Take the power back

An annual energy audit of your home is a great way to keep the family well. The less efficient a house is at using power, the more likely it is to have cold and damp spots – and the link between childhood respiratory diseases and damp housing is well known. In some regions of New Zealand one in five babies sleeps in a damp home.

The good news is that by running through an energy-use checklist you can improve the health of your home and family, cut down on sick days, cut your energy bills and reduce power consumption – which is critical to our efforts to cut carbon emissions.

Hot water 

Most households spend about $650 a year on hot water. You can easily save on this by:

• Wrap your cylinder – costs about $60; save up to $80 per year.
• Insulate hot water pipes – pipe wrapping is about $5 per metre from hardware stores.
• Know your flow – the average annual water bill for a family of four is $864. Slow down raging shower and tap speeds with a flow control device (around $30) and you could halve your water usage, saving $430 per year. Also fix dripping taps – a leaky one can drip 10 litres a day and cost $8 dollars a year for those billed for water use.
• Beat the heat – recommended levels for energy efficiency and safety are between 55-60°C.

Moisture

Checking your home for damp is an important first step. If the source of any dampness isn’t tackled, insulation and heating will be far less effective.

Check areas where moisture lurks, such as:

• Kitchen – consider installing a vented range-hood if your stove doesn’t have one.
• Bathroom – is there an extractor fan vented to the outside of the house? If not, add it to your to-do list.
• Laundry – is your drier properly vented? Can you dry your clothes outside?
• Under the house – if the ground under your house is damp, check your plumbing and drainage. It may be worth laying damp-proof sheeting.
• House structure – check for leaks and wood rot.
• Consider using a humidity gauge to measure dampness on walls, floors and ceilings. Typical gauges used for residential homes range from around $50 to $200.

Draughts

If your house is draughty with leaks and gaps, your insulation and heating can’t perform.

The typical places draughts and leaks appear in most homes are:

• Doors and windows – check that seals, latches, joinery and frames are tight and fitted snugly.
• Fireplaces – cover open fireplaces while they’re not in use.
• Plumbing fixtures and skylights – check they’re sealed well.

Ways to prevent draughts:

• Invest in good quality, floor-length, thick and lined thermal curtains – preferably with pelmets – and close them when the sun goes down.
• Think about double-glazing your windows, which can halve the amount of warm air escaping from your home, as well as reduce noise and decrease internal condensation.

Insulation

Insulation above ceilings and below floors is usually fairly easy to access. But insulation in the walls can normally only be checked if the wall cladding is removed. If you’re renovating, take the opportunity to have a look. Don’t forget to check if you’re eligible for generous Energy Efficiency and Conservation Authority (EECA) energywise subsidies on insulation at www.energywise.govt.nz.

Check your insulation for:

• Condition – if it’s damp it won’t be as effective and if the material has deteriorated, it may need replacing.
• Gaps – all areas needs to be thoroughly covered and any gaps plugged. 
• Thickness – there should be a minimum of 50mm under your floor and 120mm in your ceiling cavity. If it’s not thick enough you don’t necessarily have to replace it, just add another layer.
• When buying insulation check its ‘R’ value, which measures how well it contains heat. Eligibility for EECA subsidies is partly dependent on buying a product with a high enough R-rating.
• Does the insulation have the right gaps to allow for light fittings (200mm), fixtures such as chimneys and flues (50mm), and unducted extractor fans (200mm)?
• For older homes and those with flat (skillion) roofs, ceiling and wall installation is not usually possible. One of the most popular forms of underfloor insulation is polystyrene – a rigid foam which is cut to fit between your underfloor joists. You can DIY the installation and the material costs around $9.50 per square metre – which is about $1900 for the average house size of 200 square metres. Again, check your eligibility for subsidies.

Appliances

Leaving appliances switched on costs New Zealand about $100 million a year – enough to power over 55,000 homes. Appliances cost a whopping 40 per cent of an average family’s power bill – that’s a good $800 a year. Entertainment products such as TVs and stereos make up about two-thirds ($528) of this wastage. Switch off appliances when you’re not using them and you can save hundreds.

Other tips for streamlining the use of your appliances include:

• Check at www.powerswitch.co.nz to see if you are with the best power company for your usage.
• Find out what your appliance ratings are and what they mean. Most whiteware has energy rating labels so you can aim for the most efficient model.
• Use the power-save mode on your computer.
• Run your appliances through the cost calculator at www.energywise.govt.nz/tools/running-costs-calculator for estimates on energy consumption and cost.
• Dry your clothes in the sun – it could save up to $200 per year and is a natural way to kill bacteria.
• Check the seals on your fridge – it’s the second-most expensive appliance to run in your home. Make sure the temperature dial is set between 2 to 4°C and -15 to -18°C in your freezer.
• Use cold water for your washing – this uses only 25 per cent of the energy that hot water does and could save you up to $100 per year.

Heating

More than a third of your home energy usage goes on heating – and that’s only if you’re adequately insulated. So after checking the insulation, review the heating system.

• Temperature – the World Health Organization recommends a minimum of 18-20°C for internal daytime temperatures and 16°C overnight.
• Match the size of your heating system to the size of your home and think about which rooms need to be warmest.
• Use the heating calculator at www.energywise.govt.nz to assess what type of heater you need.
• Efficient heating systems include modern wood burners and high star-rated heat pumps. The most inefficient and unhealthy heating systems are un-flued LPG heaters and electric heaters.

Lighting

Switching to energy-efficient light bulbs is a quick and easy way to save a lot of energy and money. Ten bulbs will save you $183 per year.

Other lighting issues to consider:

• Recessed lighting can reduce the effectiveness of insulation and their light doesn’t spread far.
• Downlighting is great for small-to-medium areas but is inefficient for larger areas.

See A buyer's guide to light bulbs ADD LINK for more information.

Make your energy audit checklist

• Involve all your family or flatmates and refer to any tradesmen or handymen who have performed repairs on your house, so you don’t miss anything.
• Divide lists into areas that need checking, such as damp, insulation, draughts, heating, hot water, lighting and appliances.
• Identify the problem areas within each category, and rank them from most to least urgent.
• Estimate a cost for each problem. See which you can realistically tackle.
• Renters: contact your landlord and send them a copy of your list. Work out which items you can handle yourself.
• Tick items off when they’re done!
• Repeat your audit every 12 months for an energy-efficient home, referring to your previous audit and power bills to show how far you’ve come and how much money you’ve saved.

Regular energy audits can...

• Increase the value of your home. 
• Cut down your sick days.
• Save you up to $1000 per year – even small, cheap and simple changes. That’s not loose change considering the average energy bill for a household of four is $2800 per year.
• Slow down global warming. Twenty-seven per cent of NZ’s power comes from burning fossil fuels – so cutting your power use keeps CO2 out of the air.

Sources: Baker MG, Barnard LT, Kvalsvig A, Verrall A, Zhang J, Keall M, Wilson N, Wall T, Howden‐Chapman P. Increasing incidence of serious infectious diseases and inequalities in New Zealand: a national epidemiological study. 2012 Lancet; 379:1112‐9. 3. eeca.govt.nz. energywise.govt.nz, Watercare Services Ltd, powerswitch.org.nz.