Looking for a Gable End Exhaust Fan, Solar

[chiang mai]

As stated in my earlier post I bought two thermostat switches at the shop across from the Shell station on Hang Dong Road. I installed two wall switches for each fan, one switch going through the thermostat and one going directly to the fan so I can choose to bypass the thermostat.

Grin

Hi Grin, I went to that shop, it's the one that has an advertising display of fans at roof level? The man I spoke to only knew about whirly birds and didn't seem too interested in or knowledgeable about much else, did I perhaps go to a different shop - this one is quite a cavernous space with whirly birds spread out across the floor?

[grin]

Yes, the shop has a large fan mounted above the roof. When I bought my thermostats I printed a picture and took it in. I can't find the same picture now but a Honeywell T6054A1005 is close. The ones I bought had a similar gray metal case but had a larger black plastic knob and the coil was black, too. If they don't have any in stock they should be able to order it for you.

Grin

[grin]

FYI, the plans for my house only had 6 soffit vents, each about a half a meter wide and 2 meters long. I had 24 of them installed so that it would be less likely that my attic fans would pull air out of the house.

Grin

[chiang mai]

FYI, the plans for my house only had 6 soffit vents, each about a half a meter wide and 2 meters long. I had 24 of them installed so that it would be less likely that my attic fans would pull air out of the house.

Grin

I can beat that . My house had no soffit events and i replaced all the eves boards with vented board, 36 panels, actually quite easy to do.

I'll go try that shop again and perhaps take my wife this time, thanks for the reminder.

[scorecard]

Hang Dong Road near the end of the airport runway. A number of places there. Look for the giant fans. They sell industrial fans and will give you just what you need. 6 years ago mine cost 1000B. I have it on a timer switch. It's never missed a beat and cools the house greatly. I looked into the solar angle. Forget it. They don't have a clue and importing a solar kit gets hit with prohibitive import duty.

This is interesting to me because my bedroom gets full sun on two walls most of the day and the room is very hot. I installed slatted extra walls in front of the main brick walls but it had little effect.

From other conversations we assumed that the strong heat would NOT be coming down through the ceiling because the builders installed 'aluminium foil' type insulation as standard in every house in this village (houses now about 3 years old).

I'm assuming 'gable' is meaning a fully vertical section of the roof, probably at both ends of the house.

Unfortunately our house doesn't have that, the roof (ceramic roof tiles) has 4 main sections, all sloping down at the same angle. So I guess a fan is out of the question?

So some questions for the experts:

- Because there is 'aluminium foils insulation fitted just under the ceramic tiles (whole roof area) would the air in the ceiling cavity above the room getting full sun most of the day be much hotter than the ceiling air above the rooms that get full sun only for a few hours each day?

- Is aluminium foil insulation effective? And, does it come in different thicknesses?

- If it's not all that effective can you please give a suggestion of type of insulation / brand name etc.,for a replacement. And would it be effective to install this in the ceiling only for the roof area above the hottest room?

Any advice much appreciated.

Edited August 16, 2015 by scorecard

[chiang mai]

The aluminum foil you describe is a radiant barrier, it prevents the heat that is absorbed by the roof tiles from being radiated onto the ceiling below and it can be very effective, as long as there is an air gap between the roof tiles and the foil. As for different types of foil: any foil that has a shiny reflective (low emssivity) surface will do the job. NOTE: aluminum foil coated PE foam is sold as a radiant barrier, it's expensive and the R Value rating is hugely misleading (aka lies). Simple aluminum foil radiant barriers are a fraction of the cost and do exactly the same job. NOTE 2: Radiant barriers don't actually have any R Value rating other than zero because they don't have any insulating properties.

But whilst the radiant barrier is good at reflecting heat it doesn't make it go away, instead it converts radiated heat into convected heat (air that heated) and that has to be managed. An obvious way to do that is to allow the hot air to escape through a gable exhaust vent but you say you have a hip roof and there aren't any gables. In that case, a secondary option is to install vented sofits at the eves, these are boards with holes in them that fit under the eves and allow the hot air to escape - hot air expands hence if it can't escape somewhere it will permeate the living space.

If you take the option of vented sofits you will also need to protect the attic floor/up floor ceiling from heat by installing six inch fiberglass insulation, that will act as a barrier until the expanded hot air in the roof void can escape through the eves.

Edited August 16, 2015 by chiang mai

[kaptainrob]

Hang Dong Road near the end of the airport runway. A number of places there. Look for the giant fans. They sell industrial fans and will give you just what you need. 6 years ago mine cost 1000B. I have it on a timer switch. It's never missed a beat and cools the house greatly. I looked into the solar angle. Forget it. They don't have a clue and importing a solar kit gets hit with prohibitive import duty.

This is interesting to me because my bedroom gets full sun on two walls most of the day and the room is very hot. I installed slatted extra walls in front of the main brick walls but it had little effect.

From other conversations we assumed that the strong heat would NOT be coming down through the ceiling because the builders installed 'aluminium foil' type insulation as standard in every house in this village (houses now about 3 years old).

I'm assuming 'gable' is meaning a fully vertical section of the roof, probably at both ends of the house.

Unfortunately our house doesn't have that, the roof (ceramic roof tiles) has 4 main sections, all sloping down at the same angle. So I guess a fan is out of the question?

So some questions for the experts:

- Because there is 'aluminium foils insulation fitted just under the ceramic tiles (whole roof area) would the air in the ceiling cavity above the room getting full sun most of the day be much hotter than the ceiling air above the rooms that get full sun only for a few hours each day?

- Is aluminium foil insulation effective? And, does it come in different thicknesses?

- If it's not all that effective can you please give a suggestion of type of insulation / brand name etc.,for a replacement. And would it be effective to install this in the ceiling only for the roof area above the hottest room?

Any advice much appreciated.

Your full pitched roof can do with 2 or more passive whirlybird air extractors sold and installed (@6k for 2) by the HangDong road shop spoken about above.

The foil under tiles has minimal heat insulation properties. It's primary purpose is as a moisture barrier.

Fibreglass (wool) insulation batts in foil envelope, are installed atop your ceiling and will make a dramatic difference.

[bangmai]

Hang Dong Road near the end of the airport runway. A number of places there. Look for the giant fans. They sell industrial fans and will give you just what you need. 6 years ago mine cost 1000B. I have it on a timer switch. It's never missed a beat and cools the house greatly. I looked into the solar angle. Forget it. They don't have a clue and importing a solar kit gets hit with prohibitive import duty.

This is interesting to me because my bedroom gets full sun on two walls most of the day and the room is very hot. I installed slatted extra walls in front of the main brick walls but it had little effect.

From other conversations we assumed that the strong heat would NOT be coming down through the ceiling because the builders installed 'aluminium foil' type insulation as standard in every house in this village (houses now about 3 years old).

I'm assuming 'gable' is meaning a fully vertical section of the roof, probably at both ends of the house.

Unfortunately our house doesn't have that, the roof (ceramic roof tiles) has 4 main sections, all sloping down at the same angle. So I guess a fan is out of the question?

So some questions for the experts:

- Because there is 'aluminium foils insulation fitted just under the ceramic tiles (whole roof area) would the air in the ceiling cavity above the room getting full sun most of the day be much hotter than the ceiling air above the rooms that get full sun only for a few hours each day?

- Is aluminium foil insulation effective? And, does it come in different thicknesses?

- If it's not all that effective can you please give a suggestion of type of insulation / brand name etc.,for a replacement. And would it be effective to install this in the ceiling only for the roof area above the hottest room?

Any advice much appreciated.

Your full pitched roof can do with 2 or more passive whirlybird air extractors sold and installed (@6k for 2) by the HangDong road shop spoken about above.

The foil under tiles has minimal heat insulation properties. It's primary purpose is as a moisture barrier.

Fibreglass (wool) insulation batts in foil envelope, are installed atop your ceiling and will make a dramatic difference.

Yes, that's exactly the kind of roof I had, and did a pair of whirlies. The radiant barriers are good, like the roll of foil. It was 117F in Phoenix yesterday. It has been discovered that the thick blankets, with high R value above the ceiling aren't good in the severe heat, as it seems to absorb heat. People were getting carried away, and putting R-60 in their ceiling for neighborhood bragging rights. Getting the hot air out of the attic is more important. I wold do a little research, but R-30 would be max, maybe less. I don't think they use ridge vents here, so there is even more need for attic ventilation. Know the slope of your roof, when you buy the whirlies, so they will use the correct adapters.

[kaptainrob]

Whirlybird roof adapters are adjustable upon installation.

[chiang mai]

Fiberglass (bats) insulation will absorb the heat if there is no way to vent the hot air, the trick is to provide enough venting to where the bats remain unchallenged, 90% of the time. You can do that either via a ridge vent (SCG Home Pro carries the kits), whirly brids as Rob mentioned or eves/sofit vents.

Here's a post I wrote for a separate thread on the same subject, it might help clarify some things:

http://www.thaivisa.com/forum/topic/832060-housing-heat-reduction/page-2#entry9681892

[scorecard]

Fiberglass (bats) insulation will absorb the heat if there is no way to vent the hot air, the trick is to provide enough venting to where the bats remain unchallenged, 90% of the time. You can do that either via a ridge vent (SCG Home Pro carries the kits), whirly brids as Rob mentioned or eves/sofit vents.

Here's a post I wrote for a separate thread on the same subject, it might help clarify some things:

http://www.thaivisa.com/forum/topic/832060-housing-heat-reduction/page-2#entry9681892

Thanks to all for sharing, I'm learning a lot here and I appreciate it.

@Chiang Mai, you wrote "the trick is to provide enough venting to where the bats remain unchallenged, 90% of the time." To be honest I'm not sure what this means, can you please expand a bit.

The house actually belongs to my Thai adult son, he's also keen for a heat 'fix' but in terms of the 'whirlies' he's concerned that there could be water leakage when it rains. Any comments please.

I might add our electric bill is pretty big because we're using air-cons too much and we need to get the bill down. Also my son doesn't want his 3 kids to grow up with the concept of air-con turned on every night of the year in their bedrooms.

Apart from 'whirlies' which I will work on to get acceptance, it seems that the best solution is fibreglass bats in plastic bags. Any recommendations please about brand, R factors or whatever, and good price / places to buy.

Again, many thanks for all the comments, much appreciated.

[kaptainrob]

Global House had the best price on batts and cost me, IIRC, 25,000 for our 132 sq/m ceiling. Thickness and thermal ratings vary, as do the standards, so go look and compare.

Whirlybirds don't leak if installed correctly. Even in the worst storms this year, no problems with ours. Efficient venting of the roof cavity + ceiling insulation might see a >75% reduction in AirCon use.

Edited August 16, 2015 by kaptainrob

[scorecard]

Global House had the best price on batts and cost me, IIRC, 25,000 for our 132 sq/m ceiling. Thickness and thermal ratings vary, as do the standards, so go look and compare.

Whirlybirds don't leak if installed correctly. Even in the worst storms this year, no problems with ours. Efficient venting of the roof cavity + ceiling insulation might see a >750% reduction in AirCon use.

Thank you kaptain.

[chiang mai]

Fiberglass (bats) insulation will absorb the heat if there is no way to vent the hot air, the trick is to provide enough venting to where the bats remain unchallenged, 90% of the time. You can do that either via a ridge vent (SCG Home Pro carries the kits), whirly brids as Rob mentioned or eves/sofit vents.

Here's a post I wrote for a separate thread on the same subject, it might help clarify some things:

http://www.thaivisa.com/forum/topic/832060-housing-heat-reduction/page-2#entry9681892

Thanks to all for sharing, I'm learning a lot here and I appreciate it.

@Chiang Mai, you wrote "the trick is to provide enough venting to where the bats remain unchallenged, 90% of the time." To be honest I'm not sure what this means, can you please expand a bit.

The house actually belongs to my Thai adult son, he's also keen for a heat 'fix' but in terms of the 'whirlies' he's concerned that there could be water leakage when it rains. Any comments please.

I might add our electric bill is pretty big because we're using air-cons too much and we need to get the bill down. Also my son doesn't want his 3 kids to grow up with the concept of air-con turned on every night of the year in their bedrooms.

Apart from 'whirlies' which I will work on to get acceptance, it seems that the best solution is fibreglass bats in plastic bags. Any recommendations please about brand, R factors or whatever, and good price / places to buy.

Again, many thanks for all the comments, much appreciated.

Insulation merely slows down the transfer of heat, it doesn't necessarily stop it completely, all of the time. So if you cater for an average hot day and you insulate accordingly you'll stop the heat from penetrating the insulation, most of the time, 90% perhaps. But unless you over insulate and cater for those once in ten years days (which would be very expensive) there will always be times when it's exceptionally hot and the insulation doesn't perform as well as expected.

At present my attic space is well insulated and the bottom one to two feet of air space is very cool, above that the air heats up quite quickly. So the insulation that I've installed doesn't really get used, on most days and the foil covering remains almost cold. But as the outside temperature heats up that cool air gap starts to reduce and doubtless there will be times when the insulation starts to get hot also, those days should be very much the exception however.

Finally, insulation from Home Pro or similar: six inch insulation is the minimum I would install, a roll costs about 360 baht and covers around five square metres.

Finally finally: my electric bill, even at the hotest time of the year, runs about 1,400 baht maximum, we hardly ever need to use aircon during the day time, only at night to cool the bedroom before we go to sleep. I mention this just to let you know that the payback time on solving the heat problem can be quite short.