Title 24 Window Replacement

Specified From the Numbers, Not the Brochure

The California Energy Code, which everyone calls Title 24, does not care what the window is called or who made it. It cares about two tested values printed on the NFRC label, and whether the units you installed match the compliance form filed against your permit.

That is the whole job in one sentence, and it is why we quote from a spec sheet.

The Prescriptive Path

Most Riverside replacement jobs go down what the code calls the prescriptive path. It is the simple route. Meet the stated limits on every window and you are done, with no energy modelling required.

On that path an altered fenestration product currently needs a U factor of 0.30 or lower and an SHGC of 0.23 or lower. Those two limits are the reason so many perfectly decent windows sold elsewhere cannot legally go into your wall here.

We check the current requirement with the building department before ordering rather than reciting it from memory. The standards are revised on a cycle, and a number that was correct on the last job is not evidence about this one.

The Performance Path

There is a second route. A whole house energy model can trade one measure against another, so a project with an unusual amount of glass, or one where the homeowner wants a specific unit that misses a limit slightly, can sometimes still be approved. It costs money to have the model run and it takes time, so it is not the default. On a straightforward swap of eight or ten openings it is almost never worth it.

We mention it because it is the honest answer to why a neighbour’s job used a window yours cannot.

What We Actually Do

We measure every opening, note which direction each one faces, and write the order with that in mind. West and southwest glass gets the aggressive low-E coating with the lowest practical SHGC. North glass, which sees almost no direct sun, gets a package with more visible light so the room does not go grey. Both stay inside the code limits. The difference in cost between a mixed order and a single package is smaller than most people expect.

Then we prepare the CF2R energy compliance documentation for the permit, install, and leave the temporary labels on the glass.

Leave the Stickers On

This is the single most common way a finished window job fails its final inspection, and it has nothing to do with workmanship.

The inspector stands in the room and reads the temporary NFRC label stuck to each installed unit. They compare the U factor and SHGC on it against the values on the compliance form. If the labels are gone, there is nothing to verify, and you are into a paperwork exercise involving the manufacturer to prove what was installed.

The labels are ugly. They are on there for a few weeks. Peel them the day after sign off and not before.

When This Is Not the Right Job

If your existing windows are dual pane, operate properly, and already carry a compliant label, replacing them will not pay you back on any sensible timescale. Adding exterior shade on the west elevation would do more for the same money.

If a single pane is cracked in an otherwise sound frame, that is a glass repair.

Call (951) 556-6455 and tell us what is actually happening, and we will tell you which of those it is.