How much does it cost to NOT build energy-efficient?

12 July 2017
Posted by: Evolution
Time to read: 4 min

The most pressing consideration when planning on building a home is cost.  No matter the budget, the person footing the bill will always want optimal value for money.

Aesthetics in the form of design and fittings are an easy sell as they are visual and usually the first aspect people notice in a home.  Think of the last time you walked into someone’s home, what did you notice first?  The hard wood floors, the high gloss kitchen, the dramatic view from a picture window?

We rarely remark on the performance of the home, unless the interior temperature defies our expectations.  In a ski town like Aspen, a cold home would elicit remarks.  In an alpine resort like Queenstown, central heating is not the norm, so a warm home in the winter gets noticed.

In the end, we build our homes for our own comfort, performance and ease of maintenance.  Additionally, our homes are very often our most valuable financial asset.

Whilst it’s enjoyable to hear that our homes appeal visually, we need to plan and build our homes to deliver just as much on the pragmatics, such as health outcomes and long-term investment.

So rather than asking, “How much does it cost to build an energy-efficient home,” we need to consider, “How much does it cost not to build one?”

To answer the initial question, increasing the quality of a home building from minimum code to a level that achieves better performance commensurate with a Homestar Six rating costs approximately 10% more.

Offset that extra investment by considering the potential returns.

It takes time to notice how well a home performs; how warm is it at midnight mid-winter?  How well does the structure weather over the years?  How healthy is the environment of the home for its occupants?

New Zealand is in the period of greatest activity in terms of residential building, having from 15,000 new homes in 2012 to over 30,000 currently.  Pressure to produce quantity over quality will come at a cost, however.  Building to the minimum code, which seems outdated compared to that of countries like the US, the UK and Germany, creates homes that look lovely, but don’t perform optimally.

In addition to higher running and maintenance costs, modern homes may still incur serious issues, similar to those we have seen in the recent past.  “Experts agree that leaky homes are still being built in New Zealand, and the health costs from them could reach into the billions,” according to Tom Hunt, Sunday Star Times (June 18, 2017).

Leaky homes have historically referred to residences that suffered weathertight issues due to poor design or construction, but this adverse outcome can also result from moisture-control issues from within the home.  For example, unmanaged humidity levels on the inside can form condensation within unseen areas, such as exterior walls.  Mould is hazardous to our health and the integrity of the structure of the building.

In addition to lowering costs associated with maintenance and illness, energy-efficient homes use fewer resources and less money to operate. 


This graph documents the energy use of Evolution homeowners during Winter 2015.

An airtight envelope makes it easier to control moisture movement through external walls and to control interior temperatures using less energy.  Tapping into renewable resources such as photovoltaic panels that convert solar energy into powering the home, and even electric cars that can be recharged in the garage, means cheaper power bills and cleaner air. 

By using a holistic approach to build an energy-efficient home, we create homes that are healthier, more comfortable and cheaper to run.

Finally, as awareness of the manifold benefits of high performance homes grows, these properties will command premium prices on the property market.  The cost of securing independent certifications such as Passive House and NZGBC Homestar ratings are key to verifying that the home has been designed and built with performance as a priority.

By future-proofing our homes as we build them today, we will eliminate the need to retrofit features to bring them up to speed as the building code evolves.  The potential longevity of a house will allow its occupants to enjoy living in the home for years to come or to sell it and see it yield maximum returns on a wise investment. 

So, the real question is not how much does it cost to build an energy-efficient home; it is how much do you lose by not building one.

Read related article, "Eight Questions to Ask After "What's Your Square-Metre Rate?"


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