In hot temperatures, molecules are packed together, bouncing against each other like a game of pinball or table tennis. The closer they are together, the more kinetic energy [momentum] is given off when they bounce [could overload a vampire with energy]. In cold temperatures, molecules move apart [could cause a vampire to need more energy].
However, sunlight, bright lights, and bright colors disturb vampires whether he/she is feeling hot or cold, so let's address those as something separate.

Vampires tend to keep their homes the same temperature all the time, and that temperature is typically in-between hot and cold.
Those that lean their temperature at home a little more towards warmth, tend to also imbue the home with humidity [air with water vapors in it].
Those that lean their home's temperature a little more towards the cold, tend to also imbue the home with dampness [which, ironically, is dry air].

To Humidify A Room

A. boil water; and take advantage of the boiling water to make a hot tea
B. keep houseplants [the bigger the better]; and take advantage of them by only planting herbs, fruit, or vegetables so that you won't have to go outside in cold weather to harvest them
C. hang a line of damp laundry [squeeze out the dripping water first]; and take advantage of the indoor line so that you'll have another excuse to stay indoors from the cold

To Dehumidify A Room

A. light candles [I suggest making your own because a lot of scented candles contain parabins]
B. burn champa [incense made from the resin, halmaddi, of the ailanthus malabarica tree] incense [make these yourself too, or make sure you get ones without harmful chemicals]