Solar update - first full bill

A few weeks ago we received out first bill where we'd had solar on the roof for the entire period. We were $170 in credit, which is nice!

For the stats geeks out there:

• from our 3kw system we exported 823 kWh of energy over the 94 day billing period - almost 9 per day. We got paid 60c per kWh for these. 
• In that same period we generated 1922 kWh - or an average of 13 per day.
• Average daytime consumption is 4kWh - although this obviously varies. 
• Our average daily buy-in from the grid was 7.6 kWh of premium (ie peak energy), and 6 kWh of super saver energy (hot water only, and not many baths were had in Oct-Jan, so you see why we need to get a new hot water service at some point!!)
• We're on a green power tariff, so some of our savings went on that extra cost, otherwise our bill would have been over 200 in credit.
• The minimum power produced by our panels since they were installed is 2kWh, and the maximum has been 16.
• By using the solar power during the day (av 4 kWh) we've saved $64, plus the power that the panels have generated has more than paid for the bill, with some credit to store over for winter, when there will be less sunshine.
• With savings and power generation payments, we've "paid off" about 5% of our outlay in this 3 month period.

All in all a good start!

How about you - do you have panels? How are they performing?

Not quite so ta-da

I now know the reason for the panels to hardly stand out at all on the roof - they were installed "flat" on the roof - giving them an elevation of about 12 degrees - they should be at 26 degrees for optimum grid-connect performance across the year given our latitude (36 south) (see here for more details). So the installers will be back on Friday to fix this. I could have a nice rant about how it shouldn't be up to us to find out the panels were not at the optimal angle, and that this surely was the most important part of the whole process....but I'm going to take a deep breath and let it go. OK so maybe a deep breath and a glass or 2 of wine and THEN let it go  :-)

However, in spite of the less than optimal angle, today, on their first full day, our system produced 12 kwh. Given the installer estimated 10 for this time of year I'm quite chuffed by that!

Ta-da!

They are hardly noticeable on the roof from the front of the house, but I'm loving watching the meter spin backwards.  The great thing is that because we have an old dial style meter, they were able to plug the panels in straight away and we're already feeding power into the grid, and reducing what we will have to pay next bill.

Today in the 4 hours since installation they have generated over 6 kw, and our meter has rolled back about 4kw. Loving it!

Watch this space

Bubbleglazing update

Well the bubbleglazing is working a treat, especially in the bathroom. It is noticeably warmer in there first thing in the morning, I'd say by a few degrees - and that is the only thing we've changed. The bedroom is also staying much warmer, which we suspect has as much to do with plugging the small gap as the bubblewrap. Then again, given the bathroom results I'm sure that the bubblewrap is helping, even though it isn't on all the windows. You can really feel the difference just by comparing the feel of the window vs the feel of the bubbleglazed window

In fact the other morning Jerry and I work up and said to ourselves that it was almost too warm, the difference is so apparent!

In answer to your question Nelly we used double sided tape to stick the bubblewrap, but Jerry's found a few sites like this one that say you just spray water on the window and stick, so we're going to try that with the other windows we're planning to do. Will let you know how that goes.

It's just a box...right?

Wrong... it is actually almost 2kwh per day!

This my dear reader is a magic box that will turn my chest freezer into a fridge, and will save me power and money in the long term.

It is actually an external thermostat unit that you plug the freezer in to and then feed the temperature probe into the freezer. This box then turns the freezer on and off as required to maintain a temperature of 4 degrees. No messing around with freezer internals :).

Thanks to Mr Rudd's money, we've purchased the kit, and will purchase a slightly larger chest freezer as our new freezer (to hold more bulk purchased meat as well as frozen home grown produce). Our current chest freezer will be moved into the kitchen (luckily it fits in the space that our current fridge occupies) and will become our new fridge. Our old (17yrs) fridge that is on it's last legs will retire to the shed to enjoy a new life as a rodent proof food store.

Why a chest fridge?

• It is much more energy efficient than a standard upright fridge or fridge/freezer. Our current unit uses on average 2kwh per day. A chest fridge uses around 0.1kwh per day according to the maker and people I know that have them. That also tallies with our chest freezer that uses about 0.4 per day.
• A chest freezer is a LOT cheaper to buy than a new fridge/freezer

We're lucky that we can make all this work with only minor modifications in the utility room (where the freezer will live) and with no modifications in the kitchen so in total we will still spend less than if we had purchased a new upright unit. Thanks Mr Rudd!

If you want to read more about chest fridges click over to Mt Best, who sells the kits. I'll post updates once we are underway with the room modifications.

Cutting back the kilowatts

It's like cutting back calories, but easier! And you don't have to give up chocolate!!

I started out with the best intentions to get the filing done, but got sidetracked when it came to electricity bills. I wonder how our usage has changed over 3 years.........

An hour and a few excel charts and formulae later I discovered our annual average KWh per day has dropped from 25.8 in 2006 to 19.8 in 2008. That's a decrease of 23%. This is in spite of the fact that I started working from home during this time, which meant more electricity use during the day. 19.8 is still higher than I would like, but given that we use electricity to pump our water, plus the home office, I'm really pleased by this progress.

I should point out that we currently do not have solar hot water (it's coming when the existing system finally needs replacing), AND our hot water system is too big for just 2 people, so 5-14kw per day (depending on whether we have a bath or not) is accounted for by hot water.

You can see in the chart below we have made the biggest savings in the 'winter' quarters: Apr-Jul (29% decrease 06 - 08) and Jul - Oct (39% decrease 06 - 08!!!).

But the best thing about these decreases? We didn't have to spend a lot of money to make these savings. We did spend money on:

• gradually replaced curtains with blockout-type curtains for better insulation (when they were on sale, of course!) (2007 - 2008)
  
• making old fashioned draft-stoppers for all the doors (2008)
  
• replacing power hungry old electric oil heaters with newer electric ones that have timers and temperature sensors so they cut in and out as required, and can go off overnight (eg in the bedroom) (2008)
  
• I bought a power meter to track how much power individual pieces of equipment use (2008)
• converting to cf bulbs
• replacing the electric kettle with a stovetop kettle (we have a gas storevop)
  

But there were still more simple behavour changes we made that have clearly made a huge impact:

• over time I've gradually turned down the temperature on the hot water unit to minimise reheating time
  
• we 'curtained off' the end of the house that we don't use unless guests are here, so we're only heating the part of the house we use
• in 2008 we 'decomissioned' the second bathroom unless guests were staying - so that meant turning off the second small hot water unit for that bathroom, and not having to heat the bathroom in winter. I think this was strangely the 'hardest' adjustment as we quite liked having our own bathroom each!!
• in 2008 I relocated my home office to the end of the house that we use in winter - so I now share this room with Jerry. This was also something I resisted as I quite liked being able to have the office a bit more seperate to the rest of the house, and Jerry liked having his own room. However, as my office was in the "curtained off", and therefore unheated part of the house, I was using a lot of power to drag the temperature up from 12 to 16 every day, and running a heater 5-7 hours per day. It was a bit mad looking back on it. In the new study I might only have to run the heater for an hour or so on really cold days. And I can always just pop around the corner and warm up by the fire.
• in 2008 I also 'bubble-glazed' the study/office windows to keep the room warmer, but still let in light.
• I switched to only using 'eco' mode on the dishwasher (which saves about 50% of the power compared to the normal cycle that includes drying)
• I use my slow cooker as much as possible in winter rather than the oven to cook meals - and I try to make enough for 4-6 serves per meal to make the most of the power use
• We have progressively removed light fittings from our halogen track lighting eg over the dining table we had 6 (or maybe 7) and now we only have 4. In the main living area we had 5 and now we have 3. In addition we try to use lamps with cf bulbs rather than the track lighting whenever possible.
• We have used insulting foam or mud to seal gaps that were letting in drafts
  

But of course, there is still more we can do! On the power saving to do list are:

• solar hot water
• finish replacing old curtains with insulating curtains in the rest of the house
• moving from rod and ring style curtain fittings to track fittings so we can get the curtains closer to the window (pelmets just woudlnt work in our style of house)
• replacing the old standard fridge with a chest fridge
• keep up with the gap-sealing work
• opening up the chimney to expose more flue and replacing the fireplace with one that I can put a pot/kettle on to slow cook food during the day / keep water hot for a cuppa .
  

Alas most of these need some serious $$, so I'd best get back to work!!

The great bubble-glazing experiment

A mud brick house is great, but a mud brick house with lots of very thin windows is a PAIN to try and keep warm. We're gradually updating all the curtains to sunout (the most insulating ones we could find), I've made draft-stoppers for all the doors, and we've curtained off the end of the house we don't really use so we're only heating the main living areas.

I feel a bit like I'm living in a cave in winter as I try and keep the curtains closed when it's not sunny to keep the warmth in. It's particularly depressing in my office as I feel like I'm working in a dungeon. So I've decided to try a new experiment - bubble-glazing.

I got the idea from the MtBest website - in it's simplest incarnation it just requires bubble wrap and double sided tape. You stick the bubblewrap to the window- bubble side facing//touching the window. This is what I've gone for on my 'test windows' in my office/study. To start with I've just bubble-glazed half of the windows, as I'm interested to feel the difference between the two after a day or so.

This is how it looks.

As you can see, it does 'blur' the view to the outside - however, as I have been keeping the curtains closed the advantage of the bubble-glazing is it lets in a LOT more light, so I feel less like Harry Potter in the cupboard under the stairs! And bsides, I'm supposed to be working in the office, not staring at the view :*)

If this is successful then I'll be getting Jerry to make some wooden batons so we can make a more permanent (and more elegant) frame.