# Insulated Patio Doors - Link: https://selectslidingdoors.com/glossary/insulated-patio-doors/ - Published: 2024-08-15T20:08:04+00:00 - Author: Rowdy [Home](https://selectslidingdoors.com/)/[Glossary](https://selectslidingdoors.com/glossary/)/ Insulated patio doors Glass and weather # Insulated patio doors Also called: energy-efficient patio doors, double-pane patio doors **Quick answer:** an insulated patio door slows the heat that passes through its glass and frame. It pairs sealed double- or triple-pane glass with a frame that has a thermal break and tight seals. In Texas, that mostly means less summer heat coming in. The glass unit Two or three panes sealed together at the edges, with air or a gas such as argon in the gap. Low-E coating A thin, clear metal coating on the glass that reflects heat but lets light through. Read the label New doors carry an [NFRC](https://nfrc.org/) label. A lower U-factor insulates better; a lower SHGC lets in less heat from the sun. A cut through the bottom edge 1. **Outside pane**, the glass that faces the sun 2. **Low-E coating**, most often on the inner face of the outside pane 3. **Spacer**, a hollow strip with drying beads that holds the panes apart 4. **Edge seal**, keeps the gas in and damp air out 5. **Thermal break**, a plastic strip that splits the metal frame in two When the edge seal fails, damp air gets in and the glass fogs between the panes. ## How to check the door you have Four checks, from the glass to the frame. The answers tell you whether to repair or replace. 1. Count the panes 2. Look at the glass edge: double pane shows a spacer strip between two sheets. 3. Safe to do yourself 4. Look for fog between the panes 5. Haze you cannot wipe off from either side means the seal has failed. 6. Safe to do yourself 7. Feel for drafts at the edges 8. Hold a tissue near the closed edges. If it moves, the weatherstripping is worn. 9. Safe to do yourself 10. Decide what to replace 11. Fogged glass needs a new glass unit; a hot, drafty frame may need a new door. 12. Call a pro ## Fix it yourself or call a pro * **Safe yourself**Replace worn weatherstripping and keep the track clean so the panel closes tight against its seals. * **Take care**Swapping a glass unit means taking the panel out. Double-pane glass is heavy: two people at least, or call a pro. * **Call a pro**Fogged glass units, a new insulated door, or a frame that will not seal. More on this: [can you just replace the glass in a sliding door?](https://selectslidingdoors.com/can-you-just-replace-the-glass-in-sliding-door/) ![Cut-away of insulated window frames with double and triple panes of glass](https:// selectslidingdoors.com/wp-content/uploads/2024/08/cross-section-of-plastic-windows- profile-pvc-isola-2023-11-27-05-03-24-utc-768x480.jpg) A cut-away of insulated frames: two or three panes, each sealed into one unit. ## Single, double or triple pane Single pane The lightest glass, simple to replace Lets heat straight through and sweats in cold weather Double pane The common choice, a big step up in insulation The edge seal can fail and fog over time Triple pane Insulates the most and blocks more noise The heaviest, and usually the costlier option Heavier glass needs rollers made for the weight. ## Door letting the heat in? Select Sliding Doors handles [sliding door installation](https://selectslidingdoors.com/sliding-door-installation/), including energy-efficient glass, across Dallas-Fort Worth. Mon to Sat, 7am to 10pm. [Call 469-915-5230](https://selectslidingdoors.com/glossary/insulated-patio-doors/4699155230) [Sliding door installation](https://selectslidingdoors.com/sliding-door-installation/) ## Questions people ask Why is there fog between the panes of my patio door? The edge seal has failed and damp air has got into the gap. You cannot wipe it off from either side. The fix is a new glass unit made to size. Is argon gas worth having? Argon insulates better than air and is common in double-pane doors. It leaks out very slowly, and the door still works as a double-pane unit if some is lost. Why is my new door wet on the outside? On cool, humid mornings, dew can form on the outside of good insulated glass. Little heat from the house reaches the outer pane, so it stays cold. That is normal. See [condensation management](https://selectslidingdoors.com/glossary/condensation-management/). ## Related terms [Low-E glass](https://selectslidingdoors.com/glossary/low-e-glass-for-sliding-doors/) [Thermal break technology](https://selectslidingdoors.com/glossary/thermal-break-technology/) [Condensation management](https://selectslidingdoors.com/glossary/condensation-management/) [Weatherstripping](https://selectslidingdoors.com/glossary/weatherstripping/) Photo: own media library. Diagram: Select Sliding Doors. Ratings: [National Fenestration Rating Council (NFRC)](https://nfrc.org/).