insulation is the lowest value compared
to other areas, forming cold spots in the building. If these spots become too cold, they could
lead to the formation of moisture and condensation, so Passive Houses are built with the concept
of being thermal bridge free. A house's studs can act as a thermal bridge. The same for a home's footings or basement
slab, so the continuous layer of insulation from the first principle is essential. But one way to make this easier is to also
minimize corners, bumps-out, cantilevers, and dormers because they create geometric
thermal bridges. It doesn't mean you can't have them, but they
have to be accounted for. 3) An Optimized Orientation with High-performance
Windows & Doors** Bad orientation combined with low-performance
windows and doors can cause significant heat gain or loss in a house depending on the time
of year. In Passive House buildings, triple-pane windows
and insulated frames are usually employed. Triple glazed windows are composed of three
panels of glass separated by a spacer. The airtight gaps between the glass are filled
with an inert gas, like argon, which is a poor conductor of heat transfer. But even these high-performance windows and
doors can be inefficient if they aren’t well-positioned. That's why homes built using the Passive House
standard are optimally designed and placed to harvest natural light and heat coming from
the sun. They take the surrounding environment into
consideration when designing the structure and placement on the land. One reason for that is a technique called
passive solar heating, which allows homeowners to collect, absorb, and distribute solar energy
right through their windows and doors. Passive solar heating has to be tightly managed
to limit overheating in the summer and maximize heat gain in the winter. For instance, to optimize heat gain, windows
that feature a high Solar Heat Gain Coefficient are used on the southern side of the house,
which means they let more solar heat through, which is ideal for the winter months. And in the summer months when the sun is higher
in the sky, you have large roof overhangs to keep the sun out. Then on the east and west sides of the home,
where the heat of the rising and setting summer sun can't be blocked, you'd use low Solar
Heat Gain Coefficient windows to keep the heat out. You can also use materials inside the house
like concrete floors to absorb the heat coming in through the windows during the day. At night they'll slowly radiate some of that
stored heat back out. Also, deciduous trees are beneficial for providing
shade on the house in the summer months, but allowing the sun's heat to pass through in
the winter when the leaves are gone. 4) Airtight Envelope**
Passive house buildings are designed to minimize the number of holes in their envelope. All leaks around doors, windows, exterior
electrical outlets, hose bibs, sill plates, and piping are properly sealed in order to
not only stop heat loss, but also help to reduce moisture buildup or loss in cold weather. Reducing cold spots and places where condensation
can happen not only provides comfort, but also improves the air quality by eliminating
the risk of mold growth. But an airtight envelope brings some problems,
like ... oh ... say fresh air for breathing, which brings me to the last main principle. 5) Mechanical Ventilation**
You might think that with an airtight design that people aren't allowed to open the doors
and windows, but they can. It is allowed. But when you're trying to maintain comfortable
temperatures in a home when the outside temps aren't ideal and in balance, that's when you
have to rely on mechanical ventilation systems like a Heat Recovery Ventilator (HRV) or Energy
Recovery Ventilator (ERV). These silent, efficient devices can provide
continuous, filtered, fresh air to the house, while pushing the stale air out. HRVs and ERVs transfer heat in order to achieve
maximum efficiency and healthy inside air quality, but only ERVs transfer moisture as
well as heat. This explains why ERVs are usually preferred
in areas of high humidity and wide temperature ranges. In winters, the system uses the warm, stale
air exhausted from the inside to pre-heat the incoming fresh air. Humidity can be added to the incoming air,
which is great in the winter time. I don't know about you, but the older I get
the drier I seem to be getting with each winter. I could really use an ERV right now. In summers, the system conditions incoming
warm, humid air by passing it over coils or channels containing stale, cool air being
exhausted from the house. Desiccants are used to take humidity away
from the fresh air intake, which is good for the cooling effect. Depending on the Passive House construction
and the local climate, a dedicated heating and cooling system may not be necessary because
of the internal gains from the sun, cooking, and people just living inside the house. To get a good idea how that might be possible,
just take a look at the difference in heating energy required between a passive house and
typical homes. A northern European Passive House needs just
15 kWh of heating energy per square meter of floor surface per year (15 kWh/m2a), a
modern house would require 150 kWh (150 kWh/m2a), and a leaky house ... which a lot of people
live in ... would need 300 kWh (300 kWh/m2a). Kind of a big difference. Passive Houses can't be compared to other
certifications like LEED and BREEAM green building certification programs, which is
something that I actually covered in a recent video. Passive House is just a performance-based
energy efficiency design standard. The Passive House Institute accredits this
certification, and within the Passive House standard, there are certifications for the
house components, such as the building envelope, transparent components like doors and windows,
and ventilation systems. Also, not all buildings can be refurbished
to the Passive House Standard, so the EnerPhit certification is used for retrofits to verify
the consistent employment of Passive House components. The targets for an EnerPHit House for the
Space Heat Demand and the Space Cooling demand is <25 kWh per square meter (<25kWh/m2) per
year. Not as a good as a purpose built passive house,
but still dramatically better that a typical home. But is the cost to achieve all these benefits
worth it? Before I get to that though I'd like to thank
today's sponsor, The Cooper Foundation. They're a non-profit organization that's raising
money to help children and young adults with special needs get the help they need. Craig and Cristine Cooper, who are friends
of the channel, started the foundation because they have a daughter with autism. She's a loving child that's mostly non-verbal
and needs supervision most of the time, so they know how families could use a little
helping hand. Over 85% of the donations goes directly to
helping kids with everything from summer camps to devices and equipment for helping with
everyday living. The Cooper Foundation is always looking for
real world solutions that can make a meaningful difference. Like right now they're raising money for an
ADA compliant playground for special needs children in Brook Park, Ohio. If you'd like to learn more, go to thecoopfoundation.com
... link is also in the description. Thanks again to The Cooper Foundation and
to all of you for supporting the channel. According to the Passive House Institute US
(PHIUS), a passive home costs about 5-10% more than a conventional house, but others
estimate extra costs varying from 7-15%. Usually, as the size of the building increases
the cost difference to a typical house decreases. A study performed by the Passivehaus Trust,
the UK Passive House Organization, analyzed the building costs of several Passive House
buildings considering different construction methods and forms. The projects made in 2018 ranged from 1,296
£/m2 to 1,807 £/m2, and the major extra cost in the construction was related to wall
and roof structures. However, the costs for each project can very
depending on the size, complexity of the design, level of finishes and materials, the builder
contracted to lead the project, and other factors that can affect the building cost. Passipedia, which is a great resource for
Passives Houses, shows a study of a conventional 149 m2 single family house compared to a standard
house over 30 years. In 2010, the additional investment added up
to €15,000 (8% extra), while in 2015 the total extra cost was reduced to €10,000
(5% extra). The calculated energy savings for heating
over 30 years was €822/year, with annual additional cost of electricity for the ventilation
system of €71. In the end, the homes cut €432 of annual
cost burden. As good as all of that is, there's still improvements
being made to techniques and components. Swisspacer, from Switzerland, for example,
has introduced the Swisspacer warm edge spacer that uses one spacer bar for all three panes
in a window, providing lower weight, less risk of gas losses, as well as long service
life. Another example is EcoCocons Straw Panels
by the Slovakian company EcoCocon. This wall system is made of 98% natural materials,
such as fiber layer and straw, and it can prevent heat-loss, excess humidity, avoid
thermal bridges, provides healthy indoor air quality and building flexibility due to the
custom-made dimensions. And when you think of straw and fire, you
might be concerned ... but because of their composition they can resist fire for 120 minutes! Passive House buildings have several advantages
such as comfort, money-savings, healthy indoor air, reduced energy bills, and long lasting
quality. Since the first Passive House constructed
in 1991, which is still running by the way, there are more than 25,000 certified Passive
Houses as of January 2020. Today, many countries and some states here
in the US, provide grants and tax breaks for homeowners that install energy saving materials
in their houses. There are also low interest rate loans available
in many areas to cover high efficiency projects like these. While the focus on clean energy generation,
like solar, wind, and energy storage, is where a lot of the focus should be for combating
climate change, we shouldn't forget about energy conservation. Things like Passives Houses can not only make
a huge dent on our energy requirements, they can save us a lot of money in the long run,
too. And you don't have to do every single component
of a passive home to make a difference. If you combine some passive house techniques
with a solar panel installation on your home, it's possible to achieve net-zero pretty easily,
which is generating as much or more energy than you use. One family in Massachusetts did just that
with an Oxford, Maine built modular home from BrightBuilt Home. Including heating, cooling, hot water, and
charging a Chevy Volt, they pay a little over $400 a year for energy use. I don't know about you, but I'd love to build
a Passive House or Net Zero home. What do you think? Jump into the comments and let me know. If you liked this video be sure to check out
one of the ones I have linked right here. Be sure to subscribe and hit the notification
bell if you think I’ve earned it. And as always, thanks to all of my patrons
and to all of you for watching. I’ll see you in the next one.
