Thursday, October 13, 2011

Lifestyle compromises in an ultra-energy efficient home (or welcome to the world of ventless dryers)

Autumn at our patch of dirt
(This blog entry was written by Paul)

A Passive House uses 10% of the heating energy of a traditionally built house.  Once you spend the extra time, effort and money on designing and building a home to the Passive House standard are you done?  Is it business as usual living in a Passive House or do you need to make some compromises?

So far, we’ve been asked to get comfortable with two things that are a little different from our current way of doing things, tilt-turn windows and ventless dryers.

Double or hung or sliding windows don’t cut it in terms of energy efficiency.  They just don’t seal well enough at the seam where the windows on different tracks meet.  In the US, we have casement windows which create a much better seal, but the most energy efficient windows being made are from Europe.  These European windows use a tilt-turn system.

After searching the web to learning about tilt-turn windows, I only had one concern.  Because the windows open by tilting inwards, I was worried about being able to close a blind or shade with the windows open.  Since our house is going to have one foot thick walls, the windows can be installed such that there is a very deep window sill.  This will allow the windows to tilt in without breaking the plane of the inside walls.  Having spent the last several winters up here in northwest CT with less efficient sliding windows, I look forward to having tilt-turn windows that really keep the heat inside the house.

Ventless dryers were a different story.  The problem with a vented dryer is that it pumps quite a bit of air from the room where the dryer is located directly out of the building envelope.  One of the fundamental principals of a Passive House is air tightness.  The only air that enters or exits the envelope should be through the energy recovery ventilation (ERV) system.  Vented dryers are inconsistent with this principal.  (Dear ERV designers, it would be really cool if one could vent their dryer through the ERV system)

So, vented dryers won’t work with a Passive House.  What’s so bad about a ventless dryer? 

  • Might be slower than vented dryers:
  • Are smaller than vented dryers (7.3 c.f. vs 4.2 c.f.)
  • Are much more expensive than vented dryers.
  • Are reportedly less energy efficient (excluding venting issues, but this is difficult to confirm since no dryers have an EnergyGuide).
  • Require periodic cleaning of the condenser
  • Air cooled condensers heat up the room they occupy (I think that all the ones I’ve seen on the market are air cooled)
  • Water cooled condensers use additional tap water
  • A bunch of lint that gets through the lint trap to the condenser seems like it will be making it’s way to the septic system.
  • No need for a vent that forces hot air out of your house at > 100cfm which must be replaced with cold air from outside.
  • Air cooled condensers heat up the room they occupy (nice in the winter)
There are not a ton of models available in the US:

Cubic Feet

 4.2                  LG       DLEC855W
3.95                 Bosch  WTE86300US
4ish                  Miele   T8013C
4ish                  Asko    793C

In Europe and Asia, they also have heat pump dryers which are just like condenser dryers but 40% more efficient.  Bosch apparently has a model, the EcoLogixx 7 that uses the condensed water to clean itself reducing maintenance.  But in the US, the vast majority of dryers sold are vented, so we don’t have access to the latest and greatest in ventless dryer technology.

The main issue is that the ventless dryer is going to make doing laundry take twice as long to do.  We’ll need to do two dryer loads for every one that we currently do.  We’ve decided that we can live with this.  We might try to get around this by buying a second dryer for the laundry room.

So, as far as I can tell, apart from issues with the clothes dryer, living in a Passive House shouldn’t require much in the way of lifestyle compromises.

If you’re interested in reading more about ventless dryers in a Passive House check out

Saturday, September 17, 2011

The lay of the land

Our "patch of dirt" in early spring
First of all, thanks to all my friends and neighbors who have read this blog.  Many of you seem genuinely interested in our process and have asked several great questions about PH.  Mostly in the realm of "How will you stay warm in the winter?"  Without getting into the long answer right now, let me just say you will all be invited over next winter to find out.  All non acquaintances reading this blog, I'll address that question in a future post when the details of the mechanicals have been finalized.

Last week we met with a Site Planner/Landscape Architect from CR3 named Gary Hath.  We have many elements to arrange on the site in addition to the house that need careful planning.  Solar exposure and orientation is very important in PH design. We also have to consider water runoff management and install a septic system.  There's lots to plan such as the lawn/play field, veggie garden, stone patios, septic field, driveway/approach to the house, landscaping and flower gardens, and tennis court (after all, we are the Honigs).  These element are being mapped out so the site can be properly graded and the foundation dug once the house plans are approved.
First version of the site plan

Oh yes, the house plans.  Our architect Jamie Wolf is busily working on the detailed schematics and energy analysis of the house plans to submit for approval to get our building permits.  We have scale drawings of the layout of the house and Jamie has even created a 3D computer model of the interior and exterior.  It's starting to feel like a real place.  Jamie is doing a fantastic job of taking our needs, wants, and vision for our family and shaping them into a physical space that works on many levels: aesthetically, functionally, energy efficiently, etc.

Paul and my homework this week has been to start looking at appliances, cabinetry, flooring, tile, and fixtures. It is early in the process but we need to have all the "fixin's" ready to go in as soon as the structure is built.  For appliances, energy efficiency is paramount.  We are planning on choosing low VOC cabinetry.  I've ordered some samples of bamboo flooring and recycled glass counter tops made out of beer bottles.  The design style we are going for, I describe as Modern Farmhouse/SOHO Loft (you can take the girl out of New York,.....) which to me feels warm with an open layout and some wood elements.  There are also a few surprise architectural elements. I can't wait to throw our first party.

Sunday, August 28, 2011

What it is and what it isn't.

At this week's meeting with our architect Jamie, we were shown a wonderfully informative PowerPoint presentation about the Passive House Planning Package.  The PHPP, once again over simply, is a monstrous spreadsheet containing hundreds of different elements that effect a house's energy performance.  There are factors assigned to each of the different building variables which, when all of the numbers are calculated, will give the building a pass or fail score. The certification criteria is specific to 1) energy required for heating, 2) total specific primary energy demand, and 3) air changes (air tightness) of the building.  In other words, Passive House is about energy usage.  After the house is built, there is a rigorous certification process requiring lots and lots of documentation and an inspection.  When completed, it's either Yes or No, certified or not. 

Many people confuse the term Passive House with Passive Solar, LEED certified, or a Green Building.  Yes, passive solar gains can be a large factor in achieving Passive House standard.  Many people who are interested in Passive House strive to use "green" materials and crate as small a carbon footprint as possible with their home.  They are related but not the same.  I just wanted to clarify what Passive House is and what it isn't.

My friend Ellen Sinreich, a LEED Accredited Professional (, said to me, "You don't have to stop there."  We should also be concerned with things like water consumption, the materials we choose,  the energy it takes to manufacture or import materials, etc.  We plan on using low VOC paints, rapidly renewable flooring materials like bamboo and cork, and as many local materials as possible.  I'll also plant a large organic vegetable garden and several fruit trees.  Man! I can't wait to live in this house.

Wednesday, August 24, 2011

Welcome to our new (but not yet built) home.

Thanks for your interest in Our Connecticut Passive House.  We are the Honig Family and we are embarking on the domestic adventure of our lifetime.  We are building a Passive House (or Passivhaus) in Harwinton, CT, a lovely town in the Litchfield Hills. For those who are not familiar with the term, oversimply, Passive House is a German developed standard of building/design creating an ultra-insulated, ultra-energy efficient building.  Our home will have a sealed envelope (no air leakage) and a heat exchange fresh air ventilation system to retain most of the internal temperature.  And here is the kicker, No Furnace.  That is the part most people react to when I describe PH, especially in New England.  More later on how we arrived at the decision to build a PH.  For now I would like to explain where we are in our process and why I'm blogging about it.
We have purchased a lovely 2 acre piece of land that we affectionatley call "our patch of dirt".  We have hired a wonderful PH certified architect, Jamie Wolf ( and are deep in the design process with him and his staff. We have weekly design meetings and the preliminary design drawings look great.  At tomorrow's meeting Jamie will show us the energy model of our house design acording to the PH standard.

While we were exploring the possibility of a PH, I did a lot of web research.  One of the more helpful resources was other folks' blogs about the process of building and finally living in their Passive Houses.  It helped me to feel that we too could create this type of domocilic lifestyle of environmental responsibility and comfort.  I would like this blog to surve that same purpose,  to inform and inspire others.  Sharing information and experiences.  How can we effect change in the world with our own little patch of dirt?