Cooling a house will require all the strategies outlined by gbr in his shout.
Insulation is needed, but even the best insulation will not work efficiently if the hot air is trapped in the area between the roof and the ceiling. Hot air rises and will eventually get trapped in the peak of the roof. Unfortunately, the quatro aguas design of most houses prevent the placement of vents in the peak of the roof, where it is most needed. Most vents are placed near the gutters; this is fine but there is a need to exhaust the hot air at the peak.
This is where a tornado fan comes in handy. Installed at the peak of the house, it exhausts the hot air where it collects.
As for costs, some of the other members may have information. Retrofitting insulation may be difficult, unless there is a supplier of blown in insulation in our country. Blowing insulation to rest on top of the ceiling may be the easiest way to put in insulation. Easier than laying a mat of fiberglass or foam. BTW, the best way to lay foam, in my opinion, is for the reflective surface to face the top toward the roof.
Re: Cooling a house
Cooling a house can be done either by employing passive or active solutions. Passive( static) solutions are where heat is prevented from coming in in the first place. Active solutions require mechanical devices like blowers, electric fans or airconditioning, etc.
Passive solutions include using materials in the building envelope with high insulating values like PIR (pre-insulated roof) and foam or glass insulation for roof, composite walls (styro with wire mesh finished with mortar or palitada) or even CHB walls finished with perlite granules mixed with mortar. This also includes natural ventilation meaning large open windows facing the prevailing wind directions (amihan and habagat) and an opposite window to exhaust this air (cross ventilation). Cooling a house passively can only approach ambient temperature. If one wants to go below this then mechanical ways should be employed like using airconditioners.
Going back on topic:
Cooling a house by placing foam under the roof is very effective. 2DIY4 is correct when he said that the foil backing should be toward the roofing material. This is to reflect back the radiation coming from the roof. Most installers do it the other way around (foil facing the ceiling). While this might be good to protect the insulation against birds or insects, I believe the foil is not strong or protective enough. Foil should face the roof to maximize the benefit of insulation.
Heat gathered within the ceiling space should be discharged to the atmosphere to cool this space. If the ceiling space is hot, this heat will heat up the ceiling and eventually be felt by the occupants in the house. A dormer or other means of exhausting this hot air is very welcome to cool a house.
Re: Cooling a house
Tnx 2diy4 and tatoski. I think i will try the tornado fan, it might work for my needs, and from what i hear it's relatively cheap. Galing ng shoutbox!
Re: Cooling a house
Hi gbr,
I am interested in installing this ( tornado fan ). Can you share your experience, where to purchase, etc. Problem is my roof is of victorian design. Installing tornado fan could affect looks. What about strong typhoons?
Re: Cooling a house
does any one know of anyone locally that has tried using passive airconditioning? http://www.thefarm.org/charities/i4at/lib2/aircool.htm
I know it would work when the sun is out but what about when it gets dark?
Re: Cooling a house
I didn't use a steel framed roof for exactly those reasons (concrete deck instead - which also gives advantage for future upward extension). But my architect has said that one of the major roofing manufacturers here in the PI, sells a crown piece (sorry forgot the correct term - I mean the piece that joins the two sides of the roof at the top), which comes with built in vents. These vents are a mesh to prevent birds, etc. getting into the roof space. Again most contractors dont install them due to added expense (or ignorance)
To maximise (passive) cooling I have also included the following features;
The sala, dining room kitchen area, are connected to an atrium, which has screened vents built into the roof to allow hot air to escape.
Trees plants will be grown around the house to create a shade.
All windows have thick blinds.
All bedroom windows upstairs have double glazed windows
The bedrooms TV room and office have AC only, these rooms have doors to keep the cool air in and warm air out.
If I were to build another house I would seriously consider a passive cooling system. This would be a series of 6 inch pvc pipes laid underground, with vents to draw in air somewhere in the garden. The air in these pipes would be cooled by being suck 2+ metres below ground and the cool air would be vented into the house. A further idea possibly incorporating the above system would include a cistern built under the house.
If your house is too hot, consider vents on the peak of the roof or install a fan with thermostat to pull hot air out, as high as possible, on the end wall. Upto 40% of heat come through widows exposed to direct sunlight, install thick roll up blinds.
Re: Cooling a house
Does insulation help in soundproofing? Installing styro boards sa external wall bago magpalitada? . . .
Posted via PHM Mobile
