Are Net Zero Energy Homes now Affordable?

As a home builder, I attended a seminar on this subject yesterday and it stimulated my thinking afresh on the viability of building a home that operates on $ Zero energy costs, including electrical power, heating and cooling.  Who wouldn’t want to live in a home without having to wearily pay out $200/month or more every month for electricity and natural gas?  There has been a confluence of new energy standards in new building construction and a reduction of the cost of some energy producing methods that we are getting tantalizingly close to building Net Zero at no additional cost.

One of the presenters yesterday, a bright, talented and enthusiastic speaker made a pitch that a Net Zero home could be built at no extra cost than a conventional home.  While his premise contained a fundamental flaw of logic, he did present some great ideas which I will add in to some of the ideas here that is helpful to reaching that goal of designing and building a Net Zero for at least a minimum of extra cost.

 

Mindfulness of Energy Use

This can be a critical aspect of design of a Net Zero home.  A family who commits to being mindful of energy use can reduce energy requirements significantly and thereby reducing the power requirements of the home and reducing the cost right upfront.

In another blog post of mine, I chronicled how our family reduced energy consumption by almost 30% with effectively no lifestyle changes.  Here is my post from 2015:

How we Cut our Energy Use

There are some minor lifestyle changes which can change your energy use significantly.  For instance, a 1C change in your temperature can reduce heating or cooling costs by around 4%.  That means wearing more in the house in the winter, and wearing less (to whatever your decency standard is! 🙂 ) in the summer.  Try to get most of your cooling by fans, which are cheaper to operate than AC units…..and cost a lot less upfront too.

There are probably a hundred “mindfulness” strategies that can be employed in reducing your energy consumption.  Interestingly, many of those ideas can be accessed from your power and gas supplier, at least in our area.  If you are already a minimalist consumer of energy, then building a Net Zero home will be much less expensive than if you are a large consumer.

 

Design For Net Zero, not Design then add Net Zero

This is critical in keeping costs down.  Many new homes these days are remarkably complex in design and that adds a lot of cost without really adding much to the livability of the inner space.  If Net Zero is given the first consideration, then building costs can be lowered significantly and will make up some of the extra upfront costs in building Net Zero.

For instance, designing a home that is as square as possible can be noticeably less costly to build.  A markedly rectangular home needs more exterior walls to get the same square footage…..and exterior walls are very expensive because of the expensive exterior finish, the insulating costs, and the increased exposure to the heat and cold of the outer environment.  Also, a building that has a lot of jogs in it not only adds more exterior walls with very little increase in the coveted square footage, it also adds a lot of costly corners.

Build a two story or a bi-level rather than a bungalow.  That reduces the roof size and foundation size.  Not only are roofs and foundations expensive, heat tries hardest to escape through the ceilings.

Again, there are many other design ideas that can be employed but the trick is to put Net Zero first into the design, and then look for inexpensive ways to improve the aesthetics.

Technical Inclusions:Keep it Simple and Know your Numbers

There are no shortage of energy-saving products and techniques out there. Not only can they get technically confusing, they can also get remarkably expensive and your project will get out of hand.  The principle of Occam’s Razor suggests that the simplest solution is usually the best.  “Don’t do anything that can’t be explained and economically justified in 25 words or less” is a good rule I like to follow.  And know the numbers.  How much is this particular technique going to cost?

So in the interests of keeping it simple and lowering the costs, here some of the least cost and simplest techniques in working toward a Net Zero home without a lot of extra expense:

  1. Make your home super sealed.  This pretty much mandated by building code these days anyway but make sure the job is done meticulously.
  2. Make the exterior walls double 2×4 walls.  You can get up to R32 with very little additional cost, if any, over an R24 2×6 wall that still transfers heat through the exposed studs.  Here is an example:     8_cgh_ph05
  3. Add additional blow-in insulation in the ceiling.  R65 is not much more than code in our area, and very little extra expense, but very beneficial as heat wants to rise through the ceiling first and foremost.
  4. Preheat your fresh air entering your home by running tubing underground first to capture geothermal heat.  If you keep a small “cold room” in the basement, make sure that tubing enters that room first as well before entering the Heat Recovery Ventilator.
  5. Make your windows strategic and triple glazed.  By strategic, they should be located exactly where you either most need the natural light or will capture the view you need.  Increase your overhang on the south walls to keep the house cooler in the summer without losing the heat gain in the winter when the sun is lower.  Don’t use conventional skylights…..using the Solartube are a lot less expensive and will bring in natural light with less energy change.
  6. For a Net Zero home, you will need to produce power.  The best and simplest way to do it is Photovaic panels.  The cost of these systems have come down dramatically and are simply tied into the grid where you will get credit for power produced that is not used.
  7. This may sound like heresy, but heat your home with electric heaters.  Your capital cost will be considerably lower and the additional solar panels will be minimal but you won’t have to install a furnace and a lot of expensive ducting.  For a higher cost but most comfortable method, use in-floor heat with a gas or electric boiler, which will handle your hot water as well.

 

The Extra Cost?

Depending on design, it is certainly possible to build a Net Zero Home for very little extra cost per square foot (if any) as the average home in your neighbourhood, as long as you are disciplined on all aspects of design and construction.   It will depend a lot on your builder and how he/she approaches construction.  I have a “collaborative” model of building that has been successful in reducing building costs considerably regardless of how you build.  Not all clients are ideal candidates for collaborative building, but most who are willing to tackle a custom home project are.

In the end, the benefits are huge.  Not only do you effectively eliminate the carbon footprint of your home, but a $200/month savings in utilities is the same as your monthly mortgage costs of a $45,000 mortgage…..so it is a $45,000 benefit over the life of your mortgage.  And when you go to resell, presenting your buyer with a utility bill of $zero will make your home a pretty compelling sale.

Being carbon wise is no longer the costly preserve of a small segment of committed environmentalists, it is now starting to make sense for your cost of living, freeing you up from paying your energy providers and using the savings for things you really care about!

Bruce Murdoch, bgmurdoch@gmail.com

K-Country Homes   250-417-6681   http://www.kcountryhomes.com

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4 thoughts on “Are Net Zero Energy Homes now Affordable?

  1. Excellent article. I believe that one of the factors that keeps me from investing in solar is the fact that through competition the price keeps going down and I don’t want to miss out on the next best technology. I suppose for this reason I may be waiting forever. LOL.

    • The cost is certainly tumbling. Just a few years ago it cost about $10/watt installed and today it is under $3/watt, depending on where you live. “First adopters” usually pay too much for any new technology but with photovaic solar, we are getting very very close to this becoming mainstream. We aren’t there yet but Duetsche Bank is predicting that by the end of 2017, 80% of the world will be at “grid parity” for solar, assuming another 40% cost reduction (solar has been getting cheaper by 20%/year for the last decade or so).

      So save up your pennies for a 2018 installation! 🙂

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