Renew Magazine

Built with non-toxic materials to be energy-efficient, long lasting and with a small footprint, it was a pleasure to visit and take a look at this home over lunch.

The house has the beautiful feeling inside that is characteristic of strawbale houses. It’s a settled quiet that puts you at ease. “The straw was chosen for its insulation quality and also for its beauty. Straw also creates such a melodic ambience in the house,” says owner-builder Nikki.

The first thing I noticed is how the house enables the many social and creative visions of its makers. Designed to feel and function a little like a small town hall, the central space of their urban strawbale home includes a stage (complete with power and AV concealed in the floor) and a commercial kitchen where Nikki plans future cooking classes, drawing inspiration from their abundant edible garden.

The house is the product of two years visioning, planning and designing and one year of hard work by a committed team led by Nikki. The core building team was made up of Nikki and her son, his friend and two building apprentices in the process of retraining from chefs (is this why the kitchen is so great?), with skilled tradespeople coming in and out as needed.

Nikki says, “We chose the vacant lot (500 m2) as the land was close to main street shops, ten minutes walk to the railway station and most importantly, right next to the beautiful, magnificent Werribee river.“

They did the design themselves, and included a lot of what they wanted in their three-room house. It has two-storey high ceilings, storage cupboards that stretch almost to the roof (accessed by a ladder), a 19,000 litre galvanised water tank, a Wattworks greywater treatment system and solar hot water. In summer it keeps them cool with fans, insulation, moveable outside shades and semi-transparent inside blinds. As they plan to stay for a while, they also designed the single-storey house for wheelchair access.

Read the full article in ReNew 123

We wanted to set up the way we live on our farm to have minimal impact on the surroundings and to be as self-sufficient as possible, but without losing too many luxuries. Some of the decisions were made for us, given the farm was never going to get a phone or mains water, and power was a little distance away and therefore would have needed a few poles (at a fair cost) to get it to our dwelling.

Our current dwelling is a shed converted into a house, so we call it the Shouse. Below is how we provided for the energy and water needs, as well as what we did to make the Shouse liveable for our family of three.

Well supplied with water
Council required us to have a minimum 90 kL of water storage. When pricing tanks, it worked out only a few thousand dollars more to get a tank that was significantly bigger, so we settled on a 255,000 L steel tank. With over 200 acres we figured space wasn’t an issue! This tank filled up in a winter and a half, with no water consumption. We’ve since also added an additional 23,000 L tank and have plans for more as I do have a bit of a fear of losing our whole water supply should a pipe burst or the water in one tank get contaminated.

Off-grid generation
For the first few years we ran on a diesel generator. Unfortunately, much of this energy was wasted as the generator produced more power than we needed. It was actually quite convenient for us and not for the power companies that while we were looking at both grid and renewable options (including combinations of both), a couple of things happened.

WA was having significant power price increases, and these didn’t (and still don’t) look like easing up. Also, we had a few arguments with Western Power about some changes in billing practices for a house we were renting. It was perfect timing for a power company to annoy us, so we settled on not hooking up to the grid at all!

We checked out a couple of options and initially signed up for a package that would use the diesel generator, but included batteries and an inverter. This would reduce our generator run time to around four hours a day. Renewable generation could then be an add-on for the future.

Read the full article in ReNew 123

The thought that, after my solar feed-in tariff ended in ten years, my system would become merely a cheap generator supplying all the local air conditioners at a profit to my power company annoyed me. Especially as I would have to fund any maintenance to the solar PV system from my pension.

So I decided not to invest further in additional grid-connect panels but rather, to put my dollars into making my home office totally independent of the grid. I built an off-grid solar power system with 12 volt battery storage, supplying a 240 volt inverter at the lowest cost possible.

Online shopping for parts
I sourced a pair of new 6 volt deep cycle lead-acid batteries from a local retailer. The brand was Interstate Batteries model GC2-HD-UTL, with a capacity of 216 amp-hours each. I purchased a 200 watt, 12 volt monocrystalline solar panel for $500 from eBay store LHP Power, which came with a 25-year warranty, and found a low cost 10 amp solar controller from a Chinese eBay supplier.

The solar controller has three sets of connectors, one for the PV panel, one for the load, and the third for the battery bank. The solar controller prevents overcharging the batteries, unwanted discharge of the batteries through the PV system at night, and disconnects the load to prevent battery damage if it becomes run down.

After purchasing a couple of low cost 800 watt 12-240 volt inverters from another Chinese eBay store I was ready to roll with my first system.

With a badly damaged boot from the crash, I decided to make it a utility, with 160kg of batteries bolted to the back tray. The original gearbox and disc brake have been retained, close coupled to the electric motor, while the engine, exhaust, fuel tank and air cleaner have all been removed.

The front and rear bumpers were destroyed in the crash and have been replaced with aluminium bumpers. Standard 2cv tail lights have been recessed into the ute back and a Citroën logo has been glued in place.

The farm came with a large home—16 rooms over five levels with two open-plan living and entertaining areas—the main selling point being we liked this style years ago.

The three concrete slabs stepping down the rolling red soil hills already had hydronic in-slab tubing, heated from a diesel furnace along with the tap water. Cooking was done by bottled gas, and there were three slow-combustion wood heaters in the two living areas.

Philosophy and design

We are very keen on sustainability and want to minimise our carbon footprint, both in the home and our farm’s beef production. We were prepared to spend some money converting the heating system for a large reduction in running costs and emissions. The farm has many large trees and limbs are always falling, so using solar-powered heating and hot water, boosted by a wood-fired heater, seemed like a sensible idea.

We found the solar collectors we wanted and set system parameters. Our plumber designed and built the conversion, changed the skylights, re-flashed the house and updated much of the water collection. We added ideas as it was built over several months.

The home

The climate is cool temperate with few frosts and the house is sited on a southern slope in foothills.

We are at latitude 38.005°. There is some unavoidable morning shading in winter from a roadside glider possum habitat of magnificent eucalypt trees over 40 meters high, 30 meters away and uphill on the northern road boundary. The outside temperature ranges between 2°C and 42°C but the house has such a large thermal time constant that living areas stay between 17°C and 22°C in winter, and no more than 25°C after a run of hot days.

The house design is classic 1970s double brick with rough-sawn, exposed beams in eight meter cathedral ceilings.It had hardwood french and other windows with single-glazing throughout, and sad plastic-vented skylights. Everything was coloured mission brown.

The designer ignored the 16 kilometre view to the Strzelecki Ranges and the valley below, and modern principles of house alignment for passive heating and cooling. However, at least the sun does not load up the interior. There are a few, small windows to the east, with excellent shading from canvas blinds, and large french windows to the west. These are shaded by a pergola and close battens. The home’s north face is stepped into the hill and the windows are totally shaded by a brick cloister with archways: a very sensible design providing a great spring breakfast area.

The kitchen, living and lounge rooms, study and billiards rooms are open plan and interconnected on three levels, which does create air currents, especially with such high ceilings. We have been slowly renovating, as one does with a retirement income.

The aim is to convert major glass in living areas to high-efficiency glass and to install as much double glazing as we can afford. So far our plumber has retrofitted seven double-glazed, openable skylights. The local glazier replaced 11 clearstory windows and made three panels openable to draw up cooling air from the lower levels when a summer cool change arrives.

We use pressurised tank water for most of the home, buildings and farm animals. There are 245,000 litres available in concrete tanks, linked by a 50mm buried ring main. Our local irrigation contractor built a fire sprinkler system for all buildings on the farm, which was essential when the wind changed during the Black Saturday bushfires in 2009. Our 100-year average rainfall is 1100mm; we received 1178mm in 2010 so we always have an excess of stored water.

There is a 1.5kW solar power system on the roof, bringing an income and well offsetting the minor energy drain from the small pumps moving water into the hydronic heating and up to the solar collectors.

Hydronic system components

Our heating system has three sources of heat:

• 36 solar-collecting vacuum tubes (rated at 5.8kW)
• wood-fired, slow combustion fire, with flue water jacket
• two gas-fired instantaneous hot water boilers.

The service courtyard where most of this hybrid heating and hot water system is hidden looks Heath Robinson, but it is a credit to our local green-accredited plumber at Baw Baw Plumbing and his team. He always knows about the latest efficiency innovations and was a terrific speaker at our Landcare group’s Green Energy field day.

Heat storage

A custom made 1000 litre stainless steel tank with 75mm of insulation and a small header tank is the heat storage. It’s similar to those made for the local dairy industry. Hot water is not drawn from this water but via three heat exchanger coils in the tank, with the solar one at the base, the hydronics one at the centre and the hot water service at the top. Each is 11 metres long.

Solar collectors

I contacted eight retailers advertising evacuated tubes. Disappointingly, not many responded.

From sellers’ claims, the most efficient collectors I could find were Ritter (labelled APR), a Chinese-made German design imported by Sunplus CPC. We bought 1.6m long evacuated tubes in banks of six, with parabolic mirrors to direct extra sunlight under the tubes. Our budget limited us to triple the normal number of tubes recommended for hot tap water and a 1000 litre hot water storage tank.

The collector bank of 36 tubes is fixed to a 1.6m by 4.4m aluminium frame facing 15° west of north. I asked for it to be tilted steeper than the roof’s 17° at a calculated winter solstice angle of 60° to collect maximum energy for winter. This reduces excess summer yield and steam problems.

Importantly, the plumbing route for the tubes allows us to add more down the track.

The north roof with evacuated tube collectors for the heating system and a 1.5kW solar power system.

Inside the solar control and storage area

Solar-heated water pumping

This is a rainwater-filled closed loop heat-exchanger. Water from the storage tank coil is lifted about five metres up to the solar array by a 3-speed 30 watt 240v hot water pump with throttling valve, giving infinitely variable flow. It usually runs at 0.2 bar boost. A Zilmet model 20013 50 litre cylinder stores system over-pressure up to four bar from summer days, backed up by a blow-off valve to save water loss on hot days.

Relief valves

Four high spots in the solar array and wood heater circuits have auto air-bleed valves, allowing only air and steam to escape.

Wood-fired slow combustion heater

We changed the third wood heater to a gas unit for quick response to a cold home.

After the first winter with the new system, an existing free-standing Saxon unit in the living room was retrofitted with a 550mm tall stainless steel heat exchanger in the first part of the flue. It burns quietly from late autumn to early spring on wind-fallen mountain ash and blackwood harvested around the farm. Water to the flue exchanger is drawn from the base of the storage tank and delivered back to the top. Piping is about 25 metres long and rises about 3 metres. It is insulated with 25mm thick foam tubing and cased in colorbond. A 240v thermostat in the output pipe in a wall behind the heater senses output temperature and controls another small circulating pump at the storage tank, moving two litre slugs of hot water at 50 °C into the storage tank every few minutes. This heater provides around half our total hydronic heating in winter.

Gas boilers

Tap water is delivered via an instantaneous Rinnai V1500 gas boiler which adds heat if stored water is not 50°C. There are no adjustments for the home owner. Electronics in this unit can be damaged by our emergency home generator, so we cannot run the hot water when mains power fails, which it does for several hours at least four times per year.

Hydronic water supply is delivered to the mixing valve via a Sime Format 34e instantaneous gas boiler, rated at 11.2kW to 34kW, large enough to heat the whole home on its own. It adds heat if needed and has user-adjustments for output temp (set to 35°C). Its instruments display output temperature and pressure. The pump within this unit is also triggered by the thermostat in the master bathroom, sending heated water to a Hydrotherm P-600 Platinum tower rail, 2.2m by 600mm wide, helping provide some extra hydronic heating to the bathroom.

Both boilers stay on in summer as they do not use any gas unless heating water.

Heat users

The house is heated by hydronic coils in five zones in three concrete slabs at descending levels in the house, plus a fan-assisted radiator in the living room. Two manifolds are fed from a mixing valve, and water circulated by five, 240v Grunfos thermostatically-controlled 3-speed pumps.

We have only activated the outer coil on the lower slab coils. We are very fortunate that it flows via the master toilet and bathroom, laundry, kitchen, two guest bedrooms and to the living room on the lowest slab.
Hot tap water runs throughout the house with all piping insulated with 25mm thick foam tubing. External piping is further encased in 90mm stormwater piping.

Water delivery controls

Hydronic water is blended by the original tempering valve supplying two hydronic manifolds. Tap water is held to 50°C by a Reliance Heatguard Ultra tempering valve. This setting can be altered.

The three room thermostats in the home are very clever Honeywell model CM 907. They can be programmed in time blocks for every day of the week, can be over-ridden for one time block, set to a fixed temperature and adjusted for daylight savings. The lower slab thermostat in the living area also masters the upper slab in the entertainment area. The second thermostat in the upper level study controls the mid slab. The third thermostat in the master bathroom controls water to the towel rail.

Operation
Solar control

The electronic differential controller, made by Whitnic Services of NSW, gets its data from 10volt thermistors, one at the array output and one at the storage tank top. It has three modes and a red light indicates the pump is on, which I positioned to see from the back door.

Gas supply

Gas was originally supplied by a bank of 40kg cylinders. These were replaced by a 190kg truck-filled tank, with pressure reducers at two boilers, and a circuit supplying the guest kitchen and fast-response gas heater in the living room.

Owner adjustments and monitoring

I wanted to monitor input and tank temperatures, so I bought three $10 electronic indoor/outdoor thermometers with remote sensors and mounted them next to the differential controller. I can feel the input arriving from the solar array, with one attached to the lowest hot connection on the storage tank, indicating roughly how much hot water is in the tank, and the other reads water delivery to the taps. These have max/min displays as well, useful for checking array performance or pump adjustments. An old clock-type dial indicator measures the temperature of water returning from the hydronic system, a rough indication of how much heat is in the slabs.
The electronic gauges are particularly useful to know how much heated water is available for a big load such as a spa fill or running the lounge room radiator. Monitoring incoming temperatures from the array allows me to tune up the flow rate for best performance just below steam occurring, and tells me if we have any problems when it’s pumping. An improvement would be digital readings from the differential controller’s thermistors.
We can adjust slab heating times in two zones and towel rail temperature, and boost heat in the lounge room by activating the fan-assisted radiator. We can control the temperature of the water leaving the fire water jacket. We cannot alter the temperature trigger points for the solar array. It might be useful to keep it pumping above 80°C to stop a steam blockage occurring.

Current settings

Thermostats have six available time block settings, with the initial settings for the slab thermostats listed below:
TIME      TARGET TEMP
6am          20°C
8                18°C
Midday   18°C
5.30pm   18°C
8.40pm   13°C
10.30pm 8°C

When there’s a run of low solar-energy days we run the wood fire hotter. When there’s sunny days predicted, we can use less wood, or not light it.

As autumn starts, we open the hydronic valves and drive the wood heater hard to put as much heat as possible into selected slabs prior to cold snaps and overcast winter days. On a run of overcast days we open the damper on the wood heater.

Fine tuning and problems

We run the collector pump at the lowest of three speeds and fine-tuned the flow to 1.5l/min on the advice of the plumber. We’ve learnt that in summer we need to double the flow rate to avoid excessive pressure build-up.
The original thermistor on the solar array burnt out after one year and the surrounding insulation was charred! The new importer tells me the replacement thermistor is a tougher type.

Anything that stops the circulating pump while there’s sun on the vacuum tubes can create a blockage in the circuit that the circulating pump cannot overcome. When the thermistor on the roof fried, and when we lose power when the sun’s on the tubes, pressure builds up and the closed loop finally drops below it’s 0.2 bar pre-set pressure. This stops circulation for that day and we lose a little water as steam. When the pump is alive again it fails to get water circulating if the array is in sun. So if the system pressure gauge is zero, I know circulation has stopped and must be topped up. To fix it we fit the garden hose onto the fill point just below the pump, and run cold water until there are no bubbles passing the sight gauge. Our plumber has suggested an automatic supply for this.

Maintenance

Particle filters in the inlets to the tap boiler and both tempering/mixing valves need to be cleaned annually, the latter by removing the fitting gland, which is not a good design.

The Zilmet pressure storage tank needs its quiescent air pressure checked annually, and the whole tank replaced every five years. Pressure cylinders on my Citroen last indefinitely, with re-gassing, so we’ll see. The system needs to be de-pressured for accurate pressure checks.

The solar collector array needs to be hosed periodically to remove leaves.

Costs

Our gas costs about $730 for 550 litres per year, but my urban mate pays a fraction of our price! We really only use significant gas when we have guests, then it goes through the litres when the large boiler is doing a lot of the home heating. We average about 66 mjoules of gas per day in winter, and as little as 19 at other times. The Elgas truck doesn’t come from October to late April. In 2010 we used half the gas of 2009, mainly due to better windows and remembering to keep bedroom doors closed. We will get further significant reductions when our window conversions and internal glass partition are finished.

Total changeover cost, including towel rail and some bathroom alterations, was about $11,500 against an estimated $17,000. The local shire gave us a rebate of $250 and we received another $6900 in rebates. If hydronic slab heating was built into a new home, it may not be any more than other hot water and heating systems. Our 44 RECs were not sold because the supplier did not have an approved system with the tank size we used, so we missed out on around $1500. That’s a little plus for the environment as energy companies had to find an extra 44 RECs somewhere else.

Changed family habits

The dog is often asleep on the hottest sections of the hydronic loop, always in doorways or on the top of stairs. The cats love the laundry benches in winter.

To minimise the generation of greenhouse gas and gas bills we use most of our hot water first thing in the morning, giving the solar array the first opportunity to recover hot water lost. We built a wooden, pull-down rack below the laundry ceiling which now dries much of our cold weather washing.

We need to shut off the hydronic valve when spring is well-entrenched and must remember to open it when the first cool weather is predicted after Easter.

What next?

We are part-way through replacing most open-plan area windows with double glazing, with low U and SHGC value glass and argon gas in the space.

At the moment glaziers are installing a glass, openable air barrier at the top of the living area. This will zone the home into separate living and entertaining zones, reducing wood demands and cold air currents up the kitchen.
Stopping heat escaping is next. After a government-funded home assessment, this air entrapment work was to be financed by the now defunct Green Loans scheme. Another task is resealing all doors, and chasing air leaks along the brick-ceiling interfaces throughout the living spaces and external walls. This is to stop bushfire embers and smoke ingress; the home is to be a refuge as we’ve spent a lot of money on a 10-hour fire sprinkler system for all buildings.

I’m also planning to have the roof re-pointed; it’s amazing how much heat escapes from the fabric of the cathedral ceiling when you remove a capping tile on a cold day.

Much of the living room slab could be heated, in cooler weather, by direct sunlight, and possible when we replace dark green fibreglass on the pergola outside with clear sheets and retractable shade cloth.

I’d like an automatic system to over-ride the pump control in the main gas boiler, so the rail can be heated when the slab hydronics are off. This will probably involve some extra 240v relays to override the pump’s under-temperature and gas supply controls, which stop the pump when the hydronics are not on.

Due to firebox corrosion we will soon replace the wood heater. The next one will have a wet-back for more hydronic capability.

Suppliers

Green-accredited plumbers—Baw Baw Plumbing, Buln Buln East

Solar equipment suppliers—Phazer, Warragul

Glaziers—Walkies’s windows and glazing, and Warragul glass and glazing

Flue heat exchanger, gas room heater—Cosy heaters, Warragul

Monitoring thermometers—Dahlsens, Warragul

Fire protection system—The Farm Depot, Warragul

Gas heater installation—West Gippsland gas services, Warragul

The nickel metal hydride battery packs that came with the drills had been given a good run already and refused to accept charge after I’d used them for about a year. My preferred replacements, lithium ion batteries, would have cost so much that I could have purchased a whole new drill with new ni-cad batteries. This option being against my principles—I wanted to keep these perfectly functional drills working—I ended up buying two NiMH batteries online at a competitive price.

Two years of drilling went by and my replacement NiMHs were suffering the same fate. Using any one of four similar chargers, the charging period would only last for 15 minutes or so. Lifting the battery up and dropping it into the charger again soon became futile.

I decided to have a go at charging the batteries using solar power. A couple of years ago I was the happy winner of a 17 volt, 20 watt solar panel in ReNew’s Sustainable Sheds competition. [Ed note: read all about John’s super sheds in ReNew 107.] The output terminals of this panel were connected to the positive and negative terminals of the NiMH battery packs. They were given just a few hours each of high quality East Gippsland sunshine and wow, they have all taken the charge, although admittedly at less than their initial capacity. I now have four very functional battery packs again. The solar panel puts about one amp into the battery, so the 3Ah battery needs a good three hours to complete its charge. I’m a little unsure how the battery will respond to being left on the solar charger all day, such as if you fail to time it right. I try to start the charge mid afternoon, so the fading light tapers the charge.

Thanks ATA—what a saving in cost and resources!

Our biggest electricity use is an electric hot water system, so I decided to start there. The cost of a close-coupled solar hot water system was about $5,500. Things are quite expensive in North Queensland but I thought this was exorbitant and beyond my means. There was additional expense because my house has an aluminum roof and needed beefing up to take the weight of a close-coupled system with a collector panel and tank.

The plumber said it was not feasible to remove the large sheets of aluminum to add the timber, as it is almost impossible to put them back due to the age of the roof. He suggested that I build a leanto off the side of the house and use the solar collector as a roof for it.

I deliberated for some time (my wife says I normally do), and when the next ReNew magazine arrived I was quite surprised to see there was an in-depth article about solar hot water systems. The article started me thinking that maybe I don’t need a full system. I already have a perfectly good, well-insulated 125 litre electric hot water tank with a good element.

A retrofit seemed to be the way to go. I read about a five-way valve, a 10 watt PV panel, 12 volt pump and a solar collector and fittings. I thought this may not be as expensive as a whole system if I could find the items locally. I investigated and found that people would rather sell me a whole system. Also, a retrofit would not be covered with a warranty and did not attract a government subsidy. Back to the drawing board.

Buying a kit

I then read about a Solar-Mio/Metal Dynamics retrofit kit made by Albury Consolidated Industries. After a few emails to establish exactly what is in the retrofit kit, we decided on a SM-Tops1 squat panel PV pump system with five way fitting at a price that included freight to Townsville. We decided that one panel would be enough as we are a two person household and only use hot water to shower each day. I was extremely happy with the price as it was less than a third of the price of a leading brand close coupled system that sold in Townsville.

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In the 1960s, Abbie, a painter of landscapes, was drawn to the bush at Kangaroo Ground on Melbourne’s northern outskirts, building a mudbrick home.

In the 1980s she built an inspired home near Castlemaine in Central Victoria. Everything was done by hand and building materials salvaged from the tip, the bush and the roadside including tree trunks, stone, mudbricks, rocks, cow dung and sand dug from the riverside. This was undeniably an artist’s home, with a roof garden and an indoor dry creek bed. It took almost five years to build.

It was a different story with Abbie’s current home in Castlemaine, with the project taking only 13 weeks to complete. She had a head start with this dwelling, as it is made from a single portable classroom.

Just 20 kilometres away in Kyneton is BRB Modular’s ‘graveyard’, home to hundreds of demountable ex-classrooms. Abbie found a classroom slightly larger than most, meaning she could include two bedrooms, small as they are, so that her daughter can stay from time to time. The home has similar proportions to an inner city apartment, with an open plan living and kitchen area and a small bathroom/laundry. The main difference is that this 60 square metre ‘box’ has a 24 square metre deck added to it, with views that will only get better once the newly-planted trees grow up.

Anyone who went to school in portable classrooms might remember that they were incredibly cold, at least in the midst of a southern winter. Heating the rooms was hopeless because they are essentially steel or timber shells. To counter this, Abbie has added wall, floor and ceiling insulation, with the wall and ceiling insulation made out of recycled plastic bags. During an early morning visit after an overnight frost there’s no heating on but the full sun coming through the windows is enough to keep warm. Abbie says the house can stay warm until 9pm.

It’s a combination of rainwater, greywater and a little bit of mains water than keeps this suburban garden absolutely thriving. Keeping a garden alive in dry periods is one thing, but taking it to the next step and growing healthy produce with minimal water requires some planning.

Household greywater is used every day in this garden and has made a big difference. Karen specialises in designing and installing edible gardens and importantly, helping people learn how to grow and maintain their own veggies, fruit and herbs. Her philosophy on gardening is very much tied in with sustainability and the fact that sourcing food locally can help the planet by reducing transport emissions. Through years of experimentation she can judge just how much water is needed for an abundant crop of fruit and veg.

Karen and partner John had enough hands-on expertise to design and construct their own greywater system. Greywater can’t be stored longer than 24 hours, so the system is only big enough to hold a day’s worth of water. The header tank holds between 180 and 200 litres, with an overflow going to the sewerage system. Karen keeps track of how much water has gone into the header tank each day to ensure a minimum of wastage from overflow.

It sounds easy enough—just attach the mower blades to the electric motor shaft and mount the motor where the petrol one used to be. Sure enough, that’s what many people have done over the years, but of course, I felt the need to do it differently. After all, that is a personality pre-requisite for most of us who read this magazine!

Firstly, it struck me that the little bearings inside the electric motor that I was going to use might not be up to the job for any extended period of time. You know how it is: Whack! As you inadvertently try to slice through that massive cattle thigh bone the dog left half buried in the long grass. Clunk! As once again you give the concrete garden edging a bit of unnecessary de-glazing.  You really need big bearings and a heavy shaft to handle such treacheries of our urban war fields. I knew where I could get such equipment, in fact components designed to do this exact job—and they cost nothing!

Secondly, I wanted my new mower to be self sustaining—no trips to the petrol station, no charging cords, no wind-up springs and definitely no extra grunt from me. Obviously that means going solar or wind powered. Well there’s not a lot of wind here in BrisVegas but there’s certainly plenty of those golden rays of energy in our Sunshine State.