Cooling Your Philippines Home – Artificial Shade and Polystyrene Insulation

Staying cool in the Philippines can be a bit of a challenge.  First off, it’s the tropics, and unless you’ve actually experienced that level of heat and humidity here, adjusting to it can be a bit of an ordeal.  Secondly, the way they build homes (and apartments) in the Philippines actually makes the heat even more intolerable.

It’s April 8, 2016 and summer in the Philippines is in full effect.  It’s been over 90 degrees Fahrenheit (32 Celsius for those in more enlightened, metric-friendly nations) this past week and the humidity-inclusive “Real Feel” temperatures have been hitting 110+. 

Ugh.

The aircon went on this morning at 10 AM, and it will probably be running until around 5 PM.  It will go back on 3 hours later when I settle down for the evening and it will be running off and on throughout the night. (Our Carrier Optima aircons have a timer that switches off the aircon and turns on a fan after a set number of hours – then, when it gets too hot, I wake up and turn it on for a few more hours.)

To combat the Philippines summer heat, we’ve made a few improvements to “Pink House” since we moved in.  I’ve only actually got two photos to show when it comes to some of the house layout “before and after’s,” so let’s take a look.

NOTE:  All temperature readings are made with our trusty temperature gun.  These handy little devices accurately read temps from up to 10 meters away and only cost about 11 dollars US on ebay.

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infrared temperature gun

Pink House

Pink house shortly after moving in – no shade!

First up is the photo above that we took shortly after we moved in to our rental located on the outskirts of Dumaguete City. 

Note a few things: 

CONCRETE AND STEEL: First off, the house is made of (uninsulated) concrete block walls capped by an (unvented) metal roof.  There are eave (soffit) vents installed under the roof overhang, but there is no ridge venting.  The purpose of eave/soffit vents is to draw in cooler air from below and vent out the hot air with ridge venting.  But with no ridge venting, there’s nowhere for the hot air to go, so the cavity between the roof and the suspended ceiling (attic/crawl space) becomes super-heated during the day and radiates it down into the house much like a convection oven.  End result is that the ambient temperature outside will be 90 degrees while the ceiling temperature inside the house will be close to 98 degrees. 

SUN EXPOSURE: First off, there is VERY little shade around the house.  When Filipinos build, the first thing they do is cut down all of the trees and brush.  So, when the uninsulated concrete “hollow block” and unvented metal-roofed structure is complete, it quickly turns into a aforementioned convection oven.

Now, let’s take a look at the house after we made some changes to cut down on the heat.

NIPA CARPORT COVER:  This was the first improvement we made.  The sun beating down on the concrete driveway and walls on the western side of the house would bring those surface temperatures up to around 130 degrees.  The heat would then waft into the house, raising internal temps to 90-92 degrees.  I first made some homemade “sunscreens” to cover the western windows, and these helped somewhat but where a pain in the ass to constantly put up and take down every day (along with having to open all those windows in the evening and close them in the morn).  Finally, we asked our landlord if we could pay to have a carport cover made and have the cost deducted from our rent.  He agreed and the nipa (native material) carport was put the following week by some local workers.  The effects were IMMEDIATE – the shaded concrete thereafter would only heat up to ambient temperatures and the shade was more than welcome.  Note that they didn’t angle the nipa steeply enough so it’s not fully waterproof but that’s OK – I was more concerned with shading the entire side of the house.

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INSULATION:  Although we had decreased the house’s ambient temperature by building the nipa carport cover, we still had a lot of heat radiating down from the ceiling.  I had made the window “sunscreens” out of the 10 mm polystyrene insulation here that has a reflective radiant barrier (basically, aluminum foil) on one side.  Thinking that it might help, I once again asked our landlord if we could install the insulation atop the suspended ceiling.  Some folks on one of the Philippines expat forums noted that although thin, the insulation was pretty effective.  They also went on to note that they thought most of the effect was due to the radiant barrier/aluminum foil reflecting the infrared radiant heat coming down from the metal roof.  Again, we paid for the install and the landlord agreed to deduct if from the rent.  We first did the two bedrooms as a test, and the results were pretty significant – the insulated ceilings were consistently 3-5 degrees cooler than the uninsulated ceilings.  About a week after the bedrooms were done, we had the rest of the house done.  Our poor Filipino worker busted his ass up in the super-heated crawlspace, laying down the insulation, stapling it in place and taping up the seams.  The material cost for the two 3 meter by 3 meter bedrooms was about 1,560 pesos (78 pesos per square meter for the 10 mm poly with one-sided radiant barrier) and the later cost of the rest of the house was 3,800 pesos.  Toss in labor and the total insulation job cost 6,200 pesos.  So, for about $135 USD, we now had an insulated ceiling.

Again and like the nipa carport cover, the effects of the insulation were pretty much immediate.  Ambient temperatures in the house decreased about 3 degrees from before the installation, and even though 3 degrees might not seem like much, I would much rather be sitting in a house that is 86 degrees as opposed to nearly 90.  I also think that the insulation will help with the aircon costs.

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10 mm polystyrene insulation with radiant barrier

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fabricated sun screen with poly insulation

Combining the shaded carport on the western side of the house, blocking off one of the windows in each room with poly and insulating the ceiling have definitely made the house more comfortable, temperature wise.  Aside from central aircon, there isn’t much you can do about the humidity, but I look at it like this – at least I don’t need skin moisturizer while living in the Philippines!

Pink House front oct 2015

Pink house with nipa roof and giant bushes!

Have you made any changes to your rental or home since moving to the Philippines?  Do you have any other tips or tricks that can add to this discussion?  Feel free to leave them below in the comments section!

Stay cool, ya’all.

 

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Comments 25

  1. Simple old ways in tropics for centuries was better design for cooling…..

    with your house now, you could construct your entire roof with a cheaper palm grid weave to block sun not rain. Grid sits upon and above roof with breathing space of a few inches due to basic cheap framework construction height. Mounted at edges and points on surface of roof. Sun never reaches roof with a loose weave of large palm leaves moving hot air away from surface of hard roofing. No bugs or geckos get through. Your landlord wont like it, unless it looks nice but one can always replace old torn palm leaves with new ones for no cost. Pick them up off the ground.
    If u plan to stay longer, its worth it. But maybe better to find an apt on 2nd floor of 3 story bldg; your apt facing north.

    The perfect construction in the tropics for cooling in old days was one large grass roof, hovering 2 to 3 feet over all rooms of the house with large overhang. It allowed air to pass through during high monsoon winds with no house damage. Strong construction still held up in typhoons..most times. Air and mist of rain would blow through house, cooling the entire inside. Insects could be screened out or blocked with rolled up or down clear plastic coverings when necessary.

    Just brainstorming

    1. I’m working on all of the same issues for my new home southwest of Cebu… still in the design stages. I just want to bring out the advantage of the hot air in your attic for heating water, thus saving electricity… A simple coil of vinyl tubing in the peak of your attic should give you free hot water for your western needs, so plan for that before you get rid of the whole heat trap up there. My roof (in the present planning stage) will be corrugated metal with a double roof section at the very peak to allow the hot air to exit, but not allow any but typhoon rains near the opening. I’m thinking of ways to prevent much of the typhoon-driven wetness as well and I hope I can show pics of how I do that. I’m pretty sure that if I can adequately ventilate the attic and insulate the ceiling, my house should stay considerably cooler than any I’ve stayed in on my trips.

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        Our little 10 mm insulation works quite well. I think it cuts down on the AC costs as well. Today was the first hot day of the year, and I had the aircon on all afternoon while I was working. Thanks, Ed!

  2. Ned ,

    Good work! Dropping the indoor temperature by 3 F should make a nice drop in the cooling cost, perhaps 25 percent , depending on how far down you are cooling. Amazed that the roofs are not designed to circulate the air. Also noticed the roof was a darker color which probably soaks up the solar insolence; having a lower emissivity roof would also reduce the temperature.

    Coming over in August with my wife and am bringing a spot infrared thermometer as you recommended a while back – thank you for the very practical suggestion!

    Gary

  3. Hi Ned!
    On this topic I really do like to comment, because you are really touching an very important problem of how to stay cool in the tropical climate of the Phils! I think you are into something and you are an intelligent person who likes to make better your environment. I live currently in the opposite climate: cold! Here over time the building has changed, today we do a lot of insulation in the outer walls and roofs to lower the escape of heat that is expensive to produce! In the Philippines it is opposite: there you need to keep the cold that you obtain from modern aircons in doors from escaping out! So, just as in the cold climate there must be done insulation to walls and roofs, ceilings. But, the usual building way there is not to use such materials at all. In the old days the native people lived in huts made of nipa and when the Spanish come there they tok with their customs to build their houses in stone with high ceiling and it worked probably well. The stone houses could withstand typhoons, but were not so good when the earth begin to shake! The nipa huts were easy to build and could withstand much shaking… but poor to withstand raging storms – typhoons, they all fall down! but quick to be rebuilt! So, that’s the old ways of building. Today we have another way of living than then and other needs. We spend more time indoors with modern appliances so we need to have it cooler. And in my opinion the general filipino people are not so occupied with this problem as they are born into that climate and therefore used to it, just like peoples of Nordic or Siberian climates are. Of course they like a cool environment why would they flock off to the modern airconed malls? All day if they can and just stay there until evening!
    So, it’s a very good idea to improve your house for a cooler living in the extreme hot months of Philippine summer! And you also get a lower energy bill. Remember the use of aircon is a relative new thing there and many don’t have it or can’t afford to use it!
    New houses should be designed in green way to reduce the use of greenhouse problem. By using the same insulation as in cold climates – that’s the simple solution! Stay cool!

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      Thanks for taking the time to note all of that, Timothy. Yeah, when I look at the house we are renting now, I would definitely have added wider roof overhangs, insulation (even if just radiant barrier) and some way to vent the attic space. Thanks again!

  4. Some suggestions Ned:
    1. Get someone on the roof with a high pressure water cleaner and blast it clean and then paint it with White high gloss acrylic paint – Matt paint no matter what colour it is, just makes it a more efficient heat sink.
    2. Get 2 whirly-gigs installed to vent the hot air out. Just make sure the whirly-gigs are installed at the same height on the roof to ensure proper air flow between them. Did this on an investment property in Oz and the tenants who had been whinging and wanting me to install ducted aircon quickly stopped whinging – A $200 fix instead of a $15,000 fix.
    3. Cover the roof with Photo Voltaic (PV) panels with an air gap between the panels and the roof. The effect is similar to the previously suggested palm leaf matting and you can use the power generated to run your aircon.
    4. Rip the roof off and install insulated sarking between the metal sheets and wooden trusses and joists.
    5. Hire a punga walha to fan you when you get hot.
    6. Harden up 🙂

  5. I have started on my house here we are making our own hollow block 6″ instead of 4″. We picked a location about 50 plus meters from the road the site is shaded and has an almost constant breeze mostly from the east and southeast will be two story with a flat concrete roof. We will be able to use the roof as a patio. The house will be a 3 bedroom 2 bath house.. Will use sliding windows on the first and second floors to take advantage of the breeze to cool the house. I was told that 4″hollow block would cost me 10 Php each and 6″ hollow block would run 15 to 18 Php each. With the cost of forms, sand concrete, stone,and labor, the cost for us is 10Php each. We have already made 2,000 blocks will need in excess of 6,000 blocks for house and 3 chambered septic tank.

    1. A flat concrete roof that can be used as a patio may seem a good idea but its not. There a 2 problems.

      1. The roof might leak. Its very hard to waterproof a flat surface.
      2. The concrete will soak up the heat all day and warm the rooms below until around midnight.

      I’m telling you this because I have experienced both problems. I also know I’m most likely wasting my time in telling you but good luck.

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  6. this struggle has gone on for years. westerners looking for a cool place to live with the hottest woman. Well we got the hott woman now to beat the ambient heat.
    I have been in the heating and cooling buis for years, Convection ventilation is the best. Some high ridge venting will immediatly flow air as soon as the sun hits your roof. So many times I have cut a hole there in my work and OMG its pouring out heat for a while then gets much better.
    Heat is a form of energy and it flows to cold. The greater the differential temp the faster and harder it flows. You cooling energy used goes up by the square of the differential. So a target temp of 80 and an ambient of 90. takes less than half of the energy of trying to get your home to 78 degrees. on the 90 degree day.
    All aircons remove some humidity. But the lower eer rated ones remove the most. while the newer higher efficiency units do not remove as much. IN fact Ashrae does not recommend High seer for the tropics. Even florida because of health risks associated with the condensation and humid air in the home. So before you pay alot more for the inverter unit consider that !
    theres my 2 cents worth. David C

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      Author

      Whoa! Thanks for all that information, David. I didn’t know that the newer, more efficient aircons are not as effective in removing moisture from the air! I obviously have to do some more research! Thanks again.

  7. Ned
    I am sending u this site on building a house in Pi, tropical climate. He built it outside of Iloilo.
    Its an amazing site about the challenges of building a perfect house, down to specific details on every level of analysis in construction and problems dealt with….

    The first address is his general site, the second address was relative to the cooling difficulties he approached. An immense amount of information on his general site address: step to step on the entire build. Just good information on house building for anyone that is interested…challenges in this tropical environment.

    http://myphilippinelife.com/building-our-philippine-house-index/

    http://myphilippinelife.com/cool-roof-philippines-metal-roofs-and-cool-buildings-in-the-tropics/

    I am the same Dave at top of this comment section….

  8. Ned, we’ve just started on the house project as we arrived on the 7th of April. So far a couple of big tarps on the South-East to throw shadow on the walls. A big difference in the living room just from that. We also in stalled a .8hp Kolin in the master bedroom. I bought a 50mm x 1.2M x 15M roll of fiberglass from Citi. Installing today over the two bedrooms. If it works as expected, I will go 100mm total over the bedrooms and 50mm over the rest of the house. Couldn’t find foil one side, so may add another layer of 5mm PE foam foil one side later.

    The house is owned, not a rental so some investment is reasonable.

    Also installed a 775 liter SS water tank with a .8 hp centrifugal pump with pressure tank. That gives us a steady 35-ish psi in the house, even when city water is low or no pressure. Big problem where we are outside of town by a couple of km.

    And the new shower water heater is great. Its a multi-point installed as a single-point for now.

    We plan on adding some living space depending on estimates. If I can make it work it will be a living/dining room ground floor with attached carport. Slab roof over everything, with a master bedroom suite on the second floor with deck over the carport. Slab roof over the master bedroom, and shade roof over the carport deck. Then a shade roof over the main deck on 3rd floor over the master bedroom.

    All the roofs will be gloss reflective white. Getting shade everywhere you can is critical to being comfortable and getting the AC cost down.

    The shade roofs mentioned above will be oriented as far as possible to maximize the benefit of solar panels. Its only a little more than a buck per watt now to install solar, and you can run two or three ACs during the day for surprising little capital investment in a solar system.

    All the best,
    George and Rocel
    Bago City, Negros Occidental

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      Author

      Ah, OK – you are in Bago – I just asked where you were in your follow up post. Yeah, that sounds like an excellent plan – shade is CRITICAL here and I just shake my head whenever I see them chopping down nice shade trees. And you are right about the AC/solar – One Love cafe here has solar and they are running their AC off of it during the day. I didn’t even know that solar could run an aircon! Thanks much for taking the time to write all of that out, George – much appreciated!! Best wishes – Ned

      1. Ned, I have split system Air Con in Oz and the outside unit has got a label on it saying Inverter.
        From my experience in electronics any thing that says Inverter indicates it is either turning AC power into DC power or vice versa.
        PV panels put out DC power and it is then fed through an Inverter to power the house.
        If you are using PV panels to power your Air Con you could avoid going from DC to AC and then AC to DC to power your outside unit by connecting the PV panels power direct to your Air Con by-passing the Inverter that is built into it.
        Why would you do it?
        Because no Inverter is 100% efficient and you lose 10% to 20% if not more of the power every time you Invert it.

  9. 50mm fiberglass went in last night over the bedrooms. In fact it expanded closer to 75-80mm when unrolled. What a difference. The ceiling in the bedrooms is now cool to touch while the living room is quite warm already.

    Off to buy one more roll to finish the job. 3200 php at Citi hardware. 50 mm x 1.2 M X 15 M roll.

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  10. No reflective barrier. The good part is that you are dealing with a 4′ wide fiberglass blanket. If you have a typical suspended ceiling making it fit around the supports is trivial.

    We are very happy with the results. The guys did a good job putting it in, just overlapped where it was too wide.

    The house is small, only 360 sq ft.

    It took two rolls of fiberglass at php 3200 per roll.

  11. I am looking to do anything that will cool the inside of my home. I seen recently fiberglass panels that would cover a roof, but we have a metal roof already with radiant barrier in place during construction. So I am thinking if this fiberglass panels placed on top of the metal roof would keep the sun from heating the inside of the house. I have a solar exhaust fan on one side of the house and another fan on the other side pushing air into the attic space, still inside is to hot for us. we also have solar screens on windows that face the sun. Can anyone give me any feed back on these fiberglass panels (found in Citi and budget hardware stores in Puerto Princesa.

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  12. Ned, we have the first set of improvements finished. The roof is now gloss white. The outside walls are now semi gloss white with gray trim.

    The patio area is covered and tiled and has a ceiling fan. The dirty kitchen is finished and we have an Electroluxe tropical fridge/freezer and a six burner gas/electric stove.

    The improvement in habitability is dramatic. Hard to believe how much cooler the house is.

  13. Hi Ned, we are planning to have a house build on our lot in Batangas. My wife and I have different ideas on window type. My idea is that regular opening windows or jalousie windows would provide best climate inside. My wife refers the new awning type or closed type with coating. What would your advice be?

    We will ofcourse plant trees and bushes for shading too.

    Thanks! Ronald and Ninette, the Netherlands

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      Author

      I would use solid sliding windows with the coating. Also insulate the roof and ventilate it well. And make provision to put as much shade on the house as humanly possible. Good luck to you both!!

  14. Awesome reading. I live in oz in the tropics and roof ventilation along with ceiling insulation is a massive help in dealing with hot humid times. We sweat in the shower some times ???? when adding roof vents, gable vents etc you need airflow to suck cool aid in. Drilling 25 mm holes in patterns through the soffit sheets all around the house helps, 9 holes in a diamond pattern. Make sure it’s not asbestos though, we get glass wool batts with an r4 rating that sit on the top of the ceiling sheets to stop transfer of heat from above and loss of cool air conditioning from below. It all helps

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