Damp and associated moulds and rots can be very damaging in winter, no matter how carefully plants are watered. On sunny days, ventilate freely to shed surplus moisture. In fact, you may have to use a little heat to dry the house out, but it preferable to do this than lose plants.
Some crops, winter lettuce and alpines for example, need as much light as possible and will suffer if too much shade is cast by insulation. Avoid using materials such as bubble wrap where the plants are hardy enough to survive as they will benefit from the light.
Keeping patio plants over winter needs little light, but they must never freeze. Ideally they should be kept at no less than 7ºC (45ºF) as they don’t need to grow to survive. Insulation is also well-worthwhile. Other plants need to grow and so a compromise is needed: installing bubble polythene to the sides or the north facing roof and gable ends. Raising seedlings and keeping a collection of orchids are examples of where compromise is practical.