NYTimes: Passive House in Seattle

BB.BB. Super Moderators, Administrators Posts: 31,784 admin
A NYTimes article about passive homes in Seattle/US:

http://www.nytimes.com/2013/08/15/garden/the-passive-house-sealed-for-freshness.html?smid=pl-share&_r=0
On paper, at least, the Ritchies’ home sounds too good to be true: an environmentally responsible house without traditional heating and air-conditioning systems that will be an airy 70 to 74 degrees on the coldest day of winter and the hottest day of summer, but use only a fraction of the energy consumed by a typical house.
And yet it’s not some experiment or futuristic dream. Nearly 30,000 of these houses have already been built in Europe. In Germany, an entire neighborhood with 5,000 of these super-insulated, low-energy homes is under construction, and the City of Brussels is rewriting its building code to reflect passive standards.
But in the United States, since the first passive house went up 10 years ago, in Urbana, Ill., only about 90 have been certified. Why aren’t they catching on here?
Part of the problem is the cost. Higher fuel prices and energy taxes in Europe provide a major incentive to embrace passive standards, which are complicated and make construction more expensive. In this country, it could be a decade or more before the energy savings someone like Don Freas enjoys in his 1,150-square-foot passive house in Olympia, Wash., offsets the extra $30,000 or so it cost to build.

Includes some links to various websites/versions of passive home associations.

-Bill
Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset

Comments

  • NorthGuyNorthGuy Solar Expert Posts: 1,925 ✭✭
    Re: NYTimes: Passive House in Seattle

    It's not that difficult in Seattle. They should try this approach in Northern Canada, or in Tucson for that matter
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: NYTimes: Passive House in Seattle

    why do they always show a sliding glass door? they are over-sized wastes of energy and to me pose a security risk.
  • RandomJoeRandomJoe Solar Expert Posts: 472 ✭✭✭
    Re: NYTimes: Passive House in Seattle

    I suppose it's a tradeoff. I want a nice view from inside, and am willing to suffer the hit to energy efficiency. The house can be the most efficient in the world, but if I can only look outside through tiny portholes I don't want it!

    Still, I think I'd prefer French doors over the boring sliding patio door.

    The security risk is a bigger issue, though at least looking at my windows I figure it'd be far easier to break one of the regular windows, get inside, then open the door normally. Breaking the patio door glass would make a LOT more noise!


    First thing I thought of with this passive house was "what about air changes?" Of course they cover it - an exchanger to bring fresh air in. But that *requires* power, and that the mechanical device function. If it breaks, you may not have long before the humidity shoots up and things get nasty... The exchangers I've used typically have two blower motors and a third motor to turn the heat wheel (for the ones that also dehumidify - essential where I am). Those are larger commercial models, so maybe you could design a smaller house model with only one fan blower motor. Still, lots of moving parts. And fairly frequent filter changes to keep that heat wheel from plugging up with dirt from the outside air.
  • stephendvstephendv Solar Expert Posts: 1,571 ✭✭
    Re: NYTimes: Passive House in Seattle

    We originally planned to build a passive house, and had the plans drawn up and certified by the Passivhaus institute in Germany (we ended up building a smaller cheaper house, for various reasons). But the process was interesting and the criteria to reach certification was quite extreme even for a house in Spain. The most problematic bits to comply with were the need to insulate underneath the foundations and floor and the level of air-tightness they required, which the local builders didn't really know how to achieve.

    We used a spreadsheet produced by the PHI to do all the design calcs, and that was really interesting and useful because it included climate data from various locations and you could model potential design changes, e.g. if we reduced the south facing wall insulation, but increased the north facing, how does that influence the overrall energy use?
    The most interesting was the south facing glass. By default the northern europeans recommend using triple pane low-e argon filled windows to reduce heat loss in winter; but in the spanish climate it turns out that using double pane glass was better because it allowed more light through to heat the house. Of course, we then also needed more shading of the windows in summer to reduce the risk of overheating.

    What I didn't like about the process was that for some components like the mechanical ventilators/heat exchangers, there were a few models that were certified by the PHI and you could just plug them directly into the spreadsheet to model the results. But if you chose a model that wasn't certified then the certification process cost more because they would have to contact the manufacturer to find out how they did their testing and got their efficiency numbers.
    The certified units were hella expensive, for a small home the cheapest was around 2500 euros.
  • NorthGuyNorthGuy Solar Expert Posts: 1,925 ✭✭
    Re: NYTimes: Passive House in Seattle

    Looks like a tedious process. I wonder what are benefits of the certification?
  • stephendvstephendv Solar Expert Posts: 1,571 ✭✭
    Re: NYTimes: Passive House in Seattle
    NorthGuy wrote: »
    Looks like a tedious process. I wonder what are benefits of the certification?

    Yes it was tedious and costly and I wouldn't do it again. Benefits are potentially higher resale value in the right type of market, and the knowledge that the design was done properly. And bragging rights :)
  • westbranchwestbranch Solar Expert Posts: 5,183 ✭✭✭✭
    Re: NYTimes: Passive House in Seattle

    As to security concerns, this is the brand of window we chose though not with the added security layer... very interesting video.

    http://www.euroline-windows.com/resources/videos/clips/euro_02.html
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: NYTimes: Passive House in Seattle

    interesting that they addressed the concerns of security and i'm sure it is costly to obtain. it will still pass heat fairly well for most designs. this is true of windows as well and some homes do have an excessive number of windows that can negate savings elsewhere. if you are good with the losses then ok, but i would be content with a door and no window on it.

    the point was brought up on what direction it was facing and that can have a good influence on whether it would be a loss or a gain overall. heat gains through solar are great, but a means of making those gains worthwhile by sealing it off thermally at night pose problems as then the poor insulative nature of the glass doors at night could out weigh the gains during the day.

    face it, most of these glass doors are crap and far more expense and trouble than they are worth just for a view.
  • BB.BB. Super Moderators, Administrators Posts: 31,784 admin
    Re: NYTimes: Passive House in Seattle

    I like the idea of heat recovery ventilators (and my wife loves fresh air)--However, when I looked at them a few years ago, one for my home seemed to draw around 350 watts or so--That is ~8.4 kWH per day--Almost equal to the entire electrical load for my home (if I run the ventilator 24x7)... And in electrical power $$$, almost 1/2 my winter heating bill (natural gas).

    Figured I can leave a couple windows cracked open and not weather seal the heck out of everything and sill come out ahead even with some heat leaks.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • RandomJoeRandomJoe Solar Expert Posts: 472 ✭✭✭
    Re: NYTimes: Passive House in Seattle

    It just occurred to me getting any house I was planning to live in certified would be a waste of time. I'm always tinkering - running a wire (power, LAN, coax...) here or there, maybe doing some piping... The extreme air-tightness wouldn't last the first year with me! :roll: I suppose I *could* go to the bother of sealing things back up again... But looking at what I've done in the house I'm currently in... Nah, that's highly unlikely! :p

    One option that could greatly reduce the ventilator runtime would be to include indoor humidity and CO2 (or even better IAQ) sensors. Run the ventilator occasionally to "freshen up" the air as desired, or whenever the humidity or CO2 levels rise sufficiently to require purging. Of course now we're starting to move from simple "thermostat" controls to "smart homes"!
  • stephendvstephendv Solar Expert Posts: 1,571 ✭✭
    Re: NYTimes: Passive House in Seattle
    BB. wrote: »
    I like the idea of heat recovery ventilators (and my wife loves fresh air)--However, when I looked at them a few years ago, one for my home seemed to draw around 350 watts or so

    That sounds like too much. The PHI approved units (and many others in the same league) draw around 0.24W/m3, e.g. this one: http://www.greenbuildingstore.co.uk/media/page_content/MVHR/Technical%20downloads/Technical%20overview/Novus-300-technical-overview.pdf
    Draws 117W at full tilt, and 17W at minimum.
  • BB.BB. Super Moderators, Administrators Posts: 31,784 admin
    Re: NYTimes: Passive House in Seattle

    That would be getting better... However, the link goes 403 for me (Forbidden).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • stephendvstephendv Solar Expert Posts: 1,571 ✭✭
    Re: NYTimes: Passive House in Seattle

    that's odd, works for me. Here's the tech landing page: http://www.greenbuildingstore.co.uk/page--paul-mvhr-technical.html
  • BB.BB. Super Moderators, Administrators Posts: 31,784 admin
    Re: NYTimes: Passive House in Seattle

    The second link worked for me...

    Some light reading in the morning.

    Thank you,
    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • stephendvstephendv Solar Expert Posts: 1,571 ✭✭
    Re: NYTimes: Passive House in Seattle

    Hehe, I think the Canadian's have perfected the art of efficient and cheap MVHRs. Their units tend to be much better priced than the same stuff in europe.. can't recall any manufacturer names though.
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