Ceiling insulation

[Possum]

2 hours ago, Viking said:

I just bought something called radiant barrier foil. Looks like aluminum foil, very thin. It can be placed right on top of your ceiling and it is said to reflect much of the radiant heat. I haven't had time to install it yet so I can't say how effective it is. One roll costed me 6500 pesos, 60 m long and 4 ft wide.

I have used that foil in the USA before moving here and recently used it in the garage/workshop we just built. It works very well. 90% of roof heat is radiant and this stuff reflects it very well and is inexpensive. Another thing is to make sure the attic is ventilated to reduce conduction heat. As others have mentioned roof vents are effective, just make sure there are openings in the sofit to draw air in. Solar panels of course work well and you don't have to start with a full installation of panels. Buy an inverter that  is big enough for your eventual full size and add PV panels as you can afford. We have net metering solar. Electrical load is an inverter type multi-split AC supplying 3 units and another separate split unit. We only run one unit during the day but at night we run 2. Rice cooker and other electrical appliances as most folks have. The March electric bill was 843 peso, a record low for us.

Edited March 27, 2023 by Greglm

[Mike J]

9 hours ago, Viking said:

I am thinking of installing an attic fan but I can't decide if I shall go with a solar powered or the Whirlybird type ( same as in Jacks  post)?

What model are your solar powered fans? Are you happy with them?

They have worked really well.  Installed about 8 months ago and no problems or issues so far.  The fans start working early in the day and continue until about 5:00 - 5:30.  When I checked with Lazada to get this screen shot I saw that they also had solar powered whirlybirds.   I think the whirly would be the best for a flat roof.  We also had the radiant foil type insulation installed with the new roof.  Not sure if that is a practical solution if you only have six inch gap from roof to ceiling.  They would need to remove all the ceiling or the roofing to install it. 

 

Edited March 27, 2023 by Mike J
Added radiant foil note

[hk blues]

15 hours ago, Viking said:

I just bought something called radiant barrier foil. Looks like aluminum foil, very thin. It can be placed right on top of your ceiling and it is said to reflect much of the radiant heat. I haven't had time to install it yet so I can't say how effective it is. One roll costed me 6500 pesos, 60 m long and 4 ft wide.

Did you get the type that has foil on both top and bottom - in ACE they sell both types?

[Gator]

Houses I’ve owned in Florida over the years (except one) had the whirly bird type and they worked extremely well.  But they all also had vents in the soffits to allow air circulation. You might need to add them as well. The one house that didn’t have them had a raised n vented ridge cap along the peak (also with vented soffits). It only used natural convection and seemed to work well. It was a white metal roof and also had thick coating of white siliconized coating (Kool Seal brand in the USA). 

[Viking]

14 hours ago, Mike J said:

They have worked really well.  Installed about 8 months ago and no problems or issues so far.  The fans start working early in the day and continue until about 5:00 - 5:30.  When I checked with Lazada to get this screen shot I saw that they also had solar powered whirlybirds.   I think the whirly would be the best for a flat roof.  We also had the radiant foil type insulation installed with the new roof.  Not sure if that is a practical solution if you only have six inch gap from roof to ceiling.  They would need to remove all the ceiling or the roofing to install it. 

 

Thanks, I think solar powered fans would be great but my concern is if they will be stolen when we go back to Sweden. We plan to stay here 5-6 months per year and the remaining time in Sweden.

The regular Whirlybird is probably not as attractive to steal?

[Viking]

9 hours ago, hk blues said:

Did you get the type that has foil on both top and bottom - in ACE they sell both types?

 I specifically asked if it would matter what side is up. The answer was, No, because it's the same on both sides.

It's not the usual foam with aluminum foil on one or two sides. This is with no foam at all, just the aluminum foil.

I haven't seen it in our ACE and I bought it in a company that specializes in roofing materials.

I haven't actually had time to unpack it yet. Hopefully soon.

[Viking]

8 hours ago, Gator said:

Houses I’ve owned in Florida over the years (except one) had the whirly bird type and they worked extremely well.  But they all also had vents in the soffits to allow air circulation. You might need to add them as well. The one house that didn’t have them had a raised n vented ridge cap along the peak (also with vented soffits). It only used natural convection and seemed to work well. It was a white metal roof and also had thick coating of white siliconized coating (Kool Seal brand in the USA). 

I wonder how well the Whirlybirds work from only the hot air rising?

Our place is pretty calm and not a lot of wind.

I just ordered 9 ventilation grills, 20 x 120 cm. Hopefully that will be enough. For sure it will be better than the tiny drilled holes that is the standard way of ventilation here.

Painting the roof with a white heat reflecting paint is also planned 👍

[Gator]

9 hours ago, Viking said:

I wonder how well the Whirlybirds work from only the hot air rising?

Our place is pretty calm and not a lot of wind.

It doesn’t take much to get them spinning. Convection alone is enough. The ones I’ve had were all galvanized tin so they bend quite easily. So obviously check them before and after you install them to make sure they spin freely.

[hk blues]

14 hours ago, Viking said:

 I specifically asked if it would matter what side is up. The answer was, No, because it's the same on both sides.

It's not the usual foam with aluminum foil on one or two sides. This is with no foam at all, just the aluminum foil.

I haven't seen it in our ACE and I bought it in a company that specializes in roofing materials.

I haven't actually had time to unpack it yet. Hopefully soon.

Thank You!

I can't quite picture what you mean as I've only ever seen the foil/foam type but different thickness of foam and one-sided or both-sided foil.  I saw an online debate a while back on the subject of what way up the single-sided type should go and there were contradictory opinions.  

[Possum]

17 minutes ago, hk blues said:

I can't quite picture what you mean as I've only ever seen the foil/foam type

Look up "radiant barrier" for an explanation.