Orientation-Passive Solar Design related Suggestions needed

We intend to build the below plan from a project builder on a block with the below orientation. From my limited understanding of what I have read so far, this orientation has challenges with getting proper light. I am seeking inputs from people with more knowledge on a passive solar design about what can be incorporated in the house for more natural light and energy efficiency or is this a lost cause? I am on a tight budget but would like to be aware of any options that won't break the bank.

P:S Building on a narrow lot (10X30) in Sydney and have neighbours on 3 sides.

Are the plans approved? TBH its not too bad. I would add another window to dining.

FYI master ensuite configuration isnt great, the toilet and shower need to swap.

Also, bed 4 - if you moved the entry door to the other wall, you could have a WIL upstairs too

Thank you. These are initial plans .you are right about both ensuite design and bed4 entry(we have already communicated this). But with my new-found knowledge about orientation(very new to the land buying/building scene), I found myself freaking out about the choice of the design itself.

There's someone on here very knowledgeable, Im sure they will see and comment. Ill try find their name

Thank you. I do hope that "someone" gets to see the post.

You could message Ddarroch

Thank you.I've reached out to the member.

I assume you have already bought the land so are locked in. Not a great site or house design for passive solar design. Even if you flipped the design around the improvements would only be marginal. Best to try to make it as energy efficient as possible as you are not going to get much solar contribution.

The windows on the home theatre front of the house (NE side) will get a lot of sun in summer. Consider external shading options on these windows. Roller shutters would work – though some don’t like them. On the top floor I note that the house seems to have eaves so that should protect the North East windows on the top floor though because it is not facing true north these windows may also benefit from roller shutters.

The house is approx 9 m wide? So only 1 m to the fence on the North West. If the neighbouring house on that side is double storey on the boundary it will probably block most of the West sun at least on the ground floor so shading for those windows may not be necessary. If single storey on the boundary perhaps it would be beneficial.

Don't bother with shading for the windows on the South East and South West. Lessening the window size on these orientations will help - but that is a choice for you to make. (Windows are the thermal weak point in the building envelop (even with double glazing) lessening the size of non-North facing windows can be beneficial.)

There is a window in the stairwell. Consider scrapping this and installing a solar powered LED light that simulates a skylight.

Internally the windows will benefit from curtains with pelmets. My preference is for curtains with detachable linings for additional insulation. The curtains should fully clear the windows when open.

Consider how you are going to use the house. Do you want to heat/cool the entire house to the same temperature or will you be happy to have different temperatures in different zones. I recommend the second approach if you are interested in saving energy and the costs of heating and cooling – why condition areas you are not using? In which case your heating/cooling system should be zoned to allow this. Doors should be installed between the zones if this is possible. In particular it would be good if you can put a door at the entrance way to the stairwell. Otherwise the heat that you put into the ground floor living area will go up the stairwell. How you achieve this would be up to the designer but I would suggest a nib wall into the living room containing a sliding door – there would have to be other changes as well to make this work – too detailed to go into here. Also consider a door (probably sliding) across the entry hallway to separate the back of the house from the front of the house.

In terms of your heating/cooling system, as stated, it should be zoned. The preference is for a multi-head reverse cycle air conditioning system. It is more efficient than a ducted system and allows for easy zoning.

Consider going for an all electric house. Gas is just going to get more expensive over the coming years and with heat pump technology gas it is no longer necessary – for cooking (consider an induction cook top, if you can afford it), for house heating and cooling and for hot water – there are many heat pump hot water systems. It seems that builder’s default position is still to install gas to new houses – but this needs to change. A mega Joule of heat from a heat pump is usually cheaper than a MJ of heat from gas for all except the largest residential users, at least in Victoria. And if you have an all electric house you don’t have to pay the quarterly gas connection fees. (https://www.facebook.com/groups/996387660405677/).

Put in as much insulation as you can afford - even above the requirements for 6 stars. Double glazing if you can afford it (is any single pane glazing installed these days?)

You have a good roof for photo voltaic panels on the NW face. Install as much as you are allowed to and can afford. Then run as much electrical equipment as you can during the day. This works well with hot water systems heated by heat pump – get one with a timer (or have the electrician put in a timer circuit) and set it to run from say 12 noon to 6 pm (standard time) (because of the north west orientation of the panels) – though hopefully it will switch off before 6 pm – the system should be able to heat a full tank’s worth (or a normal full day) of hot water usage in that 6 hour period. The tank would have to be sized to contain enough hot water for one day’s use. Also consider pre-heating the house while the sun is still shining.

Thank you so much for your detailed response. I'm gonna sit with your inputs and see what we can plan/budget for.

Hehehe. I'm not expert, but will do my best. But this is certainly a tough block to work with.

A block that is 45° off the compass points is tough, as unlike a northern aspect, you can't rely on eaves to shade summer sun, will letting winter sun in.

So this would call for variable shading, particularly in the NW & NE sides, but also on SW bedrooms I'd think. A few options you'll be roller shutters, or adjustable louvred sun shades. The adjustable sun shades might be better, as you could mainly just adjust them a few times a year, unlike roller shutters, which you may want to lower & raise each day in summer. Deciduous trees (or climbers) may be another option, though I guess you probably don't have too much room down the NW side.

One area of concern is the NW facing guest room. Will this be rarely used? You might want to consider eliminating the NW window in the theatre room too, or at least minimising it too.

There's pluses & minuses to flipping the plan. NW aspect is the major concern. The sun is in this direction at the hottest time of the day, under eave height.

It really would be nice to flip the garage with those other couple of rooms mentioned above. The garage would near the brunt of the NW sun, the theatre would have NE/SE windows, & the first room a SE aspect. There would be no access from the guest room to the bathroom though.

Another thing making this tough is the fact that your "best" aspect for your living areas, the NE, is your frontage. So it's impossible to locate much of your living areas here. So you're living areas will likely be quite dark & cool.

Not much you can do about this, from a passive solar perspective.

So I'd be improving the thermal efficiency of the building.

Upping insulation levels, above the best minimum, which is likely all that the builders do as standard. For a standard (90mm) stud wall, you can fit R2.5 batts in the wall. This will bring the wall's total R value to around R3, just above the minimum of R2.8 recommended by the Your Home website. Minimum ceiling insulation on the same site is R4.1. So I'd recommend R4 or 5 batts for the ceiling. If you want to take this further if look at vapour permeable wall wraps (& tape), to greatly improve the air tightness of the build. This is a major weakness of Australian builds, they're very leaky!

In a rush, will try to write more a bit later

Oh, one other thing I was going to mention about thermal efficiency was zoning your main living area. ie. closing doors to separate your living area from the rest of your house when you want to heat or cool it. This is one reason I hate open staircases, they just act like giant chimneys. When you're heating downstairs, much of the heat will rise to the upper level, so you have to run the heater harder. So I'd add a door at the bottom of the staircase (or top if you must), & along the hallway separating the living area from the front of the house - I guess it would have to be between the laundry & the linen closet in the current layout. I prefer sliding pocket doors, others prefer normal doors, though these can be in the way when open.

I was also going to write about energy use. As, even after upping insulation levels, you'll probably need to heat & cool your home more than a well orientated home designed using passive solar principles.

I would certainly aim to build an all-electric house. This is the future. Gas is continuing to get more expensive, the trend will only continue. We're also learning that gas is worse for the environment than many experts initially suspected.

If you build a house without a gas connection you'll save money on the build costs. You'll also save money on your energy bills. Importantly you won't have to pay the daily service fee, which adds up to hundreds & hundreds a year.

And why buy your electricity, when you can generate much of it yourself, with solar PV.

One positive about your block's orientation is that you have a large roof area that faces NW. This is a great orientation for solar PV panels. North facing panels produce the most electricity over the year. While west facing panels produce the most electricity in the afternoon-evening, exactly when most people are using a lot of peak priced electricity. So NW facing panels are a very good balance.

One problem with many Australian houses is the roof design, double fronted, triple fronted, hip & valley. Means they often end up with lots of little triangular roof areas, facing every which way. Not good for a solar install! So make sure that, if changes are made, that roof design remains relatively simple, with that large NW facing roof area. I presume your roof won't be overshadowed by trees or other buildings. But also make sure there's nothing on the roof that will cast shadows on any solar panels. Even a small amount of shading can have a significant effect on solar panels! Locate the TV aerial, & any other roof obstructions (like stink pipes) on the SE side.

Depending on where you're located, most single phase households are limited to a 5kW (inverter), with panels oversized to a maximum of 6.6kW. Average panel wattage is now about 330W, meaning you'd have 22 panels to reach 6.6kW. So make sure you have room for at least 22 panels on your roof. More if you have 3 phase power.

A 6.6kW system should average between 25-30kWh a day, similar to average daily usage. Generation will be much higher in summer, & significantly lower in winter.

The cheapest way to heat a home is now with reverse cycle air conditioning. So I'd be installing a few split AC units (as these are more efficient than ducted systems). Obviously these can also be used to cool the home, although fans use much less electricity.

After space heating/cooling, the second biggest energy user in the home is the hot water heater. Again I'd be using an electrical storage heater, heating water in the day time, while the solar panels are generating. The most efficient heaters are heat pumps (300-400% efficiency), which will use about a quarter the energy to heat your water. The top brands aren't cheap, but there are government rebates to reduce the cost. Electric element storage heaters are much less efficient (100%), so use a lot of energy. They are however cheaper, so may be an option if you want to reduce the install cost, as you'll be self-consuming your own generated PV electricity on most occasions.

Plenty of people are moving to induction cooking. It's extremely efficient, with great temperature control & reaction time.

Best of luck in this exciting, stressful time, I'm talking about building, not the pandemic :0

Thank you so much.A lot of great inputs in there.I'll give them a good read and make my list.

Some really good info above!
People who have limited knowledge in this are or any area of building a house really appreciate the above posts and the people that take the time to write them..

Some other good threads here- a thread started by Jodge about house orientation. A lot of info and a few good links.


viewtopic.php?f=31&t=55057

A thread I started in the Eco section with several good links to both articles on this forum plus some external calculators for rainfall, eaves depth etc etc. Some of these links are no longer online but most are. I really should update that thread.

viewtopic.php?f=35&t=51738

Stewie

Thanks, i will check them out..