Hello everyone,
we have just bought a new house -- the developer made a big fuss of it being soo 'sustainable' -- well, it's nice that they claim that, but it's just according to the current minimum required 5 star energy rating (or so I hope).
It's a two-storey house, lower storey brick veneer, upper storey weatherboard, no south facing windows, all major windows face north and west.
We are thinking about getting an air conditioning unit, but also some solar or passive heating/cooling solution to help with both the heating and the cooling.
The loungeroom, though facing north, is overshadowed by the house next door and therefore quite cool in winter, and could need a bit of a boost with a solar heating system. The top floor will desperately need cooling, and possibly any passive and extra help that it can get -- it can even get quite hot and stuffy now, in winter. Two of the bedrooms have windows facing north. We will put shading (roller shutters, thermal curtains) over the window, but this will likely not be enough.
We have looked at HRV (http://www.hrv.com.au/) who take hot or (when the sun is down) cooler air from the roof space and pump it into the living area, then also there is SolaMate (http://www.sola-mate.com/) which uses a collector panel to heat up air, much like SolarVenti (http://www.solarventi.com.au/) does, only that Solarventi is integrating a PV panel at the same time which powers the fan, which makes it my current favourite. -- Also, SolarVenti addresses cooling, not just heating issues, like here (http://www.solarventi.com.au/generelt/koling.htm) where they draw cooler air from the cool side of the building, and then they even have earth (geothermal) cooling http://www.solarventi.com.au/generelt/koling.htm#jord which is just a gorgeous idea.
We are not the kind of people who set the air conditioner very low, in fact we would keep it off or at a relatively high setting most of the time. But then Melbourne has these blisteringly hot days when gets up to 42 degrees. And on those days, there tend to be more power failures. So a system that a) runs independently from the grid and b) uses 125 m of cool earth to draw the air through might be a godsend.
But then, I also heard of Venmar heat exchangers which would bring fresh air from the outside in, just heat it up or cool it down taking the warmth/coolness from the stale air from inside the building which is let outside.
And in addition, someone has recommended to just put a large fan at the highest in the house which will transport the rising hot air out to the roof in summer, and cooler air will rise from the bottom. The house is sitting on a concrete slab (which I think is a requirement for new houses), so there is no space with cool air underneath the house, as was with the house of the person who recommended that.
In addition -- creating cross air-flow by opening windows is something we'll likely want to minimse, the house is on a very busy road which can always be heard when the windows are open. It just turns out that in practice, when we open windows, we close them again as soon as we can. That means that we'd probably not rely on natural airflow, and actuallly need a kind of opening or fan that will bring fresh air in -- hopefully not wasting too much energy.
There are so many possibilities. We had a HRV sales guy over, but all he wanted was push his product, we'd rather like someone independent who could come and look at the house and recommend which kind of the different passive heating/cooling systems out there is best suited to our particular situation...
Or otherwise, how can we go about evaluating this ourselves?
For evaluating what the HRV could do, I would first need an indoor/outdoor thermometer, best with multiple 'outdoor' stations that I could put in different parts of the roof space. Where can I buy such thermometers? If we go for the 'top floor ventilation' solution, where can we get a fan with the required capacity, and how do I go about figuring out what capacity we require?
If we put the fan into the top of the staircase, then there is a likelihood that the bedrooms which actually need it don't get much relief. So where would such a fan be placed, or how does airflow get calculated?
(We already now have trouble heating the bedrooms at all, because the thermostat for the upper floor is located outside the bedrooms above the staircase and always gets heated by the rising hot air from the ground floor heating, and never thinks it's time to heat the upper floor now.)
But if we put a large fan into one of the bedrooms, would it then create an unacceptable draft in that room?
So many possibilities, we are totally overwhelmed, please, any help would be appreciated.
Thanks!
Barbara