U-Factor and SHGC Climate Zone 1A (warm-humid) and Fenestration

[jar546]

High Rise R2
Is this compliant with the energy code?

 

[steveray]

Typo?

 

[jar546]

Typo?

That's a great question.

 

[steveray]

For those of you following along at home.....I've never seen a U-Factor (the reciprocal of R-value) that high...1.05.... His code (and by his code, I grabbed 2021 IECC and the commercial portion at that(as he seems to above the third story from the view or it would be residential)) seems to require something around half of what that window says depending on whether or not it opens:



And it seems like the SHGC might be OK as long as it is fairly well shaded....Because that is what we should be doing...

 

[RLGA]

Regarding the U-factor—not even close.

Regarding the SHGC—depends on the projection factor and orientation. It may or may not comply.

 

[RLGA]

From the 2023 Florida Energy Conservation Code. U-factor complies with requirement for an entrance door. So if this is a door, then it might possibly be okay. However, as a window, it definitely does not comply.

Next question: did they use the prescriptive method or the component performance alternative? If they used the latter, then they may be allowed to have under-performing fenestration if other building components (e.g., walls, doors, roofs, etc.) are over-performing (i.e., have U-factors that exceed the minimum performance in areas greater than that of the fenestration).

 

[jar546]

Next question: did they use the prescriptive method or the component performance alternative? If they used the latter, then they may be allowed to have under-performing fenestration if other building components (e.g., walls, doors, roofs, etc.) are over-performing (i.e., have U-factors that exceed the minimum performance in areas greater than that of the fenestration).

All of the windows and doors in the condo were replaced. The photo is one of the windows, not one of the two sliders replaced.

 

[Paul Sweet]

A U value of 1.05 would be for single glazing, not insulated glazing.

 

[jar546]

A U value of 1.05 would be for single glazing, not insulated glazing.

These are all thick, impact-rated windows with significant wind pressure ratings.

 

[jar546]

OK, Here is the rub with this one according the the Florida Building Code - Energy. I think I've led you down this path long enough.

C101.4.2​

Buildings exempt from the provisions of the Florida Building Code, Energy Conservation, include existing buildings except those considered renovated buildings, changes of occupancy type or previously unconditioned buildings to which comfort conditioning is added. Exempt buildings include those specified in Sections C101.4.2.1 through C101.4.2.4.

RENOVATED BUILDING. A residential or nonresidential building undergoing alteration that varies or changes insulation, HVAC systems, water heating systems or exterior envelope conditions, provided the estimated cost of renovation exceeds 30 percent of the assessed value of the structure.

So basically, this is telling me that replacement windows don't require energy code compliance. What do your codes say?

 

[steveray]

OK, Here is the rub with this one according the the Florida Building Code - Energy. I think I've led you down this path long enough.

C101.4.2​

Buildings exempt from the provisions of the Florida Building Code, Energy Conservation, include existing buildings except those considered renovated buildings, changes of occupancy type or previously unconditioned buildings to which comfort conditioning is added. Exempt buildings include those specified in Sections C101.4.2.1 through C101.4.2.4.

RENOVATED BUILDING. A residential or nonresidential building undergoing alteration that varies or changes insulation, HVAC systems, water heating systems or exterior envelope conditions, provided the estimated cost of renovation exceeds 30 percent of the assessed value of the structure.

So basically, this is telling me that replacement windows don't require energy code compliance. What do your codes say?

Interesting....Does that screw up any of your FEMA money? We should do that....2021 is horrible, it does get better (less restrictive, not less convoluted) for existing in 2024.....