A well designed Energy Efficient Home can:

  • Easily maintain a comfortable living temperature, year round

  • Reduce Energy costs, costs which will increase with time

  • Minimise nasty allergens by controlling the environment 

  • Moderate internal temperature, eliminating mould and decay

  • Improve quality of life with inherently warm homes in winter

  • Fully control of ambient temperatures and humidity, regardless of outside

  • Optimise views, efficiencies of design, and general aesthetic peace of mind

  • Keep solar storage at arms length from living quarters. Best example is a basement


Health consideration

On a sunny day, a typical EEH home with only nominal ancillary heating, and when sited correctly, can maintain a comfortable temperature inside, even if the outside temperature is -40c 

"The control of internal moisture to prevent high humidity and growth of bacteria, Mould, Fungi, and house dust mites can be achieved by a combination of insulation, ventilation, and heating. Temperatures below 16.5c can cause a higher susceptibility to respiratory illness, and are also associated with higher relative humidity that allows the of bacteria, mould, fungi, and house dist mites."   

Source: BIA (NZ Building Industry Authority) News, July 2003, Edition # 133, P7



"It's not the temperature, it's the humidity"

Nothing could be further from the truth. The average temperature of a home in NZ in Winter, where the outside temperature hovers around freezing, is 9c-12.5c once the home is "cold soaked" (i.e. overnight). The house probably has some rooms close to the outside temperature of 0c. while the odd occupied room is somewhat warmer. 

In the middle of winter in Canada, when the outside temperature is often -40c or colder, the home is an economical constant +18 to +-22c inside. Some locations in Canada such as Vancouver Island (Similar to the NZ Fiordland area in moisture) have a mild climate, with VERY high relative humidity, and yet all homes maintain a constant healthy  temperature, mitigating the ambient dampness and attendant problems. The UK is another good example where energy efficient homes have turned the damp climate around using warmth as a tool to improve lifestyle, plus health and comfort, simultaneously.

There are many reasons why NZ homes are seemingly colder than most countries in the wintertime:: 

  • Cost to heat is high (Very true in non efficient homes)
  • Hereditary: Parents lived this way so it must be OK
  • Its the "British" way: (Even the Brits don't live like this any more.)
  • Poor planning and weak government construction codes
  • Cost to upgrade and generically poor NZ home designs
  • Outside temperatures generally seem so moderate.
  • Masochism & mindset that "its OK".

"As an Ex-pat Brit, I have never been so cold in my life 

than living in a NZ B&T in winter"

NZ:  Typically in NZ, Kiwis might heat only a room, one that's occupied at the time. Sleeping is normally done during a temperature inversion as the bedroom cools to a few degrees above outside temperature. This is typical of "olde English" heritage, however; even the majority of Brits no longer live like this and haven't for years.

While sleeping in a cool room is desirable, a Bedroom or any other room that sits below 16.5c is a breeding ground for all kinds of problems, not the least of which is mould and mildew. It is also a key element in the high propensity for Asthma in NZ.

If you take a cold clammy house and raise the core temperature of that same home to over 16.5c, (i.e. 21c) it will feel totally comfortable, regardless of the ambient humidity. In most developed countries, including cold places like Canada and the UK, thermostats hold the house to 21c during the occupied times and 18c during the night and while unoccupied. This is the best range for comfort and health

Of course the only way you can achieve this during the winter without breaking the bank is through heightened Energy Efficiencies in the home and optimized solar, either passive or active or both. This includes Maximum insulation in walls and ceilings, and the best insulated Windows.

As EEH homes are exactly this, only marginal ancillary heating is required. Other items such as Trombe walls, Thermal mass heat sinks, optimized overhangs, orientation, all contribute to the healthy warmth (and coolness in summer) of your home. 

All this in a land with nominal winter temperatures, where excess solar energy falls on most of the country with enough energy to heat to keep all homes comfortably year round, when  used correctly.  EEH homes are the first step: If the home shell is Energy Efficient, you can take advantage of nature to keep you warm.


Ancillary Energy Efficiency and home "Climate" control

Some efforts are common sense, i.e. hardwood floors instead of lots of carpets, other efforts are slightly more esoteric, but non the less effective.  For example:

  1. Air to Air forced heat exchangers, continuously circulated fresh and or warmed/cooled air

  2. Electrostatic air cleaners, can be used in conjunction with Air to air heat exchangers, heat pumps or simply stand alone. These units are highly underrated in NZ, but are a fantastic piece of kit. They can separate out and obliterate most of all airborne particles. Typically units can remove or reduce:

  • Pollen,  

  • Smoke, 

  • Dust,

  • Plant and mould spores,

  • Bacteria,

  • Viruses and more

Other under rated considerations

  1. Central Vacuum: Simple pipes installed during construction, allows unfettered access to a central vacuum system. The unit is located out of the way, for instance in a garage, and the exhaust vented outside. All microorganisms, dander, dust mite, and general dust is not re-circulated in your home but blasted outside. You only carry around the hose and head to vacuum.

  2. Central ancillary heating can combine items 1, 2 above, and 3 below. Even in the most southern location, a small heat pump will be able to keep an EEH home toasty warm right down to the heat pumps lower limits. (Efficiency of heat pumps generally begin to drop off as the outside temperature drops below -10  degrees Celsius.     see Heat Pump Primer)

  3. Built in Dehumidifiers.







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