Dear Jim: I would sleep better with my bedroom cooler at night, but our old window air conditioner is just too noisy. The new electronic models look jazzier, but are they really any quieter and more efficient? – Penny L.

Dear Penny: If you have not used a new window air conditioner within the past three to five years, you will be amazed at the improvements in quietness, efficiency and convenience features. Several new models have energy efficiency ratios higher than many new central air conditioners.

Even if you have central air-conditioning, installing a new super-quiet window air conditioner in a problem bedroom makes economic sense. Install an automatic thermostat to raise the central air conditioner setting at night for huge savings and then run the small window unit to stay comfortably cool.

For use in a bedroom, some models have special sleep and quiet modes of operation. The air conditioner fan starts up slowly and quietly when the thermostat calls for cooling so it does not startle and wake you. There are also other special slow-speed, quiet settings ideal for nighttime use.

Built-in 12- to 24-hour timers and hand-held remote controls are effective convenience features for bedroom use. The timer can be set to shut the unit off after you fall asleep. A remote control allows you to change the temperature setting, fan speed and mode of operation without getting up.

If you have allergies, which often become a problem during high-humidity weather, select a window air conditioner with a high efficiency filter. It will remove more of the allergens from the air. An optional charcoal filter also reduces odors and volatile chemicals in the air. A tilt-out or slide-out filter access feature is a plus.

Purchasing a model with electronic controls (with or without a remote control) is probably worth the slightly higher cost. These controls and digital readouts allow you to set the precise temperature you want and hold it to within 1.5 degrees of the desired setting. For the lowest electric bills and quiet operation, select a model with an energy saver setting. Manufacturers have different trade names for this setting, but they all cycle the fan on and off with the compressor to save electricity. In normal operation, the fan continues to run when the compressor stops.

If you are going to cool a larger room, consider adjustable airflow controllers ranging from 2-way up to 8-way. With an 8-way airflow control, you can fine-tune the cool air in one direction or for wider distribution across a room. Proper sizing of a window unit is critical for comfort and efficiency. Have the salesperson complete a detailed sizing worksheet instead of using an inexact sizing chart.

Dear Jim: I have several large south-facing windows that let in a lot of heat and glare in the summer. Is there any type of window film to apply to them that will not also block passive solar heat in the winter? – Sal P.

Dear Sal: Unfortunately, there is not any window film made that will accomplish both goals. The wavelength of the heat radiation from the sun is the same in the summer and winter, so there is no way to be selective. Since the sun is higher in the sky during the summer, a large roof overhang or small awning can be effective without blocking much of the winter sun too. You might also try removable awnings or translucent pull-down shades.

Write for (instantly download – www.dulley.com) Update Bulletin No. 548 – buyer’s guide of eight manufacturers (32 models) of window air conditioners, EER’s, airflow control, fan speeds, sizes, features and a sizing worksheet. Include $3 and a business-size SASE. James Dulley, Newspaper Name, 6906 Royalgreen Drive, Cincinnati, OH 45244