When complete, this Net Zero home will include a completely integrated green house on the south side as well as a deck and outside garden over the garage. The insulated garage roof is ready for the load.
​Design is by Dale Parkes of Project Green Architecture, Kamloops BC.   www.projectgreenarchitecture.com

Getting to Net-Zero.  Design factors that pay back and put you closer to self-sufficiency

     When many people think of a net-zero energy home the assumption is 'that's all fine if your a millionaire and willing to part with about that much money'.
     The truth is .... well that can be true for some choices, on the other hand there is a priority order of investments that bring short to medium term paybacks. Consider short term payback is within 10 years.  Medium term may be up to 15 years +/-.  Long term is 20 years +/-.
     Payback calculations in reality can be a very complicated GUESS, but what is usually seen is these facts in order of priority:

1. Insulation factors walls, roof, and floors is always the first and lowest cost upgrade. There is Zero maintenance to these items for the life of the home so it is a missed opportunity not to put more insulation in when it is the least cost. Our Graphite EPS packs in around 18% more insulation per thickness than regular EPS and 40% better than Fibreglass batt. 
   ​     Under-slab insulation is also important for crawl spaces, and more-so for slabs on grade. R16 or R24 is recommended. If the slab is to be heated, more is better.  On an unheated slab economizing could be done by insulating thicker at edges for 4' then go thinner in the core of the building. R16 type 2 high compression EPS under slab foam is only $1.35/ft2 and it goes down fast.  Radiant barriers have to work in an air space -so don't waste your time putting SilveRboard under the slab -it becomes and expensive vapour barrier.
        R-58 walls and R-60 roof is a solid start to less energy needed for space heating.  Combine that with passive solar gains!​  We always check heat loss based on the total exposure of all energy losers including windows and doors.
2. Windows and Doors are usually the next item to upgrade, often tied with the domestic hot water energy costs. Westeck windows has a very high grade 2 pane window that is close to an average 3 pane from most providers. Upgrading to triple pane is a good boost to efficiency -but monitor the cost /benefit of that. One way to economize for window upgrade is to only triple pane windows in your sitting room and dining room, where you spend most of your awake time. Minimize quantity and size of windows when you can. The frame set around vinyl windows is also a weakness of 3 pane windows.
       Put opener windows where you know you need them and the rest should be picture windows for more efficiency and save on the budget.  Casement windows seal better for wind leakage than slider windows and multi latch casement windows are a must.
       Most doors are very bad at insulating due to seal challenges and the cold sill plate. Knob and dead bolt also transfer a lot of energy. Keep the count on doors in check and try to avoid double french doors unless your paying a lot of money for highly rated doors. They will be very leaky and cold in winter months making a great room, a cold room. If you are looking for more light and visibility consider a 6' or 8' wide slider door. If you go quality you get good performance, lock set, and smooth operation.
3. Air leakage. If there are leaks there will be drafts and discomfort -usually felt at the feet in the cold weather. The bottom area of wall cavities can also get condensation of inside air leaking outwards. SilveRboard in A-Plex walls and roof is a first class air barrier and it reflects all the radiant energy back into the building also. Vapour Barrier leakage may be related to air leakage and usually is the same barrier. The vapour barrier needs to be on the warm side of the wall in winter when condensation potential is most severe.  Sealing at roof ridge, roof to wall, wall to floor floor to foundation are all leaking points.  The A-Plex system uses pre-insulated rim boards and lapping sheathing from the walls to create a glued and sealed highly structural join. A final application of A-Plex 2# spray foam seals all transition areas for a perfect system. 
4. SOLAR PANELS. If you are mechanical or electrically inclined you can take a course and install your own grid-tie PV system with some tie-in help from an electrician.
   The payback on self installed panels is around 10 years.  This represents a 10% return on investment. If you hire a total installation by a company the payback approaches 20 years and that is around a 5% return on investment -still respectable.  For most people that pays better than interest at the bank. At a 5% rate of return, a 3% loan on PV panels can net you a 2% gain right away -and as power goes up in cost you can add that to your savings. 
5. Mechanical choices. This is a long subject, but for now a short discussion. After A-plex is specified the highest energy cost will be for hot water.  Read further down for more on hot water. 
       An HRV (Heat Recovery Ventilator) also needs to be used. It is optional in the code  but when a building is tight & energy efficient there is a very real payback -not to mention healthy air factors.  The HRV captures 70% to 80% of the energy from the living air of your home.  An average adult breaths 54 lbs of air so think of the HRV as a lifeline to healthy air.   The other benefit of the HRV is ZERO recirculated air. 
       A ductless heat pump system should be source of heat for space heating and though it is expensive there is a payback.
   A much lower cost of heat is electric baseboards at only 100% efficiency and ductless heat pumps average for the year is 200% to 300%.
6. Design choices for the home should focus into and around energy efficiency -especially when it comes to maximizing good south facing exposure. If you don't have good south exposure, then that is another reason to make good energy decisions.
         The openings and exterior spaces influence the homes architectural design.  A well insulated home holds heat very well when the sun energy comes in through the glass, which is the essence of passive solar design. South windows should be maximized and the roof overhangs need to be positioned to block the summer sun yet allow full winter sun exposure.  This only works on the south.  West and East facings have exposure from a low sun -In the mornings the sun is low in the east and afternoons low in the west.  Deciduous trees are good on east and west sides.  
       The sighting location on the property for view VS sun VS the owners wants is what design consultation is all about. The layout in the home can often be made to work for both south and view.  North windows should only be installed for view reasons or natural lighting in the room. Less is better for North windows.  For rural properties it is really important to get a site review done for septic locations and discuss your wants for the home location with the septic field designer because your choices here can add many thousand onto the cost of your septic system. Detailed home design before septic location should be minimized. 

This wall pictured below is our 11.75" wall with a net R60 insulation factor. Notice the mid section with 100% insulating foam plus the Silverboard on the inside face from top to bottom and zero studs in it.   The lumber costs in this wall are IDENTICAL to a 2x6 code minimum wall with studs at 16" o.c.  The only up-cost for this wall is more insulation and the first class heat reflecting vapour barrier.  Why miss that low cost extra insulation opportunity?

A HRV (Heat Recover Ventilator)
-An essential item for air quality and energy recovery in a low leakage home

Our drawings include a full window and door listing linked to updates

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In your research for a hot water system we recommend a power pipe to recover shower hot water energy when the home layout allows this. If a shower is the daily regime that creates the most demand for hot water. A "Power pipe" www.powerpipe.com can recover 55% of the hot water energy from the drain water during a shower -so essentially this more than doubles your efficiency of hot water at least for shower time.
​    For hot water systems there are 3 choice groups from least to most cost:  

1. Regular hot water tank $400 to $1100 (1 year to 10 year warranty)
2. Tankless hot water heater $800 to +$2000 (electric VS gas & warranty)
3. A heat pump hot water system $2000 to $8000 (size and efficiency and function features).  
   ​The illustration below shows a heat pump hot water tank and there are different configuration of this.

     The basis for energy design levels comes from designated climate zones from 4 to 8 with 8 being the most severe.  Designing for Net Zero should use two zones higher. Any new home will always see payback with insulation values for the next higher zone.
     A look at the total costs of installed extra insulation and resulting energy savings should show that upgrading insulation levels always yields short term savings since the interest payments on the cost of upgrades costs is less than the savings.  There is a level of insulation at a very high level where the payback is too long.