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As we all know, Ireland is currently paying the price for the inability of its political and corporate leaders to take seriously the warning signs of an economy where property investment and borrowing generally got out of control. Looking at policy and commercial investment plans for energy supply and distribution, Richard Douthwaite asks, are the decision makers showing an alarmingly similar attitude to evident gas supply threats?
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Stephen Harte drawing a map of the house: note the compass for checking orientation
“You take attic insulation. The home energy assessor goes in, sees there’s 100mm of attic insulation and it gives a U-value of say, 0.45W/m2K. Then when he goes into the advisory report, he says, upgrade it to a specific level, which is the 2008 building regs for retrofit: 0.16W/m2K for attic insulation, which is equivalent to 300mm of fibre glass. That’s a standard. So they upgrade, then go into DEAP, put in a new U-value and that will tell you that your energy use has gone from 550kWh/m2 to 450kWh/m2 …and that process is continued on down through a list.”
On site, assessor Stephen Harte begins by measuring the external envelope of the house, noting things like window orientation and over-shading. There is, he says, a lot of detective work involved in working with existing houses. “This house was probably built sometime in the 70s or early 80s, more than likely cavity block, with more than likely no insulation or 50mm insulation.”
Sometimes the owners can date the house accurately. Sometimes they can’t. You can measure window reveals to determine the thickness of the walls, and work out the construction method from that. Whether meter-boxes have been installed inside or outside also offers a clue, while differences in weathering on the roof may indicate an extension added at a later date. The meter-box itself often provides access to the cavity, assuming there is a cavity – in particular for newer homes. Access holes for cables entering and leaving the box are usually oversized, giving the assessor a view of whatever went into the cavity when the house was built. In Lorrha, Stephen Harte shines a torch down into the hole in the meter box and sees a board of loose insulation wedged behind the cable. A similar hole at the top of the box shows an empty cavity.
Margaret reveals that the house was built in 1986, and actually recalls the insulation going in. “When I saw them doing it, they were as lackadaisical, and if it fell down wrong, there it stayed. But it was Aerobord that went in, about an inch thick.” Stephen tells her it should have been installed tight against the inner leaf.
The conservatory on the southern side of the house was added in 1998. Invariably, says Paul Kenny, conservatories drag a rating down. “You can treat them as an unheated space if they’re not heated but if they’ve any connection to the main space heating system that isn’t completely separate and separately controlled, it’s part of the house, and it’s a big windowed area, so it’s a major heat loss area…You’ll probably find that they’ve got good doors, so behaviourally, they can get round it, but with DEAP, if behaviour is involved, the worst is always assumed.”
In the attic, Francis installed around 100mm of rockwool himself four or five years ago. Stephen tells him he’ll be recommending the addition of a further 200mm to bring it up to spec. “The other thing I say to people when they’re doing insulation like that is you need to check your ventilation. There’s a requirement to ventilate your attic on both sides so you get cross ventilation. This is for the timbers in the roof. On old houses, it doesn’t come into play because there’s leakiness there anyway, but if you start to make the house airtight, you have to be careful of your ventilation…I’ll be putting it down as a note on the report to make sure that it’s in line with current building regs, which is what insulation installers are supposed to do anyway.”
In the boiler house adjoining the main house, the SIME boiler isn’t one
that either Stephen or Paul have encountered before. “If the boiler
isn’t recorded on the database,” says Paul, “you give it a default poor
value of around 65 per cent.” This is a characteristic of the DEAP
methodology. If a variable cannot be determined definitively, the
default value used always errs on the side of inefficiency. A house may
actually have a better energy performance than the BER, but it should
never be worse, assuming average behaviour patterns.
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Issue 2, Vol 5 Out Now
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