NYTimes: Passive House in Seattle

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.

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.

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

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.

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!

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"!