Someone have any solution to reduce the heat in a 2 story house ?

[JesseFrank]

Insulating the roof makes gives little result, more important is to insulate the ceiling.

I have a roof with vented ridges with reflective foil with about 1" space under the tiles and 6" fiber wool on the ceiling. I have a 17 ° degree roof, which is actually unfavorable for a hot climate, yet even now with 40° degrees in the shadow I'm running the fan at the lowest speed all day and the temperature inside is comfortable inside the house. I have opposite windows open which gives a breeze throughout the house. I have aircon in every room, so it isn't a a case of not having another choice.

Important is that you get the loft area ventilated to reduce the temperature there, then make sure the heat from the loft doesn't enter through the ceiling.

Another reason why it makes more sense to insulate the ceiling is that it works two ways. You also don't need to cool down the area above your ceiling.

Edited May 31, 2014 by JesseFrank

[KunMatt]

Keeping the house cool was one of the most important factors when I designed our house in an Isaan village. I have 20cm Q-Cons for the whole house, 15cm ceiling insulation for the whole house, 3m high ceilings, ceiling extractor fans in several rooms, roof vents, I built the house so that the sun is not shining on the wide side of the rooms we are in, a 5 metre deep veranda on the south side of the house, trees for shade and so on.

With no aircons or fans running, our house has a maximum temperature inside of about 30 to 31°C on the hottest of days of 40+°C, but on the same night no less than 29°C. If it is 28°C outside at night then no amount of airflow is going to reduce the temperature inside of your house less than this, in fact I am always 1°C more than the outside temperature at night, even when running all extractor fans and windows opened.

The only way to cool below the ambient outdoor temperature is with aircons, or you can use fans to make it feel colder, or you can acclimatise your body to this temperature.

Insulating your ceilings will make the aircons more efficient too, but I'd probably go with the cheaper thinner insulation if I did it again.

[japsportscarmad]

I insulated the cieling with 6" Fiberglass staycool and it is by far the best investment i made in my house. Before my air always needed fans and could never get the house to 28 on a hot day. Now it can easily get down to 28 also my tiles are cold when you walk on them. If i leave for a few hours with the ac off the house is still cooler then outside where before it would be hotter.

Stay cools very good.

[honoluludave]

Ceiling fans. While it does not cool off the house itself. It keeps the air moving inside. Which helps make the inside temp lower.

[gk10002000]

My fellow engineering friend here in the USA installed blinds in the windows that he could raise and lower with a remote control. Nothing new about that except he installed the blinds on the OUTSIDE of the house. obviously it is better to reflect the sunlight before it makes its way through the window and into the house. the installation was trivial. As an aerospace engineer, I appreciated his approach and to put the heat shield on the outside of the house.

[klikster]

We have large windows with 6mm uv glass. I don't like the film so just added reflective 'blackout' layers to our drapes. The difference is significant -- more than I ever expected.

Also have an off-white roof with oversize gable vents, one of which has a 24" exhaust fan. 3.8 m ceilings help as well.

Also have soffit vents.

[klikster]

Ceiling fans. While it does not cool off the house itself. It keeps the air moving inside. Which helps make the inside temp lower.

I will respectfully disagree if you are talking about the usual large ceiling fans. Because heat rises, it creates a hot air zone at the ceiling. Ceiling fans re-mix the hot air into the room.

I have been told that is why good air-con installers position the units a short distance below the ceiling.

[honoluludave]

Ceiling fans. While it does not cool off the house itself. It keeps the air moving inside. Which helps make the inside temp lower.

I will respectfully disagree if you are talking about the usual large ceiling fans. Because heat rises, it creates a hot air zone at the ceiling. Ceiling fans re-mix the hot air into the room.

I have been told that is why good air-con installers position the units a short distance below the ceiling.

Klikster,

It ok to disagree with me. I have ceiling fans in every room and am pleased with the results. No need for air con except in the bedrooms. By keeping the air moving there is no hot air zone at the ceiling. Turn the fans off and the room will heat up very quickly.

[KunMatt]

Ceiling fans. While it does not cool off the house itself. It keeps the air moving inside. Which helps make the inside temp lower.

I will respectfully disagree if you are talking about the usual large ceiling fans. Because heat rises, it creates a hot air zone at the ceiling. Ceiling fans re-mix the hot air into the room.

I have been told that is why good air-con installers position the units a short distance below the ceiling.

Klikster,

It ok to disagree with me. I have ceiling fans in every room and am pleased with the results. No need for air con except in the bedrooms. By keeping the air moving there is no hot air zone at the ceiling. Turn the fans off and the room will heat up very quickly.

The room doesn't actually heat up but it feels like it does without the air moving around you.

[IsaanAndy]

My 2 story house in Roi Et is cool, use heat reflecting paint, open the doors to let air flow through, I have 3 sets of doubles downstairs and use top quality marble flooring.

I use wall mounted and large ceiling fans downstairs and only use air-con at night in the 3 bedrooms to sleep, usual electric bill is around 2300 THB for this time of year.

[klikster]

Ceiling fans (as do all axial-flow fans) move air in a "donut-shaped" pattern roughly perpendicular to the blades. That's what breaks up the warm air zone at the ceiling. A better result is using pedestal fans or fans mounted on walls below the zone of warm air at ceiling level.

If you want to warm a room during the cold nights of winter, aim a fan at the ceiling. You will feel colder if your body is in the air stream, but the room will be warmer because the warm air at the ceiling gets mixed with cooler air.

The result of feeling cooler while air is blowing across your body is a result of disturbing the "boundary-layer" next to your skin.

Another way to cool a room is using very low volume fan in the ceiling that exhausts the warm air zone into the attic.

[SilverBeast]

Moving air with fans also causes the air to make more contact with the floor which is typically cooler. This cools the air and thus cools the room.

Putting the Shades on the outside is certainly smart indeed. Prevent that heat from getting in at all. Personally I'd go with the best insulation that could be found. Has anyone tested Geothermal cooling? Take a 5000 liter tank for example and bury it six feet below the ground. Run a pipe into it and out of it to the house where there would be a heat exchanger. Something as simply as a used car radiator. Having Radiators in the ground too would also help transfer the heat into the ground. Essentially all you can do with heat is move it. With an air conditioner you take the heat and move it outside. That is how they work. With Geothermal cooling you take the heat from the house and put it into the 5000 liter tank buried in the ground. The tank and rads you have buried in the ground then transfer the heat into the ground.

One simple small pump similar to something in a fish tank would be all it takes to move the water around and help cool the house. You would also be able to just use water in the tanks. Thailand is at 0 risk of freezing which would require glycol or some other type of antifreeze which is getting used in systems in Canada.

You could augment this system with an air conditioner also. That could help cool the water in the tank even further if necessary.

[klikster]

"Moving air with fans also causes the air to make more contact with the floor which is typically cooler."

I'm assuming you are talking about large ceiling fans. If so, I'm with you up to this point, but --

"This cools the air and thus cools the room."

Any air that gets temporarily cooled by contact with the floor is then mixed with the warmer air at the ceiling and the result is as described above. Difficult to get something for nothing.

As for geothermal, you seem to have conceptualized a system that is impossible to create -- except in theory. A prime example of wishful thinking is --

"One simple small pump similar to something in a fish tank would be all it takes to move the water around and help cool the house."

[Dakling]

My guess is the upstairs walls are the culprit, put your hand on the wall if it is noticeably warm then you are radiating heat into the upstairs from the walls and no amount of additional ceiling/roof insulation will help. Unfortunately most of the Thai 2 story houses have no insulation provision for the walls and on a 2 story house with limited overhangs these walls get a full blast of sunlight for most of the day. Getting the sun off the walls is about the only way to combat this once the house is already built. I am starting to see more houses with louvered latices covering wall area and this might be a good solution for your predicament.