Are operable windows an unnecessary extravagance in a today’s green houses?
rocket190
| Posted in Energy Efficiency and Durability on
Just wondering if in today’s climate controlled and mechanically ventilated houses if having windows that open defeat the purpose of meticulous consideration to air sealing and humidity control.
Are they strictly for luxury now? Ease of cleaning? Is there still a need to “air out” your house?
P.S. I do understand the need for a small number of egress windows for safety and building code requirements.
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Replies
Rick,
As you realize, every bedroom must have at least one operable window meeting code requirements for emergency egress.
Most homeowners like to be able to open their windows when the weather is pleasant. Even in Dubai, the weather must be pleasant for a few days a year.
I suppose the one exception I can think of is Antarctica. But even the occupants of the buildings at McMurdo Sound may like to open a window occasionally.
Rick,
I don't think operable windows defeat the purpose of a well sealed building enclosure.
As Martin points out, it's a nice option to be able to open a window...
And even if the house is "leaky" through open windows, that leakage is predominently through those window openings (not a durability concern) instead of through interstitial spaces within wall and ceiling assemblies (durability concern).
I guess I was thinking that maybe whats commonly installed is a bit overkill. If a room has four windows maybe only one needs to be operable for adequate ventilation?
For the windows I'm looking at the price difference between a tilt and turn triple glazed window with hshg is about 2.5 times more expensive than a fixed window of the same size. It seems like the money saved could be used towards something else.
It seems like every "green" house these days is a $1,000,000 home where little consideration is given to the cost of the features. For most families a $500 or $1000 dollar savings is huge. In my case, scaling back to the minimum of operable windows would save nearly $8,000
Alternatively I could ditch the triple glazing and stick with the double glazed Cardinal LoE180 package and save $2,000
Rick, I build and many times aid in the design of what I build. For decades now we have installed windows that do not open. Mountain and lake view homes have many such windows.
I just built a dormer addition that had 9 windows with 4 operable though that could have been cut to just 2.
I say continue to explore non standard ideas and plans... grouped casements often times have less that operate than the whole line.
Caveat; I am a fresh air lover... my favorite home design (never built) is my "sail" home... inspired by outside winter pools surrounded by glass walls... somehow with adding some sail cloth.... some "duck in out of the weather" spots.... radiant heat.... a source of free GEO heat.
aj
More window thoughts... transom windows, views toward the passing clouds, the upper canopy of trees.... standard 6'10" rough openings are not my cup of tea.
I think that operable windows should be chosen judiciously, considering their higher cost, lower durability, and higher potential for air leakage. I wouldn't categorically call them unnecessary though.
I was thinking about this recently with regard to my own (small, humble) home.
In the living room, we have two windows, both fixed. I think this makes sense. They're mostly for viewing and light.
In the kitchen, we have two operable windows. I think this makes sense, as temperature and air quality can be an occasional issue in the kitchen, even with good ventilation. In our house, the kitchen also looks out over the back yard, where the kids play, so we can yell at them as needed.
Dining room has one operable window and I think maybe this should be fixed instead. Then again, sometimes it's nice to hear the birds while eating a meal.
Kids' bedroom has a casement egress window and two fixed windows. Perfect. I don't think there's much use for operable windows in bedrooms other than for egress.
Our bedroom has two single hung windows. I think this would ideally be changed to one casement and one fixed.
Bathroom, not sure. We have a skylight.
Rick,
You're right that being selective about the number of operable windows can save you money and I agree that it a smart thing to think about.
I saved quite a bit on the windows in my own house by doing just that.
Another way to save money on high quality windows without compromising their performance is to look hard at options like odd shapes, custom jamb extensions, grilles, mullions etc. - these features can add up quickly.
Caveat: I can be a bit of a function over form type of guy.
Rick, it's funny that this debate has trickled down to small residential structures when it occurred in large commercial buildings decades ago.
Large residential and commercial buildings have always routinely been designed so that their occupants were not in control of the mechanical ventilation and could not open windows - and people hated it. The pushback meant that many buildings today now contain operable windows. It's important to remember that there are many reasons to want access to the outdoors.
Houses are not simply machines for living in designed primarily for efficiency. They are cultural artefacts there to fulfill all our needs, all the things that make us human.- including psychological ones.
Some evening take the time to watch an old Italian movie, perhaps something by Fellini. People talking with their neighbours or calling their children from the window. The cat uses it to go outside, a birdcage sits on the sill. Now imagine that scene with a hermetically sealed passive house. Loses something doesn't it?
Malcolm,
Your comment reminds me of a year-long stint I did training in a facility in Cornwall, ON.
The facility included residence, cafeteria, gym, pool, games, pub, classrooms, simulators, computer stations, etc. - all hermetically sealed and climate controlled.
The intensity of the training was such that, literally, a week or more could go by before you realized you hadn't stepped foot outside.
The jokes were that we were actually travelling in a spaceship.
And that the windows didn't open so that you couldn't throw yourself out.
It was weird.
Lucas,
I think there is something interesting going culturally and I wish someone with an insight into it was writing on the subject. Green building used to be very much about back to the land, dirty fingers in the soil, communing with nature - and along with that the occupants of the early houses seemed willing to put up with a certain amount of fluctuation in the performance of their houses as the seasons changed.
Now it seems to me that many high performance houses appear to be perched on the land with little relationship or access to their surroundings beyond a completely scenographic view through their windows. The idea that a brisk fall breeze blowing through on a sunny September day might be invigorating or that the conditions outside might have any influence on the inhabitants indoors seems anathema. Are we really seriously debating whether we should ever open a window in our homes?
Malcolm,
I said something similar a few years back and it wasn't a popular suggestion. I live in a building with poor insulation and aluminum windows, but easily meet Passive House energy limits. How is this possible? It's easy, you could do it anywhere, but you give up having a steady 20°C / 68°F on a dim winter day. When it's cold, close the windows. When hot, open the windows.
It's worth remembering that everyone was net zero and had no carbon footprint until the 19th century. A yurt or teepee is certainly more "green" than a building surrounded with thick layers of foam, and would historically have been much more energy efficient, despite having essentially no insulation or air sealing. But comfort is something of a sacred cow, and you get nowhere suggesting temperature is a useful variable to adjust in meeting energy use targets.
Look at the Earthship concept by Michael Reynolds--no steady climate control there, and lots of demands on the occupant to open/close windows at the right times. Probably builds character to live that way, but it's far from mainstream.
Malcolm,
You wrote, "I think there is something interesting going culturally and I wish someone with an insight into it was writing on the subject. Green building used to be very much about back to the land, dirty fingers in the soil, communing with nature."
In fact, I have written on this topic (although perhaps not with as much insight as you would like). Here's what I wrote:
"There are at least two recognizable camps in the green building community. The older camp includes hippies, owner/builders, and those in the natural building movement. These builders prefer to scrounge materials from the woods or demolition sites rather than purchase new materials from a lumberyard. Their homes might be made of adobe, logs, or straw bales.
"On the other side of the aisle is the newer camp of builders who emphasize energy efficiency and high performance. This group includes fans of triple-glazed windows and heat-recovery ventilators, as well as builders who brag about their blower-door results. The Passivhaus adherents can be found on this side of the aisle."
To read more, see Low-Road Buildings Are Homeowner-Friendly.
Matin, From reading your blogs and from the glimpses you have provided into the way you live I've long had a sense that you are aware of the divide and would be more comfortable if it were bridged. I guess my questions are more around where this new attitude to nature and our surroundings has come from. I suspect it is a larger cultural phenomenon and may have to do with other aspects of modern life, but beyond that I don't have any real insights.
I think the "third way" which may hold some promise is to look back to strategies from the past, like houses that expand and contract with the seasons and rely more on their natural surroundings for their success. Placing the whole burden on the building envelope to mitigate poor siting and cutting us off from our surroundings seems like a poor strategy on so many levels.
With current high quality windows, the tradeoff from fix to operable is mearly a budget one,
energy wise there is not much difference.
So then it becomes a personal choice of which and how often you would like to open windows,
climate situation etc..
I have many, many windows in my new house,
most are fixed, bedrooms all have operables and i've dsigned the first floor so that
we can ventilate it from using the house pressure difference from the patio to the 60ft far awning in the living room ( all first floor is 1 large open room )
I wouldn't live without hearing the hundreds of birds in the morning of spring /summer/automn days... With the current cost of mini splits AC, in cold climates, it cannot be an energy decision
as the cooling energy requried is ridiculously small ...
all comes down to budget VS personal
About the "green divise " ... if you wish to build a very green log cabin in a cold climate,
and use 2 months per year of your time to prepare wood for heating ..be my guest
i have better things to do with children, arts etc...
There is a fragile balance between "hippie green" and "neuPassiv green " ..
.
Durability and efficiency of well built/design green buildings using materials that provide the right balance between green and efficiency is where the fun is!!
Malcolm,
No I don't think we are having that debate because I agree with you.
As a "budget conscious" home builder however, I do think there is an opportunity to save some money by thinking strategically about which windows should be operable and which windows will likely never be opened.
As to the broader question of culture I agree that there is certainly something interesting going on - and not necessarily for the better either.
But the vagaries of cultural influence on individual behaviour and decision making is a very deep well to explore.
I agree with TJ Elder that "comfort" has become something of a sacred cow.
Not just in terms of tolerance for some variation in temperature or humidity, but also in terms of what constitutes a "comfortable" size, what amenities are required for "comfort" and probably more.
But isn't it one of the benefits of "progress" that human beings should be able to expect their individual comfort as a basic right (at least for those who are in a position to demand such "rights")?
Is this type of "progress" (to continuously strive to make ourselves more comfortable) an imperative of human existence?
Is this realistic?
Or is it just a very interesting story we've all been repeating to ourselves?
Lucas, By this point we have probably driven off most of the readers looking for building advice so we may as well continue. I wonder if we aren't in danger of conflating comfort with uniformity? One of the joys of the changing seasons and of travelling is the stimulus of the senses - which can include sensations that aren't necessarily comfortable. Unfamiliar smells, cold gusts or humidity that hits you like a wall. All of these things help engage us with our surroundings and enrich our experience. My fear is that the pursuit of comfort masks a detachment which may lead to us seeing nature and the outside as being inconveniently beyond our control. It is definitely a trend which has simmered among some utopian visionaries for years. Remember the domed cities of Popular Science? I hope the quest for a less energy consuming lifestyle doesn't lead to a retreat from all the wonderfully messy life that surrounds us.
TJ Elder,
It's funny how we never think twice about having to actively modulate our temperatures by donning or discarding layers of clothing when outside but bridle at any active control when indoors.
Malcom i do like you view ... Experiencing nature complexity is non exclusive of home comfort. This is still a personal decision/behavior.
As an example, i am what some would call " a true north canadian " in mind.. i would never consider living in any place that does not have a long winter with deep snow and chilly temperatures, as it is a part of my life, a necessary sensoriel experience cycle. I do enjoy working /sporting outside during all of winter ... then majestic spring with its reborn feeling and warm sun on cold ground contrast ... living without experiencing seasons, temperatures...nature would be inconcievable for me .
That said, i still enjoy having a warm ,stable, comfortable house during most of the year.
One does not preclude the other.
Then about windows, options are always better than no options nah ???
Not all windows need to be operable, even only 1 per room can make a great difference if you wish to "feel" the exterior.
Lastly, please don't bring up old views of Italian or other moderate/warm countries building design that includes no sealing or windows whatsoever .... Just does not relate to our climates in NA .
Exactly as german PassiveHaus standard does not smartly apply to zone 6-7 in NA without modifications .
Jin,
Taras Grescoe has written an interesting book on Quebec called Sacre Blues where he talked about Montreal's "war on winter". Well worth a look.
Through my open bedroom window this morning I hear the Wood Doves have come back!
Malcom, interestingly i've never heard of that book before ..will add it to my book "queue", which have not progress for a few years now :p
Your mention of " Montreal " is not reassuring as to the pertinence of this book though ..
i consider Montreal to be one of the worst place to live in Quebec.
( ok i do hate cities and close by neighbors )
I'd say as far as 50%+ of Montreal residents have no idea of what nature is other than through movies.
Malcolm,
I share your concerns...
There is much to be lost by loosing touch with the messiness and uncertainty of the natural world.
The best meals (the most memorable; those that gave me the greatest experience of satisfaction) haven't been lavish buffets or holiday spreads I've come across, but rather simple fare after a long period of labour with little to eat.
It's hard to believe how good a handful of mixed nuts and a can of V8 juice tastes when you're that hungry, until you try it.
The way I see it, embracing some adversity in life is beneficial because it builds character and allows a person to appreciate "comfort" to a higher degree without having to "crank up the volume" to 11.
Supressing the "messiness" of life creates a temporary state of relative order and certainty (and "comfort") but at the cost of quietly activating hidden time-bombs.
Malcolm,
I thought you might find this article interesting:
http://www.sparringmind.com/supernormal-stimuli/
It relates evolutionary biology with the psychology of having the "volume" constantly "cranked up to 11".
Very very interesting aticle ...
The best line is the last :
Those who do not move do not notice their chains.
—Rosa Luxemburg
:)
Great posts.... my excuse to mes with my winter habits... is Spring finally just a few hours away...
Aware of habits... breaking them even for a day.... I like that and do that.
Thanks for the links Lucas and all
aj the dinosaur