Low R-value walls and high R-value windows: inviting mold?
I have an old house with low r-value exterior walls, they are double wythe brick with an air space between the wythes and then plaster on the interrior. I reckon this wall is about R-2. I need to upgrade windows in several parts of the house and I had planned on using triple pane tilt and turn windows with an R-value of 5. I am in Climate Zone 4. My walls will be colder than the windows, am I inviting condensation and hence mold growth on the walls with this planned change?
By the way, I full understand that in new construction, the money should go towards a better wall and not the windows. But in retrofit, the cost of exterior insulation + new siding for the whole house is about 50K or more. The marginal cost of better windows if you have to replace the old ones anyways is a 1K or so. However, if joining bad walls with good windows is inviting mold, I would rather not do that. I appreciate your thoughts.
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