How important is energy efficiency when buying property?

With green homes way down the list of househunters' priorities, energy performance certificates seem pointless
Do house hunters care about how green their future home is? I've been asking around because, on 30 September, property website NetMovers will launch a service that ranks homes for sale by their energy rating — that's alongside the usual criteria of price, location and number of bedrooms. So for the first time buyers will be able to easily sort homes on the market by how green they are: good news for cutting greenhouse gas emissions and a reward for the seller who spent an itchy day insulating their loft, right? I'm not so sure.
Personally, and from what I hear anecdotally, I'm just not convinced that anyone house-hunts on efficiency. I count myself as a "greenie" and pay over the odds for reducing my carbon footprint in other areas of life (train over the plane, expensive dalliances with LEDs on eBay) but care very little how about energy-efficient my future home is.
Partly it's a practical thing. Location, price, room sizes, layout and broadband speed are aspects of a home that are difficult or impossible to change, but efficiency is something I reason I can always improve. Partly it's a financial decision: energy prices are so low that the difference in running costs between a draughty Victorian house and a near-airtight newbuild just aren't significant enough to become a deal-breaker like a dream leafy postcode is.
Opinion on Twitter and here in the office is split. "I always look to mpg for a car, so why not a house!" says @myzerowaste, "we looked at EPCs [energy performance certificates] when considering houses," tweets @aimaz, while @jamieandrews and @therubbishdiet both say they'd take into account efficiency. But I suspect these are tweeters at the dark green end of the spectrum. "[Efficiency] is a consideration when buying but comes after price and location, kitchen, bathroom and general space" says @kgannon1 and @fleming77 simply says "no I do not care about energy efficiency, location and cost most important."
Interestingly, a YouGov survey of 2,306 adults this summer (Excel file) suggested some people do care. Asked what criteria buyers looked for in a new home, they ranked energy efficiency as the third most important attribute, behind outdoor space and a garage but above value for money. But bear in mind this is what people were looking for in a new home, and the survey was commissioned by the New Homes Marketing Board, which would obviously like efficiency to be a key differentiator against prettier but leakier period homes.
A more recent survey on 1 September, this time by ICM Research for the Energy Saving Trust, said that 35% of people would pay more for a home with solar panels (or any other form of "microgeneration"). But again, there's a caveat. We don't know that those respondents actually care about energy efficiency - they may just be thinking about the savings on their future bills and the government's shiny, imminent Clean Energy Cashback scheme.
Surely, the authority and barometer on this matter is property website Rightmove. With 90% of all UK properties on sale at any time on its site - worth around £270bn - it dwarfs NetMovers' 6,000 property listings with their combined worth of £1.9bn. I asked Rightmove if adding energy efficiency filters was on their new features list or whether customers ever requested such a feature. After sounding slightly baffled that anyone would search for a house on efficiency, its press office said no on both counts.
That suggests to me that the mainstream and even so-called greenies like me — Rightmove's visitors — don't care much about efficiency. All of which, sadly, makes the energy performance certificates in Home Information Packs seem pretty pointless and a waste of money. But what about you? Is energy efficiency a deal-breaker when you're house-hunting?