Standard for this era and the single largest efficiency loss in most Oklahoma houses. Attic temperatures run well past 130 degrees in July, and mastic that has dried and cracked leaks cooled air straight into it. Sealing the duct usually returns more than upgrading the equipment.

This is most common in homes built roughly 1940 to 1980. Post-war and mid-century — copper supply, aging cast iron stacks, 60 to 100 amp panels, first-generation central air.

Related

• Ductwork threaded through a house built for floor grates
• One central return for the whole house
• Water heater vents into the chimney and the furnace no longer does
• Silver-wrapped tape on old duct joints
• Additions still on window units
• Uninsulated walls and an oversized condenser
• Furnace runs but the house never warms evenly
• Electrical panel cannot support a modern condenser

Back to Hvac.

---

Written by Jaylan Jones. I Like To Fix earns a referral fee when a call connects to a contractor. See our business-model disclosure.