Hi all we have been doing some energy modeling with the two story house I built in the fall.
We have modeled the house several different ways.
Code built house
R40 Ceiling, R20 Walls, no insulation in basement, double glazed low-e argon windows, R20 Rim joists, average (I consider below average) air sealing of 4.55 ACH.
Advanced Framing House (This is what we built)
R60 Ceiling, R40 double stud walls, R20 in basement, R10 below slab. Triple glazed Low-e, argon windows. air tight home construction 1 ACH or below.
Mechanical system changes.
from electric baseboard heat, (considered to be the least effective and energy efficient) to a geothermal heat pump system, with forced air heating. (considered to be the best of the best)
Basically in a cost vs effectiveness, making upgrades to your houses thermal envelope, was almost twice as effective as mechanical systems dollar per dollar.
Furthermore there is very low to no (maybe less) additional maintenance issues with a better preforming building envelope. There are always going to be maintenance, and repairs needed on mechanical systems.
Advanced framing techniques are actually going to save the client money. Immediately. Why is our current energy codes letting people build houses that are worse for the environment and cost the user more money. I believe we need to stop believing that technology is going to fix houses and our energy problem, and realize that a penny saved is a penny earned, in this case two penny's earned.
This is just the tip of the iceberg. when you start taking about passive house levels of insulation, and energy savings, this is what we are going to need to look to the future of energy efficiency. These advanced framing techniques I believe should be commonplace. They are going to save Everybody money and reduce our CO2 emissions.
Below I have attached a chart outlining the different changes, and have related them to the cost of ownership.
Thanks to the hard work of Garth Hood of Thoughtful Dwellings http://twitter.com/#!/ThtfulDwellings who did the energy modeling for us. Garth is a NBHBA Energy Advisor and a strong advocate for green/energy efficient building methods, also pushing hard for Passive House.
In your reply to Brad's comment, This most definitely will work with a Slab on grade, with heavy insulation levels on the exterior of the slab. That is why i have developed it... it only takes up another 3" of wall space on the inside of your structure than a typical 2x6 frame.
The windows are best installed In the center of the insulation layer of the wall. Poor installation of windows can decrease the effectiveness of the window immensely. (up to 50% less effective in a passive house, due to poor window integration with the wall)
The roof will be ventilated as per normal, it will have a 1-3 inch air gap on the top of the insulating layer to let it breathe through the soffit. depending on what insulating material we use will depend on how we accomplish it.
A little bit on terminology.
R Value (the most common of what you will hear spoken at your local building supplier) as defined by Wikipedia The R-value is a measure of Thermal Resistance, Under uniform conditions, of the materials in question. (basically how well a material resists the flow of heat from one side to the other)
R values are often given to a materials such as R4 per inch is type 2 Styrofoam. The Higher the R value the better.
The only problem with using R values to evaluate how walls perform is that walls are usually not just made up material, they are carefully put together and designed to balance structure and insulation so we need to classify our walls as a whole unit rater than individual parts.
U-value (or U-factor), more correctly called the overall heat transfer coefficient, describes how well a building element conducts heat. It measures the rate of heat transfer through a building element over a given area, under standardized conditions. The usual standard is at a temperature gradient of 24 °C, at 50% humidity with no wind (a smaller U-value is better).
Taken from Wikipedia http://en.wikipedia.org/wiki/R-value_(insulation)#U-value
Basicly U Values are assigned to a material or a group of materials, Walls/Windows/Glass/Window frames etc and oddly the smaller the U Value the better. preliminary results/modeling put my walls at around a U value of 0.1025 witch translates to R 55
The rate at which heat is transmitted through a material, measured in watts per square metre of surface area for a temperature gradient of one Kelvin per metre thickness, simplified to W/mK. The Lower the value , the better the thermal efficiency of the material .
Lambda values are what is imputed into the PHPP (passive house planing package) software when calculating U values for walls etc. and each materials has a specific value.
I have been working hard on developing my passive house walls. hopefully they will hit the R50 mark once all the wood and thermal bridging has been taken into account.
I've included a sketch, and one picture from the mock-up i built quickly yesterday to help me look for problem areas, found a few things that i needed to address, and thought of a few solutions too. sometimes you just need to build something to get away from the office work. Starting from the outside. siding - rain screen- wood fiberboard (i used scraps of osb in my mock-up) homemade truss type thing to create large space for insulation. - structural framing layer 2x4 or 2x6 - air barrier OSB tapes with special tapes - service cavity (will be stuffed with bats) - wall finish. Hopefully this all will be approved by all the inspectors etc...
Look at all the Room for Insulation!!!!!!!!
Passive Pedia, online resource for Passive House building
I feel like there is a new era before Southern Exposure. A new way of thinking, of how we even approach building. In December I attended a building course put on my the Canadian Passive House Institute ( PassiveHouse.ca ) and had my ideas of how we approach building in North America turned upside down. Before i get to into things why don't i tell the story of how i even got to this point.
I am a licensed carpenter, and i have gone through the fantastic apprentiship program here in New Brunswick, I don't know if other people are like this or if this is just my passion for what i do but i just want to keep learning how to do things better, new approaches, higher standards, high quality, healthy homes, that are comfortable to live in.
I have always had some issued with how we approached building both in building methods, and how size often trumps functionality, comfort, and quality. What we see with our eyes is often how we regulate a quality, there is a saying that can sum up this idea's of how we are tricked by our eyes " putty and paint, will make it what it aint" my hope is to look at the house as a whole package not just what you can see hear and touch, but whats behind the walls? how is this house going to preform in all 4 seasons, does it optimize the building site? the view? how are the walls going to berethe, how does it grow with your family. does it provide the best functionality for your lifestyle?
There is so much to consider when building a new home.
so where do you start? this is something i will expore over the next couple of posts.
In the meentime please enjoy a few links
I hope your day is fantastic.
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