This thesis includes an energy survey of the Herrgården pre-school, which has a modern heating- and ventilation system, and a comparison with Östers pre-school which has an older system. An energy survey of Östers pre-school has already been done by a group of three students and all the calculations and values have been collected from that survey. As of today, both pre-schools are heated thru district heating. It will be much easier to make smart and feasible energy-saving-measures by first conducting the energy survey.

Herrgården pre-school in Gävle houses 81 children, therteen teachers, one cleaner and one cook. It was finished in the middle of 2009 and the staff has been very pleased with the in-door climate. In the energy balance added heat was calculated as district heat, solar radiation body heat and heat from lighting and other appliances. As lost heat- transmission, tap water heating, heating of ventilating air and excess ventilation was taken in to account.

At Öster pre-school there are 66 children, twelve teachers and two economists. The pre-school was built in 1973. Gävlefastigheter which administrates both buildings are planning to change the ventilation system at Östers since it has been inferior and the staff has been experiencing bad in-door climate.

The purpose of this thesis is to conduct a survey of how to economically reduce the energy consumption and to establish a good in-door climate like the Herrgården pre-school. The methods used have been to make a few visits on site to collect data.

After finishing the survey it was shown that one could save 76,23 MWh/year if Öster has the same U-values as Herrgården for its´ roofs, floors walls and windows and a ventilation heat exchanger with 70% efficiency. However, none of these approximate calculations of installations at Östers pre-school turned out to be financially feasible.