Use the coffee grounds sparingly, and be careful with water after application of coffee grounds to the soil. Concerns about increasing acidity will also be eliminated by sparing use of coffee grounds around the plants. Many plants can withstand temperatures below freezing, many can tolerate temperatures near freezing, but some cannot tolerate low temperatures even when the temperature is above freezing. The time the plant must endure the cold temperature is also a consideration. Longer durations at a low temperature will result in more injury.
Many houseplants are from the tropics and very sensitive to low temperatures.
When I went to my parents home during the Christmas holidays, I set the thermostat at 50 degrees in my apartment. Later, after several dead plants, I realized that the low temperature killed my flame violet. By keeping the temperature near 60 degrees, subsequent flame violet plants survived without injury. I believe this is one of the most sensitive plants to chilling injury but there are many others, including common garden annual vegetables and flowers, which will also exhibit injury at low temperatures above freezing. I must also ask how you are measuring the temperature.