Sunday, February 6, 2011

Saving electricity and CO2

Everything's gone a bit Dorothea McKellar

In the last few months Brisbane was underwater, Queensland and Victoria were ravaged by floods and everyone else seems to be getting heat waves, record rain, floods, plagues, bush fires or snow storms.

In the news this week there were two stories which really got our attention and have burnt themselves into our subconscious.  The first says that we're got little chance of keeping climate change to 2 degrees (the limit where things might still be manageable) and we're on track for 4 (genuine biblical proportions stuff). The other one is that electricity prices are going up again and are set to double every 5 years.  Eek, it's enough to drive you to despair. 

What can we do?  Well for the Joneses, it was time for us to do what we do best, be the Joneses we want to see in the world, and show people what we're doing (including the mandatory mistakes we make along the way so that you don't have to).

Today we went back to the drawing board to see what we could do, whether we'd done the right things and what else we can do.  We're pleased to report that we're not doing too bad and some things are paying off.  Here's a bunch of stuff we did to reduce our electricity consumption since we moved here nearly two years ago.

Tackling the big things first

The electricity in our part of the world comes from coal fired electricity which is relatively cheap in the short term but is one of the most carbon intensive forms of energy.  We wanted to get away from this.  

We looked at gas but our town doesn't have access to gas infrastructure, which means if we want gas we've got to buy it by the bottle and have it trucked in.  While possibly less carbon intensive than buying electricity, it just didn't resonate with us.

We paid the extra for Green Power and the first electricity bill was so outrageous that we just couldn't afford it.  Somehow we were consuming twice as much power as we had been at The Newtown Cottage.  We also were pretty sure that electricity companies have to have a mandatory portion of renewables, and by us paying for Green Power, all it was doing was paying them extra money to let them off the hook and didn't achieve much unless they'd already hit their targets.  Not a good option.  

We looked at solar panels, but our roof gets a lot of shade and doesn't get enough sun to make sense.

Also it seems that a large part of the increased cost of electricity is due to capacity limits of the grid during peak periods, so the real key is reducing demand.  Reducing our consumption without compromising our lifestyle was clearly the go. So the most sensible option was to invest time and money now in things which will save us time and money for many years to come (and lots of electricity and carbon emissions too).

You can spend a lot of time, effort and money on things which help a little, but don't really make much of a dent in your electricity consumption. So our first step was to focus on the big things first.  Here's a chart of the energy use of a 'typical' Aussie household. 

This gave us a good hint on where to start.

Now this data is for the typical household, so we looked at the big areas and if they looked inefficient at our place then we figured they were over the average.  Our two big ones were hot water, and heating and cooling, which we figured accounted for around 65% of our electricity bills and at least 50% of our emissions.

Hot water

We were horrified to see that hot water for the house came from two electric storage hot water systems, but because that there's no gas here we can understand why they were installed.  Given that this would be using at least 25% of our electricity this was the smartest place to start.

Needless to say we were really happy when the building report said they were at the end of their useful lives and needed replacing almost immediately.  We were also stoked to see there was still a hot water rebate available to get rid of inefficient hot water systems which would pick up about half of the cost.

As a rule of thumb traditional solar hot water systems trump everything else, followed by instantaneous gas.  Everything else is horribly inefficient.  We went with the best solar system we could afford, which was about double the price for a traditional Edwards/Solahart unit, but also twice as efficient and should last twice as long.  Other than in high use days in winter our hot water is pretty much free, even though we're in an area with two hours less daylight than most people due to being on the low side of a ridge to the north and having a lot of overcast days.

Savings: $180 per annum at current prices.  4-5 tonnes of CO2 - about the same as taking a light use hybird car off the road or planing 23 trees.

Was it worth it?  

Definitely for guilt reduction.  On a financial basis alone it'll pay for itself in about 8 years, and then keep on giving for another 20 or so.  Money well spent.  And we also got to meet Stephen from Viabuild who introduced us to permaculture, so that was a big bonus.

Would we do it differently next time

If we were city and strapped for cash we'd go instantaneous gas every time, but for where we are it was definitely the right move.  We'd definitely do it again.

Here's the skinny on our system.

Heating and cooling

Most of our appliances are reasonably efficient, we've got low wattage lightbulbs in and turn off the big appliances at the wall.  The computers are laptops.  We got rid of the big inefficient clunky hotplates that take 2 hours to heat and and cool and replaced with an efficient convection system. With this out of the way we figured the bulk of our energy use comes from heating and cooling.

The Joneshack is a 108 year old weatherboard house, built in the days before insulation. Weatherboard houses are great because you can cool the place down quickly in summer when the evening breeze comes in, but they're also hard to live in on really hot and cold days.

Mrs Jones was keen to put her mark on the new place.  We opted for ceiling fans with lights in them - they are stylish and functional, and besides, have you been able to find a tasteful light fitting anywhere that looks good with compact fluros?  The fans are great to avoid having to use the aircon, and the bright lights come in handy when the energy efficient floor lamps aren't bright enough.

We planted a nice deciduous tree in front of the main north facing windows to allow heat and light in during winter and keep it out in summer, and have trees shading the west side of the house to keep the hot afternoon sun out.  Deciduous fruit trees are growing in front of the east facing windows to deal with summer morning sun.  These will take some time but will be wonderful when established.

We moved in just before winter and were struck by how cold the house got compared to our previous place in Newtown.  There was no heating in the house - the previous owners had used fan heaters in every room, which means their power consumption must have been astronomical. This could not stand.  The Jones do not abide.

We looked at the various options, and decided that reverse cycle induction airconditioning was going to be the most cost effective option for heating and cooling.  As crazy as it sounds, induction systems can be highly efficient for heating because they extract heat from outside rather than having to create it from scratch.  Similarly they transfer heat outside of the house when in cooling mode and it means only shelling out cash once instead of having to buy a heater as well as a cooler.

In the short term while we were understanding how the house works, it meant we could turn the portable heaters off, saving a small fortune and oodles of CO2, and put the hot water bottles away and stop watching the steam coming off our breath while indoors.

But it still wasn't working.  We figured we must be losing heat out of the windows and doors.  So we sealed the doors, and put in some air tight window covers (we opted for wooden shutters, they have better thermal performance and for 50% more than the price of blinds, they look a lot better and last a lot longer).

Still no good.  We turned the laundry into an airlock so the dog can get in and out without a draft.

Still no good.  We got someone around to give us a quote of underfloor insulation, which is where we figured the last 15% might be, and it turned out that there was no insulation in the ceiling. We'd squandered our rebates on the hot water service, but for under $1000 we were able to get the Battman to do our roof with R4.0 pink batts.  Superb job, and what a difference that made.

Months later, it's still wasn't quite working out.  We'd been unable to find anyone to supply or install underfloor insulation and with our uneven joists and bearers, everything was a strange size and not square. We finally sourced and installed some Foilboard underfloor insulation in a few of the rooms and the difference was noticeable immediately in the rooms we'd done.  It's an awkward job, but pretty easy once we got the hang of it and one we should have got to earlier.  The guides say that there's only 15% energy efficiency to be picked up in insulating floors, but for us it feels like a lot more.

Was it worth it?  

Mrs Jones says definitely, she doesn't like extreme heat or cold much.  Mr Jones doesn't cope with humidity so he's happy too.  The reality is without the inverters, and insulation the place would have been unbearable during the winter and in the heatwave during the last few days.

Since installing all the kit, Mr and Mrs Jones are both spending nearly twice as much time at home and our power bills have remained more or less flat even when they should have jumped significantly.  The fact that someone is at home nearly all the time and we're still tracking below average household power use, even without gas is a pretty good outcome.

All up we've spent about $5,000.  It's hard to work out what our power bills might be without all the kit, but if we say an extra 10% on our bills, that's about $150-200 per annum, so about the same result as the hot water system, so about the same bang for buck ignoring rebates.

Would we do it differently next time

Your insulation is only as good as your biggest gap. In our case we learned this the hard way. We spent time looking for gaps, only to miss big ones. If you're going to do insulation, particularly in a weatherboard house, don't do it a bit at a time, do the lot at once.  Also if you've got an attic, don't overlook this, it needs to also be insulated, including the floor and roof cavity.

If we were a bit more confident we would have put a wood stove and bricked around it.  This would have given more thermal mass to maintain the temperature in the house rather than just heating or cooling the air, and the stove could cook, heat the house and give the hot water system a boost in winter.  

We'd probably spend the extra and get an induction cooktop instead of a ceramic one.


We pretty much did a lot of the text book things to our house, and they all seem to work, but have taken us time to get right.  We'd agree with the text books though:

1. Change to solar hot water, or instantaneous gas if its an option and you're short of cash.
2. Deciduous trees as first option around the house to deal with the summer heat while allowing winter sun in - they're the cheapest option.  If we were to do it again, we'd spend more and get more established trees.
3. Get as much thermal mass into the centre of your house as you can (which we didn't do), and have as little thermal mass around the outside of your house as you can (check).
4. Insulate the house well (in progress)
5. Efficient heating and cooling solutions.

This should give you the biggest bang for buck while you're also tinkering around the edges.

One of the best resources we've found is the Your Home Technical Manual and the fact sheets are available free online.  We found it invaluable, to the point that we could talk rings around the Green Home assessors.  We'd suggest having a really good look at it.  It's clear, simple and very very useful.

The Joneses
Be the Joneses you want to see in the world

1 comment:

  1. We can't begin to explain how helpful writing this article proved to be for us.

    You see it got us thinking.

    We'd spent a lot of time and money on things which were supposed to save us time and money, but our electricity bills weren't going down.

    On further investigation - our hot water system hadn't been installed properly, and the laws of physics were working against us. In short, our system was themo-siphoning which basically meant that all the free heat gained during the day was being lost at night. Even worse, we think it had been set up so that off peak power was being used to effectively heat the sky!

    The moral of the story - check your power bills regularly, and if they don't make sense, investigate and do so early. Don't assume that just because your hot water gauges say all the right things that you're saving electricity. The electricity meter is the one to watch.

    The good news is its now all fixed. Our electricity consumption and C02 profile have dropped significantly since writing this article, which is great.

    The Joneses