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4MyEgo

Reducing The Heat In The House

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Hi Guys

 

For those of you who want to reduce the heat coming into the house during the daytime and reducing you air conditioning costs, try this cheap method that I stumbled upon by accident.

 

Background:

 

I tried all of the below:

 

1) Tinted windows to reduce the rays coming in, somewhat good, but glass on windows still got hot and heat would still enter house but at a reduced rate.

 

2) Insulated the roof with reflective thermal insulation, 60,000 baht, good at slowing the heat coming in through the roof tiles into the ceiling, however am going to also put in a few whirly birds to allow some of the hot air to escape (50/50) if it works, but that was not my issue as I found that the heat was coming through the windows/glass panels (closed).

 

3) Keep all doors and windows closed and curtains with sunblock pulled shut to keep the hot air out, although you feel a breeze, unless its a cool one, shut them, because that medium breeze actually heats up the house real quick.

 

After all of the above I found the house (blonde brick blocks rendered and painted with concrete tile roof) was hot by 10.00am in the morning, so the fans would be put on, just blowing hot air around, so the A/C's had to be turned on, until I stumbled onto something unique and cheap, which is so effective, I urge all of you guys to try this to reduce the heat coming into your home, and please let me know if it works for you.

 

I am now turning on one A/C at 3.00pm, sometimes later, as opposed to 10.00am in the morning, so its a big win on cost saving and the fact that we don't really like A/C's, (4 in all), although never put them lower than 26, or 27 when going to sleep, just enough cool, rather than cold or freezing to have to wake to adjust the temp up.

 

Some photos for you to see of the cheap product I stumbled upon, it costs 50 baht per sheet of fibro, 600mm x 1200mm put on your window ledge over your window, the sheets are about 3-5mm in thickness and have some little slits (refer to photos) in them to let some light in, they are used as a cover over the underside of the eaves of your house, and as I had a couple of spares with the sun coming through our kitchen/dining room in the morning (east) and heating our 2 x 1800 x 1100 windows, I was getting to a stage that I needed to do something, so I thought I would cover the windows with some spare gypsum plasterboard on the outside, that is, if I could fine laying around, just until till the sun moved around to the (south), I then stumbled onto the fibro sheets (spares) and as they were much smaller than the gypsum plasterboard (spare) sheets, I ended up putting them on the window ledge and covered the glass panels, unbeknown to me it would reduce the level of the heat of the area by so much.

 

I couldn't believe it, so I said to myself I have to do this to the west facing front spare bedroom (junk room), which is an oven in the afternoon, I kid you not, we close it as it heat comes into the rest of the house, even with double curtains on it with sunblock, it still gets very hot, after putting single fibro sheets on the ledge, the heat was reduced by at least 50%.....easy, so the next day I put double sheets on it and it reduced the level of the heat coming in even more, suffice to say I now have 3 sheets over the window ledge of the front west facing room and no need to close the door, the other room (south) only requires a single sheet, however if it gets really hot you can add a 2nd sheet as I do every now and again, and even put the 2nd fibro sheet it over the slits (refer to photo) to stop any small amounts of light coming through to stop the heat penetrating to the window panels.

 

This is very effective and so so cheap, so please knock yourselves out and let me know how you go, it beats putting up roller shutters if you can find them, and the only downside is that you have to take them down...which is not really a downside, I just take them down and leave them below the window for when I put them up again in the morning, some I leave on, and just remove a section, the other side of the house doesn't need any as it faces north. 

 

 

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Outside shutters do work very well, that's why many traditional Thai houses have them even if they have glass windows :)

 

I hope you have an opening set of window bars elsewhere in that room.

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Those are vented soffit boards designed to go under the eves to allow cooler air from below to replace the hotter air that escapes higher up. The problem with what you've done in your attic/roof space is that you've not vented it. You need some means to allow the hot air to escape from a higher elevations BUT you need a corresponding amount of air intake (vented soffit boards) at the eves to allow cooler air in. Whirlybirds may provide the exhaust you need but they wont work effectively without the cooler air inlet. The US roofing companies have some good web sites that explain how to balance air flow in the roof void, I have 14 square metres of roof ventilation, that's seven square metres in the form of gable vents (four sets) to allow hot air out and another seven square metres at the eves via vented soffit boards. Six inch aluminium foil covered bat type insulation is effective if laid on the attic floor BUT ONLY if the roof space is vented. Bamboo roller blinds outside the window are also good value and can be attractive.

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9 minutes ago, Crossy said:

 

Outside shutters do work very well, that's why many traditional Thai houses have them even if they have glass windows :)

 

I hope you have an opening set of window bars elsewhere in that room.

 

Agreed, however I am sure that outside shutters would cost an arm and a leg Vs the vented soffit boards as chang mai advises they are called.

 

I have double width accordion style security doors just next to the security grills in case we need to exit, front, side and rear.

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2 minutes ago, 4MyEgo said:

Agreed, however I am sure that outside shutters would cost an arm and a leg Vs the soffit boards as chang mai advises.

I have double width accordion style security doors just next to the security grills in case we need to exit, front, side and rear.

 

The soffit boards are cheap and effective and wouldn't actually need much work to make them look attractive too.

 

Glad you have your fire exits sussed.

 

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13 minutes ago, chiang mai said:

Those are vented soffit boards designed to go under the eves to allow cooler air from below to replace the hotter air that escapes higher up. The problem with what you've done in your attic/roof space is that you've not vented it. You need some means to allow the hot air to escape from a higher elevations BUT you need a corresponding amount of air intake (vented soffit boards) at the eves to allow cooler air in. Whirlybirds may provide the exhaust you need but they wont work effectively without the cooler air inlet. The US roofing companies have some good web sites that explain how to balance air flow in the roof void, I have 14 square metres of roof ventilation, that's seven square metres in the form of gable vents (four sets) to allow hot air out and another seven square metres at the eves via vented soffit boards. Six inch aluminium foil covered bat type insulation is effective if laid on the attic floor BUT ONLY if the roof space is vented. Bamboo roller blinds outside the window are also good value and can be attractive.

 

Thanks for the correction, e.g. vented soffit boards, and yes with regard to roof ventilation, I am also looking into adding 8 gable vents, front, back and side to see what affect that has, and have spent countless hours on youtube looking at the US, UK and Ozzy companies as to how they get the air flowing.

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What was the insulation thickness? 

 

I had 6" insulation above the ceiling and that foil stuff under the roof tiles. 

 

I had a gable roof and added 2 thermostatic vent fans in the top set to come on at 25 C and pull hot air out of the ceiling space. 

 

Was very very effective and living room/kitchen had 3 huge sliding doors and a lot of sunlight

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3 minutes ago, Crossy said:

 

The soffit boards are cheap and effective and wouldn't actually need much work to make them look attractive too.

 

Glad you have your fire exits sussed.

 

 

Agreed, as I only just put them up a few days ago, I haven't even gone to the trouble of painting them which I will get a round to, and as I have an artistic, not autistic wife, she can add her flare to them, or we just paint them the same colour as the house. 

 

As for the fire exits, absolutely covered, keys with me by the bedside table at night, we are not one for security grills, but don't wish to stress when we go away, not that anything would happen in the village, but why risk it.

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4 minutes ago, 4MyEgo said:

 

Thanks for the correction, e.g. vented soffit boards, and yes with regard to roof ventilation, I am also looking into adding 8 gable vents, front, back and side to see what affect that has, and have spent countless hours on youtube looking at the US, UK and Ozzy companies as to how they get the air flowing.

 

I had a gable roof with vented soffit boards, made my own fans and thermo switch kit and installed them in the gable vent area to pull out the heat. 

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9 minutes ago, Strange said:

What was the insulation thickness? 

 

I had 6" insulation above the ceiling and that foil stuff under the roof tiles. 

 

I had a gable roof and added 2 thermostatic vent fans in the top set to come on at 25 C and pull hot air out of the ceiling space. 

 

Was very very effective and living room/kitchen had 3 huge sliding doors and a lot of sunlight

 

Not sure of the thickness, but went for the maximum http://www.polynum-insulation.com/index.php?page_id=30

 

Will be looking at what you did, I also saw that on youtube and it looked very effective, thanks

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We have gable vents high up at both ends of the roof, low down venting is at the eaves via the ventilated bug stoppers (our soffits don't open into the roof space).

 

Entering the attic storage space over the bathroom one can feel the airflow even without forced ventilation.

 

The insulation and foil is on top of the ceiling gyproc, despite the roof being too hot to touch during the day the rooms stay reasonably cool (ok they're not ovens).

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One of the biggest heat problems in Thai houses is caused by the transfer of heat from the roof tiles to the steel and from the steel to the walls - think of a heating element in a kitchen kettle and that's pretty much what you've got sat on top of your ceilings/living space. If you can do it it's worth removing the top layer of block from the walls that sits directly underneath the steel roof beams and replacing it with Thermalite insulated block, that way the only points of heat transfer are from the steel in the roof beams to the steel in the posts, which is minimal.

 

EDIT to my earlier post: the ventilation should read square feet and not square metres, apologies. There's a calculation on the US roofing web sites which tell you how much ventilation you need based on square feet of living space.

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3 minutes ago, Crossy said:

We have gable vents high up at both ends of the roof, low down venting is at the eaves via the ventilated bug stoppers (our soffits don't open into the roof space).

 

Entering the attic storage space over the bathroom one can feel the airflow even without forced ventilation.

 

The insulation and foil is on top of the ceiling gyproc, despite the roof being too hot to touch during the day the rooms stay reasonably cool (ok they're not ovens).

 

So you just had the slat board kind of vents up top and the bug stoppers are the plastic things the fit at the end of the roof used for keeping birds and stuff out? 


I made a fixture for the fans and screwed them behind the slat board vents and had the thermo sensor center of the roof space. Worked real good but there was a bit of a vacuum up there when both were running. The vacuum didn't have any effect inside the house though. 

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Just now, Strange said:

 

So you just had the slat board kind of vents up top and the bug stoppers are the plastic things the fit at the end of the roof used for keeping birds and stuff out? 


I made a fixture for the fans and screwed them behind the slat board vents and had the thermo sensor center of the roof space. Worked real good but there was a bit of a vacuum up there when both were running. The vacuum didn't have any effect inside the house though. 

 

Pretty well. The gable vents are purpose made wooden (mai daeng) louvre arrangements with bug netting behind, the eaves have ventilated aluminium filler thingies that are designed to fit the tiles.

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There should be no need to use a thermostatic fan if you get the exhaust and eves intake balance right and sized correctly, the two of those things will create a natural draft as others have described. Having said that I also have installed a thermo. fan but it's more belt and braces than anything else. On a hot day there is a layer of cool air on my attic floor that is about one to one and a half feet above the foil covered insulation (the last line of defence), above that it gets very hot very quickly, that protective layer is the affect of the cool air in pushing the hotter air up and vica versa.

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