Ask the owner if you can see the certificate of any previous inspection. To check for infestation, look for mud termite tubes under porches and stoops, on the outside of the foundation, on the ends of joists resting on walls, and on windowsills near the ground. It should be structurally sound and well ventilated. Make sure insulation does not block vents, and that exhaust fans duct to the outside. The flashing around the plumbing stack vent should be tight.
Adequate insulation is the key.
Knee walls or rafters also should be insulated. Water stains on the sheathing or points of daylight through the roof may indicate there are leaks or rotting wood nearby . Examine rafters and roof sheathing for signs of dry rot, mold, or decay. If you place a marble in the middle of a hard-surfaced floor and it rolls away unaided, the floor is not level. Check for worn areas of flooring, particularly in high traffic areas.