Skylights: A Nice Feature, With Notable Tradeoffs Here
A skylight is a flashing point, no different in principle from the chimney and vent flashing covered in our thermal cycling article. It's a place where two different building elements meet, and that seam has to hold up through the same daily expansion and contraction as the rest of the roof. Skylights also bring a desert-specific issue: heat gain. With the UV intensity covered in our altitude article, an unshaded or poorly glazed skylight can add noticeably to your cooling load.
Glazing matters more here than in milder climates. Low-E coatings and tinted glazing cut both heat gain and UV transmission significantly compared to basic clear glazing, and you notice the difference more in a high-UV climate than somewhere with less intense sun.
Roof-Mounted Swamp Coolers: A Distinctly Regional Roofing Concern
This is where New Mexico differs from most of the country in a way that affects roofing. Evaporative coolers ("swamp coolers") are common as primary summer cooling here, more so than in most U.S. climates. Rooftop units sit on curb mounts that penetrate the roof membrane directly, the same kind of penetration as a skylight or vent, with their own maintenance needs.
Flashing around the curb mount deteriorates over time from the same thermal cycling stress covered elsewhere in this series. It's a common leak source that has nothing to do with the cooler's water systems.
Winterization is the detail most likely to cause expensive damage. A water supply line that isn't properly drained and isolated before the first hard freeze can rupture, sending water into the roof assembly or attic space. Albuquerque's average first freeze falls in mid-November, and service demand for winterization typically surges in October. Schedule ahead of that window, before the first cold snap.
Why Ventilation Design Is Different for Swamp Cooler Homes
Evaporative coolers need a dedicated air pathway to work correctly. Cooled air has to have somewhere to go, typically through open windows or, more commonly, through attic "up-ducts" that vent into the attic space and out through an attic vent. So on a swamp-cooler home, attic ventilation handles heat and moisture the way it does on an AC-only home, and it's also part of how the cooling system is designed to work. That's a different situation from the AC-only homes our general ventilation article covers.
What This Means Practically for Homeowners
- If you have a skylight, ask specifically about glazing type during any inspection or installation. This matters more here than the general national conversation about skylights suggests.
- If you have a roof-mounted swamp cooler, schedule winterization before the first freeze. It's the single most preventable, and most costly, failure point.
- Flashing around any rooftop equipment deserves the same attention as chimney and vent flashing. People sometimes overlook it because it's tied to HVAC service and isn't usually thought of as a roofing concern.