Apr 212012
 April 21, 2012  Posted by at 6:58 pm Shelter


This is Part #1 in an ongoing series about Eco-Thrifty Renovation, by Estwing of the ETR Blog.

This series recalls the design principles and decision making process of an eco-thrifty renovation. We believe the key components of a sustainable home include low energy use, redundant energy and water systems, abundant food production and avoidance of debt to the greatest extent possible. For under NZ$100,000 (US$80,000) and a year of hard work, we have developed one of the most sustainable and resilient suburban properties on the planet. We use 90% less electricity than the average NZ home, we aim to meet all of our fruit and vegetable needs on 700 square meters, we have no mortgage, and we share all of this information with our community.

Payback Period: Key to Eco-Thrifty Renovation

When my wife and I set out to renovate an old villa in November 2010, we made the conscious decisions to focus on energy efficiency and waste reduction above all else. We also chose a structure that many would have written off as beyond redemption due to its poor condition, and we wanted to do our best to demonstrate that a warm, dry, energy-efficient home can be within reach for people of moderate means. I have heard stories of people spending $20,000 on a new bathroom or new kitchen, but still have no insulation! Although we did install a new kitchen and new bathroom (at $2,000 each), the bulk of our budget went to insulation, solar hot water, and north-facing glazing (windows and doors). These are the investments we made that are paying us back with energy savings at a higher rate than the best term deposits of any bank. This is what we call eco-thrifty. It is a philosophy that focuses on low-input / high-performance systems.

Central to this approach is the concept of ‘payback period’: the amount of time it takes to recoup an investment in energy-efficiency with savings on your power bill. For example, a compact fluorescent light bulb costs $5, but will normally save you more than $5 per year (depending on use) in electricity. Therefore, the ‘payback period’ is one year or less. A ‘payback period’ of one year is roughly 100% return on investment. What term deposit offers that?

Another example of ‘payback period’ is solar hot water. Our system cost $4,000, and offers a ‘payback period’ of 7 to 10 years (depending on use). This represents a return on investment of 7% to 10%. What term deposit pays that? Another example would be insulation, but I won’t bore you. The long and short of it is that our money is paying us back more on our roof, in our walls and in our light sockets than in a bank. Add to this the environmental benefits and the hedge against inflation (electricity has been rising at 7% – 8% per year over the last decade, a ‘doubling time’ of 10 years), and eco-thrifty appears to be a conservative, logical approach to building (and…life, I might suggest). But there is a catch.

If you borrow to make home improvements with a ‘payback period’ over a few years, then the bulk of your savings goes to the bank, not to you. Therefore, we recommend a process we call focusing on the ‘low hanging fruit.’ These are the cheap and easy investments that anyone (owner or renter) can make immediately and start reaping savings. Then, with much fiscal discipline and gnashing of teeth, these savings are set aside to invest in ‘medium hanging fruit.’ And then…you get the picture. This new column published on Saturdays will address many of the fruits of eco-thrifty renovation and their benefits. Although this is a unique approach to renovation, many of the oldies reading these words are probably saying to themselves (or out loud), “it’s just common sense.”

On a final note, we have worked closely with Building Control throughout the process and found them very helpful. From my perspective, the New Zealand Building Code concerns itself primarily with ensuring structures: do not fall down in an earthquake or a gale; do not allow moisture to contact untreated or H1 timber; hold heat in (insulation); do not burn down from electrical wiring or internal heat sources. This list is the definition of a sustainable building. Who could argue?

Posted by The Eco School

Home Forums Retrospective #1: As published in the Wanganui Chronicle, 21-04-12

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    This is Part #1 in an ongoing series about Eco-Thrifty Renovation, by Estwing of the ETR Blog. This series recalls the design principles and decision
    [See the full post at: Retrospective #1: As published in the Wanganui Chronicle, 21-04-12]

    Peter Lyon

    Good post. Maybe I am already one of your “oldies” because I do get it. We just spent $300 on some draught and other improvements (especially a thermal wrap on our old-style hot water cylinder) that I hope will reduce our winter power bill by 5-10%, which will be a 1-2 year payback). On the other hand we are also retrofitting double glazing, which will cost a lot more and take many years to pay for itself, but that is another side of the equation: money on that now is going to help our health as we get older, and also adds to the capital value of the house, so is worthwhile for those reasons rather than any reasonable payback time.


    We also live on a small block (900 square metres) and are currently building a cost effective, simple system of harvesting water from the gravel road out the front.
    When it rains, water flows down the road at quite a pace. I have dug a small channel diverting it into trench running down the side of our house. The trench is plastic lined and filled with course sand and fine gravel which filters the water. It collects into a sump pit where it is then pumped into a 20,000 litre holding tank to be finally used watering the vege garden when times are dry.
    We also have planter boxes 3mx3m and 600mm high, plastic lined and filled with sand and gravel and planted out with plenty of reeds and ferns. This water is also collected after filtration and bacterial break down and used for irrigation. Water is transfered to the garden using gravity.
    We use zero mains water.
    Water for household consumption is collected from the roof of our house.
    Of course, the local Council know nothing of this.


    Forgot to mention that the planter boxes treat our waste water. Water from the toilet goes into one planter box via a septic tank which is used to irrigate ‘above ground’ fruit and veges. The water from washing goes into the other planter box where it is then used to irrigate root crops.


    I believe that double- or triple-paned windows are pretty expensive upgrades for minimal energy savings return (ie going from an R2 to R3 or 4). For a much lower price, you can get a substantially better energy savings from insulating the attic, for example, in some cases going from R20 to R40 or R50. As for adding to the capital value of the house by upgrading windows, again I’m not sure about this if the assumption is that house prices will decline/deflate. New windows are certainly nice and less drafty, but they usually come at a relatively high cost.

    I share the observation that people tend to focus on the superficial elements in home renovations generally (ie beautifying the bath or kitchen areas, while ignoring the overall functionality of the house). I have seen some excessive kitchens that are used for little more than microwaving prepared food purchased at the supermarket.

    Anyone get to see the Canadian documentary film “Payback”? It is based on Margaret Atwood’s Massey lecture by the same name. My comments: the movie explored the broad notions of debts, including environmental debts that can’t be repaid monetarily in some cases, and debts between individual persons which can lead to feuds where there is not legal system of redress. While the movie touched on prisons as a mechanism for extracting payment from individual criminals for their debts to society, there was no exploration of the concept of debtors prisons as discussed here on TAE. I would have liked to have seen this element. There also seemed to be more of a focus on inter-personal debts as opposed to the debts that are owed to or by large institutions/corporations. It would have been interesting to have seen some exploration of this also. Overall, some good food for thought plus some chuckles listening to Conrad Black wade in on the subject of his repaying his debts to society.

    Peter Lyon

    There is something that you are all missing by just concentrating on the electricity savings for payback time on double glazing, and I will use myself as an example. I am a labour contractor – if I don’t work, I don’t get paid. I am more likely to get sick and miss work in a cold house over winter; every day off work sick is a lot of money, and if I get sick once each winter say, and miss a day or two of work, that could be even more than the value of the electricity saved. So “comfort”, while it sounds a vague and silly measure, can be real. Maybe not so much for those on wages, if you get paid for time off sick, but just to show there is more to it than just the electricity you save, especially as you get older.


    Some serious low hanging fruit is a clothesline, which we installed and have used since we moved here 12 years ago. But they don’t fit into the ‘modern’ lifestyle of America in the teens.
    Another is insulated curtains instead of expensive double glazing. Anyone with sewing skills can make them.
    At one time I successfully used bubble wrap to insulate my windows, and not only was it quite efficient, but it also allowed in light in the winter, making the place cheerier.
    And, here in the high desert of the Western US, where humidity is incredibly low, we use an evaporative (swamp) cooler for all our cooling needs. It will give out up to 30 degrees below ambient. For a tiny fraction of the cost of a standard air conditioner.
    Of course another one is a bicycle, but we’d rather all pay for auto insurance, gas, and maintenance so we’re not seen as ‘nerdy’. I personally don’t care about being a nerd, I ride a scooter, and laugh about it all the way to the bank.


    “For example, a compact fluorescent light bulb costs $5, but will normally save you more than $5 per year (depending on use) in electricity. ”

    One big problem with any fluorescent light bulb is the issue of recycling. These are mercury containing and should never go in the land fill trash. Some retail stores say they will take them; in my area of CA Home Depot says it will take them.

    A better newer technology is the LED, but the ones slated to be available will be $30 – 50 a pop. Enough to make cfl bulbs seem better.

    Another problem with cfl bulbs is if one breaks. Mercury can become an aerosol and breathing it should be avoided. You can find the very
    exacting instructions from the EPA for clean up. The article does say that this is an extremely careful clean up.

    Before Cleanup
    Have people and pets leave the room.
    Air out the room for 5-10 minutes by opening a window or door to the outdoor environment.
    Shut off the central forced air heating/air-conditioning system, if you have one.
    Collect materials needed to clean up broken bulb:
    stiff paper or cardboard;
    sticky tape;
    damp paper towels or disposable wet wipes (for hard surfaces); and a glass jar with a metal lid or a sealable plastic bag.

    During Cleanup
    DO NOT VACUUM. Vacuuming is not recommended unless broken glass remains after all other cleanup steps have been taken. Vacuuming could spread mercury-containing powder or mercury vapor.
    Be thorough in collecting broken glass and visible powder.
    Place cleanup materials in a sealable container.
    After Cleanup
    Promptly place all bulb debris and cleanup materials, including vacuum cleaner bags, outdoors in a trash container or protected area until materials can be disposed of. Avoid leaving any bulb fragments or cleanup materials indoors.
    Next, check with your local government about disposal requirements in your area, because some localities require fluorescent bulbs (broken or unbroken) be taken to a local recycling center. If there is no such requirement in your area, you can dispose of the materials with your household trash.
    If practical, continue to air out the room where the bulb was broken and leave the heating/air conditioning system shut off for several hours.


    Here are pictures of how we reconditioned the old house.
    Below is the house at the orchard. The part you see was built in the 1940s. The inside was worse than the outside. We replaced the floor with insulation below the concrete. We tore out all the plasterboard and insulation, added two by twos so we could have six inches of insulation on the walls and ceilings down stairs. We did the same upstairs.

    So far the windows and the thermal mass of the floor keeps the house at least 30 degrees above the outside temperature during sunny days. We built insulated panels for the window to be inserted at night to preserve the solar gain. The cost was below $3000.



    Michael, Have you made any way to divert the water from your house in case your cachement system over flows in extreme rain/flooding? I ask this as I extended my down spot into my main planting bed some years ago which worked very well in moderate rain and drought years [it used to drain into the underground storm water system] but will now have to change my system as the last few years of unusualweather and fierce rains have made a swap out there…in an area with otherwise excellent drainage.

    I regard to flourescent bulbs and mercury…since nearly half of US electic power is supplied from burning coal, which produces heavy toxic pollution, a good deal of which in the form of mercury, wouldn’t a bulb which uses a quarter of the wattage for a much longer life, be lowering the pollution levels? Does anyone have any figures as to the actual mercury used in manufacture and dispersement of these bulbs?



    Our overflow drains as surface run-off down our block and through the rear block (which is vacant) into the roadside drain. Should building start on the rear block then I will install an underground drainage pipe (100mm diametre) and discharge the water formally into the council drain.
    I know the owners of the rear block are deep in debt.
    If Stoneleigh is right then that block could soon be on the market at a greatly reduced price. I live in Melbourne, Australia, and our property bust has just began.
    My plan is to buy the block and turn it into a large vegetable garden.


    A low impact woodland home

    Also, please consider geothermal. Don’t be scared off by people telling you how expensive it is to dig the trenches and lay the loops. Why? Because you do it by HAND. it doesn’t matter if it takes you all summer. So what? Geothermal is impervious to anything but a severe earthquake and even then it has to be the kind that slides some terrain one way and another level another way (extremely rare).
    With geothermal you can keep the temperature quite comfortable without the high expense of maintaining a ‘tight’ house. Remember that extremely well insulated houses can cause health problems under certain circumstances (some insulation and building materials can emit harmful vapors – also ANY mold development from added moisture can accelerate rapidly because moisture gets trapped in highly insulated material).

    Geothermal allows for more normal air exchange. Humans developed in loosely insulated shelters, not hermetically sealed boxes.


    Please check out Carl’s neat system
    which uses 4″ plastic pipe buried underground for very inexpensive cooling. And even for water collection.
    I think he says cost of pipe is


    Re: Wanganui renovation and building control. Another thing to remember is that while the New Zealand Building Code requires minimum compliance with the Standards, there’s nothing stopping you from increasing the level of compliance. This is particularly effective for insulation. The higher the level of insulation the smaller the heatloss and the bigger the energy savings.

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