..indeed, and if I can add my .02 as they say........three other factors I rarely see mentioned in 'spec' sheets,etc.
One is planning. If the CoCo say your house
must face North, for example, and that you
must have the front door/whatever there, then that I'm afraid that is that. If you are building with an eye to a specific performance level, and the planning condition/restriction conflicts with it, well people need to understand that that, basically, is that. We can't all have perfect orientation.
Second thing, a little more subjective from the client point of view, is personal choice, or taste. If a client wants a dormer, say, or a particular feature (door, window, space) then they should just have it, and if there is a small BER penalty, so be it. It's not the end of the world.
Finally, related to the second, is personal
performance preference. For example, I know an arch with a lovely, recent, sea-side house. Totally traditional cavity block construction. OFCH, double-glazed uPVC. Has zero interest in anything else, and won't construct anything else for clients, either. Is onboard with the likes of solar, windpower (when it's ready) etc, but otherwise, it's 'as you were'. In a conversation once upon ago, on the subject of airtightness, he made a point regarding his own home. As he said, and he has a point, there is absolutely no merit in either measuring, or putting materials into, making his house airtight. The reason ? Because, from one end of the year to the other, winter and summer, he
never closes the upstairs windows. This is his, 'comfort level'. My personal experience in dealing with ladies who buy, as distinct from men who buy, is that there is a gulf, between, for the same reason. We're all familiar with the 'hogging the radiator' syndrome, in an old, cold house........
and in a new build, this comes up. Take for example a 2-storey we built. No performance goal, specifically, other than 'it has to be as warm as possible', the lady said. Fine. So, fine insulated, airtight walls (u-value around 0.18), UFH, solar panels, HRV, GSHP. And, not one, but 2 open fireplaces. Yep, 2 9" holes into the house. I can get over that, from a practical perspective, she's rural, has free turf, and she just
wants them. End of story. House is lovely and warm, and she's happy. But there's a twist: in getting her doors & windows, there was one door unit the mfr would NOT make for her: because, in this fabulous, efficient, warm house, she wanted a....................half-door. Yep, for those (rare) fine days, she wants to have the top half open to the outside world.......and no, there's no point in going on about the HRV system having a hissy-fit when it is, because.............it's what the lady wants. More importantly, she's happy. Sometimes, a little 'reverse' engineering of a situation (like that) works out very well. Honestly ? She couldn't give a fig about the actual BER score, she has exactly what she wanted, her way.
I'm quite sure it kicked the rating into touch, but, pragmatically, it's still an extremely efficient house, compared to traditional stock.
Finally, just thought of this: when most people go to build, new, they aspire to the best. This is great, and, apart from the great leveller that is the current finance situation, sometimes they can't have the Rolls Royce version of their dream, and they get a bit deflated............my advice is: don't be. A lot of people think that if they are going to build at all, it 'must' be an A1. This is because they have an idea of what they think the rating of their house is (let's say a C3), and think the only leap worth making is A1, because B1 wouldn't be much better than they have. This is often folly for the following reasons: 1. A B1 house is still a good house, and 2. In reality, their existing house is probably a ..........E ? The point being, the jump to B1 is both a big qualitative leap, as well as being an affordable one.
All my 0.02, as they say........