It is complicated to work out the heating capacity needed for the swimming pool, if we base on the strict calculation way with all factors considered inside. It's not an easy things for people who are not in the field of heat pumps. Here we'll introduce a simple way to help you to work out the heat capacity needed for our swimming pool.  Before the calculation , we need to know the pool size, the initial pool water temperature (usually equal to the ambient temperaure) and the target water temperature. The following is the calculation formula. Heating demand of the swimming pool = C * 1.163 * △t  / T Where: C = cubage of the swimming pool water  ( in m3 ) △t = target water temperature  -  initial water temperature ( for instance, if you want to heat the pool water from 20℃ to 30℃, the △t  = 30℃ -20℃ = 10℃ ) T = heating duration ( we can choose 24 hours, 48 hours or 72 hours,  the shorter the time, the quicker the pool water becomes hot, as the heating power of the swimming pool heat pump will bacame larger accordingly) If we want to heat up the pool water in short time, we can put the heating duration short, then the heat capacity of the swimming pool heat pump will be larger. The heating duration is the first time to heat up the swimming pool, as usually there is thermal insulation for the swimming pool, the following heating duration will be less than the first time if the thermal insulation is well made. With the above instruction , it will help us to work out the swimming pool heat pump suitable for our pool size.