All posts by Estwing

Mas Mass

As discussed in my last post, thermal mass helps buffer temperature extremes in passive solar buildings. Including it in new construction is easy, and, may I suggest, that failing to design and build climatically-appropriate passive structures is not only ignorant but borders on criminal. Climate change and peak oil will define the rest of our lives. Enough said.

Our challenge is adding mass to a 100 year-old villa built at a time when folks had more of an excuse to ignore energy efficiency. Although you have to wonder why the English immigrants to New Zealand faced their houses toward the South Pole when clearly the sun was at the back door. I thought all the psychopaths and criminals were sent to Australia.


At this stage in the project we are focusing on increasing our solar gain (as mentioned in a previous post) but plans for adding mass are being carefully laid and materials collected. At this time they include:

Our second-hand, vintage Shacklock multi-fuel cookstove will occupy the northwest-facing wall of the kitchen and include a brick surround for fire protection. The heavy iron stove and brick will only receive direct sunlight in mid-winter when the sun is low in the sky and its rays penetrate deep into the house. In summer, when the sun is high in the sky, direct light is largely excluded from the interior. In true permaculture fashion, the stove and surround will serve multiple functions: cooking, space-heating, water heating, thermal mass and disposal of unpainted wood pulled out during the renovation. Plus, the wife thinks it is cute as hell.

While not everyone can add iron and brick to their home as we plan to do, our next strategy is one that can be installed cheaply and easily by nearly anyone. If you have ever picked up a sheet of Gib (aka ‘drywall,’ ‘Sheetrock’) you know how much mass it contains – a lot! Installing an extra layer of Gib board on top of existing Gib walls is practically invisible and fairly low-cost. Our plan is to add an extra layer of Gib to as many walls as practicable in the northern corner of the house.

Added bonus: Covering up hideous wallpaper with another sheet of Gib saves hours of steaming and scraping.


The next post will include two more strategies we plan to use and one experiment in the making.

– M.C. Estwing

Answer: Bike On A Bike

Question: How does one return a borrowed bike when their own bike is their only other mode of transportation?
Here’s a product for all of your carbon-neutral bike transportation needs.

Fine print: Must have calves of steel and a sturdy backpack for successful performance. Do not attempt with folding bike on bottom. Dutiful husband not included.

You saw it here first people. Now, don’t go running out trying to market this brain child. We are trademarking this revolutionary technology as we speak. Also in the works: furniture on a bike, seedlings on a bike, and wife on a bike.

Editors note: After substantial research, it turns out that the market for these products is extremely limited. Turns out there are significantly easier ways to transport large items.

In all seriousness, living car free presents some very real challenges for us. We rely heavily on our fleet of bikes: the little folder; the hand-made green bike; the silver road bike; and our B.O.B. trailer. And I cannot express just how very thankful we are that we now live in a flat coastal town. Finding motivation to ride this 6k into town is much easier than it was to find the motivation in Raglan where the 6k involved riding up the side of a mountain. But, as easy as the trip is, riding after dark, in the rain, or with a huge load can be dangerous and inefficient.

We also love that we live two blocks from the bust stop, and that the bus runs about a dozen times a day. We’ve done our laundry, grocery shopping, and even transported timber back from town on the bus. I’ve made a little group of commuting friends who seem to ride the same routes as I do regularly, mostly older or mentally handicapped folks, or both. My favorite is an older Maori gent named Tui, who shouts a big “There she is!” every time I board, and then proceeds to tell the rest of the passengers “She’s American, you know?”. Not sure whether that’s meant as a warning or a kudos. Either way, I like to think of him as my bus boyfriend. Don’t tell the hubs. But, as nice as the bus is, the last bus is at 5:10pm and there are no buses on Sundays. What is up with that Wanganui District Council?

So really, if we want to do anything in the evenings, or transport large items. We are at the mercy of the generosity of friends. And they have been extremely generous. If we even mention that we might want to pick something up in town, we have several offers of people who are willing to help us. Heck, even our new neighbor over the back fence offered us her car after watching us carry a load of lumber back from the bus. This offer would have been more useful just a few minutes earlier, but its nice that she put it out there. But, its not sustainable environmentally or socially to rely on people shuttling us back and forth to town.

So we are left with some options. One option is to set up a barter system with one of our friends or neighbors who has a car. If we set up some kind of car share system, then with some planning we could eliminate the extra trips involved in shuttling back and forth and would feel like we are contributing to a mutually beneficial relationship (instead of a parasitical one?).

Another option of course is to cave in and join the ranks of car ownership. And there are endless details involved in that decision. Do we buy a really flash new eco car or go down the used-car route? Would we buy a small fuel efficient model or a bigger car that we could use to haul loads? We would we really have the self-discipline to limit ourselves to mandatory trips only or would our lifestyle significantly change?


What do you think? What would you do? What do you do? How do we contribute to the creation of a sustainable transportation culture without sacrificing our individual needs? Or is that even possible?

-June Cleverer

U. Mass

Thermal mass is the unsung hero of passive solar design – the Rodney Dangerfield of eco-construction. Back in the 70’s idealistic but thermodynamically-impaired hippies built passive solar dwellings with plenty of glazing for solar gain and plenty of insulation, but little or no thermal mass. The result was dramatic indoor temperature swings from day to night. In some cases, on sunny midwinter days with outdoor temperatures around freezing, indoor temperatures in the high 80s F/ low 30s C required the opening of windows to let the excess heat escape. By the next morning, however, the house would be cold.

Let’s face our house towards the sun, man. – Groovy idea dude, totally groovy.

Last year, we did some house sitting in just such a place. At 6 a.m. when I got up for coffee and PhD research, the temperature in the kitchen was in the low teens C / 50 F. On sunny days it rose to 30+ C / 86+ F by late afternoon only to return to sweater weather (‘jumper weather’?) the next morning.

The role of thermal mass is to moderate these extremes – to buffer the system. It is like a bank account where an excess ‘wealth’ of heat can be ‘deposited’ on sunny days and ‘withdrawn’ at night. Think of a concrete stoop that has been sitting in the sun all day. It holds heat after sunset. Please note, thermal mass in passive solar design must be within the building envelope – that is, inside the glazing and the insulation.

Many new homes are built on insulated concrete slabs that can serve as thermal mass. This is smart design, but our 100 year-old villa is up on 1 meter piles with air flowing beneath the floor. The challenge is incorporating thermal mass inside our envelope in effective, attractive, eco-thrifty ways. The next post will explain some ways in which we plan to do this.

-M.C. Estwing

This picture is posted to authenticate that two real hippies were used in the making of this post. We have done our best to ensure that no hippies will be injured during the completion of this project.

Let the Sun Shine In

Free energy. No delivery charge. Service may be spotty in some areas.
As Meatloaf would say, “Two out of three ain’t bad.”

Northeast corner of the house. What a beaut!

Solar gain is a major driver for this project and represents a significant amount of the financial outlay. Although we have decided against double-glazing for reasons that will be explained in another post, cutting windows into walls is made expensive because all framing, bracing and flashing details must meet the New Zealand building code. This is in addition to the cost of the glazing.

Current wall = future french doors.

We are adding one window and French double-doors to the northeast corner of the house. (Remember we are in the southern hemisphere, and the sun is to our north.) The window will provide morning rays to the breakfast (i.e. coffee) nook, and the doors will flood the dining room with afternoon sun. My next two posts will explain how we plan to absorb (thermal mass) and retain (insulation) those lovely, free photons.

Enjoying a cuppa in the sunny coffee nook.

For the window we went with second-hand, but the new doors have just been ordered from the local aluminium (that’s right, we now us the extra ‘I’) joinery at a cost of $1,300. Our holistic design approach to gain, absorb and retain the sun’s heat will allow us to recoup the investment in the form of energy savings for years to come. This is the heart of what is called ‘passive solar’ building.

-M.C. Estwing

First Things First

Yeah, so maybe our roof had some holes in it. Maybe the brace holding up our front porch was leaning at a precarious angle. Maybe the plumbing and electricity were not quite functional yet. When we arrived in Whanganui four weeks ago, for the first time after our wedding, we knew exactly where we needed to start work here at the house… tree planting! Priorities.

Thanks to our fabulous friends we ended up with thirteen tagasaste trees, 10 kilos of compost, three native shrubs, two passion-fruit vines, a dual-variety apple tree, and a fig tree (partridge not included). . We also inherited a mass of foliage at the back of the property that looked like some sort of vine-covered monster.

Well creature from the vine-lagoon beware!

Look out vines. We are out to get you.

Who knew vine wrestling could be so addictive? After two days of work our viney-mass of unidentifiable trees went from this… to this:

Can’t tell the difference? Well, trust me. It’s massive.

Hey there’s a willow under there. And a bottlebrush tree. And three other mysterious little guys who were suffocating under a mass of convolvulous and some other crazy fast-growing parasitic flora. You could almost hear them squeak out a little “thank you” as their branches were free to reach for the sun. No worries little guys. I got your back.

Then it was time to get all those other trees in the ground. The apple went to the front of the house with the natives, right along the fence so that we can train it to run low. Lazy apple pickers or smart apple pickers? The passionfruit went along the eastern fence so they can climb up and away. And the tagasaste and fig went in the back, to create a bit of wind shelter and some fodder for our eventual chooks.

Not quite a forest yet, but give them time.

So “why?” you might ask. “Why would you spend all that time on trees when there’s so much else to do?”. It’s not as frivolous as it may seem.

We knew that once we started on the house, the project would be all consuming, and who’d be able to take time out to play in the yard? Plus, by getting the trees in earlier, they will have a better chance of survival through the summer, and we will be able to enjoy the fruits of our labor sooner. Tee hee. I crack myself up.

-June Cleverer

Nature as the Model


We’ve thought long and hard about what makes an eco-thrifty renovation. I say it is mindfulness. Specifically, we are trying to be mindful of energy, materials and toxics. To help guide us, we have adopted 7 guiding principles that we have drawn from nature. We’ll be providing plenty of examples in blogs, videos and podcasts to come, but for now, here they are:

  • Solar Gain
  • Thermal Mass
  • Insulation
  • Reduce Waste
  • Reuse Materials
  • Recycle Materials Not Reusable on Site
  • Minimize Toxic Materials

We hope that you’ll visit us regularly to learn and laugh.

Peace, M.C. Estwing