Cooling the Sweaty Horse – Managing Heat

None of us will be able to escape increasing heat, but we can make our tenants’ homes more heat resistant to help them live comfortable and healthy lives.  Here is the second of my multi-part series on adapting to climate change - see the intro here.

How well our housing copes with heat depends a lot on when it was built.  Mandatory energy efficiency standards were introduced into the Building Code in 2003, so housing built before then may have quite poor energy efficiency performance, depending on the choices the builder or owner made at construction or subsequently during renovations.  Under current legislation all new housing is required to achieve the equivalent of 6 out of 10 on the National Home Energy Rating Scale (NATHERS), and this is in the process of being raised to 7.  There is no comprehensive data on the performance of homes built before then, but Healthy Homes for Renters estimates ratings for pre-2003 rentals could be as low as 1.7, with other estimates all somewhere close to that.  There’s no evidence to suggest older social housing homes perform better than those privately owned.

While energy efficiency is not directly related to heat, it makes it easy to keep homes cool, and where mechanical cooling (i.e. air conditioning) is needed, makes it cheaper to run.  If you are designing and building new housing, you probably don’t need me to tell you how to make it more efficient as you should have qualified design and building professionals doing that.  Key things to make sure they cover off on:

• North-south orientation – this means that the main openings of the house (doors, larger windows) will face north, while the east and west sides of the house have less window space and are more protected from the sun.  This allows the winter sun to warm the home as it shines from the north, while the house is shaded from the summer sun. 

• Ceiling, wall and floor insulation – insulating the house all around makes it easier to both heat and cool and reduces the need for expensive mechanical heating and cooling.

• Shade – the house should be well shaded, especially on the east and west.  This could be by planting trees if this is feasible on the site, or through blinds, awnings and eaves. 

Most social housing is not fitted with built-in air-conditioning or heating, partly to keep the construction budget within limits and partly because tenants may not be able to afford to run it.  This doesn’t mean there won’t be any in the house, of course - tenants are likely to buy their own. A good design can help reduce their need to use it, and make it more effective when they do. 

In practice, most of the social housing in Australia already exists and a large proportion of it was built before 2003, and it doesn’t generally perform any better than privately built housing.  When you run a social housing operation, whether in government or in the community sector, cash is always short and it can be challenging to do major renovations.  With that in mind, here are some relatively affordable things you can do to improve your tenants’ ability to cool their homes.

1.       Gap Sealing

Gap sealing is not sexy and you can’t see it, but it is pretty much a pre-requisite for any other form of improved cooling.  You need to seal off gaps where air enters or escapes the house – this might include around door and window frames, where services enter the home (water, electricity, gas, communications) and places where faulty construction or movement over time has left gaps.  Doing this will ensure that cool air doesn’t escape the house unless you want it to (in which case you open a window) and hot air doesn’t leak in.  This in itself doesn’t keep the house cool but it helps other measures to work better.

2.       Shading

Another thing that can be simple and affordable is to shade windows.  Windows can be a big source of heating in a home as the sun on the glass heats up the air behind it.  Simple shading can reduce this effect.  External blinds and awnings are likely to be most effective and can cut out direct sunlight without cutting light altogether.  If this isn’t possible internal curtains or blinds will help – a curtain with pelmet can cut out a good deal of heat transfer, as can simple roller blinds.  There are also really simple and cheap hacks – one I saw recently is using bubble wrap to line windows during the summer and mimic the effect of double glazing.  The bubble wrap can be stuck to the inside of the glass simply by wetting it, and can easily be removed in winter without leaving any marks (it doesn’t look pretty but it still lets the light in while reducing heat transfer).

Trees and shrubs can also provide a good source of shade and cooling.  They can be strategically placed to shade windows, and also if the home has some yard space they can provide outside shade space.  In general, the more tree cover there is in an urban area, the more it reduces the ‘urban heat island’ effect so planting trees around the property or on the immediate footpath (if this is allowed by your Council) can provide a cooler overall environment.

3.       Insulation

The cost of adding insulation is obviously greater than options 1 and 2 but it can provide a major cooling boost to any home.  It can be difficult to add wall and floor insulation to an already-constructed home, but not too technically challenging to add ceiling/roof insulation.

4.       Fans

Most tenants are likely to have pedestal fans which you can buy cheaply.  However, ceiling fans are more effective in circulating air, especially in an insulated home, and can generally be purchased and installed fairly cheaply. 

5.       Thermal buffers

Even if your home doesn’t have built-in air conditioning, if it’s hot it’s likely your tenants will buy their own free-standing air conditioners.  Insulation, gap sealing and shading will all help the air conditioning work more effectively as they reduce the competition from external heating.  It’s also cheaper and more efficient for tenants if they only have to cool the part of the house they are in.  This can be achieved by closing doors but if there are none, you or your tenants can substitute full-length curtain between rooms or even hang a sheet – it’s remarkable how much even a thin piece of fabric will contain cool air in one room. 

6.       Cool Refuges

If all else fails and tenants are struggling in a hot house or flat that they just can’t get cool in a severe heat wave, a final option is for them to take refuge in a cool facility in the community.  In principle this is no different to a cyclone or flood refuge, except that we tend not to take heat waves so seriously (this is a mistake, as pointed out in the previous article – heat is our biggest killer!).  It’s helpful for people to know where these are in their local community – essentially, anywhere that has good air conditioning and it's fine for people to just go there to sit for a while.  A local library can be a good place to do this – there’s places to sit, access to free wi-fi and computers and plenty to read and they don’t mind how long you stay.  A local community centre can potentially be another option, even a local shopping mall although it can be a bit dull if you’re not actually buying anything.  You could even consider making your office a refuge if there’s nowhere better. 

Resources

You can find out more about NATHERS at here.

You can check out more of the work of Healthy Homes for Renters here, or read the blog post they contributed. It's also worth checking out Sweltering Cities.

Here’s some good advice on keeping cool from the ABC.

A lot of the ideas in this article come from Tim Forcey’s My Efficient Electric Home Handbook.  You can buy a copy from Tim here and there’s a quick summary of some of his ideas in his Conversation article from 2016.

If you need further inspiration on heat refuges, have listen to this lovely song by the late lamented Baterz.