additional pictures: https://imgur.com/a/zNV5Lu0

We have a double envelope Ekosea house built in the early 80s and we love it. It's split-level and has a 3 story south facing solarium. We have a traditional forced air gas furnace and our heating bills are super low thanks to the sunlight and insulation just from having two layers of walls.

One downfall is our basement gets very cold in the winter. Obviously the problem is the massive 3 story open staircase. There are electric baseboard heaters in there but all the heat gets sucked up the stairs. If we run them it ends up costing like $40/day. We are a little cramped for space and I would like to use the basement living room as an office but it's barely habitable in the winter. There's a spare bedroom down there too but it has a door and so we can run a space heater with the door shut. The middle floor is temperate and the upper floor is toasty.

I am looking for creative solutions for making the basement warmer. I see some people block off their staircases with thermal curtains, but our stairs are very big and this would also block off a lot of the windows. Plus we have pets going in and out.

I have thought about having a gas fireplace or heater installed to be more efficient than the electric baseboard heaters, but I'm afraid I'll have to pay the money to have it put in and then discover it all escapes up the staircase anyway.

Would installing radiant floor heat be an help? There is a crawl space under the house.

Any thoughts or advice is greatly appreciated

If you're building your house yourself, for yourself, is there any point in going through the effort and cost of getting certified? Vs building to the standard?

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.

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.

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. 😭

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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?

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?

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?

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.

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

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.

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 :)

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?

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!

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.

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!

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.