Lilly Jolivet is dreading her first electricity bill. She is sitting in her living room, with the blinds drawn against the Houston summer sun. To try to cool down her apartment, she has four fans running along with the air-conditioning.

The vaulted ceiling and big picture windows, which attracted her to move in a month ago, are making it difficult to cool it enough for her three-year-old daughter, Katherine, who suffers from asthma.