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Thermally Efficient Home


Maine farmer

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Reflective film over the roof? And maybe some insulation tiles on the ceiling? 

 

Yes, I'd thought of that as well. The problem is the fixing. We have an unusual climate which offers around 99.5% of the time absolute windstill. The 0.5 % is extraordinary gales which take the form of swirling gusts blowing in all directions. A lot of people get lulled into a false sense of security then wake up one morning to find their garden furniture half a mile away, torn to shreds. I can't think of a way to fix something which would reflect sunlight, and I don't even know where I could get the material.

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Yes, I'd thought of that as well. The problem is the fixing. We have an unusual climate which offers around 99.5% of the time absolute windstill. The 0.5 % is extraordinary gales which take the form of swirling gusts blowing in all directions. A lot of people get lulled into a false sense of security then wake up one morning to find their garden furniture half a mile away, torn to shreds. I can't think of a way to fix something which would reflect sunlight, and I don't even know where I could get the material.

You mean this sort of thing?  https://www.solec.org/lomit-radiant-barrier-coating/reflective-roof-coating/nggallery/slideshow

 

I'm sure there must be a way to stick it down. I suppose you could even get mirror tiles if you were that desperate. Wonder what the neighbours would think, though. Could they sue you for making them blind? 

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You mean this sort of thing?  https://www.solec.org/lomit-radiant-barrier-coating/reflective-roof-coating/nggallery/slideshow

 

I'm sure there must be a way to stick it down. I suppose you could even get mirror tiles if you were that desperate. Wonder what the neighbours would think, though. Could they sue you for making them blind? 

 

The link doesn't work, and we don't actually have any neighbours (hooray!)

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The link doesn't work, and we don't actually have any neighbours (hooray!)

The link worked OK when I tried it just now. This is a US company, solec.org, making reflective roof paint. I quote:

 

"LO/MIT-I is an ENERGY STAR certified radiant barrier roof coating that is formulated to reduce roofing surface temperatures at low cost. LO/MIT is a silver-colored, non-thickness dependent, low emissivity paint, which may be used in almost any application where infrared (heat) reflectivity or diffuse light reflectivity is required. It can be used on a wide variety of roofing substrates, from metals and rubbers, to stone, concrete, asphalt, some foams and more, no primer required in most cases"

 

Sounds like just what you need, I'd have thought. 

 

P.S. That awful scherado person has been banned, I see. Break out the champagne! 

Edited by exchemist
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P.S. That awful scherado person has been banned, I see. Break out the champagne! 

I thought the tone here seemed friendlier today :clap:   It's also nice to see more conversations involving actual science.

 

The link worked OK when I tried it just now. This is a US company, solec.org, making reflective roof paint. I quote:

 

"LO/MIT-I is an ENERGY STAR certified radiant barrier roof coating that is formulated to reduce roofing surface temperatures at low cost. LO/MIT is a silver-colored, non-thickness dependent, low emissivity paint, which may be used in almost any application where infrared (heat) reflectivity or diffuse light reflectivity is required. It can be used on a wide variety of roofing substrates, from metals and rubbers, to stone, concrete, asphalt, some foams and more, no primer required in most cases"

 

Sounds like just what you need, I'd have thought. 

 

 

I know they say it works on stone and concrete, but my experience in applying coatings to concrete proved less than ideal.  Concrete is quite porous, and it took several coats.  Perhaps they came up with a better formula that can't be so quickly absorbed?

Edited by Farming guy
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The link worked OK when I tried it just now. This is a US company, solec.org, making reflective roof paint. I quote:

 

"LO/MIT-I is an ENERGY STAR certified radiant barrier roof coating that is formulated to reduce roofing surface temperatures at low cost. LO/MIT is a silver-colored, non-thickness dependent, low emissivity paint, which may be used in almost any application where infrared (heat) reflectivity or diffuse light reflectivity is required. It can be used on a wide variety of roofing substrates, from metals and rubbers, to stone, concrete, asphalt, some foams and more, no primer required in most cases"

 

Sounds like just what you need, I'd have thought. 

 

P.S. That awful scherado person has been banned, I see. Break out the champagne! 

 

Yes, it does sound like what I need, indeed, I'm not trying to make things difficult, but the roof is covered with old clay tiles (salvaged from the older roof of the derelict house which we renovated. Because there were good reasons not to bring attention to the renovation process, we made an effort to retain the aspect of the building). These tiles are probably 150 years old, very brittle and probably impossible to paint successfully. That plus being too brittle to walk on means the process would be very difficult. But I shall investigate.

 

Meanwhile, scherado is elsewhere: http://www.scienceforums.net/topic/107226-0%C3%B70/?tab=comments#comment-1015165

 

What an idiot

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Yes, it does sound like what I need, indeed, I'm not trying to make things difficult, but the roof is covered with old clay tiles (salvaged from the older roof of the derelict house which we renovated. Because there were good reasons not to bring attention to the renovation process, we made an effort to retain the aspect of the building). These tiles are probably 150 years old, very brittle and probably impossible to paint successfully. That plus being too brittle to walk on means the process would be very difficult. But I shall investigate.

 

Meanwhile, scherado is elsewhere: http://www.scienceforums.net/topic/107226-0%C3%B70/?tab=comments#comment-1015165

 

What an idiot

 

Hahahaha.

 

And already triggering an immune response, I see:-

 

Scherado: "Yes to all that, but does anyone know the reason we can't divide by zero?

                   I give the answer in five words, no numbers. I will give my answer tomorrow."

 

Moderator: " This posting style/tactic gets really old, really fast. Discontinue your implementation of it, please. "

 

:)

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Yes, it does sound like what I need, indeed, I'm not trying to make things difficult, but the roof is covered with old clay tiles (salvaged from the older roof of the derelict house which we renovated. Because there were good reasons not to bring attention to the renovation process, we made an effort to retain the aspect of the building). These tiles are probably 150 years old, very brittle and probably impossible to paint successfully. That plus being too brittle to walk on means the process would be very difficult. But I shall investigate.

 

 

Is the house under some sort of historical preservation effort?  I understand trying to preserve history, but it can be hard to balance with modern living.  I know somebody manufactures solar tiles that can replace the old clay tiles, but I suppose that might offend the aesthetics ?

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Is the house under some sort of historical preservation effort?  I understand trying to preserve history, but it can be hard to balance with modern living.  I know somebody manufactures solar tiles that can replace the old clay tiles, but I suppose that might offend the aesthetics ?

 

No it isn't under preservation order, so theoretically I don't think it would be a problem. But we operate on a very small budget (= UK state pension *sob*) and that sounds like an expensive although brilliant solution (pun intended). The other issue is rather undefined because I'm not sure what the local building regs would say to a roof which is totally unlike any other, plus they demand a tax on any alterations (which is why the renovation was very discreetly done). Another issue is the unavailability of building materials here. You would no believe how impossible it is. 

 

Can you send me a link for more info about these tiles?

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Hahahaha.

 

And already triggering an immune response, I see:-

 

Scherado: "Yes to all that, but does anyone know the reason we can't divide by zero?

                   I give the answer in five words, no numbers. I will give my answer tomorrow."

 

Moderator: " This posting style/tactic gets really old, really fast. Discontinue your implementation of it, please. "

 

:)

 

That thread gets better. Have another look. ..

.

By the way - how do you find out about banned members? It's usually the most entertaining thread on any forum.

Edited by DrKrettin
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That thread gets better. Have another look. ..

.

By the way - how do you find out about banned members? It's usually the most entertaining thread on any forum.

Indeed! Roll up, roll up, place your bets, ladies and gents, how long will it be before scherado is banned from scienceforums.net? A new spectator sport is born. 

 

Oh, and "community rating -7, poor." When I checked earlier it was -1,  so he's going south quite fast. 

 

P.S. If you have 5 mins, this thread is even funnier: http://www.scienceforums.net/topic/110293-time-the-civilizational-edifice-and-handmaiden-of-matter/?tab=comments#comment-1015292

 

I see my old friend Strange from thescienceforum.com having some fun at his expense!  

Edited by exchemist
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Indeed! Roll up, roll up, place your bets, ladies and gents, how long will it be before scherado is banned from scienceforums.net? A new spectator sport is born. 

 

Oh, and "community rating -7, poor." When I checked earlier it was -1,  so he's going south quite fast. 

 

P.S. If you have 5 mins, this thread is even funnier: http://www.scienceforums.net/topic/110293-time-the-civilizational-edifice-and-handmaiden-of-matter/?tab=comments#comment-1015292

 

I see my old friend Strange from thescienceforum.com having some fun at his expense!  

 

 

Haha - scherado has just had a bollocking from a mod, and the thread closed.

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It's a small house with a wooden roof with a concrete layer on top, covered with tiles, and the bedroom is just a mezzanine immediately below it. With a week's worth of direct sunlight on the roof, it acts as a heat radiator at night, so no amount of freezing air from the AC had any effect apart from giving us sore throats.** So you may ask what the point of cool air from the cave might be. I was thinking possible large amounts of cool air would be better than cold from the AC.

 

My other idea was to install a water spray directly onto the tiles of the roof to prevent it heating up, but the water is metered and not cheap, plus the residue from evaporated water might might a mess. All in all, I'm rather stumped.

 

** so a ceiling fan would just draw hot air down. I have installed a powerful fan which blows air sideways into the bedroom, having removed all the security grills to make it very quiet.

You've identified the problem.  You are storing solar energy when you don't want it and trying to overcome it through evaporative cooling (which only works in very dry climates) and through conventional means like AC.

 

Where I live, anything less than 12 inches of actual insulation in the attic is insufficient.  UV barriers would help to a degree, better attic air circulation will be beneficial, and a reflective roof rather than a dark roof will certainly help, but if your problem is solar thermal storage and you can't provide for enough insulation between the roof and your ceiling, then you have a fundamental problem you will have to address and unfortunately no quick fix will be sufficient if your goal is efficiency.  Most new homes built in my area don't even approach this standard.  Insulation works because it traps air pockets and prevents heat convection.  I would venture to guess that unless you live in an extremely arid environment, no amount of evaporative cooling will be sufficient.  And if you do live in such an arid environment, chances are that the water is more precious than the electricity required to condition the air.  If you can pump in cool, dry air, then do so.  However, while you'll find many websites that advocate pumping intake air through corrugated pipes in order to bring in cool air, I venture to guess that you'll find almost none that actually address the unique situation you live in and would be worthwhile.  There's a lot of crap that can be found on the internet.  The best way to exchange heat from the outside air to the ground is not through conduction of air, but rather through more massive mediums such as those used in geo-thermal heat pumps.  Swamp coolers and any kind of buried piping system that you can install without specialized equipment are not likely to be appropriate in most situations.

 

The way I see it, you've got two ways to go.  Either abandon the high thermal mass roof you've got by separating the roof from the living space  through thick insulation or replacing the roof entirely, or go whole hog the other way and go for a living roof (if your structure can support it).  A living roof will effectively make your living area equivalent to a cave and moderate the extremes that you are experiencing due to solar heat storage, but is extremely heavy.

 

Fundamentally, you've got to consider what the average air temperature is in your environment throughout the year and how that compares to what temperature you want to maintain in your living space.  Couple this with the average solar energy that your home receives.  If it's usually more hot than cold, then you don't want to incorporate designs that retain heat.  If it's close to an even spread, then you'll want to use constructions that incorporate high thermal mass walls that allow low-incident light to heat the structure while high-incident rays are reflected or insulated against.

 

It is possible, even in hot desert climates, to maintain relatively acceptable temperatures in living areas with limited energy expenditure.  But if you are in a high humidity, warm environment, you've got to protect against solar heating, as there's no economical way to deal with it if you let your structure capture solar heat.

 

AC is literally using energy to heat the exterior to make your living space cooler.  If you're starting at an exterior temperature that is tens of degrees higher than you desire on the interior, then you're going to have to expend a lot of energy to have a comfortable living area.  Add in massive heat traps like your roof and you're swimming upstream.

Edited by JMJones0424
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The way I see it, you've got two ways to go.  Either abandon the high thermal mass roof you've got by separating the roof from the living space  through thick insulation or replacing the roof entirely, or go whole hog the other way and go for a living roof (if your structure can support it).  A living roof will effectively make your living area equivalent to a cave and moderate the extremes that you are experiencing due to solar heat storage, but is extremely heavy.

 

 

 

Thank you for your input - very thoughtful. The living roof idea is probably the ideal solution, but totally unrealistic because I would not want to subject the walls of the house to anything heavier than the present roof. The thick insulation under the roof could be an option, because the roof has exposed 8-inch beams and I could insulate between the beams and close it all off. 

 

It is a frustrating problem because everything is fine 95% of the time, but now and again we get these heat waves which make life difficult for maybe a total of two weeks of the year. The various solutions all involve a considerable expense and a lot of labour, and the thick insulation between the beams would alter the character of the place. All this just to solve a short-term discomfort in summer.

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