The climate of your area significantly impacts your air conditioning needs. For instance, in Adelaide, where the climate can be both hot in summer and cold in winter, opting for an air conditioning unit with effective heating capabilities is essential. A reverse cycle unit (heat pump) can help minimize energy use, as more energy will likely be used for heating during the colder months than cooling in the hotter months.

Portable air conditioners are a good option for renters or those needing a temporary solution. They are easy to install and can theoretically be moved from room to room (although in practice because you need a vent kit and where you put it is where it will stay). However, they are generally less efficient and powerful than other systems, making them suitable for small spaces or occasional use. They are more effective in the evening and at night.

As one salesman I knew would say:
'What have you got now?' 
The answer would be 'Nothing'
His response would be 'Well this is better than nothing.' 
In other words, only choose a portable air conditioner if it is the only option. 

If buying an air conditioner, you need to consider the energy efficiency as the running costs will exceed the purchase cost after a few years. Check the star rating on the government web site Energy Rating - Air Conditioners - AS/NZS 3823.2 .
Generally you should choose the best heating star rating you can afford and aim for at least 3-stars heating, even if you are actually purchasing it primarily for cooling as you will use more energy for heating than cooling.
It is important to choose the correct star rating as air conditioners assessed to the old rating will appear to have a higher star rating. If you are in Adelaide compare the ‘SEER Heating Star Rating’ for the ‘mixed zone’ see below.

Setting the thermostat correctly is critical to achieving comfort and minimising energy use. Setting the Temperature one-degree cooler than needed in the summer will cause a surprisingly large increase in energy use. Similarly setting the Temperature one-degree warmer than needed in the winter will also cause a surprisingly large increase in energy use.

Some old-style thermostats have a single temperature setting, and the temperature swings around that setting. Most modern ones have separate heating and cooling settings, which allow closer control. Normally it is best to set the temperature at 22 degrees for a single setting thermostat or at 20º for heating and 24º for cooling (possibly higher if you have ceiling fans) with a dual setting thermostat. For most air conditioners this would give a temperature of around 24 degrees for most of the summer and 20 degrees for most of the winter. If you can achieve comfort at a higher temperature in summer, or a lower temperature in winter, use the higher summer setting or lower winter setting as every degree change can save up to 10% of your heating or cooling energy.

In practice there are several factors that may require a different setting. For example, if in winter you get freezing air next to the windows sinking down and pooling at floor level, it may be necessary to set the thermostat at a higher temperature (although a better long-term solution would be to have honeycomb blinds or thick drapes with a pelmet to reduce the heat loss). To find out what the best solution is, it may be worth getting an energy audit as getting the right solution would save a lot more than the cost of the audit.

Often thermostats are not very accurate; this is not really a problem if you can find a single setting that achieves comfort all year round. However, it is probably necessary to occasionally tweak the setting.

You can find a suitable setting by randomly adjusting the thermostat, but if that doesn't seem to work, try the following approach:
1.On a day that is warm (to find the best summer setting) or cool (to find the best winter setting), but not an extremely hot or cold day.
2.Ensure the air conditioner has been running for at least one hour so the temperature is stable.
3.Initially set the thermostat to 22 degrees (for a single setting thermostat) or 24 degrees if you are setting cooling on a dual setting thermostat, or 20 degrees if setting heating on a dual setting thermostat.
4.Wait for a period of time (at least 10-15 minutes) to allow the air conditioner to stabilise again
5.If this hasn’t achieved comfort, set the thermostat slightly higher or lower, as seems appropriate. Don’t adjust it by more than a degree at a time or you will end up overcorrecting and take longer to find the best setting.

In summer, using ceiling fans may enable you to set the thermostat slightly higher. It will also significantly reduce the number of hours you need to operate the air conditioner.

Remember there are some problems that can’t be fixed by adjusting the thermostat. For example, if the air conditioner doesn’t have enough capacity due to the temperature of the day, adjusting the set point won’t make any difference to the room temperature. If this is the case, start with Cleaning Filters below, also see the blog post Our house is too hot, what can I do? Setting the thermostat also can't generally cure hot and cold spots, (refer Hot and Cold Spots below).
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A future post will address basic troubleshooting of an air conditioner.

Some homes have hot and cold spots, usually caused by an air conditioner serving areas that have windows facing different directions, or the difference between the old and new parts of a home.
It is possible to get ducted air conditioning controllers to give individual temperature control in each room, however this is still quite expensive. Most people must use judicious control of curtains or blinds to control temperature differences.
To save randomly trying different ideas, it may be worth getting an energy audit as getting the right solution first off, would likely save a lot more than the cost of the audit.

To keep informed of my latest posts, sign up for the Energy Saving Newsletter and as a free bonus, get  a 14 page extract from the forthcoming second edition of the book:

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If you need personalised advice or you are thinking of spending some real money on air conditioning or improvements to the house, get an energy audit. I guarantee I can cost effectively save you the cost of the audit or the audit is free.

Feel free to leave a comment or question below.

Have you just received your latest energy bill and been shocked?

Bills have typically gone up 20-25%, but many who were on good deals have found their discounts cut heavily and for these people the increase is often even more (up to 40%)!
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Well, what can you do about it?

If you google for example ‘reduce energy bills’ you will get pages and pages of energy saving ideas, but are they relevant to you? Some will be relevant, but most won’t be (or will have a miniscule impact).
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There is no silver bullet, and whatever you do it is going to have to be a combination of savings in different areas. But as an example, our total energy cost for this year was less than $135. Yes, that’s right, $135 for the year!

Now that took many years and there are reasons I could cost effectively reduce my energy use that low. However I can make a dramatic difference to your energy costs. see Energy Audits.

Whether an idea will work for you depends on:

• The size of your bill
• Your cost of energy
• Where you live
• House design
• How you operate your home
• The number of people in your home
• Whether you are at home on most days

​But how do these affect your energy costs?

The first thing is to understand what is using your electricity and gas.

The chart shows typical household energy use; however, you aren’t the average person and your use could vary dramatically (up or down) from the pie chart. Hence you really need tailored advice.

Anything requiring heating or cooling for an extended period is likely to contribute significantly to your energy costs.

For example, room heating and cooling are usually the biggest single energy users for most people. On average, 40% of home energy use but it could range from less than 20% to over 70%. Especially if you have whole of house heating or cooling this should be a big focus for your energy saving efforts. surprisingly, for most Southern Australians, Heating is a bigger energy demand than cooling. See also More on keeping warm 

Another big item is hot water, typically 25% of energy use.

Appliances are typically around 30% of energy use. However, if you have a spa or swimming pool it could be much larger.

If you have LED lights, lighting energy use is quite small. (If you don’t, it is worth only buying LED replacement globes where feasible.) If you have halogen downlights, that is a complicated problem, which will need to be the subject of a future post.​

Because heating and cooling energy use is so large, keeping the heat in in winter and out in summer are likely to give worthwhile savings.
See:
More on keeping warm
Winter comfort
Stop air leaks in your home
Get insulation right
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Another action worth doing is checking you are on the best tariff. Beware of comparison sites that are set up to make money, it is better to use a government site like Energy Made Easy or in Victoria https://compare.energy.vic.gov.au

 Hence you really need tailored advice.​Advice like ‘have your hot water system on a timer so it only heats at certain times’ could save on hot water heating costs, but this depends:

• If you have gas water heating it is irrelevant
• If you have a decent sized solar system and a heat pump hot water system, it could save heaps if you set it to come on at 10 am, provided the water is fully heated before the sun goes down.
  • If you are thinking of solar, find out how to ensure it is right for you, and where to get quotes from reliable installers here. As I said above my total annual energy cost was $135.)
  • Note, beware of dodgy marketing, there are some companies encouraging people to buy solar when it doesn't make financial sense for them. Get tailored advice.
• If you are on a time of use tariff scheduling it to come on when you have cheap electricity makes sense.

Although for many people solar energy has cost effectively reduced their bills, it depends on many factors and some aggressive marketing can lead people to believe they are going to save cash from day one, which could be true, or more likely be false. Again, you need tailored advice.

Well, you can guess which of the hundreds of ideas out there will work for you, or you can get an audit done by an experienced auditor who will sort through the options and give you a manageable number of options that will work. See Energy Audits.
​

Stopping air leaks in your home can help you save money on heating and cooling bills and increase your home's energy efficiency. Here are some ways to stop air leaks in your home:
1.     Identify the leaks: Check for air leaks around windows, doors, and vents.
2.     Caulk: Use caulk (no more gaps or similar) to seal any gaps or cracks around windows, doors, and other areas where air may be leaking in or out. Make sure the sealant is appropriate for the location (e.g. exterior, interior, wet area as appropriate)
3.     Weatherstripping: Install weatherstripping around doors and windows to prevent drafts. If using self-adhesive weatherstripping, choose one with a plastic backing (rather than paper) as they are much easier to apply. Raven weatherstripping has a plastic backing.
The problem with self-adhesive weatherstripping is that if the gap in the door or window frame is too small the weatherstripping gets over compressed, and the door or window won't close properly.
An alternative style is available from Ecomaster ecomasterstore.com.au/. They have a range of sealing options for different applications, which tend to work better than what is available at your local hardware store.
If you can't afford weatherstripping, at least get yourself a door snake for each outside door and for the room you spend most time in of an evening.
​4.     Seal air ducts: Make sure air ducts are sealed and insulated to prevent air from escaping. Assuming you have an attic roof, check your airconditioning ducts and if necessary use duct tape to seal them. Any leaks from the ducts are particularly significant as the air in the duct is either hot or cold and under pressure so you can lose a lot of heat. Furthermore this reduces the amount of air entering the room compromising your comfort. If there are problems that you can't rectify yourself it will probably be worth paying to rectifying them.

By following these tips, you can significantly reduce air leaks in your home, which can help lower your energy bills and make your home more comfortable.
Stopping air leaks in your home can improve comfort in several ways:

• First, by sealing air leaks, you can reduce drafts and cold spots in your home, which can make your living spaces more comfortable. Under door leaks are among the worst for this as in winter they exacerbate the cold feet, hot face syndrome that many people experience in their homes.
• Second, air leaks can allow outdoor pollutants, such as dust, pollen, and other allergens, to enter your home. By sealing air leaks, you can help reduce the amount of these pollutants that enter your home, which can improve indoor air quality and reduce allergy symptoms.
• Third, by reducing air leaks, you can help your heating and cooling systems work more efficiently, which can help maintain a more consistent and comfortable indoor temperature.

Overall, sealing air leaks in your home can help improve your comfort and quality of life.

If you are planning on doing more to reduce energy use, I suggest you consider creating a plan to ensure you achieve an optimum insulation level and consider what options you should do when. See Energy Audits.

If 10% of the ceiling is bare due to insulation being tossed aside or being incomplete, the heat loss can double.

I have rarely gone into a roof space (even a new one) and found the insulation properly distributed. Since I have bought a thermal imager, I have not found a ceiling without an insulation fault of some sort.

The most common issue is ceiling batts tossed aside by a tradesman and not replaced. (Although there are many good tradies, there are too many electricians, air conditioning installers and plumbers who don’t make a habit of checking that the insulation has been returned to the correct place after they have finished their work). If you are employing someone who will be working in the roof space, let them know that any insulation that needs to be removed, needs to be replaced properly (for example trimmed around a fan)

Some of the worst examples of failure to replace insulation occur with down lights. If you have down lights you might have a dozen in the room and if a ceiling batt is tossed aside at each light, you would have 12 displaced ceiling batts, which may well more than double the heat loss or gain through the ceiling.

Often this can be readily improved if this is in an attic roof space. Do bear in mind that depending on the type of downlight you may need to give a gap, which depending on the light and insulation may need to be up to 100mm clear around the light. Check the make and model of the downlight to determine the clearance required.

Although I prefer surface or pendant lights to downlights, some of them, particularly the newer IC4 LED downlights can be safely covered with insulation, however check the manufacturer's instructions. (The light should be labelled as IC4 but it can be difficult to read so take a bright light if you are checking yourself in the ceiling. 

Another common issue is exhaust fans. they need a clearance around them to avoid jamming the blades, but often a whole batt is tossed aside. Ideally the exhaust fan should be a ducted fan and discharged above the roof. If the ceiling space is well vented, e.g. an un-sarked tile roof, depending on your climate you may get away with it discharging into the roof until you replace it. However, it is preferable to install a DraftStoppa  so that you can safely insulate to the DraftStoppa and also so that when the fan is not working you don't get air leakage and lose the heat or cool in your house.

When improving the insulation, gaps in the insulation, for example around framing timbers or at edges, should be filled with offcuts.
 
Insulation that has been wetted or compressed doesn’t perform as well as it should and should be replaced.

Ceiling access covers are often uninsulated. Sometimes the insulation contractor leaves a loose piece to be placed over the access cover, but I have often found that the next contractor doesn't replace it. If the insulation is thick fiberglass it won't glue to the access cover very well. Other options include using a construction adhesive (liquid nails) to glue one of the following:

• Foilboard 25 x 2400 x 1200mm Cathedral 25 Insulation - Bunnings Australia
• Bastion 1200 x 600 x 50mm XPS Multi Use Foam Board - Bunnings Australia
• A cheap alternative would be to glue some bubble wrap (using a liberally spread sealant) to the access panel

Another issue with insulation is often the extent is insufficient.  Ideally the insulation should extend over the top of the walls. 

If you intend doing the insulation yourself there are a number of considerations:

• Downlights may need clearance to avoid overheating (check the manufacturers recommendations for the model) (not required if they are IC4 LED downlights.
• Fans opening direct to the ceiling space need a DraftStoppa so you can insulate directly up to them.
• As with any DIY project, consider safety, e.g. safe access, don't work in the roof space in the heat of a summer afternoon etc.

Insulation can be installed deeper than the ceiling joists, however you need to:

• ensure you don't cover electrical cables unless an electrician has confirmed that the cable is safe (cables clipped to the structure can have the insulation butting up against it, if it is modern wiring.) If there is any doubt, get it checked by an electrician.
• consider whether it is safe to move about the ceiling space. If there are appliances in the ceiling (air conditioners, hot water services etc.), you need to ensure safe access for maintenance. This can be achieved by laying the insulation between ceiling joists so the gaps correspond to the location of the joists. Consider installing permanent crawl boards for safe access.) 

If you are planning on increasing the insulation thickness, I suggest you consider creating a plan to ensure you achieve an optimum insulation level and consider what options you should do when. See Energy Audits.