Cooling down a house in tropical climate
 

I've a long term project to implement over the next two years, that is to make my house more ecologically compliant and energy efficient.

I live in a tropical country (Philippines) which has only two seasons (very hot and humid and extremely rainy non-stop for weeks at a time) so temperate climate methods do not work all the time here.

I'm planning to

-repaint the metal roof in white
-repaint the interior and exterior with newer stuff (paint keeps on bubbling and peeling)
-replace the windows with bigger ones to bring in more light and also have the new ones tinted
-and a lot more you guys can suggest

Bigger windows will bring in more heat when you don't want it and also windows have terrible insulating value so they are a detriment at night with the cold on cold nights and on hot days too much windows and you will be baking in your house and need more cooling.

Shade the house from direct sun, but not from airflow as much as possible.

Thermal mass works in both directions.

If you have a source of cool water around you, start a siphon flow through a radiator with a fan attached to it. It's free A/C. Keep a pan under it, it will attract moisture.

Save a lot of the rain water if you can, and keep it spraying on to the roof during the hot season. The high humidity makes it less effective, but evaporative cooling still works.

Depending on the type of house you have, instead of using the fan, you can radiate the cool from the water by installing tubing under the floor boards just like hydronic heater units do, although it's less effective as an overall cooling system.

Of course, you know that it's always cooler underground than it is on the surface. That applies when you build a hill, too. If you can waterproof part of your walls and build a 'hill' against the house, it will help.

Instead of tinning your roof, look at something like a green roof. It will actually make the water spray more useful and effective, too.

Other than that stuff, if we have more details abotu your situation, you might be able to get a few more suggestions.

Wow thanks for the quick replies.

Never thought of the drawbacks of those windows. Ill guess Ill just replace the existing ones with some sliding

glass with screens..and get the tinted ones and maybe add additional tint on it and use those thermal blinds

instead of the drapes I'm using at the moment on all the windows.

It's quite hard to dig below ground since the place gets a huge amount of rainfall and the ground is made up of

adobe..had to use a jackhammer just to dig some pillars for the garage.

Waterproofing has always been a problem for me, the paint on the interior keeps on bubbling no matter if i scrape

and reapply paint...and that happens even on the second floor of the house.

I already have a rainfall collector, all the rain collected in the roof goes to the roof gutters then gets

channeled down a pipe which I can tap with a hose to fill some barrels and buckets.

Here are some pics of the house. The satellite pics shows where the sun is coming from in the morning. (from below

the picture) the front part of the house faces SSE.

http://i43.photobucket.com/albums/e3...ps558d2ea3.jpg

http://i43.photobucket.com/albums/e3...psd7e28529.jpg

http://i43.photobucket.com/albums/e3...Picture066.jpg

http://i43.photobucket.com/albums/e3...ps0c52360b.jpg

the whole side of the house absorbs the brunt of the sun in the noon till the sun sets...its the hottest side of the house...you could bake in that heat LOL. It doesnt show but at afternoon that whole side is covered with direct sunlight from top to bottom.

http://i43.photobucket.com/albums/e3...pse8a24f7e.jpg

Can you hang trellis away from the walls of your home? Maybe something like Kudzu [ick] kept in check will grow where you are and keep the sun off the walls.

How about extending the roof and/or adding awnings to the windows for more shade?

White paint and white roof coverings come to mind, along with the window shades Piwoslaw mentioned.
Something i have always wanted to do is this:
In ground cooling pipes, to cool water to be used in a radiating cooling system,driven by a solar powered water pump.
Also having PV panels on the roof and selected walls would cut down on the houses heat absorption.

I see that you don't have room to plant tall trees nor to do lots of earthwork for ground loops.

Close to the equator the sun will mostly be hitting the roof, so +1 on the PV panels. If that is too expensive, build a second roof on top of you roof, raised 10-20 cm, like an umbrella. It will shade and allow ventilation of the hot air already trapped.

Also, do you have an attic, or is the roof directly above the upper floor ceiling? Any kind of insulation will reduce heat gain from above.

Another idea is to make a ventilation heat exchanger that will allow you to replace stale with fresh air without losing/gaining too much heat, and reduce humidity a bit. Your house would have to be tightened up, but this is also the case if you have any kind of air conditioning.

As for A/C (I saw that you have a unit), maybe hack it a bit? Use a larger condenser (the hot side) and place it in the shade.

I love the white roof paint idea!

Used to have a bamboo trellis in the front but wood rot/moisture softened it and typhoon winds (10-16 hurricanes a year) knock down anything not built out of concrete...maybe a concrete one will last better but those are kinda expensive.

I've always dreamed of putting on PV panels except I have to find an affordable supplier that are windproof and sun-resistant...my neighbors who used polycarbonate sheets/panels got theirs cracked in just 2 years. Even car paint fades in a year due to the conditions here.

There is a space but there's nothing there. Just the I-beams holding the bolted down metal roof sheets on top and a gypsum ceiling. Distance from ceiling to the roof are 6 feet to just a couple of feet in some areas...so far, the gypsum has been termite resistant but fails as soon as moisture seeps through the roof.

I think your insulation idea will work because in the 2nd floor in high noon, when you raise your hand above your head, the temperature is wayyy hotter than on eye level.

on the ground floor, there is a gypsum ceiling about 1 foot from the concrete top.The ground floor is a lot cooler than the second floor (obviously)

I'd love to do ground loops but like you guys pointed out..no space...yet

I am looking at that heat exchanger thread of yours and I am very interested in it. Once I replace the current AC with a more efficient screw type one, I could do that with the old one.

Man, i love this forum!

PS. Planning to put up a garage roof for the car, it can't take any more punishment from the desert-like sun. I think the additional shade will help cool down the side of the house.

By the way, am looking at these rolls of insulation from home depot. They're foil with foam in the middle. Do you think these would help?

http://i00.i.aliimg.com/photo/v1/271..._Fire_Foam.jpg

You install them above/behind the gypsum ceiling or install them behind the metal roof sheets? Which would be more efficient?

the ecorenovator in me wants to insulate both the roof and the ceiling with it hahaha

http://www.plasterandinsulation.com/...ionforroof.jpg

Cant use any cellulose/wood-based material..moisture and termites will kill it instantly.

I agree with Piwoslaw that insulating the roof from the second floor would be a good thing to do. The sun will heat your metal roof which then radiates an enormous amount of heat onto your gypsumboard ceiling.

Do you have access to your 'attic', can you get us a picture?

A fairly easy and cheap way to isolate would be to cover the top of the ceiling with EPS plates. Just put them on the top of the ceiling and cover the entire atticfloor. You can add another layer later. This will isolate your second floor from the hot air in the attic.
Right on top of that you can lay the insulationfoam you found, with the aluminium to the top. That way the aluminium radiates heat away from the floor.

The first thing I'd do though is get those foam/aluminium rolls and hang them underneath the metal roof with the aluminium facing upwards.

How closed is your attic? Is it windy in there during a hurricane?

Anyone ever tried putting ground loops down into the ground like through a basement floor?

The attic is sealed, I haven't built a trap door yet but I will have to so I can install the insulation you guys mentioned.

At this very moment (noontime here) the gypsum ceiling is hot and it radiates to almost 2 feet below it..

Here are some pics I took of the roof extension over the kitchen. the primary roof is constructed the same way using the same materials.

http://i43.photobucket.com/albums/e3...ps2982bc4c.jpg

http://i43.photobucket.com/albums/e3...ps51e74eb2.jpg

My neighbors have the same construction done on theirs too..here's apic of their roofs.

http://i43.photobucket.com/albums/e3...ps0ade149c.jpg

Here's a top view of the kitchen roof..the bolts need repainting/replacement..the roof itself needs to be painted white...

and the translucent roof sheet needs to be replaced..it's way past its age..

http://i43.photobucket.com/albums/e3...psa23482bf.jpg

Thanks for the tips, now all I have to do is build a trapdoor and measure the entire roof so I can estimate how many rolls are needed to insulate the roof...and repair any holes/leaks in the flashing.

The attic is not that airtight, there used to have brown rats living up there (from the rice fields nearby) until I finally got rid of them. It is very windy outside the house but I do not feel that much draft inside except for the windows...I could hear whistling from them during typhoon winds.

@Christ
I've asked around and no one has ever done it here nor does any local contractor have the experience yet. I believe those located nearer to the metropolis would have better or actual experience in building those.

I only ask because 1 basements are typically a cooler space and 2 it might work where ou don't have enough of a space outdoors to install such a system, especially where most of the basement/crawl area is unused.

I duno what ground rights are like there... some places you're only 'titled' just several feet below ground and the locality retains the rights of the remainder of depth.

Thanks to you I had a good laugh buddy. I went to the city hall, looked for the guys in charge of it and also the city engineers office and asked about ground rights..

the reply was (translated) "ground rights? you have the right to do whatever you want to parcels of land you legitimately own. Heck, you can even dig for Yama****as treasure if you want to"

So now that gives me an idea...:thumbup: Thanks!

^^ I'd get that in writing from them before investing in a shovel.

If you have a lot of moisture in your roof will the insulation attract mould?
This happens to houses in Thailand

Also, try vented window coverings, like shutters, either on the inside or out, and if you have double hung widows, open the windows down low on the windward side of the house, and open them up high on the leeward side of the house (the sides the wind is coming from and leaving to respectively). This is an old trick from old houses in the South and Southwest parts of the USA.

Yes, insulate under your roof, but I have seen major impacts by just painting the roof 'white' with elastomeric roof paint. And every year or two, just spray the roof with chlorine bleach and let it dry. That will help reduce the mold and mildew that happens when the roof is exposed and 'browns' for a long time.

If you could, a 'second roof' with air space between the top and lower roofs with ventilation between helps. ... I have seen people do that with sheds and barns to reduce the heat load in the summer. This works well especially where there is no summer shade or deciduous trees around. ... I have thought that mounting solar panels a few inches above the roof would help on roof heat load too, but that has it's own challenges as well ( using the micro-inverters to grid tie seems to be a good solution in well served areas ).

If you paint the roof, get some of the microscopic glass beads to spread on the wet paint of the roof. They tend to help reflect heat load (and in the moonlight, your roof can appear to 'glow' with reflecting the moon light).

On window treatments, the shutters on the inside can help keep 'hot light' out, and still let the breeze through. If you have them on the outside they might be more effective if your area will allow it.

Just a few thoughts.

"If you paint the roof, get some of the microscopic glass beads to spread on the wet paint of the roof. They tend to help reflect heat load (and in the moonlight, your roof can appear to 'glow' with reflecting the moon light)."

Servant74, the beads never occurred to me. That's a great idea. They are also available as 'micro spheres' through several aircraft supply houses for lightning up fiberglass resin. The cost is reasonable.

A second inside roof to provide shade and a breeze through the void is the easiest way. Be sure not to forget to vent the peak of the roof.

Did you end up doing anything to reduce your heat gain?