Bring a compass when you visit the house or
Make sure the main living area's are on the
north side to capture the sun in winter.
Check if it has wide eaves to leave the sun out
in summer. In
winter the sun is lower in the sky so will shine into the
house under the eaves. See pictures.
Look for shadows like trees and
Big windows on the east and especially on the
west side will cause overheating in
Windows on the south side will lose heat and
contribute negligible to solar heat
Ask if there is insulation in the ceiling,
walls and floor and how much.
Avoid ventilated down lights, they act as
little chimneys and draw the heat out of your living
Check if there is some thermal mass inside the
house (e.g. tiles on concrete slab). Thermal mass stores the
heat and releases it slowly, so it reduces temperature
fluctuations. Is works especially well if it is directly
heated by the sun.