For many more, see the impressive list of one-liners on the Usable Buildings Trust website. It partly inspired this list.
‘In south-facing houses, the sun enters through the portico in winter, while in summer the path of the sun, as we have described, rises overhead and over the roof, thus there is shade’.
Xenophon, citing an earlier statement by Socrates.
‘I’d put my money on the sun and solar energy. What a source of power! I hope we don’t have to wait until oil and coal run out before we tackle that.’
‘Energy-saving technologies keep improving faster than they’re applied, so efficiency is an ever larger and cheaper resource.’
‘We live in a society exquisitely dependent on science and technology in which hardly anyone knows anything about science and technology.’
‘It is a miracle that curiosity survives formal education.’
‘Someone told me that each equation I included in the book would halve the sales.’
‘The US, France, Germany and Canada have all responded to the financial crisis by boosting rather than cutting their science funding. The UK has not.’
‘… I’d prefer not to look at freelance window fitters’ lousy work on a daily basis and have verbal punch-ups with them … things should be done to avoid the problems occurring in the first place …’
‘A doctor can bury his failures. An architect can only advise his clients to plant vines’.
Frank Lloyd Wright.
‘There are two seasons in Scotland: June and Winter.’
‘… Evolution does not work by teaching, but [by] destroying.’
‘Events which models predicted would happen once every 10,000 years happened every day for three days’.
Head of Quantitative Equities, Leaman Bros., Inc.
‘[The planet] provides enough to satisfy every man’s need, but not for every man’s greed’. 
‘If you are not willing to lead, please get out of the way.’
Papua New Guinea delegate, Bali environmental summit.
‘640K ought to be enough for anybody.’
‘Space isn’t remote at all. It’s only an hour’s drive away if your car could go straight upwards.’
‘Whichever party is in office, the Treasury is in power.’
‘The [Energy Efficiency Office] is like the everlasting broom, whose brush is replaced each spring and whose stick is replaced each autumn.’
‘The process by which banks create money is so simple that the mind is repelled.’
John Kenneth Galbraith.
‘If economists could manage to get themselves thought of as humble, competent people on a level with dentists, that would be splendid.’
John Maynard Keynes.
‘I guess I should warn you, if I turn out to be particularly clear, you’ve probably misunderstood what I’ve said.’
‘I’m a wet liberal really, and always have been. But I’m sort of an aggressive wet liberal.’
‘I liked it when we had ugly politicians who droned on about issues.’
‘It seems to me that the way to remove people’s cynicism is, when asked a straight question, to give a straight answer.’
‘The difference between tax avoidance and tax evasion is the thickness of a prison wall.’
‘If you file your wastepaper basket for fifty years, you have a public library.’
 Reportedly the correct wording; see http://www.academia.edu/303042/Gandhi_on_providence_and_greed.