franks
Member
I have planned at least 6+ star dwelling, heating cooling/heating typically 80 to 100 watts per square metre required.
Can I assume typical pre star rating home is around 2-3 stars ?
Each star inprovement is aprox 10% less energy required. (3 to 6 star 30% less)
Would I need around 60 watts per square meter for 55 metre dwelling (granny flat shed conversion).
Wolud a 3.6kW aircon/heatpump be enough ??
Please comment with suggestions and Ideas.
dlvb19
Member
Errrr not sure about some of this stuff but your certainly covered with the heat pump.
A modern 3.6kW heat pump will have a COP of about 4 (or 3 at worst). That means it will put out 4 x 3.6 = 14.4 kW of heat, thats a lot of heat!
My 6.5 star home is ~ 150m^2 and only needs a 2.5kW aircon to survive a Ballarat winter.
alfresco24
Member
Franks,
Here's some info from the HERS rating tool (2010)
Ballarat is HERS climate region 66 and has the following energy requirements according to the following table; Pre 1990 housing.
Stars - MJ/m2 p.a.
2.0 - 618
2.5 - 525
3.0 - 448
3.5 - 386
4.0 - 335
4.5 - 293
5.0 - 257
5.5 - 225
6.0 - 197
6.5 - 169
7.0 - 143
7.5 - 117
8.0 - 91
8.5 - 66
9.0 - 42
Your question isn't possible to answer given the lack of info about the construction and insulation factors pre and post renovation.
Go to Google if you don't know how to convert MJ to kW.
John P
Member
franks, if you think it might help, you are welcome to come and check out my zero emissions place at Lexton - no heater (other than the sun) - no aircon - no worries.
We are not far from Ballarat although the micro-climate is different.
Benny
Member
I tried raising this in another thread Franks and there hasn't been much response.
http://www.ata.org.au/forums/topic/12253
As shown by the data above from alfresco you can data for the annual energy requirements but not power. Even the energy required is not separated in to heating and cooling from what I see. As you ask, people want to know at the coldest part of winter (or hottest part of summer) how much power do I need to maintain temperature.
Forgetting star ratings, have you tried the usual heat flow calculations ? e.g. area of ceilings is 55sqm, Heat flow = 55 * deltaT / R.
So if R is 2 and deltaT 15C, P = 412W. Then there's walls, windows etc.
alfresco24
Member
Again, if you want to do this properly go to a house ratings review company such as Sustainability House http://www.houseenergyrating.com/ or your nearest trustworthy equiv and in consultation with a designer builder do it right the first time.
Be aware that retro-fitting improvements after a house is built easily costs 3 to 5 times more than it would if done at the outset.
Don't listen to well meaning amateurs - they'll only confuse and mislead you - and don't look at items in separation of each other. The exercise has to be integrated and planned, and then you have to live in it and operate it, that's where behaviors play an immense role in the outcome. One persons cool is another persons cold etc etc
This forum is great, but lots of feedback and suggestions include, should, could, might which frankly is of no help at all without the context.
