Cool at home, what I was trying to get at is that the heat gain might be coming from downstairs and just ending up upstairs. Something to consider. I noticed one display home that was split level with closeable louvres that could adjust the amount of heat coming up from the lower level. Likewise at night you should be able to open up the windows on the top level and bottom level and thermosiphon the air from downstairs up.
Venting for top floor cooling???
(63 posts) (24 voices)-
cool at home
MemberWe installed very large internal glass doors in our living area to create a 'thermal zone' for heating purposes, so we do have the ability to trap a lot of the heat downstairs, although this is mainly from our northern side and not from our western side... although we have low-use rooms all along the western side, with solid core doors and insulation in both the external and internal walls, and closing these rooms off in summer helps a great deal.
At night we have security grilled windows on the ground floor on the southern side of the house - alongside the water tank and the above plantings - that are left open all summer long, to allow cool air in the house at night, and security grills on patio doors in the top floor corridor - plus other windows in the bedrooms - to provide an exit point for hot air. It works 'ok', but not as well as hoped. And a new neighbour has just put a huge air con unit near those doors, and we're now anxious about the noise at night in summer.
We tend not to close the doors in summer as we want the heat to dissipate, and it also gives us our cross ventilation (breeze path through the house). So we are consciously sacrificing the upstairs comfort for the downstairs, we know. We'd just hoped to improve on how it currently functions.
Thanks for all your comments.
Posted Wednesday 18 Aug 2010 @ 1:22:39 am from IP # -
Buzzman
MemberWhat prices have you been quoted for the Ecopower 400?? Or the Maestro for that matter?
And while the data sheet rates the EP-400 at 2400 cu m/hr, is this 'open vented' or with ducting attached?
I read somewhere (now can't relocate it) that ALL fans are less efficient when ducting is attached as opposed to 'free-flowing' but not sure what/how much difference this makes or could make.
Any of you lurking engineers got any data that would answer this question???
Might need a bigger EP 600 or EP 900 if this is the case, depedning on roof volume.
I ask because the 400 would be ok for my roof space, so am also self-interested....
Posted Sunday 22 Aug 2010 @ 5:22:56 am from IP # -
dymonite69
MemberA few metres of ducting generally doesn't make too much difference to flow rates.
Proper data sheets for fans provide flow-pressure curves at different rpm. Some fans can provide constant performance over a range of pressures. Others may only generate high flow within a narrow band.
For a given rpm and static pressure in the system you can predict flow rates.
There is corresponding data nominal static pressures for grilles, vents, metres of duct, reducers and other gear.
You simply add the static pressures of the components and then read off the fan data sheet for the predicted flow.
The important things about installation is to ensure that you have nice gentle curves in the ducting, avoiding sudden changes in diameter at the connections and not to place obstructions near the intake or exhaust. This maximises laminar flow. Turbulent flow will increase resistances in the system.
Posted Sunday 22 Aug 2010 @ 10:18:11 am from IP # -
cool at home
MemberThank you.
As I want to vent the top floor of the house not the attic, ducting is pretty much a given. CSR Edmonds have visited the house and advised a ducted EP400, although getting a firm quote and installation has proven more difficult... they seem to be a little chaotic in that regard. I'm now seeking a local supplier, but expecting to pay around $2K... ideally I'd like it to be an awful lot less than this, but I'm bracing myself...
Regards
SusanPosted Sunday 22 Aug 2010 @ 2:07:27 pm from IP # -
Bearamundi
MemberWhat a brilliant site, I have read these posts with interest as I have been in to thermal efficiency for years.
I may have glossed over some detail but I understand that your location is Sydney. Mine is Newcastle so we are basically in the same climatic region. How hot exactly is your built environment getting? I understand that the optimum thermal range for the home is 21-25 degrees and I work on that. Is your upstairs getting above 25 degrees? On a couple of days mine might exceed that but rarely.
I think it is a lot of fun to track down the problem and solve it cheaply.
Firstly, have you data on how the house is performing thermally? I started with a thermometer outside, one inside, and one in the attic. You might need a few more. I took temperatures over the course of a month and gradually figured out how the heat was moving. Then I blocked the main culprit before collecting more data, and doing what I thought might be the next best thing. I found a systematic process heaps of fun and confidence-building. It makes me proud to see my wife and family comfortable year round for next to no money.
For example, do you have solar panels? They shade the roof and provide a good return on your investment and cost under $2000. Might be a good option. Whatever you decide have fun as you goal is entirely achieveable.Posted Monday 23 Aug 2010 @ 11:41:45 am from IP # -
cool at home
MemberWe installed 3.24kW of mono crystalline solar panels on the N-W aspect of the roof (too much shading on the N-E), but since last summer so haven't yet seen what impact they will have on upstairs heat. Also have a large deciduous tree on the S-west, plus external awnings and thermal curtains on all the windows, lightish grey roof, good roof and wall insulation including reflective, etc... but there's still a lot of sun hitting the roof and the house walls.
Upstairs will go over 30 degrees regularly, but we night vent and have ceiling fans above the beds so get this down to a reasonable sleeping temperature without too much difficulty. As the kids get older however, they want to study and slouch about in their bedrooms listening to music etc and this is unbearable in mid summer. We built the house and put the 'playroom'/games room downstairs, so ok heat wise. Was great when they were younger but they want to put distance between us and them these days.
I'm sure that blocking off the stair well would improve things a bit, but I don't want to make the downstairs hotter. It stays below 26 most of the time, and I'm not sure it has gone above 28 degrees ever. We have porcelian tiles on a concrete slab downstairs which helps with thermal mass.
We have monitored the house with 2 internal/external thermometers (about $30 each from Australian Geographic). One measures both downstairs northern rooms and shaded external northern aspect, and the other measures middle of the house downstairs and the top floor immediately above... ie; we put the external monitor upstairs rather than outside. Can be very interesting!
Many thanks for everybodys input. I feel we must have exhausted all possible options by now...
Posted Thursday 26 Aug 2010 @ 8:27:44 am from IP # -
Bearamundi
MemberPerplexing isn't it? Looks like you have done everything but even 28 downstairs is too warm by my reckoning. House should stay below 25 most days of summer for best longevity. My biggest discovery was that radiant heat is 100's of times more potent than convective/air movement. That leads to foil, and lots of it, and shading. When does the internal temp start to rise? If it is before approx 1pm it must be coming through the roof. If after 1pm then it is probably your western wall. What are the eaves like?
Our place rises 1 degree per hour after about 1pm, house is usually less than 20 at that time, and it gradually warms to around 25 or so before plateauing and then starting to cool.
I diy'd a good Bunnings foil product (gold outer layer, with a sandwich of heavy bubble-wrap looking filler and silver underside. Not cheap, $250 per 20m @ 1.5m wide). Tacked it onto underside of rafters and then installed two whirly-birds to vent the thin layer of air above this insulation and below metal roof. I sealed it off from the roof space pretty carefully.
That basically broke the back of the problem and allowed other measures like shading, to get traction.
From memory I multiplied the govts recommended insulation R values by 4 to get the desired effect. It was worth it to have a cosy home in winter and a nice cool hit of quality air as you enter the house in summer for free. I reckon there is a mistake somewhere in your insulation.
In the walls I ignored the fancy installation guide and just put a layer of foil vapour barrier on the outside, then Batts, then another layer of foil stapled in as deep as possible to generate a good air gap behind gyprock.
I retro-fitted the walls, using a skill-saw to cut the gyprock off below the cornices. Then gyprocking over again.
This will be the first summer we will go through in 3 years as we have travelled the last couple of summers. My thermometers are out in force again as I look to create even greater cooling as cheaply as possible.
Other things, I scored secondhand awnings and ran them all along the western wall so it is almost in total shade. Over the windows that we don't look out of a lot I tape heavy clear plastic to create cheap double-glazing effect. I'm DIYing the windows we do use with removable perspex to generate more double-glazing.
This summer I'll install whole house exhaust fans and maybe roof space fan if needed. I'll look at North walls more carefully, maybe a sail over outdoor tiles to reduce indirect radiation.Don't give up, it should not be a huge problem.
Posted Sunday 29 Aug 2010 @ 8:07:51 am from IP # -
Jaymak
MemberInteresting discussion. Just came across this forum by accident. My home in Perth consists of three levels. On a hot summers day I measure a differential of 3 degrees per level which makes the top floor pretty unbearable. I tried using a Whirlybird vent but air will not rise unless the outside temp is cooler than the inside (second law of thermodynamics or something!) unless you give it a helping hand so I have combined the Whirlybird with a Mistral fan mounted in the base, the one with self closing blades available at Bunnings for about $100. The Mistral will move an average roomful of air about every ten minutes. The fan operates from a thermostat set to 27 degrees and mounted at ceiling height. The system works well and we can now live comfortably upstairs on a hot day and the self closing fan prevents warm air from venting during the cooler weather.
Posted Tuesday 31 Aug 2010 @ 3:04:05 am from IP # -
questionman
MemberHi, Jaymak, may I know the particular Whirly bird - Supavent, Windmaster, Maestro? or others- and the model no. or particular name of the Mistral fan you have mentioned in your post? Thanks, for any additional info.
Posted Wednesday 24 Nov 2010 @ 5:41:30 pm from IP # -
questionman
MemberAlso , if the Mistral fan is connected to the whirly bird , how was it done and who did the set-up - handyman, or which tradeperson to hire? When you say whirly bird , are you referring to a Vent-a-room ( Supavent connected to ducting and closable ceiling register or a Supavent just installed on the roof but with ceiling register grille/vent below it. I am very interested on how you did this as we are having the same problem in our home in perth. Thanks again for for helpful info.
Posted Wednesday 24 Nov 2010 @ 5:49:31 pm from IP # -
Jaymak
MemberHi Questionman, no register needed as the fan takes its place. The whirlybird I use is an Edmonds Windmaster but any whirly will do. The Mistral fan no longer appears to be available at Bunnings but I have seen an identical one called Expressaire which is available at Universal Fans.com.au. This fan mounts in the ceiling of the room in the normal way. Between the ceiling and the underside of the roof in the roof cavity I have fitted a metal flue of about 400mm diameter which sits on the ceiling over the fan and ducts the exhaust up to the whirlybird. The thing runs off a Honeywell bimetal thermostat which I happened to have in the junkbox but there is a nice electronic thermostat available from Jaycar for about $40. Being a retired tradesman I did the installation myself but you will need a qualified person as there is electrical wiring and a power outlet needed for the fan. Hope this helps.
Posted Thursday 25 Nov 2010 @ 1:24:43 pm from IP # -
cool at home
MemberSummer is back and here we are again... deeply disappointed in the performance of our top floor despite insulation 'to die for', window awnings, in ceiling vents and 2 Supavents on the roof. We priced the ecoPower unit but at nearly $3K installed we just can't do that at this time. Back to thinking about the Maestro or the Skydome Powervent. Has anyone tried this in a situation similar to ours? Our intention is cooling of the bedrooms and improved night venting. The attic 'climate' per se is of no interest.
Posted Friday 10 Dec 2010 @ 11:02:52 am from IP # -
thatmosis
MemberWe have only a single story home but in one hot place,42c is normal for Summer, we have air vents in all ceilings that can be opened in summer and closed in winter and two whirly gigs on the top of the roof. This seems to work quite well and with certain windows open sets up its own current in the house. Every room has its own vent and insulation in the ceiling and the walls facing the morning sun and evening sun keeps the house very cool. As we are on Solar we only use a very small fan at times to help the flow.
Posted Friday 10 Dec 2010 @ 10:41:17 pm from IP # -
cool at home
MemberThanks for that Thatmosis. It's interesting that your experience is so positive and mine so opposite. I'm not sure that it is any better at all since we installed the Supavents.
We put Aircell under rafters too and it seems that the house is taking longer to cool at night now, but that might be me being a bit 'hyper' about the whole thing. And of course summer is just here now, and I have to get back into the habit of opening the house right up as the evening cools down.
I am in Sydney and it rarely makes it to 42, but humidity can be an issue at times - and was when I was prompted to write to the post again.
We are not well served by cross breezes but I do leave windows open on the south side of the house during the day unless it is hotter outside than in (have several 'inside/outside' thermometers so that I open/close windows as temperature changes through the day).
And I'm relying on cooler air from downstairs being drawn upwards - perhaps that is the problem... need to open more upstairs windows.
Posted Sunday 12 Dec 2010 @ 5:22:17 am from IP # -
matas
MemberJust wondering if powered exhaust fans in the ceilings might help ?
(I gather the Supavents is just a whirlybird on the roof)
I have just bought an Arlec MEF25 fan, to try out.http://www.arlec.com.au/viewProduct.aspx?productcode=MEF25&catalogueID=10&parentCatalogueID=3
Apparently it uses only 4 watts.
So would only cost $5 to run 24/7 for a year.
It was only $27 at Bunnings.
You could have at least one in each room, at those prices.
You would have to put in wiring though.I was also thinking the 3.24kW of panels would have improved things, by shading the roof.
Posted Sunday 12 Dec 2010 @ 7:46:27 am from IP # -
thatmosis
MemberI suppose that you house doesnt have large eaves over the top floor. This is a problem and for the life of me I cant understand why we in Australia build houses that dont have verandahs alround. This creates a shaded area before the sun hits the walls and reduces the temperature considerably. Its okay to have a lage house but common sense should dictate that unless there is protection from the sun then the houses are going to need some sort of airconditioning.
Posted Monday 13 Dec 2010 @ 1:54:35 am from IP # -
termite
Membercool at home, I re-read your initial post. Those canvas awnings should be reducing the direct heating up of the interior of your upper level, but not the materials of the walls or roof. If you want your interior to be cool, not just keep heat out when airconditioned, you will also need to keep the environment around your house shaded as well.
Question: Is your upstairs level the same size/shape as the level below? If not, I'm wondering if you have any of the roof of the downstairs level adjoining/below the line of the windows upstairs. If so, this unshaded area would be heating up the air going into your upstairs windows. If you can't shade this or the walls of your upper level, my only suggestion is 'tactical shade' from carefully-chosen trees. In Sydney, you have some choice of properly-deciduous trees, though of course they will take some years to have effect.
Do you have the space to grow trees to shade your walls?Posted Monday 13 Dec 2010 @ 2:16:48 am from IP # -
cool at home
MemberThatmosis, we have eaves but not particularly wide ones. We have fully retractable canvas awnings over the windows as well.
Termite, I'm sure you're right about the walls, although we do have sarking and R1.5 batts in the walls. We have bathroom windows along the N-W side of the house... best rooms to 'sacrifice' we thought, but kids are not good at keeping the doors to those rooms closed, which might help stop the heat getting to the bedrooms.
We also have a larger lower floor than upper floor, and I can see how heat might reflect off the lower roof tiles into a couple of bedrooms. How to solve that, though??
We have a Magnolia tree out the front (S-W aspect) which is big but... you know, the house is tall (2.7 and 2.6 ceilings on each of the floors). No more room to put in trees! And trust me, we've tried... we are only in suburbia (so blocks are not huge) but far, far ahead of the neighbourhood average for trees/shrubs/shade (which admittedly is pretty low).
I think I'm getting a good handle on what is causing the problem (thanks to all who've responded)... still nervous about rectifying.
Posted Monday 13 Dec 2010 @ 5:35:29 am from IP # -
termite
MemberI quite understand; good luck and I hope you crack the code. To put in all that insulation and awnings, but still to have it unbearably hot in summer, is disappointing to say the least. Yes, there is a big problem with the overall design of Sydney's current suburban developments, which bulldoze all greenery and provide no escape from the summer sun.
Here in BrisVegas I'm in an uninsulated single-storey b/v cottage with a metal roof, yet I think I'm not too badly off. Though I don't get sea breezes here, I compensate with a ceiling fan on a low setting all night.
What makes the place is deep shady verandahs front and rear, with fixed awnings over side windows, lots of lawn (only the driveway and a small front path is paved), mature lilly pillys and palms (plus the ubiquitous mango hanging over the fence), and finally, the bars on the windows that allow me to leave them wide open all summer. All those awnings and verandahs act as a big umbrella around the house, which doesn't heat up nearly as much as others in the suburb. It still gets hot and stinking humid, but I don't find it unbearable as long as a fan is in reach. I have quite a few paperweights.When the street trees mature it'll be even better, as I won't have to contend with air heated by the asphalt road surface.
Posted Monday 13 Dec 2010 @ 6:35:00 am from IP # -
matas
Member"the bars on the windows that allow me to leave them wide open all summer"
Termite just wondering if you close the windows on hot days, and just open them when the outside temp drops below inside temp, after sundown (and close in the morning)
or just leave them open permanently ?Posted Monday 13 Dec 2010 @ 7:30:43 am from IP # -
Frateco
Membermatas, living in Brisvegas as well, I can assure you that closing the windows through the day is not a smart idea. Our temperature drop is probably at best 10 degrees but it's the humidity that is unbearable. If the house is closed and locked up, the heat seems to take forever to escape. The fan and breezes keep it bearable when you get home.
Posted Monday 13 Dec 2010 @ 8:21:56 am from IP # -
termite
MemberI leave the windows open all day, all summer, autumn and spring (and much of 'winter') - but there is the exception of when I have guests on a hot day, in which case I shut the place up, isolate the living area as best I can, and put the air conditioning on.
When I am away visiting family in Sydney, I hire a 'cat lady' who feeds the cats, brings in mail and flyers, etc, visiting twice each day. She commented that my place is the coolest of all those she takes care of, when she opens the door in daytime.It is so much less hassle to not have to open and shut the windows all the time. Plus, I avoid the stuffy feeling of a sealed room. This is the way the old Queenslanders were supposed to work, with the addition of an elevated timber floor with a cool, shaded concrete slab beneath it (which I don't have - this place is mid-1960s vintage and lowset, but at least slightly elevated).
Posted Monday 13 Dec 2010 @ 8:25:18 am from IP # -
matas
MemberThanks termite and Frateco for that experience.
I am trying to make my house in Sydney a bit cooler in summer.
It has cathedral ceilings with no roof space and no insulation.
A lot of the windows are fixed, or outward opening casement, and outward opening doors.
Very difficult to screen.
I am gradually adding screens that hinge to allow access to the latch.
Like you I find that the windows that I have screened, are left open permanently in summer.
No bars or grill yet, but I will take that risk.
The house has the long axis east west, and only one room deep. which are pluses.
If I can somehow convert the high north facing fixed windows, to opening, there would be really good cooling cross ventilation at night.
I am now toying with the idea of taking the fixed panes of glass out completely and replace them with screen, just for the summer.
I have just put shade cloth over the north facing windows, so no sun enter the windows in summer.
I also hope to grow a grapevine on the east and west brick walls (luckily no windows on these)Posted Monday 13 Dec 2010 @ 9:04:29 am from IP # -
termite
MemberActually, that was one thing I was going to suggest to cool at home. Is it at all possible to add frames to any north- or west-facing walls (perhaps 30cm clear of the walls themselves), that provide direct shade by way of slatted timber shade screens, or which may hold lightweight vines or climbers? Boston or Virginia creepers (parthenocissus) spring to mind; are not nasty and overbearing like true ivy, and as a bonus are deciduous and colour well in Sydney. Grapevine (non-fruiting vitis vinifera) is similar - and VERY fast-growing as well as being long-lived.
Convenient quote from Wikipedia:
"Virginia creeper can be used as a shading vine for buildings on masonry walls. Because the vine, like its relative Boston ivy, adheres to the surface by disks rather than penetrating roots, it will not harm the masonry but will keep a building cooler by shading the wall surface during the summer, saving money on air conditioning. As with ivy, trying to rip the plant from the wall will damage the surface; but if the plant is first killed, such as by severing the vine from the root, the adhesive pads will eventually deteriorate and release their grip."My Sydney house (also cathedral uninsulated ceilings) had just two awning windows on its eastern wall, despite being in the direct line of fire of sea breezes. About 8 years ago I replaced them with 17 double-glazed panes: 3 fixed and 14 casements (western red cedar frames). It was hugely expensive then (and I still am astounded and annoyed that they used stays that rusted within a year, despite my warning of high-salt air), but the immediate effect was that the entire Easterly now flows through the living area. For your clerestory windows, I would suggest possibly louvres (max 90cm wide) in 'comfort plus' 6mm glass or shallow wide hopper windows, perhaps double-glazed. See if you can hang shady louvred awnings off the edge of your eaves - stopping the light hitting the wall is so much more effective than just shading the interior.
Posted Monday 13 Dec 2010 @ 10:36:46 am from IP # -
matas
Membertermite, I like your climbing plant ideas.
Plants also seem to cool by transpiring a lot of moisture, as well as their shade.
Might be a bit more difficult for cool at home to get them up to the second storey.
And they do have few maintenance issues.
But a brick wall covered in a creeper can look great.
And I am suprised they are not used more.I was thinking of getting custom sash windows made to to replace the fixed, as you did.
But I have heard that the cost for this is high, as you also said.
At the moment I am toying with the idea of trying to make a few myself.
I do have most of the tools (triton bench, router etc) and wood.
But the last time I tried a mortise and tenon joint was at school, and wasn't too good.When I said I put shadecloth over the windows, I did mean on the outside.
I have a skillion roof, and the celestory windows are all along the top of the northern wall.
So I have draped the shadecloth over all of them, hanging from the roof ridge.
There is plenty of light in summer.
And the shade is removed at in autumn.
In general measures like this, that are only put in place for the summer, or winter can be quite effective, if you can be bothered making the change each year.Like cool at home, I do have an issue with a lower roof being directly below some of my celestorey windows.
The roof would radiate a lot of heat, so opening the windows may not be as effective as I originally thought, if the wind is from the north.
It is hard to explain, so I might take some photos and upload them somewhere.Posted Monday 13 Dec 2010 @ 10:43:35 pm from IP # -
Buzzman
MemberSusan/coolathome
As you say the block is a smaller subruban block, I'm guessing you have the standard 1.5-2.0m offset from exterior wall to boundary in places, which can make for adding any of the mentioned solutions a bit awkward, but here's a cost-effective suggestion from an old builder....
On the western side, or northern side (or both) mount a frame that can take a shadecloth roller blind over the entire wall.
Couple of thoughts:
- for those parts of the house where the downstairs is larger than the upstairs, and you have skillion or hipped roofs below the vertical upper walls, attaqche the frame to the exterior cladding but return the shadecloth below the frame and anchor it to the wall. This will prevent light and heat reflecting back upwards and inside the shadecloth barrier.- for those parts of the house where it is two storey from ground to upper-level eave soffit, build a frame using 4 X 4 timber posts or 3 X 3 steel posts mounted onto 400 X 400 x 300 deep pad footings. Post spacing 3m. Approx 300-450mm off the wall.
Tie the posts together with 100 X 50 timber or 75 X 50 steel rails, bolted through, again at 3m spacings.
Anchor the top of the posts to the wall using 75 X 50 steel tube welded onto 75mm wide 10mm thick plate. Properly treat all steel prior to building (hot dip galv or anti-rust sealer, undercoat and topcoat.
Attach DIY shadecloth blinds (staple the cloth to 50 X 25 DAR HWD) bolt them at the top and attach to tensioning ropes or ties at bottom. Need not reach all the way to the ground.
Designed to shade entire wall. Use max density shadecloth. Roll-up or remove blinds in winter.
Using wires at lesser horizontal spacings would facilitate growth of a grapevine as previously suggested. Be warned, if you decide to use such a frame for a grapevine, it might pay to have more fixings in the brackets at the top, and possibly even do the same thing at the mid point up the wall to spread the load created when wind howls around. Brick veneer is not renowned for its ability to resist windloads.
A competant handyman could achieve the above.
Posted Tuesday 14 Dec 2010 @ 5:58:54 am from IP # -
andyfurlong
MemberHi..just discovered this forum...very interesting for me as I pretty much want to do very similar to "cool at home" regarding venting the top floor and in particular the bedrooms of my brisbane replica queenslander. I am in a similar situation regarding poor brezes into the house and a lack of eaves. I found Jaymak's post above the most relevant to this. One of the things I dont fancy though is installing a fan in each bedroom, and the living space, each connected to its own roof vent. Also I wonder how bad would the noise be in the bedrooms? Any feedback on thi would be appreciated. I do have ducted air con which feeds my upstairs living space as zone 1 and the 3 bedrooms as zone 2. I thought I could tap into the common ducting (which sits in the roof space) that feeds the bedrooms and insert a new duct feeding to a new fan on the roof. So with this the plan would be to leave the a/c off and switch this fan on, pulling fresh external air through the bedroom windows, up and out the individual bedrooms a/c ducts (i.e. the opposite way to which the a/c air would normally flow if on) and out the roof via this new fan. This way I can use the existing a/c ducting into the bedrooms as part of my venting system. Any comments on the viability of this, how likley it is to work etc? What sort of sized fan would I require given I'm stuck with the ceiling vent and a/c ducting size I've got, and again would it introduce a noise problem to the bedrooms?
By the way my insulated roof space gets very hot on summer days due to lack of ventilation so I am already planning on installing a separate temperature controlled fan in the roof space (rather than whirly bird) and putting some louvres in the gabled ends (front and back). That should reduce the roof space temp nicely and hopefully our air conditioning usage and power bills!
Posted Saturday 18 Dec 2010 @ 3:07:04 am from IP # -
Johnnojack
MemberAnyone considering installing exhaust fans to remove heat from rooms to ceiling space should make sure each one has a Draft Stopper or similar fitted. If not on a hot day windy day suction can drag superheated air from the roof space down through the fan heating the house rapidly.
Posted Sunday 2 Jan 2011 @ 6:39:09 am from IP # -
If the wall heating and other sources of rising heat can be eliminated and appropriate venting is in use could the main heat load be coming from the roof ?. Replacing a roof is expensive but if it needed to be done or an additional skin could be placed over the top al la Glenn Murcutt and/or use a cool paint eg; http://www.solar-cool.com.au/roof-membrane.html
I expect this is at first a very expensive option but if you could measure the thermal environment and identify the roof as the main source then it is the answer even if it is rejected by cost.
I am also in Sydney and have two Thermal Loggers that can show the temperature over time. Let me know "Cool at Home" if you would like to use them to determine the real source of heat load. I expect if you can see the temp rise when the roof is in the sun (or shortly there after) that this could be the cause.
Posted Wednesday 5 Jan 2011 @ 7:19:51 am from IP #
