Adelaide: heating city: 70% of comfort energy- heating, 30% - cooling, (Sydney 50:50) low humidity.
What is the best value for money – Solar PV. Any money left over – Shade (loose) around house with breeze-way (walls and pavers). Roller-shutters on East / West windows. Thick curtains and closed pelmets. LED lighting. Increase roof insulation.
Our House Top-down (feel free to photograph this paper with your phone)
Solar PV on roof - mono-crystalline – grid connected
2kW PV on car port (12 panels), 5kWPV on house (22 panels)
Average use 3.71kWh/day - Over the last 365 days
Average production 25.47kWh/day - Over the last 365 days
Average import 2.19kWh/day
Gas 5.42kWh/day (hot water, cooking, heating)
House total kWh ~ 9/day. Save 8 tons of CO2 per year
Install as many as you can put on. Putting panels on East / West is ok as panels are cheap (if only one side and = sunlight, choose East - light is cooler and morning is cooler than afternoon (heat reduces panel efficiency)).
Want a suggestion – Tindo are Australian made in SA and have two great panels – one has micro inverters which reduces shade issues.
(Batteries – wait a couple of years or get a small battery just for the (LED) light circuit and maybe a low use power circuit for laptop and modem and alarm clock.)
Rules for low energy use. Reduce draughts – External doors. All internal doors open in summer to share internal thermal mass. All internal doors closed with draught stoppers in winter to reduce heat leakage to unused rooms. Put in fridge only what you need soon – don’t store drinks cold for weeks. Pedestal fan if warm inside (better than ceiling fans. Ceiling fan in bedroom for warm nights. We use evaporative cooling at night only when it is most efficient (then only 8-12 times a year). Solar hot water (240 days), instantaneous gas water heater for winter – set the temp to minimum for good operation uses less cold water (pointless having 55C and cooling it to 40C, might as well set to 40C). Switch off appliances at mains when not in not use (incl printer, Wi-Fi modem, laptop, Stereo, TV, hot water heater over summer). Make high star ratings on appliances a priority. Use a laptop instead of a full-sized PC (much lower power use) and only use a large external screen when you have to).
White roof (tiles). Colour as light as possible. Painting tiles (or steel) roof works ok. Ceramic paint ($4,000) is marginally better. On hot day tile temp is 2C warmer than ambient under eves – black tile can be 30 degrees warmer. Paint before new solar panels.
Insulation only 7cm in roof – thin Rockwool batt, Aircell and sizalation.Inside- Gyproc, gap, Kingspan Kooltherm K18 ($20,000).
Windows. Big topic. I have double glazing on all windows (except the tiny ones) with e-glass layer (although only need the e-layer on the south (cold) side). Frames – wood, very thick – no heat transfer. If you use aluminum make sure there is a thermal break. Our kitchen window is uPVC (make sure they have fly screens) and the glass is our best window thermally. Double glazing has less effect in summer and does not prevent heat increase from direct sunlight. We have narrow cross ventilation windows.
Curtains – very thick, blackout curtains or cell blinds ($600 ea) – floor to ceiling. (Venetian blinds and vertical blinds are useless for blocking heat.)
Pelmet – I have fitted closed pelmets to all windows. Pelmets are essential and covered to prevent air cycling - cool floor air being heated and rising in summer, warm ceiling air falling and cooling in winter.
Roller shutters –Roller shutters to all South (front) windows and bedrooms. Good for keeping out heat, light, bush-fire heat, burglars and most wind. I chose black as the bare windows looked black from the street. White shutter on window at the back (north side) to reflect the morning sun in late spring / early autumn. If you have east / west windows use the lightest colour you can on the shutter – white is best. Shutters are built on frames to allow the hopper windows in the bedrooms to be opened slightly in summer (blinds slightly open) to allow night-time cross breeze or use of Evaporative A/C.
Infra-red image our house (my car), neighbour’s house
Note – WINTER SUN is always north of East/West – at the solstice is weak, the angle is +/- 62 degrees about North with an elevation of 32 degrees – neighbours trees can block your sunlight. Sun rises exactly East and sets exactly West at the equinox (for everyone not inside the arctic circles). SUMMER SUN rises and sets South of E/W +/- 120 degrees (that’s 30 degrees south of East/West) and has an elevation of 78 degrees at summer solstice. So summer sun can spend many hours hitting your East, South and West walls / windows under the eaves. Good sun-blocking foliage is useful – we have citrus trees to the South West and a carport to the South East.
Walls –Double brick and I’ve added blown-in Rockwool insulation ($1,500) into the cavity to reduce the thermal coupling (helps a little bit). Solid wooden doors ($600 ea).
SUMMER - Internal brick walls have thermal mass - an advantage for summer because cool nights cool the walls inside, shut the house up during the day and the internal thermal mass keeps it cool. Adelaide’s big plus - summer cool nights (often with cool sea / gully breezes) and low humidity. (High humidity causes hot or cold to “leak” everywhere so in humid areas, open windows and use fans for air movement.)
Only need the evaporative air-conditioner on 8 to 12 nights a year (best at night when the ambient temperature is cooler). A problem I had - that the outside bricks and the paving heat up on summer days, only after midnight was the air near the house was cool enough to allow inside. I solved this by having large movable shades on all walls and paving. Shade 90% black is best and loose with walkway. Sometimes I push back the shades at night to allow wall and paving heat to dissipate. I pull the shades over again for the next day. At 7am usually the outside walls are within 1 degree of the ambient temperature in. This house works well in summer.
WINTER – This house thermally poor in winter - internal walls are brick - the thermal mass inside the house in winter needs heating up every day for 120 days, whereas Gyproc internal walls have little thermal mass so you’re only heating the air and floor.
Winter temperatures - the maximum day-time temperature is almost always below the minimum human comfort temperature and so the average temperature is even lower.
You can build sun capturing systems and I have several but in winter the sun is weak – if at all, low angle, day-time is 10 hours and at our house, trees stop sunlight for part of the day (3 hours in the middle of the day in my case).
However a 21 degree day in August (2016) meant free hot water and no need for a night time heater, If the sun shines in winter the gas space heater goes on an hour or two later.
Table below August 17th internal temperatures at 12pm and 2pm.
FLOOR – We have wood - floating above Tassie oak. We like wood floors but it is the worst product for insulation, summer thermal mass and winter heat capture. Best is dark polished concrete for 2 metres inside north facing windows (3M for high windows). If you want more thermal mass (because you have Gyproc internal walls) then rip up your carpets, put down dark tiles and use a few rugs where people sit and next to beds.
Hot Water. Solar (Solarhart panel & 200L storage tank $2000) followed by instantaneous gas with 2 controls – be careful, at the start and end of the solar season, when the instantaneous gas is still on, the setting could be 44C but the water could be hotter from the solar). We get 240 days continuous solar hot water except for 2-3 days in a summer cold spell. We get solar support all winter and 100% solar hot water on 5 sunny winter days. When our solar hot water was first installed there was no tempering valve which mixes cold and hot water to a max of 50 C. Prior to that, temperatures of 95C were common on hot days. I had an over-temperature protection valve fitted (now standard) which “shuts-down” the panels on very hot days. The latter concerned me as the heat build-up could be great and a high pressure hot-water leak could be serious. So I added a variable shade system over solar panel - mostly in the fully shaded position over summer.
Lighting. LED – simple. You have at least three colour temperatures to choose from.
Pergolas. Two pergolas, winter – PVC on all walls and clear roof. Wood heater. In Summer, high pergolas are good, no blinds, full ventilation and ceiling added and blinds up for main pergola. Deciduous vine also helps. Pedestal fans.
Cooking. Gas. Inside on cold days and outside on hot days (even for boiling the kettle). Wood oven is for relaxing gatherings.
Fruit Trees – (drive-way, around house to back) – Jujube, Passion fruit, Mulberry (dwarf, fruits spring and autumn), Almond, Lime, Loquat, Fig, 2 Pear, Nectarine, Grapefruit, Lemon, Orange, 2 Plum, 2 Peach, 2 Apricot, Kaffir Lime, 2 Orange, Mandarin, Pomegranate, Kalamata olive (5), Frantoio olive (fertilizer), Quince, Pistachio (pair) and 130 grape vines.
Wicking Beds. The problem - my wife spent 2-3 hours a day watering by hand (only rain water outside (76,000L from tanks)) every day for 5 months AND the eucalypt trees took the water and goodness from the soil. Wicking beds are self-watering from the reservoir below and closed so no tree roots get in. Watering is once a month for the herbs on the east side of the house and every 2 weeks for the vegetable beds. The advantage is that the plant only draws the water it requires from the reservoir.
Chickens. Provide eggs, fertilizer, companionship and fun for the grandchildren.
Rainwater. 76,000 Litres. Both front tanks provide front garden, front wicking beds and house – Laundry 8kL pa, dish-washer 2.5kL pa & two toilets 9kL pa total 52kL pa saving $55 pa. Cost of 2 tanks, pump, filter, switches and plumbing $3,000.