COOL ROOFS
We have a topic we can now discuss that until recently had been outside our sphere of interest in energy conservation, and that topic is the “cool roof”. Most people tend to think of either the white “Snow-coat” you put on a metal mobile home roof, or that brilliant silver comp shingle or 90 lb. rolled roofing you see on low slope roofs when the term “cool roof” is used. And while those are examples of early cool roofs the products have come a long way. They are of interest to us now because a cool roof is a fundable item under the CHF loan program and PG&E will also pay a rebate on it which makes it worth looking into if you have a roof that is going to need replacing soon.
So, what is a cool roof? There are substances that can be added to a number of different roofing types that cause it to react differently to sunlight. There are two measurements that pertain to a cool roof, “high solar reflectance”, which is the ability to reflect light, at all wavelengths including infrared and ultraviolet, and “high thermal emittance” which is the ability to radiate absorbed solar energy. Both of these measurements are on a scale of between 0 & 1 where 0 indicates a surface that absorbs all solar radiation and 1 represents total reflectivity. The number is expressed as a percent or decimal. Almost every kind of roofing has a cool roof option. Built-up roofing, foam roofing, metal, comp shingle, slate, tile, single ply torch-down, pretty much any kind of roofing has a cool roof branch of the family. They do tend to cost a bit more because the processes required and the special materials needed to cause the sun to “reflect” and “emit” from their surfaces in the proscribed manner are more expensive than the standard materials. But it’s worth in over time. Both the DOE and EPA have calculators at the CRRC website where you can figure your payback and get much more information. And they come in far more interesting colors than white and silver. You won’t find black but you will find shades of dark brown and greens and the “textured” look of the 40 & 50 year comp shingle products, while some carry a lifetime guarantee.
A STUDY DONE
In 2001 the Lawrence Berkeley National Labs did a study on a big building in Texas. They took a lot of summer time measurements while this building had its standard black built-up roof, and then put on a new vinyl membrane cool roof and took the same summer measurements. They found the surface temperature dropped an average of 43 degrees, the average daily temperature went from 168 to 125 degrees, this cut the air conditioner average use by 11% and peak use by 14% and cut the buildings one year cooling costs by $.07 per sq ft or $7,200. Must have been an airplane hanger. But the point is the cool roof works. If it didn’t PG&E wouldn’t be offering a rebate on it. You have to live in climate zones 2,4,11,12,or13, all the zones with lots of cooling degree days. They offer $.20 per sq ft and you can include the overhangs. But what’s really cool, so to speak, is if you need a roof and you qualify for a CHF loan (make less than $87,200 yr, current on mortgage & prop. Taxes). Then you can get the cool roof as part of your 3% loan (Mendocino, Sonoma, 0% in Lake County) and then you get to stick the PG&E rebate in your pocket. And the loan will even cover tear-off and new plywood over skip sheathing if you had a wood shingle roof.
FREE HOME ENERGY ASSESSMENTS
Here is something else that just started that ties into all we’ve been discussing. If you want to know how energy efficient your home is (or isn’t) and to get an idea of what you might be able to do about it, or if you want to see if you can participate in one of the PG&E or CHF loan programs, the first step is a home energy assessment. The CEC has sponsored a rebate for the cost of this home assessment. Administered by Ecology Action and funded by ARRA monies it makes this service free. You can Google Energy Upgrade California, put in your zip code and follow the prompts for the $500 assessment rebate. That’s the first step in a cool roof and some cool information on energy savings. Sign up for the free HERS II rating and get a low interest CHF loan. There’s funding through the end of the year, so don’t wait too long.
We have a topic we can now discuss that until recently had been outside our sphere of interest in energy conservation, and that topic is the “cool roof”. Most people tend to think of either the white “Snow-coat” you put on a metal mobile home roof, or that brilliant silver comp shingle or 90 lb. rolled roofing you see on low slope roofs when the term “cool roof” is used. And while those are examples of early cool roofs the products have come a long way. They are of interest to us now because a cool roof is a fundable item under the CHF loan program and PG&E will also pay a rebate on it which makes it worth looking into if you have a roof that is going to need replacing soon.
So, what is a cool roof? There are substances that can be added to a number of different roofing types that cause it to react differently to sunlight. There are two measurements that pertain to a cool roof, “high solar reflectance”, which is the ability to reflect light, at all wavelengths including infrared and ultraviolet, and “high thermal emittance” which is the ability to radiate absorbed solar energy. Both of these measurements are on a scale of between 0 & 1 where 0 indicates a surface that absorbs all solar radiation and 1 represents total reflectivity. The number is expressed as a percent or decimal. Almost every kind of roofing has a cool roof option. Built-up roofing, foam roofing, metal, comp shingle, slate, tile, single ply torch-down, pretty much any kind of roofing has a cool roof branch of the family. They do tend to cost a bit more because the processes required and the special materials needed to cause the sun to “reflect” and “emit” from their surfaces in the proscribed manner are more expensive than the standard materials. But it’s worth in over time. Both the DOE and EPA have calculators at the CRRC website where you can figure your payback and get much more information. And they come in far more interesting colors than white and silver. You won’t find black but you will find shades of dark brown and greens and the “textured” look of the 40 & 50 year comp shingle products, while some carry a lifetime guarantee.
A STUDY DONE
In 2001 the Lawrence Berkeley National Labs did a study on a big building in Texas. They took a lot of summer time measurements while this building had its standard black built-up roof, and then put on a new vinyl membrane cool roof and took the same summer measurements. They found the surface temperature dropped an average of 43 degrees, the average daily temperature went from 168 to 125 degrees, this cut the air conditioner average use by 11% and peak use by 14% and cut the buildings one year cooling costs by $.07 per sq ft or $7,200. Must have been an airplane hanger. But the point is the cool roof works. If it didn’t PG&E wouldn’t be offering a rebate on it. You have to live in climate zones 2,4,11,12,or13, all the zones with lots of cooling degree days. They offer $.20 per sq ft and you can include the overhangs. But what’s really cool, so to speak, is if you need a roof and you qualify for a CHF loan (make less than $87,200 yr, current on mortgage & prop. Taxes). Then you can get the cool roof as part of your 3% loan (Mendocino, Sonoma, 0% in Lake County) and then you get to stick the PG&E rebate in your pocket. And the loan will even cover tear-off and new plywood over skip sheathing if you had a wood shingle roof.
FREE HOME ENERGY ASSESSMENTS
Here is something else that just started that ties into all we’ve been discussing. If you want to know how energy efficient your home is (or isn’t) and to get an idea of what you might be able to do about it, or if you want to see if you can participate in one of the PG&E or CHF loan programs, the first step is a home energy assessment. The CEC has sponsored a rebate for the cost of this home assessment. Administered by Ecology Action and funded by ARRA monies it makes this service free. You can Google Energy Upgrade California, put in your zip code and follow the prompts for the $500 assessment rebate. That’s the first step in a cool roof and some cool information on energy savings. Sign up for the free HERS II rating and get a low interest CHF loan. There’s funding through the end of the year, so don’t wait too long.
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