Reworking an Existing Building Envelope for a Hot-Humid Climate
Long time lurker, first time question asker
Background: I am renovating an old Sears and Robuck’s house- my second over hundred year renovation- and it needs to be fully reworked so I am spending a lot of time thinking about the envelope since I will be rebuilding it anyway. I live in the Southeast (45 NE of Atlanta in climate zone 3A) with “hot humid summers” and “mild winters” but my family’s usage pattern in our current home and likely in this house do not match most other households. We do not use our air conditioning. Our bills are high in late December, January, February, and early March due to heating but beyond that we don’t really use our HVAC system. My plan for this house is to make sure that I have lots of cross ventilation and fans for open windows in summer and to plant some shade trees- we’ve spent a lot of time up there and even without those changes it doesn’t really get crazy hot. For winter we are planning insulated shutters inside and out to reduce heat loss from the windows and are very excited about having a wall of south facing glass under our porch. However, I think I will need lots of insulation and at least a ductless mini-split for heating those 3 months. Currently the house has basically no insulation, standard ventilated attic and crawlspace.
This leads me to my question: Should building envelope design change based on behavior? How should I think about those modifications?
My primary concern is how I should think about/approach the building envelope, especially considering that several months of the year the indoor air (if you can even call it that since the entire house will likely be open). I want my house sealed up in winter to keep the warm air in, but am concerned about trapping moisture inside, spending too much money insulating the wrong thing (there is a lot of information on closed roof space in my climate zone to reduce heat but given my usage I don’t think its beneficial) or relying on lots of electricity powered equipment for minimal results. GBA has a lot of guides for my area that center around optimizing for a high heat climate and maximizing cooling which isn’t right for us, but for sure treating my home like a house in Ontario isn’t the answer either. Any good resources for figuring out the right for us building envelope?
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