Attic ventilation: What to do?
Hi GBA,
I have a 1950’s brick cape in southern CT (believe zone 5) with an ~5ft tall attic, gable vents only, no ridge vent or fans. Being an old house it is far from air tight. Soffts are open between rafters but filled with solid, rather than perforated material. Attic is insulated to R39 and rafter vents are installed.
We do not have a particular issue w/ hot ceilings, but with a black asphalt roof the attic does get very hot on sunny summer days. The house is almost exactly north-south gable to gable and receives direct sunlight pretty much the entire day. We have central air w/ ducts installed in the attic, which is a bit leaky but at least it’s insulated. It is mostly flex which I plan to replace with metal soon, and can address sealing issues at that time, and I would also like to further cover in deeper insulation eventually.
I have a pro working on some post-remodel siding and was asking him about cooling the attic. I have already been sworn off cooling fans due to several articles detailing their fallacy, including ones here on GBA (so thanks for that info!). I am considering to replace the solid soffit materials with perforated, but the cost is pretty high since it will require removing gutters and old fascia trim and re-bending and re-installing.
My question is simply whether it’s worth it to do just to get some additional ventilation. My concern is without a fan and ridge vent, will perforated material improve anything significantly to justify a cost of 1-2k of work? I also don’t want to waste money on half solutions, so if I need a ridge vent to make it work, that will just be additional cost and pressure on ROI.
Any advice appreciated, and thanks as always for this wonderful resource!
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Replies
G.S.,
1. Improving attic ventilation will not appreciably lower your attic temperature.
2. Unless you see signs of mold on your roof sheathing, there is no reason to believe that you need more attic ventilation. For more information on this issue, see All About Attic Venting.
3. If your attic didn't have any HVAC equipment or ducts in it, the first order of business would be to perform air sealing work at the ceiling level (under the insulation). But since your attic has an air handler and ductwork, you should consider converting your vented unconditioned attic into an unvented conditioned attic -- or, alternatively, you should consider abandoning your attic equipment and ducts, and purchasing one or two ductless minsiplits to provide air conditioning for your upper floor. (This approach is sometimes cheaper than creating an unvented conditioned attic.)
For more information, see Creating a Conditioned Attic.