In a previous post Ten things to do to have have a healthy home I concluded with a promise that the next post would be How to build a healthy house from scratch. It is now many weeks later, because the task is a bit daunting, figuring this out. But if I was still practicing architecture and a client came to me with a request to do the healthiest house possible, a new build on an open site, (which of course we shouldn’t do but it is a client, right?) in a temperate to cool climate, this is what I might propose these days.
It will be built of solid wood.
I have been a fan of wood for a long time, but lately have been really impressed with some of the techniques developed in Germany and Austria for connecting and building solid wood panels without glue. TreeHugger has shown Brettstapel, a dowel-laminated wood, Thoma Holz100, a cross-laminated wood held together with dowels, and now here is Nur-Holz, with threaded dowels. Solid wood is an all-natural material, is non-allergenic and is “an open-pored, breathable wood surface catalyzed smells and pollutants. The fine smell of essential oils, the typical wood smell, animated to the deep breath.” There is a proven biophilic effect where it has been shown to calm us down and soothe the nerves. Solid wood also moderates the moisture content of the air.
More on Wood and Human Health in a pdf from FP Innovations.
It will be Passive House standard.
That’s because wrapping a house in a blanket of insulation to Passive House standard means that it needs very little heating or cooling, eliminating products of combustion either on site or off. But I have also learned from engineer Robert Bean’s Healthy Heating website how important it is to consider the temperature of the walls of a house. All that insulation saves a lot of energy, but as Robert notes,
“Where an energy efficiency approach says adding insulation reduces energy consumption, the indoor climate approach says adding insulation results in higher mean radiant temperatures in winter and lower MRT’s [Mean Radiant Temperature] in summer.”
Windows built to passive house standard are also comfortable to sit by, any time of year. Passive House design is great for saving energy, but where they really excel are on those other three most important things: comfort, comfort and comfort. And a comfortable house, with no drafts, condensation or cold spots, is a healthier house.
It will be insulated with rock wool.
TreeHugger has shown some plastic foam systems recently that are effective, but Roxul and other rock wools are totally inert and free of chemicals, non-combustible, inorganic. It will also be wrapped around the outside of the wood structure, much like Susan Jones did in her house in Seattle, and might well be covered in shou-sugi ban like hers was.
More: Does Foam Insulation Belong in Green Buildings? 13 Reasons It Probably Doesn't
What's The Greenest Insulation? It's Getting Harder To Decide Every Day
It will be built on stilts.
Le Corbusier did it "to provide an actual separation between the corrupted and poisoned earth of the city and the pure fresh air and sunlight of the atmosphere above it." And Corb didn’t know about radon gas. Whether it is moisture or radon or vermin, there are a few good reasons to get up off the ground.
But there is also detailing and insulation. By being built on stilts, the whole house can be wrapped in insulation without using any foam- the same rock wool that is in the walls can be under the floor. There is no issue of the connection of the foundation to the house because there is no traditional foundation. The need for careful detailing of thermal bridges is pretty much eliminated.
The stilts will be helical piles, that are just screwed into the ground; they are the least disruptive foundation and will enable the house to essentially be concrete-free, because Yes, concrete is pretty much as terrible for the climate as we thought. See more on the house shown above at A Passive House is built on stilts; Andrew Michler followed a similar path without stilts here.
It will be heated electrically.
It won’t take much; perhaps a few radiant panels. Some might want an air source mini-split heat pump, but that’s another fan and AC motor that I would like to avoid. I never used to think this, but now I really do believe that we live better, electrically.
It will have a big honking heat recovery ventilator with a HEPA filter.
Passive House designs are so airtight that it is essential that a source of fresh air be provided, so HRVs are necessary. It will take stale air from the bathrooms and deliver fresh air to the bedrooms. Air quality is critically important for a healthy home; with a wood home built to passive house standards, you are not going to get mold, but still need lots of fresh clean air. It might even be a unit like the Minotair, Boreal, an HRV with a heat pump built right in so that it does everything- heat exchange, heating and cooling.
Planning: It will have a big vestibule with lots of storage.
Shoes should never come into the house. I once was in a house where the designer actually put a bench right across the vestibule so that you had to consciously sit down, take off your shoes and then rotate around to the other side to put on your slippers; there was no way anyone was walking into that house with shoes. You want the outside to stay outside.
Oh, and there will probably be a sink in the hall.
It will have a separate kitchen that can be closed off.
I know that this is controversial; everybody loves open kitchens these days. But I am not convinced they are such a good idea. Even with electric instead of gas ranges, air quality is an issue. Robert Bean has written:
Since there are no environmental protection regulations governing indoor residential kitchens, your lungs, skin and digestive systems have become the de facto filter for a soufflé of carbon monoxide, nitrogen dioxide, formaldehydes, volatile organic compounds, polycyclic aromatic hydrocarbons, fine and ultra fine particles and other pollutants associated with meal preparation. Toss in the exposed interior design features and what is left behind is an accumulation of contaminants in the form of chemical films, soot and odours on surfaces, similar in affect to what one finds in the homes of smokers.
It is really hard to design an exhaust system that works well; a lot of Passive House designers simply use a recirculating fan (often derided as a forehead greaser) and then have the home’s HRV handle the fresh air. I suspect that an exhaust to the exterior is a better idea, but that we then need a makeup air unit to replace what is lost. But always, the idea of having a big open kitchen, with all that stuff going everywhere, is not conducive to good air quality.
In China, where cooking is fast and smokey, you see a lot of this now in high end homes, modern kitchens with floor to ceiling glass. It is separate in terms of air but not separate visually. Perhaps we will see more of this in North America.
More: Worrying about kitchen fans is exhausting
Hyperventilation about kitchen ventilation
Which is more energy efficient for cooking: gas or induction?
The most screwed up, badly designed, inappropriately used appliance in your home: the kitchen exhaust
The closed separate kitchen makes a comeback
Oh, and the fridge will be very small.
The bathrooms will be very Japanese.
As shown in the series The history and design of the Bathroom and my own Why am I building such a weird bathroom, the tub and shower will be in their own room, the toilet separate in a separate room and with a bidet seat. It is designed around people, not plumbing. (You can tour my bathroom here, it is designed around these principles).
I am torn about whether it should have a composting toilet or not; A good long-drop foam flush toilet, with air exhausted from below, makes for a better smelling washroom without splashing and without putting bacteria into the air when it is flushed, but it doesn’t play well with a bidet toilet seat. Perhaps a traditional bidet, separate from the toilet, is in order.
More: Composting toilets are coming home
Yes, Civilized People DO Have Composting Toilets In Their Homes
The furniture will be vintage.
All of that mid-century modern furniture is made of solid wood and metal, and if there ever was anything to out-gas, it is long gone. Unlike carpets, rugs can be aired and shaken.
Then there is the earlier modernist furniture, the Thonet chairs, the Miesian tubular metal chairs; it was all designed to be light and easy to move. Mies wrote:
It therefore promotes comfortable, practical living. It facilitates the cleaning of rooms and avoids inaccessible dusty corners. It offers no hiding place for dust and insects and therefore there is no furniture that meets modern sanitary demands better than tubular-steel furniture.
The wiring will be DC.
Outside of the kitchen and laundry, except for our vacuum cleaner, every single electrical device in our house is now powered by direct current, through wall warts, and transformers built into the base of every LED bulb in the house. It is already common in boats, RVs and tiny houses, like the Minihome, to go all DC.
It’s time for a residential version of PoE, or Power over Ethernet, now being done in offices. Then we can get rid of all those transformers and run everything more efficiently, can control it more easily. And although the idea of electrosensitivity is controversial, this can eliminate EMF and WiFi from our houses too, with CAT5 plugs everywhere, really at every electrical point in the house.
Another reason for going with CAT5 instead of traditional wiring is that it is available in a PVC free version, a Low smoke zero halogen version designed for plenum use. This makes it possible to go entirely PVC free.
Interestingly, all of the massive wood panel manufacturers claim that their products shield from EMF, blocking up to 95 percent of high frequency radiation like cell phones. The only study I could find indicated that the panels would have to be 18 inches thick to do any good.
More:I converted my home to 100% LED lighting and you should too
Happy Birthday Thomas Alva Edison. You Were Right About Direct Current After All
Is DC Power “slow electricity”?