I recently bought a 2 storey corner lot house with windows and sliding doors facing east. The house is still empty as I'm waiting for design from ID, but I've tried sleeping on the 2nd floor a few times and found it to be unbearably hot. I bought a cheap temp and humidity sensor and placed it on the 2nd floor, and found that the 2nd floor temperature fluctuate between 32c and 35c. My house already has radiant barrier installed underneath the roof tiles. Recently I have also installed solar panels on the roof, and found that it helped to reduce the 2nd floor temperature by 1-2c (it now fluctuate between 30c and 33c).

Now I'm considering to add insulation on the attic, because I've read somewhere that for house in hot climate, most of the heat enters through the roof, which explains why adding solar panels helped to reduce the temperature a bit since it shades the roof from sun. The idea is to minimize heat transfer from attic to 2nd floor through the ceiling by adding thick insulation. So far I received quotation from TCL to add 100mm blow in cellulose on top of 2nd floor plaster ceiling for rm4 psf.

Basically my goal is to reduce my house temp as much as possible using passive cooling, so that when I add aircond later, they don't have to work that hard, thus saving more money. I've heard about turbine ventilators, which are common here, but from what I understand, it doesn't play well with aircond, since it will actually pull cold air out as well, so your aircond has to work harder to keep the room cold.

Has anyone done something similar before? Does it actually help to reduce house temp? Is the price of rm4 psf about right?

Interesting. Since the solar ventilator will vent air out, how does air enter the roof to replace the vented air? AFAIK roofs in Malaysia don't have soffit vents for air intake.

I'm worried if I install solar ventilator without soffit vents, it will end up pulling air from 2nd floor through small cracks in ceiling, since the CFM of the solar ventilator is pretty high. I guess I need to add soffit vents and air seal the ceiling before proceeding.

Did you do air sealing before putting the insulation? Or TCL did it for you? I read online that insulation is only effective if you air seal cracks and holes as much as possible (especially around ceiling down lights). Otherwise heat transfer will still happen via convection, especially if there is difference in air pressure.

So far my plan is to do all of the following:
- Add temp/humidity sensor in every rooms (including attic) to measure difference before and after
- Air seal the 2nd floor ceiling
- Add cellulose insulation
- Add ventilation in attic to promote airflow in attic ONLY (I see people typically add vent in 2nd floor ceiling, but that nullifies benefit of insulation and air sealing)

Oh nice, I was going to open another topic regarding fresh air. I'm considering it as well, but problem is HVAC knowledge is so limited in Malaysia so I don't know who to ask haha. If you don't mind answering:

1. Are you using the fresh air or ERV series?
2. Is it expensive to install? Airegard provide installation service or you find contractor yourself?
3. Is it expensive to maintain? I'm assuming you can't just hire any aircond maintenance guy.