I am working with a builder on a custom home, over 4,000 sqr feet. Is it possible to have too many windows? Looking through Houzz, I see walls made out of windows; large arches and transoms, etc. – need sunglasses to sit in the living room?
These are certainly beautiful. I am sure they are expensive. Any drawbacks?
What type of ‘flair’ features (transoms, etc) are worth the money? My builder tells me these adders above the windows can come close to doubling the price tag.
Thanks,
Ted
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Replies
There are a few drawbacks to windows
They can complicate HVAC loadings, you can have UV issues, you mignt need more structural support and they can present problems in "windborne debris" areas.
Modern low E, thermal, impact rated windows are far more expensive than a standard wall.
I do agree, when the view is worth looking at, big windows are worth paying for.
no draw backs if the price tag doesnt give you a heart attack.
HVAC contractors are required manual J's to pull permits (at least here) in those calculations they are suppose to show how they have taken into account all these things.
It can get kind of awkward when they install a window between the bathroom and the party room. (Though it may make the party a bit more lively.)
In California....
...if you use a prescriptive approach to energy design windows are limited to 20% of the floor area total and 5% west facing. If you want more than that calculations are necessary which most likely will require substantial increase in the building energy efficiency elsewhere.
it's all relative
You may as well begin to answer this question by asking yourself the inverse: "Can I have too few windows?"
Mike:
Is the 20% guideline related to the Energy Star program for residential houses?
Also, are there any areas of construction and design that would adequately compensate for more windows? I have seen some framing jobs with 2x6, which I assume is for added insulation (energy and/or noise).
Thanks,
Ted
windows are an energy effeciency compromise
I think the important thing to remember is that windows will always be a compromise to your thermal envelope effeciency. In the past, most typical 2x4 walls (insulated with fiberglass batt) could easily achieve the code value of R-13. Currently, most good windows will have an R value equivilent somewhere between R1 thru R3. Even triple pane windows will rarely achieve better than an R-6. Since most energy codes and energy performance standards are now requiring R-19 or greater for walls, (with the best windows thus only able to achieve roughly a third of that value) you can see that it is, from an energy performance perspective, a good idea to limit glazing area*.
*However, an exception to that rule is if you intelligently using passive solar heating techniques that utilizes glazing exposure to your advantage. This would mean incoprating heat sinks in terms of thermal mass in the correct places and movable insulating panels over glazing area during the night to reduce loss of daytime heat gain. In my opinion, most builders and homeowners are currently not up to this joint effort.
Performance.
The 20% guideline is a prescriptive requirement. To exceed this requires energy calculations on the entire building envelope. In the past there was a point count system that could be manually applied, but no more. Trade offs for more windows include insulation. Increasing wall insulation is certainly one way, but not necessarily the cheapest. Factors in the calcs include wall and cieling insulation, mechanical systems efficiency, thermal mass and passive gain etc. I haven't been through the process in a long time so I don't know what trade-offs are typical. My son knows alot more about it than I do. I'll ask him. Calif. is divided into 16 climate zones the requirements vary by zone. See the attached table.
I think the term "too many windows" is pretty subjective. Lots of room for opinions.
My opinion is that the fewer the better, within reason. Obviously you need some for egress and ventilation. But even for ventilation - With modern HVAC systems and the risk of break-ins, I don't see many people leaving their windows open any more.
I'm very suspicious of the concept of passive heat gain. In the winter when you need heat, you have 2/3 of the day is dark and 1/3 is light. In the summer when you don't need heat, it's just the opposite.
Although if you can afford a 4,000 square foot house, the cost of the windows and utilities most likely isn't a concern.
Why be suspicious?
BossHog wrote:
I'm very suspicious of the concept of passive heat gain. In the winter when you need heat, you have 2/3 of the day is dark and 1/3 is light. In the summer when you don't need heat, it's just the opposite.
Passive solar building techniques have proven successful for a long time. You may not be as suspicious if you considered sun angles change seasonally. Or, maybe you're suspicious of overhangs as well.
passive solar rocks...
Passive solar heat gain is completely predictable with engineering tools. It would be far more common if house design was more often form follows function.
Here is the state university spreadsheet for how many window the state legislature syas you can have and still get a building permit in the state.
All states are different, some locals dont have codes, so whatever you want. Too bad we got codes here, thanks due to the few ripoff artists in the building trades.
I guess it depends where this home is being built. In the summer, they will let in a lot of heat from the sun and in the winter a lot of cold. the owners should consider what type of drapes/curtains/blinds will be the most energy efficient.
but with the view and all the natural lighting im sure its worth it
Drapes etc should be considered of course, but proper siting of the home and architectural details could provide more bang for the buck. These give results that take care of themselves to keep the warmth of the sun outside in the summer while allowing the heat in for the winter.
retaining the warmth in the cold months is a bit more difficult. Insulated shutters can seal up a window well. Loose drapes and blinds allow circulating air to pass, almost defeating their purpose. I've worked in some northern homes that had electrically operated quilted drapes contained by channels. Pretty good seal and with a timer, not much effort for the resident.
Wall space?
I think any improvements/new construction should keep in mind what will affect the sell-ability of the house. Would future buyers want to have some wall space? Besides the additional cost of heating/cooling and loss of shear value (in CA) you need space to hang artwork IMO. And I cringe at the thought of cleaning all those drapes or blinds, although those who don't feel the need for privacy opt out of window coverings.
Well, you can have too much of anything, including nubile girls, alcohol, drugs, money, food, spare time, even windows, etc. I know it's unbelievable, but it's been proven over and over.
I'll believe the one about nubile girls when I see it.
Well...
Everybody was nubile once upon a time.
Well.....
calvin wrote:
Everybody was nubile once upon a time.
I was once nubile ...
Then I started drinking beer.
Last night
Had a bottle of beer last night that registered 10 point something on the label........
whoa!
much less filling.
.
I read that part on the internet, can't speak from experience.
I think the real answer is that the number of windows has an inverse relationship to the weight of the women living in the house. The relationship is linear up to around 140 pounds and becomes exponential once you pass 2 bills.
Apology time
No, I strongly disagree. It was not a nice thing to say at all.
I'm not even sure what it's supposed to mean. Fat women don't like windows? Skinny women are exhibitionists?