Building Energy Rating info for a new build

M

micheller

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Hi All,

I've just spent the last hour reading some excellent info here & was hoping maybe to get some more info, if anyone can help :) We're hoping to build at the end of this year and I'm trying to do up some kind of Spec to ensure we get a good energy rated home.

Here's my list of things so far for the builder- all comments welcome:
- Block work- solid not cavity. Are there any more options to be aware of?
- Insulation- Lambswool in walls and roof- at twice the standard depth?
- Non electrical UFH.Where under wood nailed to battens sunk into screed?
- Modulating condenser boiler?
- Electrical water heaters for on demand Hot water- good/ bad?
- Windows and doors- ensure double glazed- any other options?

The other main areas that I'm not 100% on are:
- Fabric heat losses (insulation?)
- Heat gains (solar, retention of heat, anything else? What methods?)
- Ventilation rates- ????

I know this is probably a bit of a behemoth so thanks in advance for any help :)
M.
 
First things first:
Since you're employing a builder he/she needs drawings and supervision.
Have you got someone to that job? An energy adviser and an engineer would be the right adress. Most civil engineers should be able to do both - figuring out what needs to be done and SIGNING a guarantee.
The fabric should be small compared to the surface of usable space. No bay windows, no pebble dash.
When going for blockwork the insulation should be on the outside , not on the inside. This would give your building a heat storage capacity.
Insulation: twice of the standard minimum demand is good, it's not necessarry to use lambswool, the cheaper sheeps wool is just fine (smiley). Any other form of apropiate insulation would do for a good U-value as well, but a natural untreated material will certainly increase the initial costs- as well as the the retail value of your house.
On the outside use a non decaying material like EPS or PU or foamed glass.
Glass/rockwool is only apropiate for an outside insulation if your builder can guarantee a watertight cladding - most of them simply can't/won't do that.
UFH: use plenty of insulation under it. More then 10 cm for to be sure.
A modulating combi condensing boiler needs no water tank. But it would be better to have a buffer tank that would act as a storage tank as well, esp. when used in conjunktion with a solar panel. Not less then 300l for domestic hot water, more then 500l (better 1000l) if using solar power for for heating.
Doors and windows: triple glazing is becoming standard on the continent, some Irish companys are selling (but not manufacturing) it here as well.
All the necessarry links for products and standards can be found here on the previous posts.
The entire project for a zero energy home might cost about 5% extra for the building costs (not the land purchase etc.) compared to the minimum standard home, so if your builder can't do it shop around. The Austrians and Germans and the Dutch will be helpfull, I read somewhere that a zero energy home can be got for €200.000 excl. site and foundation.
So first find a civil engineer/builder who can do the job.
 
Thanks a million for the response Heinbloed. I've found most of my info already on your posts!

We have a QS/ Planning expert who has done up the drawings & application process for us. Once these are complete, he will progress it to tender with a few builders. Do we need to involve a civil engineer as well definately or will a one sheet 'energy spec' be adequate? Do any of these things have to be shown on the planning application?

Unfortunately, our building will be onto the end of a terrace which is dry dash so we have to go with this on the exterior- so insulation on the exterior & interior of the walls? Also, I don't think we're going with Solar panels at the moment, we're hoping the technology might come on line over the next few years to hook up to the grid direct rather than batteries/storage so we're waiting for that.
Anything else you'd recommend on the above? Thank you :)
 
The drawings for the planning permission show only the rough plans, position etc.. They will not give the builder any advice on HOW to construct the walls. A drawing from a civil engineer is better for this purpose, these would give exact material choice, workmanship etc..
The insulation should go on the outside of the walls, not on the inside. This insulation could be then covered with any plaster design, but a civil engineer would give detailed material choice. Important is that the wall is build to let water vapour out of the building but it should not let in water droplets. So ANY wall construction with SOME sort of insulation would not do the job, and most builders just do what they think is right without having any clue about moisture diffusion calculations especially when it comes to ouside insulation.
About the solar panels: Since you're still in the building process it is very easy to lay two insulated extra pipes from the attic to the utility room plus a ducting pipe with a pull rope in it to provide for cabeling. Once these two insulated pipes are in space (they're cheap!) you would have little trouble to put a solar panel in place at a later stage. The most costs with a solar panel installation is in the actual installation process, so having this major job done would reduce the costs for a solar installation dramatically.
And get the best doors/windows incl. frames you can afford, these would be with the building for the next thirty/fifty years or so. A "cheap" choice would cost a lot over the years to come.
You would not have to show on the planning aplication the U-value of your home, the building regulations concerning the min. energy conservation meassures are legal binding.
 
Thank you so much for all that info- that really is superb.
Will definately look into talking to a Civil engineer before it goes out to tender with the builders. This way at least we'll be sure of what we're getting.
Also, thanks a mil for the advice on the solar panels :)

Cheers,Michelle.
 
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