Home energy efficiency

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					Home energy efficiency
There can be a big difference between an energy efficient home and one
which is not. To help you get an idea of how you make your home more
energy efficient, the following gives a room by room breakdown with simple
tips on improving the performance of your house.

Create your own energy
Most New Zealand homes are well placed to produce their own power. This
can be achieved by micro hydro or wind, and/or photo voltaic panels (solar
panels). Producing your own energy does have an initial set up but this is
paid back through reduced or absent power bills. We have plenty or sun,
wind and water to be utilised, and producing energy where it is consumed is
the way of the future. In New Zealand you can already sell power back to
the grid if you produce a surplus! For more information contact the
Sustainable Electricity Association of New Zealand www.seanz.org.nz.

Ceiling and under floor insulation are the most important aspects of a homes
thermal performance as 40% and 10% of heat loss occurs here respectively.
The ceiling should have thick bulk insulation which covers the joists and is at
least 200 mm deep with no gaps. The under floor should have at the least
foil which is taped to ensure there are no air gaps. Foil-lined bulk insulation,
polyester batting or polystyrene insulation are more expensive but more
durable options. If the ground under the house is damp, putting polythene
sheeting directly on the ground will reduce the amount of moisture entering
the home.

If your home has insufficient ceiling and under-floor insulation (or none at
all), EECA has the EnergyWise program for subsidised insulation. For more
details of the subsidies and grants available and to find out whether you
qualify, see http://www.energywise.org.nz/
Wall insulation is also a very effective way to create extra warmth in your
home. On average, a home loses around 15% of its heat through the walls.
While it is not easy to install wall insulation retrospectively, if you are doing
major alterations or redecorating we recommend removing the gib-board
(especially on exterior facing walls) and installing wall batts.

Note that there is a New Zealand standard on installing insulation which is
well worth looking at if you are planning to do this work yourself. See

Living and Bedroom Spaces
Lounges, dinning rooms and kitchens are communal areas where we spend a
large amount of time. Similarly, bedrooms are where we spend at least a
third of our lives, so making them comfortable and efficient is important.

The first step is draught proofing doors and windows. Draughts may be
responsible for up to 15% of the heat loss in a home. There are a few things
you can do:
    • Plugging gaps with expanding foam (good for big gaps), just be
       mindful about the toxicity of the product you choose.
    • Putting stick-on draught blocker around the door and window frames.
    • Using material snakes at the base of doors or rubber or bristle door

Secondly, make sure you have a good thermal seal with your curtains.
Thermal backed curtains are a good start, but make sure they fit snugly
against the walls and frames. Typically, curtains in New Zealand houses are
designed with aesthetics in mind as opposed to heat retention. Large gaps at
the top, bottom and sides of the curtains allow convection currents to
actively circulate warmth out and though the window and bring cold air into
the room. Ideally all sides should hug the wall/frame and floor, but at the
very least three sides should (you need two of the four sides exposed to
create a convection current). To create a tight seal you can:
     •    Attach Velcro strips or dots to sides of the curtain and wall to
          eliminate gaps
     •    Have curtains long enough to touch the floor
     •    If the curtain isn’t attached by rail and doesn’t have a pelmet (over
          hang at the top of curtains popular in the seventies) construct a
          temporary pelmet in winter with an appropriate material
     •    Replace overly extended brackets with shorter ones
     •    Line curtains with detachable thermal backed linings to increase
          the insulation (see a furnishing or fabric shop for purchasing these,
          or for the materials to make them yourself!)

If the cost of curtaining is an issue, find out if there are any curtain banks in
your area. TradeMe is also good for bargain second-hand curtains.


Something to make sure of is that heated areas can be partitioned off from
other parts of the house so that you are not heating so-called ‘dead spaces’.
Make it a priority to create temporary or permanent barriers, to partition
off heated spaces from hallways, conservatories, laundries etc. You can also
keep power bills down by using timers to switch heating off when it is not
required (for example, you are out of the house or everyone is in bed).

Heat pumps are a very efficient way to heat your home. They have a COP
(coefficient of performance) of up to 3.5 which means you get 3.5 units of
heating for every 1 unit put in.

Wood burners provide an effective, drying form of radiant heat and are
cheap to run. It is important to burn only dry wood and to stoke the fire up
to get it burning at a high temperature. Both these measures improve
burning efficiency and reduce particulates which impact air quality.
Portable gas (LPG) heaters are cheap to buy and relatively cheap to run.
However, there are a number of problems. Firstly, they release around one
litre of water vapour for every litre of gas burned, which can add to the
moisture and condensation issues in a home. Secondly, traces of other gases
such as nitrogen dioxide, sulphur dioxide and carbon monoxide are released
into the air as the LPG is burned. Both of these issues can cause adverse
health effects in susceptible individuals. Ideally - avoid portable gas
heaters, but if you do use one it is important that the space is ventilated
(healthier, but partially defeats the idea of heating!)

An alternative form of portable heating such as electric radiant and oil
heaters is a better choice, but monitor how much you use them as they can
use a lot of electricity when run for extended periods. Electric fan heaters
are useful for quickly heating a small space but as most are rated at least 2
kW, they are quite expensive to run. Again, beware of prolonged use.

When you are space heating, there a few basic guidelines you can follow to
be more efficient:
     •    Only heat when necessary
     •    Ventilate during the day heating as it is more efficient and
          healthier to heat fresh dry air as opposed to stale damp air
     •    Close the doors to areas that do not need to be heated
     •    Keep exterior doors and windows shut and close curtains before
The Energy Efficiency Conservation (EECA) have a subsidy program for clean
heating and have a range of specified clean heating options. For more
information, go to http://www.energywise.org.nz/funding-available/clean-

In the kitchen the most important energy saving focus is the refrigerator.
Make sure the seals are in good order and create a tight seal. If they are
damaged or broken your fridge has to work harder to get to the desired
temperature. You can test seals by shutting a piece of paper in the door and
pulling it out – if it has a bit of resistance then you have a good seal, if not,
you don’t - so get the seal repaired or replaced. Fridges that are more than
10-12 years old are likely to become less efficient, and may use two or three
times the energy of a more modern efficient fridge. This could be costing
you anywhere between $100 and $200 annually (or more if you open and
shut your fridge a lot). You can organise to have your old fridge collected
and get a refund. Check out http://www.eeca.govt.nz/news/energywise-

In the kitchen it is important to have an active ventilation system which is
vented to the outside. This will reduce moisture build up in the home while
cooking. Other easy steps you can take to reduce moisture build up from
cooking include keeping lids on pots and keeping the dish washer shut until
the dishes are dry.

In the laundry the biggest gain you can make is by only washing full loads
and making them cold washes. Half loads waste both energy and water, and
hot washes use up to eight times as much energy as cold washes. If you are
buying a washing machine, go for a front loader as they use a lot less energy
and water.

When drying clothes it’s obviously more efficient to line dry as opposed to
using a drier. If you do use a dryer it is important to vent it to the outside to
reduce moisture build up in the home. In a wet climate (much of New
Zealand) use a covered line or clothes horse and keep inside drying to a
minimum to avoid moisture issues.

Showers can be the most energy intensive part of the house as hot water
uses around of a third of a home’s energy. Measuring the flow rate of your
shower is the easiest energy efficient activity you can carry out. To find out
your shower flow rate, get a large bucket and collect the water delivered in
15 seconds. Measure the amount in litres using a measuring jug and then
multiply the amount by 4. This is the litres per minute. A range of 6 - 9
litres per minute is considered energy efficient. Any less than 6 and you can
give yourself a real pat on the back!

If your shower flow rate is over 9 litres a minute you should seriously
consider replacing the head with a low flow shower head which will pay for
itself relatively quickly. Another option is to put in a flow restrictor in the
base of the hose where it meets the wall. These steps will be especially
applicable to households with mains pressure hot water systems. Obviously
aim to keep showers short (less than 10 minutes) and down to one a day if
you can.

Hot Water
As mentioned above, hot water heating uses around a third of a home’s
energy, so getting it wrong here can have a big impact on the amount of
energy a home uses. The easiest efficiency step you can take for an existing
hot water system is to control the temperature. The lower the temperature
setting on your hot water cylinder, the less heat is lost through standing
losses; however your cylinder should not be set lower than 60 0C for health
reasons. The thermostat on the cylinder may not be accurate. To check the
temperature put a thermometer under the nearest hot water tap. The
temperature at the tap should be in the range of 45-55 degrees 0C,
depending on how far away the tap is from the cylinder. To adjust the
temperature if it is set too high, go to the cylinder and at its base you’ll see
a cover, unscrew it and there is the thermostat. Use the screw driver to
adjust the temperature accordingly and you have saved power and money
with one small turn. If you are uncomfortable doing this, contact a qualified
electrician or plumber. If your hot water cylinder is unwrapped (even if it is
AAA rated) put a reflective bulk insulation wrap around it to conserve heat
and reduce standing losses. Likewise, wrap the exposed hot water pipes
with insulation lagging.
The next tips are a question of habit. If you don’t need to use hot water,
don’t run the hot water tap! Every time you go wash your hands with hot
water which never arrives, you are still drawing on the hot water system
and wasting energy. If you have mixer taps set them on cold and only turn
them to hot when you have to. If you have single taps only use hot water
when you actually need it.

Utilising the sun is an extremely efficient way to heat water. Solar hot
water heating can provide around 75% of a homes hot water and can often
work in conjunction with existing cylinders. New research from BRANZ
http://www.branz.co.nz/cms_display.php shows closed loop drain back
systems work best so it is recommended you install this type. Also, make
sure you use a supplier an accredited member of the Solar Industries
Association. EECA offer a $1000 grant or loan towards the cost of solar hot
water systems, visit http://solar.energywise.govt.nz/consumers/financial-
assistance or phone 0800 358 676.

If you are considering installing a wood burner or replacing an old one there
is the option to utilise it in winter to heat water by choosing a wetback.
Wetbacks heat water as you heat the home in winter (when your solar hot
water system may not be as effective) meaning you are saving large
amounts of power on water heating.

Old style incandescent light bulbs use around five times as much energy as
compact fluorescent light (CFL) bulbs. If you have incandescent bulbs,
switch to CFLs. As they contain small amounts of mercury dispose of them
properly by taking them to a hazardous waste centre or wait for a hazardous
waste pickup in you local area. Don’t put them into the rubbish!

If you have halogen lights you can install energy saving halogen lights which
use a third less energy. There may also be the option to use LEDs (light
emitting diodes) which are the most efficient lights of all. And finally, turn
the lights off in rooms you are not using!

Stand By
Appliances on standby power use a surprising amount of electricity. In some
households up to 10% of energy consumption comes from appliances on
standby! Even if an appliance is turned off with the remote, it can still be
using electricity. In a modern home where their may be 1-2 computers, a
DVD player, microwave, and a number of stereos, the cost of leaving things
on standby can really add up. Get into the habit of turning things off at the

To reduce the running costs of appliances purchase ones with high energy
efficiency ratings. The rating is a based on a star system with the more stars
the better. For more information, go to http://www.eeca.govt.nz/labelling-

Hopefully this has given you a few ideas on making your home more energy
efficient. For further information, contact your local Home Energy Advice
Centre on 0800 388 588 (note that if you are outside the toll free area you
will get a message telling you the best landline number to ring).
Alternatively, you can email an advisor on either:

The Advice Centres are generally open Monday through to Thursday.
We aim to respond to phone calls within 3 working days and emails within 4
working days.

Courtesy of Aaryn Barlow (energy advisor, Auckland)
Edited and posted by Sarah Free (energy advisor, Wellington)

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