Currently have a split level with 600 sq ft each with 1 turbine and 1 louvred vent on low side and 2 louvred vents on high side. ACU operates excessively. Look at intake, insulation, new ACU, ridge vent but feel attic air not moving out fast enough is the problem. This could be restricted intake or vent.

  • Installed approx R30 to R50 additional blown fibreglass insulation 4 yrs ago. Not much benefit in hot summer with AC on all day every day in hot summer rising above room temp. (12~18" in addition to existing R30?)
  • noticed previous renovators blocked off soffits over garage , so I tore out alum. slit soffits and plywood and put in mosquito netting for soffit stapled in place over frame inserts.
  • Upgraded to New 5 ton ACU installed 2 years has improved home cooling but still can run excessive times, often all day but acceptable temp (25'C)
  • roof is getting old on solar side and getting it replaced soon and there are some minor rain leaks with ceiling very slight damage in 2 spots.

What I want to do is reduce the ceiling air temp from roof heat penetration so AC has less work to do. Roofer is planning to use large square tall vents like Japanese pagoda but not curved. Looks OK, but HOW much better are they? if any. Often the turbine is not moving in no wind days.

Should I invest in motor-driven turbine? or what do you suggest?

louvered vents enter image description here

ridge vent enter image description here

turbine enter image description here

With 600 sqft of sun exposure I estimate 60kW of solar heat with R50 but it still seems like a thermal air flow problem.

1 Answer 1


I would suggest a solar powered vent that way when it is sunny or more heat load the solar powered vent(s) can do a better job at removing the excess heat.

the first house I added a fan I used a standard 120v thermally activated fan it would kick in mid morning and cut out in the late evening it made a massive difference in that homes comfort but did cost a few dollars for the power.

the next house I used solar. The great thing about solar is I have the highest airflow in the early afternoon when it really needs it and it was still cooling until the evening. I live right at the 45 parallel so your results may be different than mine But the solar fan was great really reduced the heat load in each house and became the first thing I have done to my houses Before the first summer. I have not lived in any of my last 3 homes long enough for the fan to fail or the solar cells but as with most motors greasing or oiling the bearings extends the life and the solar cells were rated at 20 years. I have had really good luck with solar but Oregon rarely gets 100+Lots of hazy cloudy days so maybe my solar cells are lasting longer because of that reason. I do have to spray them off with water as the horses kick up dust and that slows the fan down. But that is the extent of my maintenance at my current home after 5-6 years.

  • 1
    I am now wondering about rafter vents to the peak or rigid foam between joists, southern roof gets really hot Aug 15, 2020 at 7:07
  • I have used ridge vents that one looks much larger than what I have used. To tell the truth I did not think the ridge vent I used on my shop worked that great it looked great. I quit most roofing about 15 years ago but since I have had both knees replaced may do it for myself and family. Do you have any specs on that ridge vent? The type I used was fairly low profile. Thermal barrier stapled up on the south may reflect more heat you may check into that.
    – Ed Beal
    Aug 15, 2020 at 14:42
  • I also put up a low profile one too to prevent ☔️. But not good enuf. I have decided to go metal roof but wonder if they have an air gap for cooling on firing strips or does that make them too noisy? But I too cannot do heavy work since my bypass to arm with nerve damage Aug 15, 2020 at 14:44
  • I have not used the high profile the standing seam roofs I put up were in contact with the decking but a lighter color will help.
    – Ed Beal
    Aug 15, 2020 at 14:50
  • Can you overlay on shingles ? Some black paints are light grey to infrared Aug 15, 2020 at 15:03

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