Home wellness, but make it physics
Home wellness from a physics lens: daylight, acoustics and air quality decisions you can lock in at concept stage.
“Home wellness” right now mostly means:
a freestanding bath no one uses,
a rubber plant trying to survive in the dark,
and some candles.
Meanwhile:
the bedroom is 18°C at 10 pm but 28°C at 3 am,
the ensuite fogs up if someone even thinks about a shower,
and the kids’ rooms smell like a school bus by morning.
So let’s say the quiet part out loud:
If you care about wellness, start with thermal comfort and indoor air quality.
Make that the wellness trend. Everything else is garnish.
ASHRAE 55 and ISO 7730 – the “comfort standards” – are basically science’s way of asking: “Are normal humans actually comfortable in here, most of the time?”
Not “is it 20°C by the thermostat,” but “does this space feel good to sit in, sleep in, work in?”
After 15+ years staring at data from homes that look like retreats on Instagram but feel like a sauna / fridge combo in real life, I can tell you: the projects that age well nail three things, in this order:
Thermal comfort
Indoor air quality
Daylight (yes, still important – but not first)
Let’s walk through each in plain English.
1. Thermal comfort: not just “what’s on the thermostat”
Thermal comfort in ASHRAE 55 / ISO 7730 is a mix of:
air temperature
radiant temperature (how hot/cold the surfaces around you feel)
air movement
humidity
what people are wearing and doing
Or in client language:
“Do I feel too hot, too cold, or ‘can’t get comfortable’ even when the number on the wall looks fine?”
You’ve seen this play out:
Winter: thermostat says 21°C, but someone sitting by the window is freezing because the glass and slab edge are radiating cold.
Summer: air temp isn’t terrible, but there’s no air movement, so it feels like a slow cooker.
The standards just put numbers around that experience. Your job at concept stage is to set the house up so most of the year, most people are in the “I forget about the temperature” zone.
Concrete moves you control early:
Envelope quality
Decent insulation where it actually matters (roof, walls, slab edges)
Thermal bridges tamed – not just “we’ll tape it” and hope
Reasonable airtightness so you’re not heating the neighbourhood
Drafts vs gentle air movement
No cold jets of air at ankles from leaky doors and downlights
Some deliberate path for air movement in summer (ceiling fans, night‑purge paths)
Zoning and set‑ups
Bedrooms that don’t share walls with uninsulated garages
Heat sources where they can warm people, not stair voids
A quick litmus test with clients:
“If I can keep most rooms in your house inside the comfort band where people forget about temperature 90% of the time, is that worth more than stone benchtops?”
Most sane people say yes. If they don’t, great – you’ve just learned they’re here for aesthetics only, and you can stop pretending otherwise.
2. Indoor air quality: the invisible wellness feature
Now for the awkward truth the wellness marketing rarely touches:
A house can look like a spa and still give you a headache and a cough.
Indoor air quality (IAQ) is mostly:
CO₂ – stale, stuffy air when rooms are closed and people are breathing
Humidity – too high = mold and dust mites; constantly wet bathrooms; never‑dry towels
Pollutants – cooking fumes, VOCs from finishes, random stuff that off‑gasses
ASHRAE and friends have opinions on “acceptable” levels. Clients don’t care about ppm; they care about:
“I wake up with a clear head vs. fuzzy”
“The bathroom actually dries between showers”
“The house smells clean without smelling like chemicals”
This is where I’m going to repeat myself from Post 2 because it’s that important:
Ventilation is key above everything else.
Not sure what to spend your money on? A balanced, low air‑flow ventilation system for the whole house will quietly do more for wellness than 90% of the lifestyle features.
At concept stage, this means:
Deciding the ventilation strategy upfront (natural + smart openings, or balanced mechanical, or a hybrid)
Drawing real extract locations for bathrooms, laundry, and kitchen that vent outside (not into the roof)
Ensuring supply air reaches bedrooms and living spaces even when doors are shut
Designing the envelope tight enough that ventilation is controlled, not random
We’ve tested hundreds of homes that “meet code” but hit tropical humidity inside the minute winter starts and everyone closes windows. The ones that feel genuinely healthy — lower CO₂, reasonable humidity, no mystery damp smell — all treated ventilation as a core system, not a finish.
Awkward but important: if your design is even moderately airtight and there is no coherent ventilation strategy, you are building a wellness brochure with a hangover built in.
3. Daylight: important, but not a substitute for comfort
Daylight still matters. Humans like bright spaces. It helps with mood and circadian rhythm. But too many “wellness homes” start with “wall of glass” and never quite make it to “how does this actually feel in February at 3 pm?”
Here’s how I’d position daylight, after comfort and IAQ:
Ensure key spaces (living, kitchen, main work spaces) get useful daylight for most of the day
Avoid “cave” rooms that need lights on at midday
Control glare and solar gain with shading and reveals so the daylight doesn’t wreck thermal comfort
So yes, it’s still one of your three big levers — just not the first cab off the rank. You’re designing for eyes plus skin plus lungs, in that order.
Turning standards into design moves (without turning meetings into lectures)
You do not need to quote ASHRAE 55 or ISO 7730 at clients. Please don’t.
But you can quietly use their logic:
Aim for temperature ranges and air speeds that feel neutral most of the time
Avoid big temperature swings between surfaces and air
Keep humidity in a “not swamp, not desert” zone
Supply enough fresh air that CO₂ and smells don’t build up
Then talk like a human:
“The goal is a house where you don’t think about temperature or air – it just feels right most of the time. Not perfect every minute, but no big swings, no sweaty nights, no damp seasons.”
That’s literally what the comfort standards are trying to do, just with more equations.
A real‑life “wellness” house that actually behaves
Take a compact 3–4 bedroom home with the usual wishlist: calm, healthy, low‑energy, not weird‑looking.
What we locked in, at concept stage:
Thermal comfort
Continuous insulation, including slab edge
No heroic glass on the worst orientation; decent shading where we did go big
Aiming for tight‑ish but not obsessive airtightness, so the building is controllable but buildable
Indoor air quality
Proper extract to outside in all wet areas
A small balanced ventilation system sized for gentle, continuous airflow
Ducts and grilles drawn on the plans so they didn’t end up in stupid places later
Daylight (as the third lever)
Solid daylight to main living and work areas
Daylight “good enough” in secondary spaces without creating glare or overheating
One or two well‑placed roof windows, not a glass roof
A year in, the client’s feedback wasn’t, “We love the curated greenery.” It was:
“The house feels the same almost everywhere.”
“We barely think about turning things on and off, it just works.”
“We noticed the kids get fewer colds since moving here.”
That’s ASHRAE 55 / ISO 7730 doing their thing quietly in the background, without a single graph on the wall.
When “wellness” is more buzzword than brief
Sometimes a client says “wellness” and means “nice bathroom and maybe a sauna.”
That’s fine. You’re not here to police their lifestyle.
But you can be clear about the trade‑offs:
“We can absolutely invest in those features. If we also invest in thermal comfort and air quality — the boring backbone — those spaces will actually feel like the retreat you want. If not, it’s a luxury bathroom in a house that’s still cold, stuffy or damp half the year.”
If they still choose the tapware over ventilation and envelope upgrades, that’s on them. At least you said what others won’t.
Make this the new wellness trend
So if you’re selling “wellness homes” or even just “good homes,” I’d put it like this:
Thermal comfort – calm, stable, no big swings
Indoor air quality – fresh, dry, low‑drama lungs
Daylight – bright enough, not blinding
Focus on thermal comfort and indoor air quality, health, wellbeing. Make that the new wellness trend.
A builder told me last week, “Clients will drop five figures on a tub they use twice a month but won’t spend half that on ventilation they use 24/7.” He’s not wrong.
And no, your house isn’t “healthy” just because it has plants and a yoga mat. It’s healthy when the physics quietly has your back.
