# New builds-anything but passive is daft?



## smarthinking (10 Sep 2008)

Reading a lot of these posts from people building a house, a lot of talk about which type of heating etc to install.  Does it not make much more sense to build a passive house, and thus no need for heating at all?  The only extra heating (extra to lights, cookers, body heat) normally required is a small stove / electrical fire etc.  
Why on earth are new-builders not all building passive houses?
The air quality is generally better than conventional houses - as there is continuous fresh air blown in, heated by the outgoing air.  You can put a concrete floor on the second floor even in timber frame houses.
So, newbuilders, why waste a glorious opportunity to rid yourself of oil / gas / pellet burners, and radiators?


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## jhegarty (10 Sep 2008)

*Re: New builds-anything but passive is daft?!*

the question has to be asked , how much extra does a passive house cost ?


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## sydthebeat (11 Sep 2008)

*Re: New builds-anything but passive is daft?!*

jhegarty has nailed the reason in one.

the majority of people building a new dwelling have a budget. Their main aim with this budget is to engulf as much space within the building envelope as possible. The running costs and maintanence costs are not generally considered when giving an architect a brief.


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## dereko1969 (11 Sep 2008)

*Re: New builds-anything but passive is daft?!*

there's also a lack of experience in building passive houses here so for most people being some companies guinea pig is probably a risk too far but in my opinion it is the way to go


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## krissovo (11 Sep 2008)

*Re: New builds-anything but passive is daft?!*

Negative equity is my reason!  I could spend 400k building a passive house and add the land value to the total of 550k.  The house regardless of the build method would only be worth 400k, 150k buys a lot of wood chips!


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## wexford dude (12 Sep 2008)

*Re: New builds-anything but passive is daft?!*

I agree with Krissovo,

I finished a self-build in Wexford in 2006 (garage & lawns still ongoing).The cost of these so-called passive houses do not tie in with real house values.The only change I would make is I would dry-line the inside face of the masonry walls.I think it's much more cost effective to build this way.I think the cost *& QUALITY *of these installers of heat pumps, wood pellet boilers etc. will need another few years to perfect.

Can anyone tell why the cost of house insurance is different for timber frame houses.Would be interested to find out why?


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## sydthebeat (12 Sep 2008)

*Re: New builds-anything but passive is daft?!*



wexford dude said:


> I agree with Krissovo,
> 
> I finished a self-build in Wexford in 2006 (garage & lawns still ongoing).The cost of these so-called passive houses do not tie in with real house values.The only change I would make is I would dry-line the inside face of the masonry walls.I think it's much more cost effective to build this way.I think the cost *& QUALITY *of these installers of heat pumps, wood pellet boilers etc. will need another few years to perfect.
> 
> Can anyone tell why the cost of house insurance is different for timber frame houses.Would be interested to find out why?


 
wexford dude, you seem to miss the point. The idea of a passive houses is that you dont need a heating source, no oil, gas or solid fuel, no heat pump, no wood burner etc.. i completely agree that the installation costs of these are very intensive at source.

2 dwellings build last year in carlow are passive, they get their heat from solar gains, from internal gains ie heat from people, heat from machines etc... they are so well insulated and airtight that they dont need a large heating system. These dwellings in carlow have only one heating mechanism, this is a small electrically run element in the ventilation system that is only to be used on very cold days. 
A passive house has to be certified to show it uses, on average, less that 15 kwhr/m2/yr.... compare that to a house rated C1 under current min building standards which uses 150 kwhr/m2/yr.

The most important factor in passive houses is the workmanship and attention to detail.


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## polaris (12 Sep 2008)

*Re: New builds-anything but passive is daft?!*



sydthebeat said:


> The most important factor in passive houses is the workmanship and attention to detail.




There's the problem with passive houses


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## sydthebeat (12 Sep 2008)

*Re: New builds-anything but passive is daft?!*



polaris said:


> There's the problem with passive houses


 
agreed, and probably the reason many of them are built off-site as prefabricated closed-system structures


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## krissovo (12 Sep 2008)

*Re: New builds-anything but passive is daft?!*



sydthebeat said:


> 2 dwellings build last year in carlow are passive, they get their heat from solar gains, from internal gains ie heat from people, heat from machines etc... they are so well insulated and airtight that they dont need a large heating system. These dwellings in carlow have only one heating mechanism, this is a small electrically run element in the ventilation system that is only to be used on very cold days.
> A passive house has to be certified to show it uses, on average, less that 15 kwhr/m2/yr.... compare that to a house rated C1 under current min building standards which uses 150 kwhr/m2/yr.



Is there a link to these homes anywhere and the cost they were to build?

My current planned build I feel will be better value.  I am building a ICF with a decent u value, the windows are Ecco therm again with a decent u value.  Solar with a large water tank (700 lts) for heating and water, wood pellet boiler and a stove with a back boiler.  Solar gain should be decent as I am south facing with glass windows.  Also installing a HRV system and from the plans a A rating is looking good.  

I should complete build for about 220k > 250k and that will be a decent spec, with the land value I would be in possitive equity right from the time I move in.  My engery bills should still be low so very manageable.


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## sydthebeat (12 Sep 2008)

*Re: New builds-anything but passive is daft?!*

[broken link removed]


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## lazylump (15 Sep 2008)

*Re: New builds-anything but passive is daft?!*

I notice from the post above that most peoples idea of a passive house is an airtight house with a heat exchange unit. This concept is pushed by the prefabricated house builders. But has anyone ever looked at the alternative to this which I believe can and has been built in Ireland. It’s a passive house which is not airtight and uses solar gain for heating. You can also include a stove for those very cold days or just for looks if required.


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## sydthebeat (15 Sep 2008)

*Re: New builds-anything but passive is daft?!*

[broken link removed]

_*The external envelope of a building should be as airtight as possible* - this is true for conventional as well as for passive houses. It is the only means to avoid damage caused by condensation of moist, room warm air penetrating the construction (see the figure on the left hand side). Such damage not only occur in cold climates; in hot and humid climates the problem can occur from airflows from the outside to the inside. The cause is the same in both cases: a leaky building envelope._


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## krissovo (16 Sep 2008)

*Re: New builds-anything but passive is daft?!*



sydthebeat said:


> [broken link removed]




Not the best looking homes out there plus @ €465k is a lot IMO for what looks like 1/8th of a acre.


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## wexford dude (16 Sep 2008)

*Re: New builds-anything but passive is daft?!*

I would be interested in hearing from anyone living in a passive house that the house is cheaper to run.

Personally I built a bungalow & in the next few years I will install a HRV system (at the minute using wall vents).Even now I have no issues with airtightness.Still stand over the fact that u can achieve an A-rated masonry house (dry-lined) and that is a significantly cheaper way of building than some of the alternatives being suggested.

How u heat the house is a separate issue.


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## sydthebeat (16 Sep 2008)

*Re: New builds-anything but passive is daft?!*



wexford dude said:


> I would be interested in hearing from anyone living in a passive house that the house is cheaper to run.
> 
> Personally I built a bungalow & in the next few years I will install a HRV system (at the minute using wall vents).Even now I have no issues with airtightness.Still stand over the fact that u can achieve an A-rated masonry house (dry-lined) and that is a significantly cheaper way of building than some of the alternatives being suggested.
> 
> How u heat the house is a separate issue.


 
im sorry, wexford dude, it seems like im picking issues with you, but its definitely not deliberate, its just that your posts probably reflect the general consensus.... and theres some mis-information and misunderstanding out there regarding this whole 'energy conservation' issue.

Firstly, theres no co-relation between a 'certified passive house' and an 'A rated' dwelling under the BER. 
have a read of this article: [broken link removed]
You are correct in that you would be able to achieve an a rating with a masonry build, however without due care to airtightness it would be very difficult. Its easy just to keep over specifying insulation to counteract bad airtightness, but in the end, its more economical to ensure good workmanship than to overspecify insulation.

secondly, HRV systems installed into a dwelling with bad airtightness is simply a false economy. Without getting an airtightness test done you wont know what level of tightness you have. If you have an open fire, forget about HRV. Plus, HRVs loose quite a significant amount of efficiency in single storey dwellings.

The factors that affect a building energy rating are, in order of importance, in my opinion:
1. orientation, design and passive solar gains
2. insulation levels
3. air tightness
4. control over heating system
5. type of heating system

its my opinion that the more emphasis that is put on the first 3 factors, greatly diminishes the requirement of the last two, ie if you have a well designed and orientated dwelling, with high levels of insulation and airtightnes, then you wont actually need any heating system at all.


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## wexford dude (16 Sep 2008)

*Re: New builds-anything but passive is daft?!*



sydthebeat said:


> im sorry, wexford dude, it seems like im picking issues with you, but its definitely not deliberate, its just that your posts probably reflect the general consensus.... and theres some mis-information and misunderstanding out there regarding this whole 'energy conservation' issue.
> 
> Firstly, theres no co-relation between a 'certified passive house' and an 'A rated' dwelling under the BER.
> have a read of this article: [broken link removed]
> ...


 
Sydthebeat,

I dont mind you pointing out the issues at all.I am fairly well up on energy ratings.I accept that a passive house is not necessarily an A-rated house but to say there is no co-relation is pushing it.I accept that you are well read in this area but I make the following reply:

- As an engineer with over 10 years experience in construction (with loads of hands on experience) I find it very easy to ensure that a house is built correctly using masonry.I promise I dont work for the concrete industry.There is no need to over-spec insulation ar anything else you just have to plan it properly and keep checking the build as it progresses.To suggest that airtightness is more difficult to achieve using masonry is probably down to a lack of hands on experience.

If you hire a company to supply & erect you a passive house what guarantee do you have that it actually is what it says it is.At least if you build the house by direct labour you can check it all the way yourself.I am all for erecting houses within 2 weeks but who is checking the house independently as it goes along.

- In my own house I am using wall vents to allow fresh air in at the minute.This does not mean that the house will not be airtight when the HRV is installed and (90%) of these vents are closed permanently.
I dont have an open fire but a stove with all gaps sealed.
Again I think the efficiency of the HRV depends on the quality of the build.

- I agree with you completely that orientation, insulation levels & airtightness are key factors in the design & building of a house.But again I would like to hear from someone who lives in a passive house to see what the actual heating bills are.

Sydthebeat, I have had this conversation many times with well-read guys like yourself.The reality of planning in Ireland is that if unless you are building your house on top of the hill with very low wind chill factor and plenty of sunshine (somewhere you probably wont get planning) that the constraints stop you getting the maximum from your 1 acre site like - the front of the houses must be in line, no two-stories allowed etc.

I am a real world sort of guy and I accept that it takes 1.5 tanks of oil per year to heat the house (dont worry eventually I will be using a stove with a back boiler).The reality still remains for the cost par square foot for a passive house is at least double (if not more) than a masonry build and unless you are building a house on a fantastic site with faboulous views it will take  a lifetime for the house to actually be worth what it cost to build it.


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