RV Motor Home in Florida insulated with Super Therm®
One weatherisation agency’s experience with a new product
This article has been modified for Australian consumers. May 2011. Read full pdf
Successful Super Therm® outcomes
- Average internal temperature improvement was 5.6°c – 12%
- 2 hours to pressure clean the roof the day before and fully dry
- 4 hours for two employees to apply the coating 87m2 by roller
- Applied Super Therm® to the 14 x 60 feet – 840 ft2 (4.8m x 18.2m – 87m2) RV – 2 pails
- The exterior surface temperature was 73°c…after application dropped to 30°c (59% improvement)
- Roof surface temperature of a similar mobile home with a white elastomeric paint was 51.6°c
- The motor home owner reported that she had not turned on her air conditioning since the day the roof was coated
- SJHP’s assessment is that Super Therm® works well and meets their purpose and budget. It was relatively easy to apply and does not require significant application skills, other than normal diligence and care. They were very impressed with the immediate temperature changes after application.
The St. Johns Housing Partnership is a private, nonprofit agency in St. Augustine, Florida, that promotes safe, decent, and affordable housing. The repair and weatherisation of single – family and multi-family residences are a main focus of our work.
In addition to residents’ security and comfort, a specific intent is to reduce residents’ utility bills. Toward this, we occasionally have the opportunity to experiment with new products and technologies. Recently, SJHP experimented with a new “green” product: Super Therm®– a liquid insulation that blocks the loading of solar heat on roofs. Interior building and ceiling temperatures are said to drop within minutes of applying Super Therm® to the roof surface – and even more over days when the application cures.
As its promo reads: “Super Therm® is leading the green movement by turning black roofs into insulating white roofs.” And you just paint it on!
As primarily a roof coating, the product can be used on any roof surface – wood, metal, or tile – when used with a recommended primer product (Super Base).
We applied Super Therm® to the 14 x 60 feet – 840 ft2 (4.8m x 18.2m – 87m2) metal roof of an older single – wide mobile home and took comparison readings of “before” and “after” temperatures to see what impact this insulating product has on reducing interior temperatures and utility costs. The mobile home’s roof had not been cleaned in years. First, we pressure washed the roof to clear it of debris, dirt, and fungus, common in the hot humid Florida climate.
Then we applied Super Therm® with paint rollers. Even our high school intern was able to apply the paint with ease. Super Therm® is a multi-ceramic coating that combines high- performance urethanes and acrylics with resin additives in a waterborne formula.
The only care required in application is to ensure the film thickness in order for the coating to be effective. Super Therm® should be applied at 18 mils wet and never less than 10 mils dry. The coating dries within one hour in 70° F (21°c) and bright sun. Always allow for two hours of direct sunlight to properly dry after application. While we used regular paint rollers, it can be applied with a paint sprayer, but remove all filters when using a sprayer . According to the manufacturer, the product fully “cures” in 21 days.
The SJHP’s interest in Super Therm® as an insulating paint w as to test its promise of reducing heating and cooling costs by up to 70%. The manufacturer states that “Super Therm® blocks 95% of the three sources of heat: visual light, ultra-violet rays, and infrared rays. The surface temperature of a roof will always be within 5 degrees of ambient temperature, once Super Therm® is applied. The manufacturer claims additional benefits of Super Therm® to reduce water and moisture penetration, prevent mold and mildew, and r educe air infiltration —all important features to weatherisation work.
According to its MSDS reports, Super Therm® is water based and environmentally friendly. Its volatile organic compounds (VOCs) are only 67 grams per liter when the safety limit is 420 grams. Super Therm® is also 11.9 times less toxic than typical latex paint, whose VOCs are 250 grams per litre. To measure the effectiveness of Super Therm® for lowering interior temperatures, we took readings with an infrared camera. We used a Flir B40 thermal imaging infrared camera pointed at the ceiling from a distance of 3.3 feet (1 metre).
Because inside temperatures are claimed to drop within minutes, we took initial readings of a portion of the mobile home’s roof painted with Super Therm® compared with a portion of the roof not painted. We saw an immediate drop of 7° F (3.8°c).
For a more extensive comparison of temperature differentials, we took interior photos throughout the mobile home before we applied the product and then returned two days later under similar weather conditions and took additional photos from the same interior locations. The differential among the set of nine before-and-after photos ranged from 7.9 to 12.5°F – (4.3°c to 6.9°c) an average reduction of 10.2°F (5.8°c).
Data in the following table reflect the differentials in the infrared photos that follow.
|Photo Location internal||Temperatures °F||Differential||% improvement|
|Within Mobile Home||Before 26 May 2011||After 28 May 2011||Degrees F (c)|
|Kitchen ceiling northwest side||84.7||73.0||11.7 (6.5°c)||13.9%|
|Kitchen on west side||84.6||72.1||12.5 (6.9°c)||14.8%|
|Kitchen ceiling at center||82.6||72.9||9.7 (5.3°c)||11.8%|
|Bathroom ceiling||83.7||73.8||9.9 (5.5°c)||11.9%|
|Living room southeast ceiling||83.6||72.4||11.2 (6.2°c)||13.4%|
|Living room ceiling at center||82.8||74.1||8.7 (4.8°c)||10.5%|
|East bedroom at ceiling fan||83.8||75.9||7.9 (4.3°c)||9.5%|
|East bedroom ceiling||83.7||73.9||9.8 (5.4°c)||11.7%|
|West bedroom ceiling||84.6||74.3||10.3 (5.7°c)||12.2%|
Average differential for internal comfort is 10.2°F (5.6°c – 12% improvement). For all entries, reflected apparent temperature was 68.0°F (20°c) and emissivity was 0.98.
The application of Super Therm®, although labor intensive, did not take long: 2 hours to pressure wash the roof the day before and 4 hours for two employees to apply the paint. A 5-gallon (18.9 litres) pail of Super Therm® covers about 100 feet2 per gallon at a cost of $200 per gallon.
The exterior surface temperature of the mobile home’s metal roof on a windy 85°F (29.4°c) day was 164°F (73.3°c). After application, the surface temperature dropped to 86°F (30°c).
When we measured the roof surface temperature of a similar mobile home whose roof SJHP had coated with a white elastomeric product, the exterior surface temperature of that roof was 125°F (51.6°c).
When SJHP weatherization auditors returned to the original mobile home a week after our experiment with Super Therm®, the owner reported that she had not turned on her air conditioning unit since the day the roof was coated.
The interior temperature was comfortable, which offers a tremendous savings for this particular elderly mobile homeowner, who carefully watches her expenses in order to purchase necessary medications.
Follow-up measurements may be taken in the weeks after application to verify additional readings. Even without further readings, SJHP’s assessment to date is that Super Therm® works well and meets our purpose and budget. It was relatively easy to apply and does not require significant application skills, other than normal diligence and care. We were very impressed with the immediate temperature changes after application.