Friday, 17 November 2017

How to build a house Part 4. Paying for the bloody thing

Financing is the main thing stopping many people from building their dream homes. Still others are forced into building a house because they have access to finance​, and that may turn into a nightmare.​

Unless you are one of the lucky few with enough cash to pay for a house up front, you probably need to get a mortgage. Banks can decide who to lend, or not to lend to, but as with many things, the biggest factor is whether you want to borrow money or not. As Henry Ford said, "whether you think you can, or think you can't—you're usually right."

I've heard foreign residents in Japan say that banks won't lend to them if they don't have permanent residency and permanent employment somewhere. That's certainly true if they think it's true, and don't go and ask any banks.

If you want to get a loan, then get it while you are employed. The bank will be happier to lend if you have a steady income, that has been paid into your bank for several years. Before I got a loan I was worried that I would be stuck to my job forever. I was also somewhat scared of monthly repayments until I'm into my seventies. As it happens, after getting the loan I felt much less chained to my current job, and I hardly think about the monthly repayments. ​They're just like rent, which I had got used to paying. ​

Money used to be bits of metal, then it became bits of paper and later bits of plastic. Now it's just bits on a computer somewhere. It's not a particularly scarce resource, but that may be easy for me to say with an overly privileged background and a life of undeserved comfort​!​


But​ whether you're paying in cash or from a hard-fought loan, the question remains: how much is the bloody thing going to cost?

It's like when you go to a restaurant and look at the prices on the menu. Except there are another few noughts on the cost of everything.

Glass of wine 300 yen. Light fittings: 300,000 yen.

Salad 500 yen. Bathroom: 500,000 yen.

Paint. You want paint?

This should not be surprising when you consider how big a house is.

The glass in our windows could have made a thousand drinking glasses, and the tiles on our floor could make a thousand ​plates. I don't want to think about how many chopsticks the wood could be split into.

It's important to understand the difference between price and cost​, which are not the same. Basically price is what you pay to get something, and cost is what the person who gives it to you had to pay. Businesses stay in business because of the difference between price and cost, and often the relationship is arbitrary. The price depends on how much ​the customer ​is able to pay, and how much other people are charging, not on how much it will cost the​ supplier to produce. The costs can't stay above the prices for long, unless that is funding another revenue stream​, as when Gillette sold shaving handles below cost, or even gave them away because they could make money out of the razor blades.

​House builders are in almost exactly the opposite situation. Once you buy a house from them, you will never buy anything from them again. In fact there is a chance that you will demand some extra work from them to fix the inevitable problems that houses come with. This means they need to ​make all their money up front.

There is a large margin on houses in Japan, ​and​ they will basically charge you as much as they can get away with. If you start asking questions, they can easily justify any price they want by producing pages of lists of items with prices to the yen. Most of these item prices will also have large margins either because they have hiked them, because they are list prices and the actual amount they pay suppliers is much less, or because they are over estimating numbers or lengths or weights.

You could pay anything between 10 and 50 million for a house. Paying more will not necessarily increase the resale value of the house. ​In Japan, the value is basically in the land. In most places land is​ a good investment​ because they don't make it any more so its ​value increases over time​. There are some fluctuations, so timing can make a difference, and the exact location could be vulnerable.

Building a house may not be a good investment in financial terms. But in terms of security it gives you a more solid foundation in the community, and also​ more​ psychological​ stability​, so is worth it if you plan to stay in Japan. Find somewhere you want to live!

​Building a cheap house may end up costing a lot more long term in heating and maintenance.​ These costs are usually not taken into consideration when you're building, but the heating bills are also coming out of your bank each month, just like the loan repayments. The difference is that one day the loan repayments will stop, but you're still going to have to pay for heating and cooling. Even when they do tell you how much the energy bills will be, actual heating and cooling costs are typically twice the estimates and simulations.

​Building a Passive House, or at least using Passive House software during the building process, will give a much more reliably estimate, and will allow you to make realistic comparisons between the cost of heating and the initial costs. ​

Friday, 10 November 2017

How to build a house part 5: What exactly do you need to know about heat

Some people spend six years studying for architecture degrees, and it can take a lifetime to build the perfect house. In fact it's now 90 years after Gaudi was knocked over by a tram, and his is still not finished. Admittedly that wasn't your everyday family house, but I digress.

So, you'd like to build a house in the next year, and you're also going to be busy at work, and spending time looking after your family. What do you really need to know?

If you're trying to build a low energy house, two important areas of knowledge are thermodynamics
and economics. Structural knowledge is essential, but if you are working with professional builders in Japan, they should have all the structural knowledge necessary to keep your building standing, probably even through the strongest earthquake ever.

As well as knowledge of what to do, you need to know how to do it, and procedural knowledge is also important. So you need to know how the design process works, but I'll get to that later. First, here are five things you should know about thermodynamics. In most places in the world, the biggest energy use of buildings is heating and cooling.

1. Heat will leave the building by the easiest route in the winter. And it will get in by the easiest route in summer. Heat is a lazy opportunist. This means that you should be worrying about the parts of your walls, ceilings and floors with the least insulation rather than being impressed by the parts with the most insulation. Be aware of the performance of doors and windows, and anything in your thermal envelope that is poorly insulated. There may be conflicts between the structural desires of the builder and the thermodynamic needs, but it is possible to make buildings that are structural sound and thermally right.

2. There is less heat loss as walls get thicker and areas get larger, and more heat loss as temperature
differences increase. So thicker is better for your walls and roof, and smaller is better for the surface area of your house. When you are designing the house, you can't do anything about the temperature. It will get hot and cold outside, and the people inside will want the temperature to be within their comfort zone. If the building does not deliver that comfort zone, the people in the building will use electricity or other fuel to change the temperature.

3. Heat loss depends on the insulation performance of the material in your wall, roof, floors and foundation. Very broadly, metals are the worst insulators, or the best conductors, followed by earthy things, including stone, concrete and glass. Next come plastics, which we can start to call insulators, then fibres, which include wood. Foams are generally better insulators than fibres. In both cases their
performance comes from the excellent insulation credentials of air, but foams also stop the air from moving, and in some cases can use different gases to air. Other gases are better insulators than air.

This table shows the thicknesses of different materials needed to get the same insulation effect as 10 cm (4 inches) of glass wool. Depending on where you are in Japan, you may need the equivalent of 20 or 30 cm of glass wool to make a low-energy building.

Krypton (gas)2 cmthree times better than air
Argon (gas)4 cm
Phenolic foam5 cmtwice as good as glass wool
Air6 cm
Polystyrene, expanded styrofoam8 cm
Glass, wool Insulation10 cmthree times better than wood
Cork, re-granulated11 cm
Hardboard high density38 cm
Wood, oak43 cmthree times better than medium concrete
Polycarbonate48 cm
Concrete, lightweight50 cm
Polyethylene low density, PEL83 cm
Concrete, medium1.4 metresthirty times better than stainless steel
Concrete, dense3.5 metres
Stainless Steel40 metrestwelve times better than aluminium
Brass270 metres
Aluminum500 metresYes, half a kilometre!

4. There are five to ten litres of moisture in the air inside your house, and given any opportunity it will build up and cause condensation, mold or rot. This happens where air is not moving and there is a cold spot or a sharp temperature difference. It will happen where you are not looking, possibly on your favourite coat. This can be stopped with airtight insulation.

5. Reflective coatings are a good idea, since they will reduce the amount of heat radiated in or out of your house. However, most heat is lost through convection or conduction, so the first priority is to add insulation. Things that look shiny may just look shiny.

Bonus: It may be useful to know how a heat pump works. There's a great explanation here using a rubber band refrigerator.


While 500 metres of aluminum has the same insulating performance as 10 cm of fibreglass, metals are not effective as insulators. As the insulation gets thicker, the outside area of the house also gets bigger, so you will more heat, not less heat, as you put on more layers.

Monday, 6 November 2017

Passive House News

​There's another Passive House blog​ here:​

​And news of an affordable Passivhaus ​development in the UK here: ​

And a great story here about Fridtjof Nanse, possible creator of the first Passivehouse, which floated, and went to both the Arctic and Antarctic over a hundred years ago. While the mess on Scott's ship was underneath the ponies they were taking to Antarctica, Amundsen was staying in comfort on the Fram, with high insulation and airtightness. It also had a windmill generating electricity for the lights inside.

Friday, 27 October 2017

How to build a house in Japan part 3.14159265... How much do you need to know?

Disclaimer: you're going to have to wait for the next post if you want some ideas about exactly what you need to know.

If you buy a car, you don't usually start making suggestions about where to put the seats, where the filler for the fuel tank should go, or the timing of the spark plugs. But when you build a house it's possible to make all kinds of request and suggestions. You may also have noticed that almost all cars are built in factories, where standard parts are assembled in quality-assured processes. Although cars were all bespoke in the beginning, to build a car by hand now you would need a lot of expertise, time, money, or perhaps all three.

It's tempting to think that the same economic forces will push all houses to be factory-built, leading to higher quality and lower cost. But that happened to the automobile industry well within a hundred years, while house building is perhaps a hundred times older, and many houses are still built by hand. So some other factors are at play. Of course there are logistical issues with actually building houses in factories: wall and roof structures can be factory-produced and assembled on site, and sometimes are, but it would be very difficult to transport whole buildings over inevitably large distances from these huge factories. Cars, on the other hand, could be literally driven off assembly lines.

Another conclusion is that building a house is much easier than building a car, and it is within the capability of many more people. So one question you may want to ask is: how much do you need to know to build a house yourself? The short answer is that if you can ask that question, you probably know enough, or at least will find out enough in the process, which you should appreciate will take at least a couple of years.

But before you start thinking about doing everything yourself, how much do you need to know before you start commissioning others, and looking at part 4, which is paying for the project.

High-volume, low-cost builders are likely to give fewer options, but as the scale comes down and the price goes up, so do the choices you can make. Building professionals should probably be giving clients simple choices between limited options or within small ranges, with the kind of user friendliness that Steve Jobs brought to Macintosh. But people do have opinions about the way a house should be, and it may not be on the menu. These ideas may be based on things you have in your existing house, things you saw in someone else's house, things you read about somewhere, or something from your fertile imagination. Whatever ideas you have, if you are paying for your own house, it's reasonable to request it to be your ideal house.

But be careful of what you wish for, as you might just get it. Indeed your imagination may be playing around with what some of those things in other people's houses and in magazines actually are or do. And if you have a great idea for your house, but have never seen another house that uses that idea, then it's possible it's not actually a great idea, and there are very good reasons for not doing it. It's also possible that you have just invented something. 

And it's also possible that it is a great idea and has been used in several other houses, but you just haven't seen them. If the architect or builders tell you it's impossible it may just be beyond their experience. I remember in the early stages of our project suggesting to the architect that we could take heat out of the air leaving the house and use that for generating hot water. The architect laughed at me. Later I was talking about the same thing to the passive house lady, and she said, "Oh yeah, that's what they do in Sweden."

So visit as many houses as possible. You can also look at houses in magazines, but beware that they may be idealised houses that are lived in very differently, and any of the features may have lost their sparkle a couple of years, or even a couple of weeks after the paint dried. Or the features may still be there but are invisible under layers of magazines, homework the kids didn't do, bits of clothing that you're not sure who left behind, and jars filled with pens that mostly don't work.

The internet is a great source of information and you may often be in a position where you know more about a topic than the professionals. Materials and techniques around the world are developing all the time, and what your architect learnt at college twenty years ago may have changed, been superseded or debunked. Watch this you tube video for some brilliant tips for doing it yourself. I particularly liked the idea of putting a rubber band over the head of a worn-out screw to get some purchase on it. But also remember that a lot of professional builders now make a living from correcting projects by people who watched one youtube video and thought they knew what to do.

Stick some foam in, she'll be right! (not)
But beware of the Dunning-Kruger effect. This means that your ability to know how good you are at something depends on how good you are at doing it, because the skills needed to judge an ability are similar to the skills needed to have that ability. This should make you humble about your ability to specify the building you want, choose contractors, or take on a project management role. It may also apply to the architect or builder if you are expecting them to do something new. They may have no relevant experience with insulation, airtightness, installing high performance windows, ventilation systems or any other features essential to low energy buildings.

So when talking to professionals, while they probably know more than you know, remember:

  • they probably know less than they think they know 
  • you probably know more than they think you know
  • you may know less than you think you know

People say that a little knowledge is a dangerous thing, but in fact any amount of knowledge can be dangerous.


1. For most calculations, pi is a bit over three. The precision in the title would give you the length of a piece of string around the equator to within 40 centimetres, if the earth was perfectly round, which it is not, and you knew the diameter to within a few centimetres.

2. How long is a piece of string?

Friday, 20 October 2017

Are renewables helping gas burn, or is gasoline stopping electricity going to cars?

First they ignore you
Then they say you're stupid
Then they say you're wrong
Then they say you have an interesting idea
Then they say they thought so all along

"You have enough electricity to power all the cars in the country if you stop refining gasoline." According to Tesla Motors CEO Elon Musk via green transportation. "You take an average of 5 kilowatt hours to refine one gallon of gasoline, something like the Model S can go 20 miles on 5 kilowatt hours."

We often hear complaints about renewable energy not really being renewable, because it uses some fossil fuels to produce the materials. It's interesting to note that the petrol that goes into cars is actually using electricity.

As usually things are much more complicated than it seems. Advocates of renewable energy see a future with 100% renewable energy. Skeptics see the energy costs of producing renewable infrastructure, and the source of that energy, and claim that the march to renewables will produce more carbon emissions so we are better off burning fossil fuels directly.

Some of the nuclear lobby, meanwhile, attack renewables and claim they are just being used as greenwash for the fossil fuel industry, which wants to be there when the wind stops blowing and the sun stops shining. In fact there are many common interests of the nuclear industry and renewable industry. One is electrification. Also, they can also both benefit from increased capacitance in the system: renewable energy because the production is unreliable and may not meet or match peaks in consumption; nuclear for exactly the opposite reason that production is constant and energy storage will mean demand can be met with less plant.

It's very unlikely that burning fossil fuels will lead to a fossil-fuel free future, unless you are cynically hoping that the only realistic fossil-free future is one where they have all been burnt. As a technological development, electrification makes renewables possible since the energy is easy to convert and transfer over large distances. The internal combustion engine has a much more limited diet.

Low-cost solution to the grid reliability problem with 100% penetration of intermittent wind, water, and solar for all purposes  is a 2015 paper by Mark Z. Jacobson, Mark A. Delucchi, Mary A. Cameron, and Bethany A. Frew from the Department of Civil and Environmental Engineering, Stanford University, and the Institute of Transportation Studies, University of California, Berkeley.

They claim that existing technologies can be used to get the US onto 100% renewable power. The paper has some critics, of course.

This podcast from Science Vs asks whether 100% renewable energy is possible, and features Jacobson and Delucchi as well as some of their critics and more neutral observers. The answer is not exactly yes, and they point out a few areas will be very tricky to get onto renewables, such as iron smelting. But they suggest it's a pretty good direction to think about moving in.

In the conclusion, the podcast suggested people may need to change the way they live, using energy depending on how much is being generated. Use the air conditioning when the sun is shining. Do the washing when the wind is blowing. It's easy to see some logic there. It may be more tricky if people are expected to switch off the heating when there has not been much sunshine, since that's known as winter in several places.

It's interesting to note that at no point did the podcast mention efficiency. Increases in efficiency do not rely on people's behaviour. Also they are cumulative and compounding, so a seven-percent annual improvement in efficiency means half the energy use in ten years. This is certainly a high level of improvement, but the predictions of most of the renewable skeptics assume efficiency improvement of zero. This is also true of fossil fuel advocates and the nuclear industry, whose forecasts are consistently based on increased consumption of energy, and whose forecasts are consistently wrong,. Since they are in the business of selling energy, increased consumptions is in their best interests, and it's not at all surprising that it gets into their forecasts. If I was running a bakery I'd be hoping to increase my sales, and if I was planning for fewer customers in the future, I should probably be taking an early retirement, or at least changing my profession. Even in the paper by Jacobson et al., future energy production is based on the predictions of the IEA, International Energy Agency, who have been predicting the end of solar power growth for fifteen years.