Before you rent a holiday home in France, take a moment to think about whether you need a home with heating or air conditioning. It all depends on where you'll be and at what time of the year. Heatwaves are increasingly common and are likely to be the bigger problem. Excessive heat is most likely in July and August, but be prepared for the possibility in June and September, especially in the southern half of the country.
Central air conditioning is not routine in French homes, but many holiday homes will have an air conditioning unit in the bedrooms, for a more comfortable sleep. Don't assume that the living room and kitchen will be air conditioned too. If not, you can spend the day by the pool in the shade. Some old home have thick stone walls that keep the indoors relatively cool during the day, and may have a cellar for a soothing retreat. It's a good idea to confirm with the owners.
Freezing temperatures are rare in most of France. But if you're taking a holiday between November and March, check with the owners what heating is available, and if it's likely to be needed. Wood-burning stoves are a common and very pleasant amenity in some holiday homes.