[roadrnnr]

just wondering if this is done in here to reduce heat in the garage?

I have a small courtyard villa

[jrref]

I resisted insulating the attic above the garage for a long time. But after I did it, I find my garage is about 5 -10 degrees cooler than the outside temperature assuming the car was not driven in hot and the door was closed. We had ours done by the Solar Guys. You can take a credit on your income tax for this home improvement.

[CarlR33]

Originally Posted by roadrnnr

just wondering if this is done in here to reduce heat in the garage?

I have a small courtyard villa

Might do a search as there have been many posts regarding reducing garage and attic heat as well as using solar fans, etc. as I had the same questions.

[retiredguy123]

The basic concept of insulation is that you add insulation between a conditioned space and an unconditioned space to slow down the rate of heat transfer between the two spaces. Builders do not insulate the garage ceiling because the garage and the attic are both unconditioned spaces. Heat always flows from a hotter space to a cooler space until both spaces become the same temperature. If you park a hot vehicle in the garage, the garage will actually become hotter until the heat from hot vehicle flows into the attic. So, in that case, an insulated ceiling will actually act to prevent the garage from cooling down. But, regardless of whether or not you insulate the garage ceiling, the insulation will only slow down the normal heat transfer process until a state of equal temperature is achieved. This process usually takes less than about an hour. After that, the insulation does nothing. So, insulating the garage ceiling will not result in a consistenty lower temperature in the garage. Actually, in the evening, when the attic cools down, an insulated garage ceiling will slow down the time it takes to cool down the garage.

[asianthree]

Originally Posted by retiredguy123

The basic concept of insulation is that you add insulation between a conditioned space and an unconditioned space to slow down the rate of heat transfer between the two spaces. Builders do not insulate the garage ceiling because the garage and the attic are both unconditioned spaces. Heat always flows from a hotter space to a cooler space until both spaces become the same temperature. If you park a hot vehicle in the garage, the garage will actually become hotter until the heat from hot vehicle flows into the attic. So, in that case, an insulated ceiling will actually act to prevent the garage from cooling down. But, regardless of whether or not you insulate the garage ceiling, the insulation will only slow down the normal heat transfer process until a state of equal temperature is achieved. This process usually takes less than about an hour. After that, the insulation does nothing. So, insulating the garage ceiling will not result in a consistenty lower temperature in the garage. Actually, in the evening, when the attic cools down, an insulated garage ceiling will slow down the time it takes to cool down the garage.

Interesting thought process. We had Solar guys insulate our south face doors. Asked about insulation above garage. He said give us a call if you add a mini split, without mini split, blown extra insulation in garage is good for snow, not heat. But if we wanted to add insulation to rafters that would help? Thoughts?

[dewilson58]

We did our garages during construction.

Depending on the day..................10 to 20 degrees cooler.

Very cheap investment.

[retiredguy123]

Originally Posted by dewilson58

We did our garages during construction.

Depending on the day..................10 to 20 degrees cooler.

Very cheap investment.

20 degrees cooler than what? My HVAC system doesn't even keep the inside temperature 20 degrees cooler than the outside temperature.

[dewilson58]

Originally Posted by retiredguy123

20 degrees cooler than what? My HVAC system doesn't even keep the inside temperature 20 degrees cooler than the outside temperature.

Attic temperature.

Thanks for asking............not.

[asianthree]

Originally Posted by dewilson58

We did our garages during construction.

Depending on the day..................10 to 20 degrees cooler.

Very cheap investment.

But if you insulated during construction what do you have to compare temperature that it is cooler?

Looking for before and after insulation results. Just with door insulation we found a 12 degree difference from June before door insulation and June after. Keeping temperature for those months was pretty consistent. Other months temperatures were too far apart for accurate comparison.

Our garage is 20° + less early morning (5-7a) than 10pm temp. Above garage is only builder insulation.
We are considering adding insulation in garage roof rafters, but haven’t noticed any newer facts.

[dewilson58]

Originally Posted by asianthree

But if you insulated during construction what do you have to compare temperature that it is cooler?

Looking for before and after insulation results. .

Have wireless temperature sensors in attic, in garage.

Don't need "before & after insulation results"..............I have realtime facts.

[retiredguy123]

Originally Posted by asianthree

But if you insulated during construction what do you have to compare temperature that it is cooler?

Looking for before and after insulation results. Just with door insulation we found a 12 degree difference from June before door insulation and June after. Keeping temperature for those months was pretty consistent. Other months temperatures were too far apart for accurate comparison.

Our garage is 20° + less early morning (5-7a) than 10pm temp. Above garage is only builder insulation.
We are considering adding insulation in garage roof rafters, but haven’t noticed any newer facts.

Correct. You really need to compare temperatures in the garage before and after installing the ceiling insulation, and at different times during the day. The attic temperature doesn't mean much because hot air rises. The temperature inside my garage almost never exceeds the outside air temperature, and my garage ceiling is not insulated.

Personally, I don't think adding insulation to the rafters will provide much benefit, if at all. It could even keep the attic hotter longer after the sun goes down.

[Tvflguy]

Originally Posted by dewilson58

Attic temperature.

Thanks for asking............not.

Yikes. Perhaps change your title to “Mr. Sensitive”….

[Boffin]

Originally Posted by roadrnnr

just wondering if this is done in here to reduce heat in the garage?

I have a small courtyard villa

Installed radiant heat barrier on rafters.

[dewilson58]

Originally Posted by retiredguy123

Correct. You really need to compare temperatures in the garage before and after installing the ceiling insulation, and at different times during the day. The attic temperature doesn't mean much because hot air rises. The temperature inside my garage almost never exceeds the outside air temperature, and my garage ceiling is not insulated.

Personally, I don't think adding insulation to the rafters will provide much benefit, if at all. It could even keep the attic hotter longer after the sun goes down.

Insulating the rafters above the house will not provide much benefit either.

[It's Hot There]

Originally Posted by asianthree

But if you insulated during construction what do you have to compare temperature that it is cooler?

Looking for before and after insulation results. Just with door insulation we found a 12 degree difference from June before door insulation and June after. Keeping temperature for those months was pretty consistent. Other months temperatures were too far apart for accurate comparison.

Our garage is 20° + less early morning (5-7a) than 10pm temp. Above garage is only builder insulation.
We are considering adding insulation in garage roof rafters, but haven’t noticed any newer facts.

Before and after results are pretty much impossible because duplicating conditions is impossible. Duplicating inside/outside temp, rising temp rate, clouds, etc.