Waikato House, BY SOLAREI

listed by SOLAREI- Design by nature

Nice house, any futher temperature data? 

Nice house, I applaud the energy efficiency measures, although the house style itself is not to my own liking.
You mention 16C inside when outside is -1. I assume this was an early morning reading before sunrise? Do you have any temperature figures regarding late afternoon in midwinter that you could share? Also I'd be interested to know what the occupancy numbers and pattern is for the house. I'm building an energy efficient home at the moment using the Cornerstone System and I'd be interested to compare with my own place (3 adults 4 children)
many thanks
Pete

Re: Nice house, any futher temperature data? 

Hi Duncan

The info above shows it uses double glazing: did you look at triple glazing at all?

It seems that with so much window area, even double glazing still only achieves an R value of about 0.3....

Seeker

Re: Nice house, any futher temperature data? 

Hi Pete and Seeker,

Thanks for the comments. The house is designed for four, located in the Waikato, gusty windy site, two adults and their two sons, a typical farming family early rises and early to bed; - well for mum and dad anyway.

Those are good and important questions you’re asking about mid June temperatures. Give me a couple of days because I don’t have the temperature stats with me at the moment…but will gladly tell you what they are.

The glass spec was 5mm annealed + 12mm air gap + 5mm annealed glass and Seeker is correct we achieved a .33 R Value, still very expensive cost wise but justifiable. My current project has a 6mm+6mm laminate+ low-e + 12mm argon gas cavity +6mm and we are achieving a U value of 1.3 Kw/ per m2 which is almost as good as it gets and costs a truck load.

Where budget is a an issue, like most projects a cost alternative could be 5+5mm t/p laminate with low-e coating and internal thermal drapes, this will still perform energy wise/ or good enough so is an option worth investigating with your window supplier. If the thermal drapes are designed correctly into the architecture then they should look ok, perform ok and not be to much of a hindrance aesthetically.

Cheers,

Duncan.

Re: Nice house, any futher temperature data? 

Hi Duncan

Thanks for the detailed reply.

What is the R or U value for the "5+5mm t/p laminate with low-e coating" you mentioned for the budget conscious? What spec are you achieving when you add the thermal drapes?

I guess this would also be much lighter than your 6+6+6 on your current project, with the U value of 1.3 translating to an R value of 0.77 ??

It seems to me that we try to reduce losses through walls and floors (ceilings are a no brainer), when the glass areas look like a "hole" for heat to race out of, with R values that are impossible to raise significantly.

Seeker

Re: Nice house, any futher temperature data? 

Hi Seeker,

Glass is never going to be a great insulator, so fewer & smaller windows (especially glass area) is the way to do it, look at European houses. Hence my comment about the house not being in a style that appeals to me. I know though that the big windows style is the one that most of you "locals" go for.
I suppose at the end of the day if that's the style you want then the best option is to beef up insulation values in areas where it is possible to offset the greater losses occurring through the glass

Pete

Re: Nice house, any futher temperature data? 

Pete, you also need to consider the benefits of solar gain, which throughout most of NZ can be quite considerable. It's a balancing act, but I think it's a little deficient to simply put this down to local 'style'.. especially given that the glazing is heavily weighted toward the north face, with little or none to the south. It's obviously something that they've very carefully considered.

There are, of course, multiple ways to skin a cat.

Re: Nice house, any futher temperature data? 

Hello Anon,

Yes you are correct regarding solar gain, but I'm not so sure that "big windows" aren't definitely a bit of a kiwi thing. Have you ever been to Greece, Spain or Portugal? Hotter and just as sunny as NZ, but the local vernacular is for heavy thick walls and small windows. I think for the majority its more down to fashion and following the trend than any conscious decisions on solar gain. I'm not knocking big windows though, just making an observation and responding to Seekers point about the difficulty in improving the insulation value of windows.
cheers
Pete

Re: Nice house, any futher temperature data? 

Fair play Pete. I think as you say, those places are definitely hotter than NZ, and probably warm enough already that it makes a lot of sense to keep the sun out (OZ is interesting in that they make wide use of external shutters for this purpose). NZ is relatively temperate/cool, but also quite sunny.. so at least to my mind it makes sense to let in as much sun as you possibly can (during the cooler months), store it and keep the heat gain inside for as long as possible. Wouldn't small windows, while definitely preventing heat loss, also prevent maximizing solar gain? Heating of course offsets this, but at a cost.

In any case I'm planning a new build myself, and I think that for me - after a tonne of research - that the solution probably lays somewhere in the middle. I wouldn't be able to get past having to clean all that glass (especially with three young kids plastering their mucky hands all over it all the time :)) And, of course, the expense.

Re: Nice house, any futher temperature data? 

Yey we agree, best wishes with your build plan
Gloves and tie wraps work well with kids (ha ha)
Pete

Re: Nice house, any futher temperature data? 

Hi Duncan

I have been doing a mountain of research too, and I am still seeking that elusive total energy solution!

Would you answer a couple more questions for me:

What heating does the house use, and what water heating? The list on the left of the original listing looks like it has every technology: gas water heating, solar, electric, and an open fireplace.

The 3938 kWh is a pure electric figure I presume, excluding firewood, natural gas etc?

Seeker

Re: Nice house, any futher temperature data? 

Pete and Seeker,

We’ve been collecting data for one and half years now. The June temp for 2009 inside ranged from 15.4 to 22 c, while the outside was -1 to 20.6c. This is over the entire month, 24 hour cycle. The house relys on its passive solar design for 95% of its heating, so those large windows on the north elevation are fundamental. Without them or there size the house couldn’t work heating wise. And also its quality of light and living; - don’t box yourself in Pete! There is a back up gas fire located in the living room ( in a concrete wall) for when it gets really cold, all hot water is passively heated with a electrical back up if its gets to cold. Correct the 3938 kWh is total electrical load, interesting comment though. Glass is very complex creature and you’d need to talk with M&E regarding the exact U Value you’d be looking at with a 5+5 laminate, low-e coating + drapes, my estimate would be somewhere around U value 3.5- 4 which is better than normal and fine for a passive solar building. The key ingredients to heating this house are its large north facing windows, concrete and a centralized tromb wall (can see in pictures) radiant heat is then dragged southward towards the lower temperature in the bed rooms….which then heats them.

Hope it helps.

Cheers.

Re: Nice house, any futher temperature data? 

Duncan wrote:

"U value 3.5- 4 which is better than normal and fine for a passive solar building"

With regards to glazing a U value of 1.1 for DG lowE argon and 0.7 for triple is normal these days and 5.5-4 is 1960's (if you look beyond our Islands)
Your temperature and your calcs might work in theory but in reality you can't eliminate discomfort if you don't eliminate cold surfaces.
New Zealand's architects scare me with their strange upside down theories.
While a passive house is comfortable AND energy efficient, passive solar is limited comfortable and limited energy efficient.
If I was building such a house I would use amuch better balance between thermal mass and thermal envelope.
Thermal envelope with uPVC or timber with 0.7 u-value triple glazing is today's prefered method and your double or even single glazing (with drapes) and aluminium frames is years behind.
I am still waiting to meet a NZ trained architect who can build a house that is 2010 and build to suit NZ conditions.

Re: Nice house, any futher temperature data? 

Hello 'another' anon.
I would like to know how many, $/m2 overall, you would be prepared to pay for a properly designed house incorporating timber or uPVC triple glazed windows???

Also what R-values do feel are acceptable for the entire building envelope????

steve@timbercrete

Re: Nice house, any futher temperature data? 

Hi Anon,
Yes, all the glass surfaces are cold in the house and the glass isn’t thermally broken. All the concrete surfaces conduct heat and for the main living area this is around 50% of the material surface. I’d have to disagree with you on the U value issues, 1960’s are much higher than what you’re saying and I haven’t come across a u value of .7 ( ever) and I think unless you’re a very wealthy person achieving a u value of 1.1 is not normal and will beyond what most projects can realistically achieve. The 1.3 u value I have spoken about is for a government building/ not in NZ and has been achieved at great cost.
Its good that you ruffle the feathers of NZ architects and I’d actually agree most are totally disconnected from the reality of green building technology; - You need to go back to Architecture schools to see what their been taught there….its more of a ‘egoist architecture’ than an architecture of creative green practicality.
Cheers.

Re: Nice house, any futher temperature data? 

Hi Duncan,

if you havn't come over 1.1 double glazing you will need to update yourself on glazing ;-))))
I have constructed a conservatory for my parents back in Europe in the mid 90's.
Very basic double glazing at normal costs and the u-value was 1.1

Currently the standard triple glazing is U 0.7 and the better ones are 0.5.
In Germany they are working on the development
of a new manufacturing technology which will achive U 0.3 in the coming years.

I do understand cost thats why we import triple glazing from Germany at a same cost or even less than the standard double glazing in NZ

The problem is that those (minority) who want better stuff really want it and the NZ companies taking advantage of that and inflate the prices.
This is quite extreme in the glass industry.
If you consider that we have lower labour costs than Europe, most glass from China and quite often 2nd grade the glass here should be not more expensive compared to Europe or America.

Germany triple glazing 4/12/4/12/4 annealed lowE argon , U 0.7 costs from 25 - 45 Euro vs
200-300 dollars here for lesser performance and lesser quality

Germany double glazing 4/16/4 annealed lowE argon U 1.1 10-25 Euro (Euro-Dollar is times 2)

Of course you add some transportation cost and time and insurance but still way cheaper!!!


In my own experince here in NZ if some supplier doesn't have some product they tell you they don't make it, it is not existing or not suitable for NZ conditions instead of being honest about it.
If we constantly remind them about how far they are behind we will catch up in no time and prices will come down.

Cheers

Re: Nice house, any futher temperature data? 

Hi,
Thanks;-That’s useful information about the U Values & costs ….. Yes, sure understand the minimum requirement in much of Europe is U value 1.1. Also keep in mind/ to build over there is beyond most people’s financial capability; - I guess that’s why NZ and AUS are attractive places to live & build. I’d also be keen to learn how to get hold of this affordable triple glazing as your mentioning, sounds very good !
Cheers.

Re: Nice house, any futher temperature data? 

Hi Duncan,

I am very busy at the moment but I will get in touch with you about the glass :-)

Anon Posted 6 Mar 10 6:03 PM

Re: Nice house, any futher temperature data? 

HI Anon,

Can you please share with the forum as there will be a number interested.

Cheers,
steve@timbercrete

Re: Nice house, any futher temperature data? 

I second steve@timbercrete! Share the love!

Tim

Re: Nice house, any futher temperature data? 

Hi Duncan,

Congratulations on a superb house. To me this is just what New Zealand houses should be about - energy efficient passive solar design based around a New Zealand indoor/ outdoor lifestyle.

As always on Ecobob I see you are attracting a lot of criticism regarding your windows and their insulation rating.

Traditional New Zealand house construction in general is heavily criticised in comparison to Northern European construction techniques and rightly so but this does not mean that we should be building houses the way northern Europeans do. I think that what those pushing this view forget or perhaps do not understand is that with our latitudes here the sun angles are ideally suited to solar gain, and properly utilised solar gain will provide the majority of the heating required.

There appears to be this obsession over insulation levels and heat losses but this is only half the equation, what New Zealand houses need most is proper orientation and layout for passive solar gain, the right amount of correctly located thermal mass, and good natural ventilation. They need to be properly insulated sure but this idea that we should be living in heavily insulated bunkers with small triple glazed uPVC windows just does not fit the New Zealand climate or lifestyle.

I know from designing and living in passive solar houses that an hour of sunshine is enough to adequately heat the house for 24 hours or longer, and I conservatively estimate we spend 4 times as much time venting heat from our house than we do heating it.

Homes are for families and living, and should be built around lifestyles and enjoyment of living. This house you have here will achieve this splendidly and with very modest energy usage. It is a huge improvement over standard NZ construction, and also allows a huge improvement over the lifestyle offered by northern European style construction.

Keep up the good work!

Dean

Re: Nice house, any futher temperature data? 

Great post Dean, I agree whole heartedly with all your comments.

but as one of the Northern Europeans here, I will reserve comment on
"allows a huge improvement over the lifestyle offered by northern European style construction".
except to say Kiwis and Northern Europeans are as different as chalk and cheese. :)

Pete

Re: Nice house, any futher temperature data? 

Thanks Dean.
I went through the exercise of comparing degree days for various cities in NZ & overseas. Refer below. What I have done is totaled the months that were over 100deg days @ 15.5C. You will see that the heating demands for NZ are considerably less than Northern Europe. And as Dean suggests the sunshine hours are considerably higher ie; 1300~1500 hrs for most of Northern Europe & UK compared to the 2000+ for a lot of NZ.

93 sydney
391 tauranga NZ
444 auckland NZ
481 athens
620 san francisco
782 nice
837 melbourne
962 wellington NZ
992 rome
1035 hastings nz
1105 hamilton NZ
1304 rotorua
1328 madrid
1691 plymouth UK
1717 dunedin NZ
1757 london
1776 christchurch NZ
1809 paris
1813 invercargill NZ
1874 queenstown nz
2117 geneva
2509 hamburg
2522 berlin
2521 munich
3496 stockholm

This is verified when I model houses in HERS AccuRate. With good solar passive design the minimal gains to be achieved with thermal break aluminum or even 'E' glass are difficult to justify for the extra cost of those elements. As 99% of clients do not have an open cheque book, common sense must prevail if, as a designer, I do not wish to become a 'dream buster'
steve@timbercrete

Re: Nice house, any futher temperature data? 

Steve,

sorry I'm probably being dumb, but can you explain again what the figures above are?

Pete (not logged in)

Re: Nice house, any futher temperature data? 

Hi Pete

Degree Days (heating or cooling) is the basic data used when thermal modeling a building. Here in NZ, BRANZ's ALF & HERS AccuRate are the common modeling software.
When modeling a project, the software is already loaded for the degree days for that locality ie; Rotorua, Geraldine, Hokitika etc. This means you can check the performance for that building relative to it's locality.
The higher the degree days (heating or cooling) means more energy is needed or more insulation is required ie; beef up walls, ceilings, subfloor or windows. In NZ degree days cooling is not an issue

Obviously, a place in Tauranga requires little heating compared to Munich, & therefore the energy savings by upping to uPVC windows are negligible as indicated by modeling. As a designer, we must be honest if the client is on a tight budget; as most are.

To find out more on Degree Days, go to www.degreedays.net

steve@timbercrete

Re: Nice house, any futher temperature data? 

@ Steve

From your point of view the extra costs for timbercrete are not justified either.
If you think that way I asked myself what is the point of your product.
If I buy Porsche and can't afford the alloy wheels I leave it.
If I buy a timbercrete home and can't affrord appropiate windows I just forget about it and use timber frame.
If you think like this one could say I import a cheaper product (lightweight concrete) that does the same or even better than timbercrete. That way one can buy the better windows and you are out of business :-(
I am afraid there is very little understanding of the importance of glazing and window frames to the thermal envelope amongst some posters here and architects and builders.
No matter what designs, methods or theories you apply a cold surface in the wall is not comfortable and the heat loss through windows is significant (especially with your beloved ali windows with such low standards)
Yes NZ is warmer than Europe but is has frosts in most places, and foggy days, cold southerlies and cold and wet weather. You guys seem to assume Queensland climate here ??????
Alone the statement that Europeans live in bunkers
with little windows shows the narrow minded thinking around here without knowing the reality.
How come that an average modern European house is heated throughout with a 10 KW boiler and the the lounge of a house in NZ is heated with a 20 KW or more woodburner and the rest of the house is cold.
Keep dreaming guys but I can't recommend your services to my clients as you do go in the right direction but without understanding the whole concept of what you are trying to achive