Topic: Zero Energy House

Zero Energy House 

Anyone see this house featured on TV last night? Definitely worth checking out. http://www.zeroenergyhouse.co.nz

Re: Zero Energy House 

I was a bit skeptical of the claim that it would need no heating at all. I missed what part of the country it was in but thought the extra 50ml of wall thickness would not be enough. Perhaps they meant no conventional heating, and there was a heating element in the MHRV unit.

Also the price differential of, I think, $20-30 thousand seemed a bit optimistic. Perhaps if you didn't include the PV and solar HW in that.

I thought putting the dwangs/bracing on the outside to create the 50mm was interesting.

Re: Zero Energy House 

Yes I am a bit skeptical too - the surrounding houses look like Auckland location.

$20-$30K looks low to me too. Must have a lot of thermal mass somewhere to make the claim of no additional heating, especially since having double glazing only means the windows are now say, best R value of about 1.3, so they will still be losing a massive amount of heat when the sun isn't shining - is the cost of the [assumed additional] thermal mass part of the $20/$30k???

The thing that worries me the most is the BIPV (building integrated PV). The reason is to do with the "form factor" of the PV system - if any of the panels need replacing, would the product still be available in that same exact physical dimensions so that you don't have to redo all the brackets and seals, as the PV panels are actually the roof? Also, in a PV fire, how do you deal with what's left, and how do you integrate any new replacement product into part of the roof?

Seeker

Re: Zero Energy House 

The number quoted definitely smells fishy. The windows alone would be at least $20k more than minimum spec. There's probably $5-10k more in the walls and insulation, then there's the slab, ventilation, the $20k PV roof, LEDs, etc.

Good on them though.

Re: Zero Energy House 

What is minimum spec? If you compare something sub standard with reasonable quality the sub standard solution is always cheaper but not a datum line for measure and comparism.
Do you sleep on the floor because a reasonable bed costs 2000 dollars more than minimum spec which is floor?!?

Re: Zero Energy House 

Guess what: the issue we are wondering about is cost, not whether the house is considered high or low spec.

I think that the Zero Energy House is a worthwhile "dream home" for those people for which long term operating costs are given a far higher rating than capital cost (higher than what is justified on pure economic and net present value terms I might add - especially given NZ home turnover rates of moving home once every 7 years).

I would put the additional cost at about $80k plus.

Also, the people said on the programme that with the additional cost of $30k, it is not a high price to pay if you consider that the savings in power bills will be between $50k and $80k over the next 25 years - they have not valued-in the "net present value" which takes into account the "time value of money", something that the majority of people simply won't have a clue about, nor do they care.

BUT if you factor in the time value of money, I would say that in pure financial terms, the savings would not justify spending more than an additional $20k TOTAL, especially since this assumes the people will stay in the house for the full 15 to 25 years over which calculation is based.

One of my questions (which has had a few research studies done on it, and no doubt there will be more over time), is whether you get your money back when you sell - so far, the research results are not really that clear cut. In other words, there is nothing that actually shows that you will get the additional costs back when you sell the house.

This is really the problem I see we have to fix: if we say to the market that you have to have a HERS rating ("home energy rating scheme") published for every house that is for sale or sold in NZ, which is an independent assessment of how much a house will cost to heat given a standard set of assumptions that can't be fudged, then perhaps people will start getting their money back.

The PV thing is a bit of a red-herring - how long is a piece of string? A family that leaves all the lights on and standby's "on" and takes long showers will have quite a different power use profile to a family that is careful with power use, so I am only really talking about the house infrastructure, not household energy behaviours.

Seeker

Re: Zero Energy House 

GW - I'm not questioning whether the windows are worth it (they certainly are), or that minimum spec is generally sub-standard (it certainly is), I wouldn't be on this forum if I thought otherwise. I spent tens of thousands on my own place going well above minimum NZ building code requirements in every area.

I'm questioning the claim that did everything for $20-$30k.

Re: Zero Energy House 

I totally agree with you that the costs will be higher than they indicate, especially with the PV and such.
My point was to question the datum line from which they derived the 20 or 30 K "extra" costs.
Even on the low code level there can be huge difference in cost and quality. They would do themselves a big favour and say upfront that it costs say 2500 or 3000 or 3500 or whatever $/m2 to build this. Everyone who has done the research like us will understand realistic pricing.

Re: Zero Energy House 

Zero energy homes are becoming increasingly affordable. At the home show in Christchurch over the weekend Beattie Air had 3kW of grid tied PV generation available for $10k installed. At that price why not put 5kW on, it would probably only add another $2500 or so.

Build a well insulated air tight passive solar house, reduce the floor area by 10-15% (GBC issued figures that NZ houses are second largest in the world after Canadian houses - our average size is bigger than the US or Australia) and you are probably building for a similar cost to conventional housing.

One group who get a significant advantage from Zero energy homes is people in their mid 40's to 60's who are planning to keep their home for their retirement. Generally they will retire onto a fixed income or at best inflation adjusting through investments etc. Minimising utility outgoings at that time in your life means a more comfortable lifestyle in your retirement.

Younger people with larger mortgages should look at the benefit of adding $20-30k to their mortgage when they build and reinvesting their energy savings back onto the mortgage. If you can save $200 per month in power bills and pay that down on the principal of the mortgage, generally you will find that your mortgage period will reduce substantially. On-line mortgage calculators should be able to give you this answer, or a mortgage broker.

There is always the discussion about payback periods on energy saving systems, and it's not hard to do some numbers and base a decision on that. The way that I look at it, if you are not going to spend your money on energy saving devices where do you spend it?

This will often be on holidays, cars, appliances where we don't expect a payback period or return on investment because these are lifestyle choices. My belief is that energy saving devices that save you money can also be used to enhance your lifestyle by freeing up disposable income in the future.

We all know that low or zero energy use houses are the right thing to do, I don't understand why we find it so hard to convince ourselves to actually do it. Perhaps we all find it hard to believe that there is a free lunch.

I'm toying with the idea as I write this of designing a simple 2 bedroom zero energy low cost home, perhaps 80m2 or so, maybe pre-fabricated or transportable and getting it priced up to see how economically it can be done. What sort of build cost would this need to be to work? Would $160K meet the market expectations for value for a small home where you would never need to pay a power bill again? My gut feeling is that it should be achievable for under $2000/m2

Re: Zero Energy House 

Hi Dean

How are things in CHC?

We are also looking at building a very small low energy requirement home - and low maintenance as well, as part of retirement planning when there simply isn't any spare cash for a large maintenance budget. I import high quality solar panels and solar hot water collectors so I will use those: but it is the additional energy input when the solar isn't there that I am working on. Under $2000/m2 is probably do-able - I am the administrator for a small building construction company so have up to date costings on most things.

Have a look at this link (just another example of new building thinking going on around the world):
http://www.gizmag.com/warburg-energy-efficient-home-costs-less-than-100k/22745/

Seeker

Re: Zero Energy House 

Wow, that is extreme minimalism. Interesting when you compare it with Japanese architecture which is very space efficient that the Japanese tend to incorporate storage everywhere. A chair would make this place look untidy.

I like the idea of being grid tied for PV's, generate excess when the sun is out, draw it back when you need it. Theoretically you use the hydro lakes to store your generated energy by reducing demand for generation.

If I were to put together a plan would you be happy to look at cost estimates for it as an exercise?Hopefully we could find somebody willing to do an energy analysis on it based on some different locations. I would be happy to make the plan available as an open source arrangement where others would be free to take it and develop it further to meet their needs if they wished.

Christchurch is an exciting place to be at the moment, it probably does't show on the surface but residential rebuilding is taking off, I have some really great clients at the moment, many about to start rebuilding in the next few months. All of them are focussed on quality energy efficient construction and it is a joy after so many years of battling to try and raise standards that people are insisting on building well.

Re: Zero Energy House 

Dean, I think the worm has definitely turned with regard to the momentum to build low energy houses though I imagine it can appear frustrating when you are trying to push for it in the industry.

I think it's a bad thing that much of the public has a kind of a "gee whiz" attitude towards new technology and often lacks the ability to analyse it to any great depth and gain the benefit of that. For instance, it was frustrating to me that the Close Up reporter didn't ask even slightly in-depth questions about the project. Had he done absolutely no research at all?

Re: Zero Energy House 

Dean, I think the worm has definitely turned with regard to the momentum to build low energy houses though I imagine it can appear frustrating when you are trying to push for it in the industry.

I think it's a bad thing that much of the public has a kind of a "gee whiz" attitude towards new technology and often lacks the ability to analyse it to any great depth and gain the benefit of that. For instance, it was frustrating to me that the Close Up reporter didn't ask even slightly in-depth questions about the project. Had he done absolutely no research at all?

Re: Zero Energy House 

Dean, I think the worm has definitely turned with regard to the momentum to build low energy houses though I imagine it can appear frustrating when you are trying to push for it in the industry.

I think it's a bad thing that much of the public has a kind of a "gee whiz" attitude towards new technology and often lacks the ability to analyse it to any great depth and gain the benefit of that. For instance, it was frustrating to me that the Close Up reporter didn't ask even slightly in-depth questions about the project. Had he done absolutely no research at all?

Re: Zero Energy House 

Dean, I think the worm has definitely turned with regard to the momentum to build low energy houses though I imagine it can appear frustrating when you are trying to push for it in the industry.

I think it's a bad thing that much of the public has a kind of a "gee whiz" attitude towards new technology and often lacks the ability to analyse it to any great depth and gain the benefit of that. For instance, it was frustrating to me that the Close Up reporter didn't ask even slightly in-depth questions about the project. Had he done absolutely no research at all?

Re: Zero Energy House 

Sorry!

Re: Zero Energy House 

Hey, it echoes in here!

I think one of the mistakes we make in the industry is trying to push the technology. Compare it with an iPhone. Sure, there are a few people out there who want to know all the technology, but the majority of the people want them because of what they can do for them.

Maybe we should drop all of the eco/ sustainable/ energy efficient/ passive/ techno speak and talk directly to people about "What does it do for me?" "You can have a sunny, warm healthy home that is a great place to live and bring up your kids and you'll never have to pay a power bill again, all for the same cost as an ordinary home".

Ok, it may be a few square metres smaller but that's one less cold room that doesn't get used, or one bathroom that doesn't need to be cleaned each week.

Re: Zero Energy House 

Hi Dean

Yes happy to help price your house design - been meaning to get in touch anyway. I've been on your website in the past.

Seeker

Re: Zero Energy House 

A very interesting discussion indeed! I have just a few things to add:

1) Close Up goes out to around 1mill viewers, mostly the general public who don't know much about zero energy houses and what its all about, unlike the people that are on Ecobob. In five minutes all you can get out is the simple message - its not that difficult. Unfortunately detailed questions were out because of that.

2) A cost of $20-30k isn't actually that helpful for most people in my opinion as that's quite specific to the ZEH and to Auckland, but the presenter of Close-up really wanted to put a figure on it. A $/m2 rate isn't either because the smaller the house is the higher the $/m2 is likely to be anyway. We think achieving zero energy adds somewhere between 5-10% to the build at the moment based on initial calculations. It is possible to do some of the things we have done cheaper, for example the PV system and the windows.

3) During design we trimmed 8m2 off the house and worked out this move paid for the solar system. It is a very good point about house sizes in NZ. Do we really need them that big? It just makes them harder to keep warm in the winter and more expensive to build. A Studio have designed the space in the ZEH effectively, so that useful floor area is maximised.

4) We do have lots of info on our website about the build, costs with a value case will be coming when we get final figures and final savings. These will be based specifically on the additional cost due to energy efficiency and generation measures. I have also been looking into ways of finding out what the added value of all these items are. Interestingly Real Estate did a survey a month ago which they presented at the Sustainable Housing Summit 2012 which showed that the two most important features of a house to home buyers were orientation and insulation. Unfortunately the survey did not look at how much more people would pay for this. They are repeating the survey later in the year and I will be asking them to include that. So keep an eye on our website...

5) The house is based in Auckland so it should be easy to remove the need for heating due to good design. We currently live in a townhouse which isn't particularly well insulated and only has single clear glazing, but does have the benefit of a shared tenancy wall and surrounding buildings providing some protection from winds. The last two nights it has been over 21degC on the top floor and still relatively warm in the mornings (I haven't checked the morning temps unfortunately - a job for tomorrow morning!).

Jo - ZEH project

Re: Zero Energy House 

Hi ZEH,

I am going to import a kitset passive house and our design is 22m long and 7 m wide, single storey with mone pitch roof, double french doors in all living and bedrooms facing north-north/east.
Windows/doors uPVC R 1.0 and external shutters.
Even with the passive house standard and the exeptional high standard with every single bit of wood precisely cut on CNC equippment, exposed rafters with 200mm wood fibre insulation on top, over 300mm walls consisting of 100mm solid nordic pine and 160mm woodfibre insulation, it will be less than 1700 NZD a m2 landed.
And it is so well pre-fabricated that I can put it together myself with some help.
The whole assembly is done with screws.
Nordic pine is also very durable and working with it feels and smells like wood, not like the chemically treated stuff.
The Euro exchange rate, the reasonable price for timber and insulation and modern pre-fabrication methods makes it possible to build a high quality house at a reasonable cost.
I would prefer to have more than concrete and coloursteel roofing sourced locally but it is just not available yet without breaking the bank.

Re: Zero Energy House 

Hi Guess what, I'm interested to know more about the kitset house you're importing.

Is this just for yourself or something you are going to be selling?

If it's not commercially sensitive do you mind putting down the landed cost of the house etc?

Re: Zero Energy House 

Whether it is a one of or not, I am not sure yet.
It depends on the red tape, economy and other things like suitable people to assemble it properly.
Landing costs for this size are approx 110 K plus, foundation/concrete floor/screed UPVC windows and coloursteel locally, plus Gs.t

Re: Zero Energy House 

Hi GW,
R1.0 for windows locally? Presumably this is Triple glazed?

Re: Zero Energy House 

Hi Jo,

Great to have you here in the Forum.

Alistair Helm's presentation from the NZGBC Sustainable Housing Summit is now available (in pdf form) here:
http://www.nzgbc.org.nz/index.php?option=com_content&view=article&id=352:market-insights-and-selling-sustainable-homes-how-to-get-it-right&catid=218:2012-sustainable-housing-summit&Itemid=371

It's encouraging to think that people are starting to ask about sun and insulation.

Re: Zero Energy House 

Nikoftime

Well to be correct the windows are made here with imported components and the triple glazing as well.