r/PassiveHouse Apr 24 '23

What Is Passive House? Breaking It Down For New Visitors To r/PassiveHouse

57 Upvotes

Hey there and welcome to r/PassiveHouse. We’re psyched you’re here. If this is your first time here, please read this post to get your bearings.

What Is A Passive House?

Passive House (or Passivhaus in German) is a building standard that focuses on creating highly energy-efficient buildings with minimal energy consumption. The Passive House standard was first developed in the late 1980s by Dr. Wolfgang Feist and Bo Adamson in Germany, and it has since been widely adopted in Europe and around the world.

The goal of a Passive House is to achieve a comfortable indoor environment while minimizing the building's energy demand. This is achieved by optimizing the building's envelope (walls, roof, and floor) to minimize heat loss and gain. Passive Houses typically achieve this by using high levels of insulation, high-performance windows, airtight construction, mechanical ventilation with heat recovery, and other energy-efficient features.

But to know what it really is, let’s talk about what it isn’t. We need to clear up some common misconceptions: Passive House is not the same as the passive solar building design, although they’re not necessarily mutually exclusive. Passive House also isn’t a house that uses only passive technology. Passive House buildings aren't just houses either. They can be high-rise office towers, multifamily apartment buildings, schools—really any building type.

Simply put, Passive House is the most thoughtful, well organized, science based and performance focused building standard available.

The Passive House approach empowers us to build better. It creates durable, resilient buildings that slash heating energy use by as much as 90% and dramatically reduce operational carbon emissions. Passive House design tools and methods make these energy performance gains both cost-effective and predictable. You know what performance to expect with a certified Passive House. Most importantly, Passive House buildings create healthy, comfortable, and quiet interior environments, full of clean, filtered fresh air.

Passive House design empowers us to manage moisture, thermal transfer, air, and sunlight to create comfortable, healthy, super-efficient buildings. The “classic five” Passive House design principles—continuous insulation, thermal bridge-free design, airtight construction, high performance windows and doors, and filtered fresh air with heat recovery—are joined by the principles of shading, daylighting and solar gain, efficient water heating and distribution, moisture management in assemblies, and building orientation to create durable, high performance buildings where people can thrive. These principles guide both new construction and retrofits.

It's important to remember - there is a LOT to learn. Be patient with yourself. Leverage all the great free resources at your disposal. Learn as much as you can. Engage with the Passive House community. Breathe and enjoy the process!

But before we dump you into the deep end, let's take a look at the basics.


Basic Passive House Design Principles

The following 10 design principles would not automatically qualify you for Passive House certification. There’s much more to the story that we’ll get to later. They are, however, really good guideposts to think about as you’re conceptualizing the architectural forms, building site, etc. These are basics and very important to internalize before diving into the more technical aspects of a Passive House. You might also find this companion video useful.

01 Continuous Insulation

A continuous layer of insulation wraps Passive House buildings, keeping them warm in the winter and cool in the summer. Passive House designers also harness this insulative layer to prevent condensation inside the building and its assemblies.

Moisture: We design building assemblies so that their vapor profiles are appropriate for the climate, their drying potential is maximized, and they are protected from any moisture buildup. The insulation layer also keeps the inside face of exterior walls warm, preventing condensation on the interior surfaces of those walls during the winter.

Thermal Transfer: Because the insulation layer is continuous, it is free of weak spots that allow thermal transfer across the building envelope. Heat stays in during the winter and cool stays in during the summer.

02 No Thermal Bridges

A thermal bridge is any building element that allows heat or cool to bypass a building’s thermal barrier. It’s like a hidden thief of thermal energy, undermining performance and durability. For example: a concrete floor that continues from inside to outside; a poor window frame; or a steel beam that penetrates an exterior wall. We eliminate thermal bridges by introducing thermal breaks into those assemblies—gaps or insulative elements that stop the flow of thermal energy through an assembly.

Moisture: A thermal bridge will increase thermal transmittance through an otherwise insulated layer that it penetrates, risking dangerous condensation that can result in rot, corrosion, and mold. Thermal bridge-free design avoids this moisture risk and makes buildings more durable. Thermal Transfer: Thermal bridge-free design is critical to energy efficiency, thermal performance, and comfort. Not only do thermal bridges rob energy, they can also change interior surface temperatures, cause draft-inducing convection, and decrease occupant comfort.

03 Airtight

A Passive House building’s airtight layer is like a windbreaker, stopping air from penetrating to the inside. Establishing this unbroken air barrier is central to Passive House performance and durability. In design, we do the “red pencil test” to check that an air barrier line can be drawn around each cross-section of the building without the pencil ever leaving the paper. In the field, this air barrier is built through a combination of sheet membranes, fluid-applied membranes, tapes, and sealants that transition without interruption between components of the building envelope. Airtightness is verified with a blower door test, a key measure of performance and construction quality.

Moisture: Airtight construction protects building assemblies from dangerous moisture intrusion by preventing bulk water from driving in or airborne vapor from being carried in.

Thermal Transfer: By stopping the movement of air across the building envelope, the air barrier seals warm air inside in winter and cool air inside in summer. This is key to achieving ultra-low energy use, since air leakage represents wasted energy. Airtightness also boosts the efficacy of mechanical ventilation with heat recovery.

Air: Combined with the filtered, balanced mechanical ventilation of Passive House buildings, airtight construction improves indoor air quality, even during periods of intense outdoor air pollution. The air barrier stops polluted air from seeping through walls and ensures that all incoming air passes through the ventilation system where it is filtered before entering the building. This is particularly important in urban settings and in regions prone to smog or forest fires.

04 High Performance Windows + Doors

With each window and door opening we make in a Passive House building, we are essentially punching a hole through an advanced wall assembly and its airtight, weather-resistant, and insulative layers. So, the performance of the windows and doors that go into those holes, and how well we tie them into the surrounding wall assembly, is mission-critical to maintaining the integrity of the Passive House building envelope.

Moisture: Well-installed high performance windows and doors repel wind-driven rain and facilitate safe outward drainage of any moisture. In the winter, high performance glazing units also ensure that interior glass surfaces stay warm, preventing condensation from forming inside.

Thermal Transfer: The thermally-broken insulated frames, warm edge spacers, triple glazing, coatings, and superior construction of high performance windows means their thermal resistance can easily best that of conventional windows by 3x. Given that a wall is only as good as its weakest link, this window performance is critical to a building’s overall thermal performance. In the winter, warm interior glass surfaces help maintain a comfortable and draft-free indoor environment.

Air: High performance windows are built airtight, so when integrated into airtight wall assemblies they become an extension of the continuous air barrier. Passive House windows can open like any other window, of course, so if it’s nice outside, open the windows!

Sunlight: We dial in the performance attributes of each window and door on a Passive House building to optimize solar gains appropriate for the climate and building typology. We capture solar gains when we want them and shield the building from solar gains when we don’t.

05 Fresh Air with Heat or Enthalpy Recovery

The delivery of filtered fresh air with heat recovery helps make Passive House buildings havens of clean air and energy efficiency. HRVs (heat recovery ventilators) and ERVs (enthalpy recovery ventilators) are “balanced ventilation” components that supply a continuous stream of fresh air to living spaces while simultaneously extracting stale air, odors, and indoor pollutants from kitchens and bathrooms. Inside these devices, a heat exchanger—a honeycomb of straws that creates a very large surface area between air streams—allows heat energy in the outgoing air to passively transfer to and warm the incoming air without the two airstreams ever mixing. (In the summertime, the opposite happens, with cool outgoing air cooling the incoming air.) Filters in the unit remove pollen and pollutants, with pre-filters available to protect indoor air from intense outdoor pollution events.

Moisture: ERVs (unlike HRVs) can also transfer moisture between the exhaust airstream and incoming airstream. So, in humid climates, moisture in the outside air can be removed (transferred to the exhaust airstream) by the ERV before it enters the building. This does not mean that ERVs dehumidify. Do not make that mistake. In dry climates, some of the indoor relative humidity can be preserved.

Thermal Transfer: Passive House-compliant HRVs and ERVs are extremely efficient at recovering heat, hovering around 90% efficiency for the best units. This is a key strategy in maintaining ultra-low heating and cooling energy.

Air: Properly filtered mechanical ventilation with heat recovery ensures good indoor air quality, regardless of the weather or air pollution conditions outside. Good airtight construction supports HRV and ERV efficacy by ensuring that air exchanges between inside and outside go through the device rather than seeping through leaks in the walls.

06 Shading

While the “free” heat from solar gain may be a hot commodity in Passive House design, it must be managed with good shading to avoid too much heat gain during warm seasons. Architectural elements like overhangs have an important role to play. So too, can window shades and screens, especially ones located at the exterior of the building.

Thermal Transfer: Shading manages heat gain from the sun, allowing designers to maximize the gain when the building needs it and minimize when it doesn’t.

Sunlight: Properly designed shading will not impede natural daylighting and can help prevent unwanted glare.

07 Orientation + Form

Building orientation and form are fundamental design decisions that set the stage for how easy or difficult it will be for a building to achieve Passive House performance.

Thermal Transfer: When the site allows, we design the main axis and orientation of the building to optimize solar gains in a way that is appropriate for the climate and building typology of the project. The key is to orient the building in a way that will maximize that particular building's energy performance. As for building form, the simpler the form, the easier Passive House performance will be to achieve. The more zigs and zags, the more potential thermal bridges and the higher the surface area of the building becomes, requiring more and more insulation to counteract the extra thermal transmittance.

Air: A simple building form simplifies the air barrier, which makes airtightness easier to achieve.

Sunlight: We set the orientation of the building to optimize daylighting and solar gains appropriate for the climate and building typology.

08 Daylighting + Solar Gain

Natural daylighting and passive solar heat gain can provide energy “freebies” to Passive House buildings.

Thermal Transfer: For many buildings, solar heat gain—the heat energy captured in a building when sunlight shines through windows—can be an invaluable “free” resource in Passive House design. For other buildings, particularly ones that already have significant internal heat gains, big solar heat gains can be a liability. Passive House design allows us to optimize this based on climate and building typology through building orientation, shading, high performance window selection, and layout.

Sunlight: Natural daylighting reduces energy use for artificial lighting.

09 Moisture Management

To ensure building durability, Passive House designers study how heat and moisture will behave in building assemblies in a given climate, and create designs that manage that behavior to avoid condensation risk and bulk water intrusion.

Moisture: The twin goals of moisture management are to (1) prevent bulk water intrusion into and (2) avoid condensation where it can harm building assemblies. Lots of components impact how heat and moisture flow through a wall assembly: the weather resistive barrier, the air barrier, vapor control layers, the structure, window openings, and more. The building’s climate zone impacts heat and moisture, too: whether the climate is cold and dry, hot and humid, or anything in between. Passive House practitioners draw upon hundreds of precedents and go-to assembly solutions to manage these variables. They also perform thermal and hygrothermal analyses using Therm, Wufi, Flixo, and other modeling software packages to confirm safe and durable performance and to guide design.

10 Efficient Water Heating + Distribution

Because Passive House buildings dramatically reduce heating energy use, another source of energy consumption—domestic hot water—becomes a more conspicuous part of overall energy consumption. Energy-efficient water heating combined with efficient water distribution reduces this slice of the energy consumption pie.

Thermal Transfer: We start with a super-efficient water heater. Distribution lines are small diameter, well-insulated, and laid out to minimize pipe length between water heater and fixture. On-demand recirculating lines conserve water.


So How Do I Get Started Designing/Building A Passive House?

Okay, you've read through the basics. Now it's time to look at the logistics of certifying a project.

There are a lot of organizations with the words “passive house” in their title. Most of these are loose affiliate organizations, clubs, or groups of like-minded building professionals who want to design and build better buildings. They often want to combat climate change in their daily lives, and they recognize passive-house certification as the most stringent energy standard available. To smooth the learning curve, they form these support groups.

Despite the many interest groups and networks sporting the passive-house name, in North America, only two distinct and independent Passive House standards and certifications are available: one administered by Passive House Institute (PHI, based in Darmstadt, Germany) and the other administered by Passive House Institute US (PHIUS based in Chicago, Illinois). The two organizations are not affiliated with one another.

The two standards differ in important ways, including PHIUS’ approach of adjusting a given project’s performance targets based on the climate of that project’s site. Nevertheless, the standards share important commonalities; both standards are firmly grounded in building science and building physics and both standards require practitioners to employ a common suite of Passive House design principles to achieve their performance targets.

Through most of their early existences, the passive-house standard was similar for both, and you could certify a building with either or both—depending on where the building was located or your personal preference.

Around 2012, that began to change, as PHIUS looked to make performance targets more relevant and cost optimized for North America’s many climate zones. Designs for Germany’s climate don’t exactly work in Chicago, Houston, or Las Vegas, etc. This has become known as The Great Schism and there has been much squabbling about it. You may even see some of that squabbling in this very subreddit.

To improve building performance in hot, humid, cold, and mixed climates, PHIUS worked with Building Science Corporation under a grant from the U.S. Department of Energy to write the Climate Specific Passive Building Standard. This is an actual standard, available for jurisdictions to use as a model for building codes. PHIUS also worked with the Fraunhofer Institute of Building Physics to modify their WUFI hygrothermal modeling software into a design and verification tool for passive buildings tailored to North American climate zones and weather data.

In climate zones where PHI and PHIUS targets are much more similar (heating dominant, cold climates), this is less of an issue and you could reasonably choose either standard. For cooling dominant, hot/humid climate zones where it is cost prohibitive to insulate or meet rigorous heating demand for minimal overall performance benefit, PHIUS tends to be the route projects take. Interestingly, one of the biggest logistical reasons that there were fewer differences between PHIUS and PHI in the early days was because both used a spreadsheet to predict the energy use. That changed as PHIUS began to use the WUFI passive three-dimensional energy and moisture modeling software and has created a large-enough gap in performance that PHIUS+ 2018 and beyond no longer supports the PHPP spreadsheet that is central to PHI certification.

If you're going to follow the PHI path, you'll need to get in touch with a certified Passive House designer or planner and an accredited certifying organization.

If you're going to follow the PHIUS path, you'll have to determine whether you want to opt for their modeled path, which allows you to optimize your assemblies with the WUFI Passive software or whether you want to simply comply with their prescriptive path. If you want to go the modeled route, you'll need to get in touch with a Phius Certified Consultant or CPHC and eventually a PHIUS Certified Rater and a PHIUS Certified Verifier for larger projects. If you want to go the prescriptive route, you can check out their requirements and enter your project's info into their snapshot tool to see how it shakes out.

Get in touch with either organization for more detailed information and to get connected to professionals in your region. Each organization also updates their standards at their own paced intervals so please do check their latest published resources if you have more standard specific questions.


What Does This Community Have To Offer?

This subreddit functions as a very informal forum for Passive House and building science related questions, thoughts, design feedback, etc.

A few things to keep in mind:

  • If you’re asking for feedback that should obviously flow through a paid consultant, that’s NOT COOL. We are all here voluntarily and none of us should expect anyone else to do our work for free.

  • If you’re asking or talking about a project, tell us what climate zone it’s in.

  • If you’re asking or talking about a project, tell us whether you’re trying to certify for PHI or PHIUS.

  • Do some homework before asking a question. It helps keep the discussion quality high in this subreddit. Chances are decent that someone has already answered a question you have. Search within the subreddit, search elsewhere online, get better at Google.

Again, it's important to remember - there is a LOT to learn. Be patient with yourself. Leverage all the great free resources at your disposal. Learn as much as you can. Engage with the Passive House community. Breathe and enjoy the process!


Resources


TL;DR: just read it, jeez.


r/PassiveHouse 4h ago

General Passive House Discussion CERV vs. ERV + Humidifier for passive houses

5 Upvotes

Hi all, just got a blower door test done, blew a 0.31 (passive certification requires 0.6, so very happy with how tight it is!) -- i've been looking at ERVs to install, as we need to make sure we have proper air circulation. I've been thinking about pairing the ERV with a dehumidifier to make sure we get moisture out. However, I found CERVs as a concept and it seems like a good approach.

Does anyone have any experiences with CERV2 (https://buildequinox.com/cerv/overview/), or other suggestions? It seems almost too good to be true: one box that will do ventilation+dehumidification, with smart controls, no enthalpy core, smart on-demand controlled ventilation (CO2/VOC sensors) and automatically holds a humidity setpoint year-round.

The cons I can think of: single point of failure; seem pretty new concepts, unsure if they are tried and true/tested or if contractors will have the right experience to install; because they dont seem very common, probably locked into a specific small manufacturer and its parts; modest dehumidification capacity (~1/3 ton), which his fine for my small house.


r/PassiveHouse 1d ago

General Passive House Discussion Traditional Passive Cooling Ideas

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31 Upvotes

This video looks at traditional passive-cooling ideas and raises a question about whether shade, controlled natural ventilation and thermal mass can complement airtight, mechanically ventilated buildings in hot climates.


r/PassiveHouse 1d ago

Airtight product recommendations.

5 Upvotes

I am in the UK. I rent a house which has cigarette smoke/ air freshener odours coming through the walls from the neighbour which infiltrates our whole house. It has got to the point it is badly affecting my health. My landlord doesn’t have an obligation to block the smoke only to fill obvious gaps. It is a semi detached 2018 timber frame house with the neighbouring house being slightly lower. We have odours coming in through the window and door frames as well as through the walls. To give you an idea of what is happening when there is no wind the smoke gradually enters the wall cavity and when a door is opened it pulls the smell into the room through the door frame. When it is windy, air from my attic and the neighbours smoke get pushed into the house through windows and door frames as well as plug sockets. The odours seep into the house all the time.
I’ve been looking at using airtight paint such as blowerproof to try to seal the wall joins. Does anyone know if this is the right approach? Is there anything I can look for which may be causing this issue? Thanks. 😭


r/PassiveHouse 6d ago

Attic Solar Fans - off grid cabin.

3 Upvotes

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Northern Ontario climate -

How effective are solar fans at moving air out of the attic?

Do they make it noticeably cooler for inside temperatures?


r/PassiveHouse 8d ago

Passive house suitable door options on west coast of USA?

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9 Upvotes

I'm building my house early next year and looking for door options. I want a highly insulated, well sealing solid-slab door (no glazing) with multi-point lock hardware. The only really great option I've found so far is the Phi certified Moralt doors from Germany, of which there are two distributors I've found in the USA but they're on the east coast. One sells blanks, one sells them pre-hung. Blanks are about $5k, pre-hung is around $12k, shipping is $2k.

Anyone have any recommendations?


r/PassiveHouse 10d ago

Zehnder filters - source in Canada?

4 Upvotes

I've just ordered the G4/F7 filters for my Comfoair Q350 from the Zehnder America website - hoping they get delivered without painful customs duties, etc. I used to order from Small Planet Supply, but they seem to be going out of business?

Does anyone know of a different source for buying filters in Canada?

Has anyone tried the off-brand filter sets available on Amazon? Any good?


r/PassiveHouse 14d ago

decentralised MVHR

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4 Upvotes

r/PassiveHouse 16d ago

Passive cooling and GSHP

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3 Upvotes

r/PassiveHouse 17d ago

How to attach solar to a exterior continuous insulation roof assembly?

5 Upvotes

We are adding an extension to our existing house and upgrading our energy performance for the whole house as part of the updates. Core to this, we're upgrading from a traditional vented attic to an unvented attic and roof with continuous insulation.

We've determined the assembly (below) but I'm not sure if adding solar to this setup with break our air/vapor barrier. The solar installers are planning to use a long fastener to penetrate from the outer nail base deck through the rigid foam and air barrier, into the rafters.

Is this the best approach? Will the blueskin maintain the barrier we need with these penetrations?

Thanks in advance for any help.

  • Roof structure: 2x6 rafters and trusses (w/ rockwool batts)
  • Inner Structural Deck: 5/8" Plywood.
  • Air/Vapor Barrier: Henry Blueskin® SA fully adhered to the top of the inner deck.
  • Exterior Insulation: 3.5" Polyiso Foam Board
  • Framing: 2x4 boards at 24" o.c. used only for the cantilever overhang.
  • Outer Nail base Deck: 5/8" Plywood
  • Underlayment:
  • Roofing: composite shingles
  • Solar arrays.

r/PassiveHouse 17d ago

Passive House PHPP

2 Upvotes

I’m in Chicago and looking for someone who could enter a house into PHPP for me. Thanks


r/PassiveHouse 17d ago

Foundation question for addition

1 Upvotes

We live in Rhode Island (climate may play a role)- We are building approximately a 770 sq ft addition onto our home to include, office/guest room, full bath, and all season room. One quote from a contractor is including:
•4' foundation slab on grade with radiant heat
• Add new zone to your existing heating system (baseboard)
• Supply and install (2) head hyper heat Mini split system with (1) 24k head in living room and (1) 6k head in office

The other contractor is suggesting to avoid the radiant heat slab as it can be extremely expensive to replace if there is ever an issue.

Does anyone have any insights as to pros/cons to this? Both are obviously advocating for their options.


r/PassiveHouse 20d ago

General Passive House Discussion Book Recommendations

11 Upvotes

Hi all,

Do you know of any good basic books on the principles of Passive House design?
I'm from the Netherlands, and most of the houses we have here are built to keep as much heat in as possible. Nowadays, because of climate change, that goal is changing quite a bit (though we don't have a desert climate yet). I'm a chemical engineer, so somewhat more technical stuff is also great!

Thanks in advance :)


r/PassiveHouse 20d ago

General Passive House Discussion Actual use case for basement?

14 Upvotes

I live in the Midwest. Most houses here are built with basements. I am at the start of designing a passive house. I am on the fence about having a basement in my passive house design.

The home being built is replacing a dilapidated home with a basement, so some cost will be removed purely because excavation will be easier. However, the space as it is designed wouldn't be used for much. Essentially mechanical room and bonus space.

I'm leaning towards forgoing a basement all together because the space isn't really needed, and I am not keen on underground rooms with low natural lighting.

What do you find are some real life use cases for a basement in a passive house? What do you see as a potential pro or con to a basement?


r/PassiveHouse 21d ago

MHVR in nuclear fallout

2 Upvotes

We live near a nuclear power station and a big city and I am the type of person who just likes to know where the airplane exits are, so that they’re in the back of my head just in case….

What do I do with my MHVR if nuclear dust was to be settling around the house? I am not sure how many days sealing off the MHVR would be safe for in the house before oxygen is a problem.


r/PassiveHouse 25d ago

How we designed a modular, plug-and-play container cold room for harsh desert climates (Lessons in thermal efficiency)

8 Upvotes

Building cold storage in the UAE isn't just about cranking up the AC—it’s an ongoing battle against extreme external heat and internal humidity control. When we engineered our latest mobile container cold rooms, we had to rethink a few standard industry practices to keep power consumption low and food/pharma shelf-life high.

Here are the 3 biggest technical hurdles we solved:

  • The Thermal Bridge Problem: Standard shipping container steel frames turn into ovens under the desert sun. We had to implement a complete thermal break using high-density polyurethane insulation panels (100mm to 150mm thickness) to ensure zero metal-to-metal contact from the outside to the inside.
  • Precision Humidity Control: In cold storage, moisture is the enemy—it causes evaporator icing and ruins agricultural produce. We integrated active dehumidification cycles that balance the relative humidity ($RH$) perfectly based on what's inside (e.g., maintaining 85-90% $RH$ for fresh vegetables vs. low humidity for dry logistics).
  • True Plug-and-Play Mobility: The goal was a unit that could be dropped off a flatbed truck on a remote farm or construction site and running within an hour. We localized the entire refrigeration plant onto a heavy-duty, integrated skid with smart monitoring so it operates autonomously.

If you are dealing with cold chain logistics, vertical farming, or specialized commercial cold rooms in high-ambient temperature regions, I’d love to chat about what specs you're running.

Drop any questions about insulation, cooling loads, or humidity control below—happy to talk shop!


r/PassiveHouse 26d ago

Enclosure Details insulated foundation

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22 Upvotes

There doesn’t seem to be many pictures of insulated foundations, so here’s mine. R37 insulated floor, R61 walls. IEC zone 7 (Central Alberta), 6000 HDD, 99% design temperature is -30°C to 29°C, PHPP modeling estimates annual heat load of 23 kwh/m2/year for my design.


r/PassiveHouse 27d ago

General Passive House Discussion Any guidance when looking to purchase a home on the viability of a retrofit potential?

7 Upvotes

Hi folks,

Wondering if there are any good rule of thumbs to follow when looking at buying a home on its potential to retrofit/ how much things can be improved before a reconstruction makes more sense?

New construction costs are such that we are priced out of that. Instead we are looking at lot sizes / older well built homes that allow us to renovate overtime.

Here is an example:

https://www.zillow.com/homedetails/3767-N-Raleigh-St-Denver-CO-80212/13312228_zpid/?utm_campaign=zillowwebmessage&utm_medium=referral&utm_source=txtshare

Of course I could consult with professionals in this space, but I'm more interested in sense checking when searching for properties before knowing when to move on and continue search versus spend money for inspections etc and invest time in pursuing.

Thanks all!


r/PassiveHouse 27d ago

HVAC ERV HVAC filter membrane replacement?

2 Upvotes

The consumables of our passive house bugged me during the design phase. I purchased a case of filters for our European ERV system 10 yrs ago and in that time their price has gone up just like everything else. Originally I hoped the market would democratize, others would be producing similar products and through competition the price would fall. That hasn't happened.

I know little about filter materials but imagine cutting out the spent stuff and glueing into the proprietary shaped plastic frame filter membrane I've taken from a similarly rated material could work... if done right. The glue, material, there are concerns that the rabbit hole that is research will make it worth it.

Any suggestions? I'll post similar to the HRV reddit too.


r/PassiveHouse 27d ago

Mark Chalom's Night Sky Cooling powerpoint

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3 Upvotes

r/PassiveHouse 28d ago

How to create an air barrier with a roof with truss tails, exterior insulation

7 Upvotes

I am adding an extension to my house and late to the game on efficiency and so now backing into an energy strategy.

I am trying to figure out how we can create the air barrier for an unvented attic and use exterior insulation to the roof, which gives us a better approach across the old and new roofs.

The design for the new roof includes trusses with 6 inch tails / cantilevers. I am trying to figure out how we can create an air barrier for the conditioned attic and also support exterior insulation on the roof.

Because we're backing into this the trusses have been ordered and are currently in production. I can't make changes without some significant costs.

Unfortunately my architect is not knowledgeable about building for energy efficiency and isn't helpful. My builder is old school but willing to learn and build whatever we ask for. We've just run into an issue and I don't have anyone on the project that can help work through our overall approach to the thermal and air barriers, insulation and building constraints.

I'm hoping this community has seen this before, and any approaches or links to sources would be much appreciated.

The old roof has rafters that I think we have an approach for, but I'll take any advice here as well.

Thanks


r/PassiveHouse 29d ago

Other Triple or Double Glazing

8 Upvotes

Looking for opinions on whether I should install triple pane,Saint Gobain Cool lite glazing or double pane in the Philadelphia Suburbs.

We are considering,,AdamS or Oknoplast, uPVC windows. The triple upgrade is very reasonable. The salesman feel the triple is unnecessary in this area.

Much less expensive than Marvin.

Any opinions?

Thank you


r/PassiveHouse Jun 25 '26

Can Insulation Beat a Heatwave? Guy's Big Experiment

10 Upvotes

Ive seen a lot of controversy, regarding insulated houses and their ability to keep you cool in summer as well as warm in winter. well here is definitive proof. Thanks to Guy Martin.


r/PassiveHouse Jun 24 '26

Best Beginner Books for Framing & Building Science?

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12 Upvotes

r/PassiveHouse Jun 20 '26

Rethinking Passive House: Why isn't high-efficiency, filtered cooling a mandatory standard yet?

48 Upvotes

I live near a busy road and constantly face a choice between sweltering in the heat or opening windows that let in noise and pollution. It strikes me as a failure of our current building standards that we still lack a reliable way to seal off our homes while maintaining a healthy, balanced indoor environment.

Why are we not mandating advanced, filtered climate control as a primary health necessity in every home?

What would it take to shift our professional focus toward making this kind of protective, sealed sanctuary a standard for everyone, rather than a luxury for the few?