Air Conditioning For Tiny Houses In Australia | How to achieve thermal comfort
Living in a tiny house comes with a number of benefits. Most tiny enthusiasts will agree that, to make the most of tiny house living, a lot of planning needs to be done to be able to utilize that small space as effectively as possible.
A really important component of achieving a great tiny house is having a comfortable indoor temperature – no one wants to live in a house that feels like an oven in summer or a freezer in winter.
Air conditioning is one of the most obvious tools we have to be able to control indoor temperatures. Nevertheless, it’s important to think of air conditioning as one piece of the puzzle and not a one-stop solution to achieving great “thermal performance”.
Thermal performance is a ‘fancy’ term to simply describe how much cooling or heating a building needs to achieve a comfortable indoor temperature.
In this article, we’ll talk about air conditioning for tiny houses as well as other elements that play an important role in delivering thermal efficiency for tiny houses.
Air conditioning systems for tiny houses
Arguably, the most popular air conditioning solution for Australian homes – tiny or not – is a split system air con. It’s easy to understand why!
This type of system consists of 2 components: an outdoor pump/compressor and an indoor equipment that releases ‘air’ according to the desired temperature. Split system units are relatively portable, small, easy to install and comparatively affordable.
The second most popular type of air conditioning system is centralized air con or ducted air con. This type of system is mostly found in large premises with multiple rooms – the opposite of a tiny house!
For a tiny house, which is a relatively small space, a split-system air conditioning unit is probably the best solution as it’s capable of providing cooling or heating to a decent size area.
How to choose a split system air conditioner for your tiny house
In a tiny house, particularly those that are fully off-grid and rely on solar panels, it’s really important to choose an air conditioner that minimises power consumption. On the other hand, tinys that are connected to the main grid can save a lot of money on their power bills.
Air conditioner capacity or size is measured in kW. Ideally, in order to save on power consumption, you want the smallest possible system – maybe something around 2-2.5kW.
However, for small systems to be able to efficiently cool/heat your tiny, you will need to consider other elements, including the tiny’s overall size, its location, the parking positioning in relation to the sun and its design features. All these elements need to be looked at when choosing a system.
Tiny’s overall size
Predictably, the overall size of your tiny will be an important factor in determining the capacity of your air conditioner. Generally and simplistically speaking, the smaller your tiny, the smaller your system will be. However, a bigger tiny that is well-insulated, southern or eastern-faced, with lots of cross ventilation may also be able to achieve great thermal performance with a small system.
Generally speaking, here is an approximate guideline of air conditioning sizes in relation to the square meter footprint.
Room Size | Approx. Size/Capacity |
Up to 20㎡ | 2-2.5kW |
20-40㎡ | 2.5-5kW |
40-60㎡ | 4-6kW |
Over 60㎡ | 5-9kW |
Location
It’s easy to imagine that a tiny house in Queensland will have different requirements than a tiny house in Tasmania. It’s easy to guess that the hotter the climate, the more power you may need to cool down your house.
In Australia, we can benefit from energy ratings labelling requirements on all appliances. When it comes to air conditioning purchases, another piece of valuable information is the “zoned energy rate label”. Simply put, this label provides an easy to understand guide to energy efficiency in relation to where you are. The rule is simple, more stars equals more efficiency.
Parking Orientation
Your parking positioning in relation to the sun is a very important factor in achieving thermal efficiency. If your main living areas face north or west, you will get a lot of heat (particularly in summer). On the other hand, a south or eastern facing tiny will minimise its sun exposure in the afternoon – the hottest time of the day.
Parking orientation is also closely linked to location. Maybe a tiny that is parked in Tasmania, as opposed to one in Darwin, may actually benefit from sun exposure.
Design features:
We could write an entire article on how good design will improve thermal comfort because there’s so much that good design can do to deliver optimum indoor temperatures. Here are going to focus on just a few elements that we think are essential.
Good insulation: the layer of wall, floor and roof that separates your tiny and the outside world can be either your best friend or your worst enemy. Investing in good, thick, gap-free insulation will simply keep your house warmer in winter and will protect it from the outdoor heat in summer. Your air-conditioning capacity and power consumption can be reduced to a small footprint with great insulation.
Ventilation: the ability to capture breezes is a major advantage in the warmer months, particularly in places where warmer months represent ¾ of the entire year. The best way to make the most of winds – a wonderful free natural resource – is to allow cross-ventilation by placing windows on opposite walls allowing wind to get in and get out. Cross ventilation is particularly important for sleeping areas that get heavily used at night time (when temperatures are cooler) as it may allow you to sleep comfortably without the need to have air conditioning near you.
But designing for good ventilation does not stop with windows, skylights are also a great addition that will help to cool the house – hot air tends to go up and the ability to be released via the ceiling may also help with maintaining a good temperature.
Last but not least, ventilation can also be provided by ceiling fans! While not quite a natural resource such as wind, ceiling fans consume a lot less power than air conditioners and can be a great solution for mild-temperature days.
Sealing: making sure your tiny does not have ‘gaps’ where outside air goes in and out as it pleases is a great advantage both in cooler weather – when you don’t want to let cold air in – and during hot summers – when you don’t want all that cool air brought in by your air conditioner to quickly get out. Areas to be mindful of possible gaps include floorboards, skirting boards, window frames and door frames. The good news is that gaps are often an easy, quick and inexpensive fix!
Curtains and Blinds can be your best friend both in hot and cold weather. When closed, they provide an extra layer of insulation to your tiny. Blinds and (thick) curtains can keep the warmth inside the house during cold weather and can keep the heat outside when it gets hot.
How to Install a Split System in a Tiny House
When it comes to electrical work, engaging a licensed electrician is your best option. It’s also fair to say that a lot of qualified sparkys may not have a great deal of experience with tinys. A few things to keep in mind with regards to installation and to discuss with an electrician include:
- Where are you going to install it
When installing an air con unit, the location you place both the indoor and outdoor unit is very important. You have to ensure the outdoor unit is placed somewhere where it can get proper ventilation and hopefully not too obvious, so that it doesn’t ruin the aesthetics, and ideally in a place where the noise is suppressed and doesn’t carry. Another very important consideration, unique to tiny houses is that the placement of the external unit must not push the tiny house over its width limits. In most cases this means the outside unit must be installed at one of the ends of the tiny, not the front or back where the 2.5m allowable road width would be exceeded.
Also, as most tiny’s are built to maximise the allowable 2.5m width, even any small piping used to house the air conditioning gas/water lines would push it over the road limit and so these pipes must be at an end, or positioned inside the house. As you don’t want the external unit placed too far from the internal unit, these considerations may also impact where you’re able to place the unit internally.
Equally as importantly, the indoor unit needs to be placed somewhere where it cools, and heats the room efficiently. If placed improperly the entire purpose of the unit can be rendered useless. You may also want to prioritise areas where you spend the hottest hours of the day in.
2. Strength of the wall
When mounting a split unit on the wall, it’s vital that the wall is strong enough to hold the weight without causing any long term structural damage. It’s important that you speak to the builder of your tiny home to ensure that the material the tiny home is built with is strong enough and durable enough to hold the weight of the unit without any consequences. It’s very important you do this beforehand otherwise it could lead to a lot of money being spent in repairs and expenses. A good electrical contractor may also be able to advise when extra reinforcements are needed (i.e. a bracket).
3. A tiny house is exactly that, so extra space is of the premium. Not only do you have to make space for the unit, you also need to ensure that there is 10 to 15 centimeters of open space all around the unit. This is needed to ensure proper airflow for the unit in order for it to function correctly.
If the airflow is restricted the unit will be unable to expel heat which will lead to the air conditioning unit overheating and eventually malfunctioning. This could lead to potential compressor damage which will drive the cost of repairs very high.
Alternative Options for Heating and Cooling
Ceiling/Standing Fans
For the hotter months, an investment in a fan could be made. A ceiling fan costs more and requires more work regarding mounting and wiring, however it does a better job of dispersing the air, covering more area.
A standing or even desk fan is the cheapest option and can do the job for a period of time.
It only requires a power source and for it be plugged in. If where you live doesn’t get too hot during the summer then these can be viable options, which can be dismantled and moved easily.
Ceiling fans are great when the temperatures are mild as they consume a lot less power than air conditioners.
Electric/Oil Heaters
Similar to the fan options, when the opposite season of winter comes along, a simple purchase of a heater could be made. As the home is quite small, it may not require much to heat the area up.
An electric heater just needs to be plugged in and will start heating. Aside from being very cost effective it’s also portable and only requires a working socket to plug into.
Oil heaters can also be considered, which take longer to heat up however maintain the heat for much longer than an electric heater. Whereas an electric heater stops functioning as soon as you switch it off, which could require you to turn it on and off multiple times throughout an evening, an oil heater continues to radiate heat after it’s turned off.
Wood Fire Heating
Wood fires give off a rustic and romantic feel to a tiny house. However, it’s important to point out that a reverse-cycle air conditioner is considered a more energy-efficient tool for heating, even when compared to the more modern slow-combustion wood fire heaters. Wood fire heaters are no use for your cooling needs.
Remember when using a wood heater that you must always have a source of fresh airflow within the tiny (ie. crack a window), and we recommend getting yourself a carbon monoxide detector for your tiny in-case the fire, or any other appliances produce unsafe amounts within the limited space.
Can I install my own split system?
Aside from split systems specifically designed for DIY installation, installing a split system should only be done by a qualified professional. Given the electricals involved, and the cost , we highly advise you to only have a licensed electrician install your system and do not try and do it yourself as this can lead to a potentially dangerous situation which could also lead to great financial damages.
