Cooling my hot house.......

Hi everyone.
OK, so, I and my lovely other half have been living in our house for just over a year now, and we have a problem. It's just too damn hot! I'll try to describe it as best as I can, and hopefully someone will have some advice for us........

Single skin brick lowset. Colourbond roof. 1 Whirlybird. Cathedral ceiling in family room (approx 4 inches between ceiling and roof. Rest of the loft has thermosealed R3.0 batts. 1 x split system aircon (Fujitsu) in lounge, not sure of power, and split system inverter in master bedroom. Again, not sure of power, but it does stink when we use it!

Basically, all 3 bedrooms are on the East side, the lounge and dining room on the West. Kitchen and entrance hall is to the South, and bathroom, toilet and laundry are the North. They all meet at the family room in the middle.

The aircons are great at cooling the relevant areas, but as soon as you turn them off, the temp starts rising. On average, if its 28 odd outside, it's 32 ish inside. Now, we have a nice breeze that blows most of the time, but it blows onto the N/E corner of the house, and the only windows it comes through are the toilet and bathroom due to the 2 storey house next door, and therefore, it doesn't really do much for the inside temps.

We really don't want to have the aircon running all day every day during summer, so does anyone have any ideas as to a reletively simple (and therefore cheap!) way of a bit of additional cooling. The other half really doesn't like fans (some kind of childhood phobia), so is there some sort of simple draw through equipment, more effective than the whirlybird, to pull more heat out of the roof space, as I'm sure a lot of the heat comes in through the family room. We have shade on the windows from the eaves and don't open the blinds on most windows, but we're really struggling!

Any advice would be most appreciated.......

Thanks very much

Quote:

---

Originally Posted by anawanahuanana

Any advice would be most appreciated.......

---

Move to Melbourne
:wink:

Ya just beat me Gumby :D

As they say

Great minds think alike :2tsup:

Only one whirlybird with a colourbond roof? My guess would be that the roof cavity is heating up and forcing hot air down through the ceiling and wall cavities.

Best fix is as mentioned, move the roof to MLB, or, failing that, try a few more whirlybirds. Not sure how many as they vary by type and roof area to vent.

Sounds like you have outdoor blinds, but if you don't - get some.

A colleague (of my Father's) in NZ has been trying to convince people of the benefits of pumping air from one area of the house to the other. Not fans (well, yes fans), but used instead in trunking to pump air from the attic into the house in winter, and from under the house in summer. The air down there is much cooler, so why not use it?

He's converted a few houses to this system, and apparently it is very energy efficient (ie a lot more cooling / heating effect than the power used by the fans).

So there you go, perhaps a bit of a solution from left field. Good luck!

Quote:

---

Originally Posted by echnidna

Great minds think alike :2tsup:

---

that's easy for you to say :)

Y'know, if the inside temp of your house is exceeding the air temp outside, the cheapest thing you can do to lower the temp is to open up the house and let the outside air in.

What sort of windows have you got? I'd be looking for the window to create a large hole as high up in the room as I could get it (hot air rises) and create as much cross-flow as I could get (openings on both sides of the house)

I love cathederal ceilings, but they are a challenge to insulate. What you do about that probably depends on whose house it is :) Are there windows up there?

If the house doesn't pick up enough breeze, you could pump it in with an evap cooler - the evap side of it won't work in high humidity, but the fan will move a lot of air for not much energy (money).

We had a townhouse that was locked up all day and used to get stinking hot inside (cough... Cathederal ceilings) We added a decent evap to the roof with just 2 outlets, and when we got home we'd switch it on and leave the front door open. By the time we parked the car and fussed with the withering garden the house was at or near outside temperature.

woodbe

With the whirly birds you want to make sure you have vents in the eaves to allow outside air to enter the roof space. I think you would need at least 2 to 3 to keep the roof cool

A friend of mine built a thermal chimney in his house when he was living in Bourke. Its just a big rectangular tube made from sheet metal by an air conditioning duct builder going up from the ceiling through the roof and projecting out about 1200mm with a gable top on it to keep the rain out with the gable ends open.

He painted the outside black to get the themal going and put a airconditioning grille on the inside and in the winter he just covered the grill with a piece of board to stop the thermal.

What he did was open all the windows and doors and it would suck air through the house and keep it cooler.

Also, if the bedroom A/C is smelly, pull the covers off and wash everything in a disinfectant cleaner. See if you can get hold of a new air filter for it, and make sure that the condensation drain is not blocked (should drain outside freely)

Quote:

---

Originally Posted by Barry_White

thermal chimney

---

Great idea. That's what the Spanish and Mexicans do with their Hacienda's - those towers are not just there for good looks!

woodbe.

Thanks to everyuone for their suggestions (except perhaps the MEL ones! Don't want to have to pay for aircon AND heating.........!)
I was thinking along the lines of the thermal chimney idea, or some kind of ducting that ran through the roofspace from the corner where the wind hits the house, to out the other side, with several vents in the ceiling at strategic points joined onto this. Do you think this sounds plausible? Has anyone done this kind of thing?

Thanks again

Quote:

---

Originally Posted by Stuart.

Sounds like you have outdoor blinds, but if you don't - get some.

A colleague (of my Father's) in NZ has been trying to convince people of the benefits of pumping air from one area of the house to the other. Not fans (well, yes fans), but used instead in trunking to pump air from the attic into the house in winter, and from under the house in summer. The air down there is much cooler, so why not use it?

He's converted a few houses to this system, and apparently it is very energy efficient (ie a lot more cooling / heating effect than the power used by the fans).

So there you go, perhaps a bit of a solution from left field. Good luck!

---

have you been near one of these to vouch for the benefits? it sounds bloody perfect for what i need. we have a good ac in the lounge but its too much trouble getting it to cool the bedrooms. something like this sounds so simple yet so perfect. i also know the temp under our house is always very cool.

Quote:

---

Originally Posted by vlv8vic

have you been near one of these to vouch for the benefits? it sounds bloody perfect for what i need. we have a good ac in the lounge but its too much trouble getting it to cool the bedrooms. something like this sounds so simple yet so perfect. i also know the temp under our house is always very cool.

---

Sounds similar to Cardiffair, and I'll vouch for the benefits of that. A friend has it and I was very surprised when I found out his house wasn't air conditioned.

One of the downsides of batts in summer is that they act as a heatsink.

If you have access you could consider replacing them with double sided reflective sarking or foil concertina batts.

http://www.concertinafoilbatts.com/

As for rotary ventilators, I use three. There was a bit of improvement with the second and no noticeable change with the third - on a pitched tile roof with no sarking.

Quote:

---

Originally Posted by Gumby

Move to Melbourne
:wink:

---

This advice isn't as silly as it sounds. As someone who lives and works in the Brissie heat, my suggestion is turn the AC on, or move to melbourne.

We live in a sub tropical climate, and humidity ignores insulation. Our solution: ducted air and insulation and learn to accept that, just as Melbourneans have to spend to heat their houses in winter, we have to cool ours in summer.

In a nutshell: AC.:cool:

Melbourne is not for me. I just spent the last 7 years living in Scotland, so I've done my fair share of cold winters!

However, I did a bit more feeling around today whilst the sun shone brightly. All of the internal sides on the outside walls, if that makes any sense, are cool to the touch when the house is roasting. The vast majority of the ceilings are also cool, no doubt owing to our R3.0 insulation. However, the heat is not only coming in through the cathedral ceiling in the family room, but also through the ceiling just inside the perimeter of the house. Like the guys that installed the insulation didn't go all the way to the edges.

So, next chance I get, I'm gonna have to shoehorn myself around my roofspace to check all the edges to see if I can make then a bit better. I'm also going to add a whirlybird at the top of the roof directly by the cathedral ceiling to try and remove some of the heat in that area. To finish it off, I'll buy me some pink batts or something, and secure these to the "walls" of the cathedral ceiling in the loft, if you know what I mean. Obviously in the loft there are 3 walls which form the cathedral, and there is some amount of heat coming in through those.

Hopefully, this may be enought, along with the shadecloth outside the bedroom sliding door, to take the edge off it. If not, I'll have to investigate the more advanced methods as advised above.

I realise that living in QLD is hot in the summer, and we do use the aircon when we're in and its too much to bear, but I'd like to get the house to the stage where we didn't walk through the door after being out for a couple of hours and have to sprint to the aircon controller before dehydration sets in........:2tsup:

Thanks again guys

dude ad a feww whirly birds they really make a big difference.

thing is have all the guards in place like wirley birds, insulation, good air circulation and vetilation and then your air con wont run anywhere near as hard to cool that same space.

Also Tin roofs and even tiles roof cavity hold #### loads of heat. As the other said get vents in your eaves otherwise the wirley birds wont do ####!!!!!

I was in my roof a few weeks back around lunch time fixing the tv anntenna and runing new cables for it. I had a thermometer with me and it got up as hgh at 63 celcious. I could onlt spend 10 mins up there and i was dead almost because it was so hot and sticky. nex time ill wait until winter to do any renovations.

Your house alignment sux but oh well.....

Silver foil reflective batts or glass fibre roofing blanket or something like Aircell under the Colorbond in the loft would be very useful especially if there is no sarking.

And it sounds like you don't have anything insulation wise between the roof and ceiling in the cathedral section........which'd be the first thing I'd fix if you don't. Pull the roof and go for those silver foil batts (double or triple layer) again.

There are also heat reflective paints available.

Insulation in the walls would be nice but a mongrel to do when the walls are lined!!

For an insulation overview try www.insulationsuperstore.com.au

Reverse cycle AC is a crutch for unimaginative people with no social concience who are happy to eke out an existence in poorly designed and built boxes. But what the heck........it's only an opinion.

I tend to agree with you regarding aircon, which is why I'm trying to sort it out in a more energy efficient manner. Can't see the point in burning up even more fossil fuels to cool my house. Seems ironic at best.

Anyway, the gap between the cathedral ceiling and the roof is only a few inches, so as mentioned earlier, I guess I'd have to pull the roof off there to put something in. Now, this may be easy to do, but having had no experience of a metal roof in the past, sounds likle a big job to me! I'd be happy to be corrected though.....

As for vents in the eaves, I'm intending on putting some of these in on my next days off. Is it simply a matter of the more the better, or can there be too much of a good thing?

The walls I intend to insulate are not lined as such. If you imaging looking in my loft, there is what appears to be a 3 sided room with no door, if you like. As these "walls" form the walls that are in the upper part of the family room, the loft sides consist of just the studs. So, I'm going to throw some batts up agains this on the roofspace side and gyprock over them to make an insulated cavity. This seems to be where the majority of the heat is coming in.

It's such a sod though. Sitting in the garden you get a fantastic, almost constant, breeze. Just can't seem to get it in the house........

Quote:

---

Originally Posted by Gumby

Move to Melbourne
:wink:

---

But the anti depressants would cost more than the aircon :doh:

Don't know if you have these on the east coast. These may assist but you will need vents in the eaves to create flow through.

http://www.combinedmetalind.com.au/Brochure/eventr.pdf

I have a couple on my roof. They are very neat and unobtrusive on the ridge line.

When I'm near one of the eaves vent I can feel the suction draft being created.

It's worth doing your research on insulation.

Fibreglass or polyester batts have been criticised as acting as heat sinks and some folk advocate double sided foil or foil concertina batts stapled between the rafters or studs. Most downward heat passage is radiant and is best dealt with using reflective foil.