Practical Eco Friendly / Sustainable Options

BestBuilder · Nov 03, 2007 12:13 pm

Hello everyone

I am interested to gather some information about practical things people have added to their house design to make it eco friendly or sustainable.

There is a lot of information out there, but it doesn't really give a sense of what people are actually doing.

So if you have added something to your design I'd love to hear about it.

Best regards

kristofw · Nov 03, 2007 6:23 pm

Light coloured roof; eaves on the north side; large windows looking north, small windows looking south; internal doors positioned to force a cross-breeze; thermal mass in the slab and walls; dark floor tiles in the northern rooms to capture winter sun warmth; ducted heat-shifter; thermostat-controlled eco-vents in the roof instead of a whirly bird; rainwater tanks. My architect assures me that with all this I won't need AC in summer and heating in winter.

Michelle · Nov 03, 2007 6:35 pm

I’m wishing I thought more about it when I built 20 years ago!

My home is an oven in summer, by putting on the new back awning that has taken care of one hot spot in my home.

Now all I need to do is address the 3 large front windows! The timber blinds are just not cutting it!

But I am thinking of putting up 3 pass curtains for the summers only, as well as the blinds.

Of course there is always the aircon!

Good question BestBuilder!

Casa2 · Nov 03, 2007 8:02 pm

kristofw

Light coloured roof; eaves on the north side; large windows looking north, small windows looking south; internal doors positioned to force a cross-breeze; thermal mass in the slab and walls; dark floor tiles in the northern rooms to capture winter sun warmth; ducted heat-shifter; thermostat-controlled eco-vents in the roof instead of a whirly bird; rainwater tanks. My architect assures me that with all this I won't need AC in summer and heating in winter.

kristofw,

Well put. However a couple of things to think about.

Dark coloured roof may be better than a light coloured one. Basix doesn't support this, but I think if you vent to the outside during summer and vent to the inside during winter, you get an extra heater in winter. Your roof becomes a solar collector! I'd be interested to see what others thing about this.

Dark floor tiles may not necessary be bad, as long as the winter snlight doesn't just bounce in and then straight back out. The idea is to catch most of it, but you can have it bounce around a bit. And if you're internal walls are brick, then a dark coloured feature wall in the path of he reflected sunlight will help.

However, if you want to play it safe, what your architct has mentioned, I think, is spot on.

Yak_Chat, what are your thoughts?

Cheers,
Casa

DeeElle · Nov 03, 2007 9:19 pm

good advice Kristofw

Yak_Chat · Nov 04, 2007 9:45 am

Casa - Sure it all helps - but I look at it like this - You also have to live there and enjoy the look and feel and energy of the house too.

So in Perth I don't think it makes that much difference in these lower impact items - if it was on Macquarie island - yes it would matter

I think the dark walls as well as a dark floor would make it all a bit to dark and heavy.
But that's a personal thing. I like light and airy houses and the dark floor as the heat bank is all I'd do. Also - relfected light off a dark floor is not as warming or energy filled as direct sunlight.

Re the light roofs V dark rooves - again in Perth - I'd go for a light roof for the hot summers they get - and it's an eco house so they should not need the roof space heat. Again in Tassie your idea might work and be required.

But Perth also gets Freo doctor coming through each arvo - and this cools the city down in those really hot afternoons.

I'll start a new post on my things.
Steve

Yak_Chat · Nov 04, 2007 10:29 am

Bestbuilder
Do our ideas get posted on your web site for profitering by your clients :wink:

So far
I've converted a 20,000 litre unused swimming pool into a rainwater storage system. The beach is only 2km away - So why have a pool?

Mulched the gardens to reduce water wastage.

and I'm midway renoing to get some light and openess into the house, a new kitchen, open up to the north and a dark floor as a heat bank - insulation on the vertical ceiling areas, and + some double glazing and heavy curtains plus ways of capturing the warmth and move it around in the house as required including pulling hot air down from the upstairs section.
Plus things like Casa suggested, but you need to be careful re ceiling air as it must be filtered to stop dust and fibres being pulled into the house.

How I use my house.
Warm weather - I open windows at night to let cool air in - close them at 6am to trap it in the house and lock the hot air out.

Leave windows open on diagonally opposite sides of the house to encourage airflow during the day while I'm not home and it's totally secure.

I have a interesting but ugly feature in my brickwork which is a lattice like system (some bricks missing) in front of the bathroom and ensuite windows, makes it very secure and if they want to break the bricks down to get in via the open window behind it - go ahead

Futures.
Underfloor insulation, build a new heating system I've thought of and a few other things to start to capturing more winter warmth.

In summer the place is pretty good except for upstairs that needs more (any would be good) shade on the western windows and an awning (eaves) on the northern windows. Love those eaves

And I get a nice summer breeze nearly every night - so even if it's really hot the place cools down pretty quickly - if not - I head down to the beach for a cooling swim with Mr and Mrs Chomp

Steve

Pebble · Nov 04, 2007 10:50 am

I will keenly follow this thread as we are looking at building very soon (south west WA). Very interested in making it somewhat energy efficient.

So far I'm thinking of double brick construction and slate floor to everything but the bedrooms (carpet) and bathroom/laundry (tiles).
Double Glazed windows are high on the list.
N-S orientation for the living and most larger windows.
All round verandas is more of a want rather than any sort of eco consideration so plastic roofing if required for sections which we want sunlight coming through
No air conditioning, maybe ceiling fans if we really found the need some time after construction.
A nice wood heater somewhere in the middle of the open living area for those cold winters. It will be a carausel type (glass all round) to throw heat out in all directions, which should warm the slate nicely.

We already have a dam & large water tank on the propetry. We will most likely install yet another large water tank to collect runoff from the house roof. After all there is no mains water in the case of a bushfire so not something you can overdo I don't think!

I think ceiling fans seem very under rated in the southern parts of Australia. In places like Darwin they are understandably everywhere. We lived in a place with old noisy air cons and got through a couple of years living there without using any air con, just the fans, and in a well built house I would take them over air con any day!

Yak_Chat · Nov 04, 2007 11:06 am

Pebbles - I'd go slate in the bathroom and laundry too. I've had that in one house and with good sealing it works well. We had a deep green marble on the walls of the shower recess with gold fitting and slate on the bottom of the shower and it wasn't all that hard to clean either.

and yes - fans are very under rated in southern climes.
Steve

kristofw · Nov 04, 2007 11:51 am

Well, Freo doctor used to be as reliable as the Old Faithful, but seems to be failing of late. Last two summers were very still, if there was any breeze, it was weak and brief, so the city sweltered. What's more, the summers here used to be dry and hot, these last two though were quite muggy. The weather's really going strange.....

Yak_Chat · Nov 04, 2007 6:35 pm

Sounds like you tookm the Darwin weather down with you. :shock:

More fans

Steve

kezza · Nov 04, 2007 8:14 pm

We tried to do as much as possible using passive solar design within the confines of a project home. Our living area with lots of windows faces north and has a large awning which keeps out summer sun, but lets in the winter sun beautifully. We have tiles to soak up the winter sun. Only one bedroom has a window on the west side, and as we're a bit sunk into the hill on that side, it is sheltered by later in the afternoon. We put ceiling fans in all bedrooms and two in our living area. We have very high ceilings, and high awning windows to try and release hot air in summer. Also insulation, e-vents (to let hot air out of roofspace). Our east windows are sheltered by our carport and the bedrooms are mostly on the south side of the house. We did put one split system air conditioner in for those extreme days, but hope not to use it too often. So far it's been great, will be interested to see how summer is, but we are near the coast and the sea breezes should also cool our house down at the end of the day.

BestBuilder · Nov 07, 2007 12:22 am

Thank you all for your comments. Hopefully this thread can continue for a while and once there are a few consistent ideas we can build a list.

Yak_Chat - If there seems to be a good list I may post on BB, but hardly for profiteering! (I wish! Haha)

I think people who are building would really like to get an idea of some of the more practical things which won't cost a fortune. eg $5k on top of your building costs might be a painless exercise but $25k might break the budget.

So far it would seem these are ones to look into if you are building:

-Double Glazing
-Use of Heat Sink or Reflection (Light or dark colours)
-North facing
-Insulation (a given really and requirement in most cases)
-High ceilings

The heat transfer ideas are interesting and it would be good to hear more about those. Re from roof space or perhaps top storey/bottom storey.

Best regards

Casa2 · Nov 07, 2007 8:49 am

Bestbuilder,

Four more to add to your list are;

1) Thermal mass. Thermal mass on the inside of the building helps smooth out temperature differences during the day.

2) Night time ventilation. during summer, makes sure that the house is cooled down by allowing air to flow through it. This works well with a large thermal mass that is therefore allowed to discharge its heat. During the next hot day it will take a long time for the thermal mass to heat up, thereby keeping your house cool until late in the day where the process is repeated.

3) Right-length north shading. Let the low winter sun in and block the high summer sun. Shading that extends about 0.45 times the distance from the window bottom to the shading device is good.

4) Zoning. Have smaller areas that you can retreat to in the evenings (useful in winter) or very hot days, thereby limiting the amount of space you need t heat or cool.

Cheers,
Casa

kasiakm · Nov 07, 2007 7:57 pm

- rain water tank hooked up to the toilet
- high ceilings downstairs
- north facing
- tinted windows
- good insulation
- solar hot water system
- ceiling fans throughout the house
- big windows
- water saving devices: mixer taps, european showers, 5A toilets
- solar panels hooked up to energex (5KW/day)
- one phase superinverter ductude aircon - hardly used in summer

cheers
kate

Jet79 · Nov 08, 2007 7:58 am

Hi Casa,

Can you tell me a little more about thermal mass? We're building in Brisbane and have to have 25degree roof pitch for covenants and want to use some of the roof space for storage. I don't like the look of whirly birds. Do you also know the rough cost of these (ballpark fine)?

Jet

Casa2 · Nov 08, 2007 9:34 am

Hi Jet,

Thermal mass is not an item you buy and bolt on. Instead it's part of the building. Good examples of high thermal mass are bricks and concrete slabs, which are great if you are building from scratch. Others have put water bottles in their gyprock wall cavities. Basically what you are trying to do is get a large amount of mass inside the house.

It's important that the thermal mass is inside the house. This is why reverse brick veneer is touted as a much better thermal solution than (normal) brick veneer.

A great example of a high thermal mass house is the traditional full brick house. For those that have lived in one of these they know that if you keep the doors closed during hot summer days it’s comfortable inside while it’s sweltering outside.

Also, keep in mind that high thermal mass does not work well in northern Queensland. An explanation of what is going on will hopefully help.

Let's consider an example of a house without any heating or cooling. If there was no insulation and no thermal mass then the inside temperature would be exactly the same as the outside temperature. If you had a very high combination of insulation and thermal mass then the temperature inside the house would be constant and at the average temperature throughout the day, which is roughly the average of the high and low of the day. In practice, the higher the insulation and thermal mass the more smoothing of the outside temperature there is. This ranges from no smoothing (following the outside temperature exactly) to maximum smoothing (constant temperature inside). In practice, all houses are somewhere between these extremes. For the purpose of explanation, so far, we are assuming there is no sunlight entering or air exchange happening.

This is why high thermal mass does not work in northern Queensland. If in summer your minimum temperature is 25 Celsius and maximum temperature 45 Celsius then the ideal high insulation and thermal mass house would sit at about 35 Celsius, which is not very comfortable.

So, before going for high thermal mass, ensure that for summer the average of the high and low of the day is below at least 30 Celsius.

Now thermal mass works best in concert with other passive solar techniques. For instance, during summer you open the house to night time ventilation and close it up during the day. This shifts the average temperature inside the house below the average outside daily temperature. In winter, let northern sunlight in during the day (using the right amount of overhang above the widows that blocks the sunlight during summer). This shifts the average temperature inside the house above the average outside daily temperature.

Still examining a house with no heating and cooling, it’s interesting to note that it’s the combination of insulation and thermal mass that determines the level of temperature smoothing. If you half the insulation and double the thermal mass then you have the same performance. This is significant since it’s very hard to go from R4 to R8 insulation, but it’s easy to double your thermal mass (brick houses with concrete slabs would have thermal masses a hundred times larger than lightweight structures).

Before we close this analysis, it’s important to consider artificial heating and cooling. If your climate means that using high insulation/thermal mass, northern sunlight entry and night time ventilation the internal temperature is fine then high thermal mass is great since you can easily achieve very high values.

Now, if you need to heat or cool the house there’s something to consider. The high thermal mass will also need to be heated or cooled and this means that it will take a long time to heat or cool the house. If you need a lot of heating (Tasmania) or cooling (tropical areas) then high thermal mass can work against you. Here it may be better to have low thermal mass with high insulation and let the heater or air-conditioning unit do the work.

I hope this helps.

Cheers,
Casa

Cookiemonster · Nov 08, 2007 9:53 am

Great explanation Casa!
Very clear and concise.

kezza · Nov 08, 2007 11:11 am

Quote:

I don't like the look of whirly birds.

Our house has E-Vents, which let the hot air out of the roof space, but are much more subtle on the roofline. They look like just slightly raised lengths of the roof ridge (for colorbond roofs).

Casa2 · Nov 08, 2007 12:26 pm

Cookiemonster

Great explanation Casa!
Very clear and concise.

Thanks Cookiemonster. And I did it without being sarcastic or facetious!