House Inspection and Energy Conservation

Although a house inspection doesn't address energy conservation directly or propose to audit energy use, it does have an indirect bearing on them. The house inspection unveils defects that result in unwanted energy leakage and the corresponding report will contain recommendations for remedying them. A top-notch inspection report's usefulness lasts long after the real estate transaction has closed and can be referenced when new problems materialize or some home renovation takes place. Herein we delve into this subject more deeply.

House inspection determinations related to conservation are usually connected with heat, air, or moisture flow. Heat flow problems cause cold and hot pockets in the home regardless of thermostat settings. Airflow problems cause drafts if too great and stuffiness if too little. Moisture not flowing condenses and/or promotes mold and mildew. The inspection does not test specifically for extremes in flow, but it examines building conditions and draws inferences about flow from the evidence found.

Heat transfer takes place in three ways: conduction, convection, and radiation, the transfer always being from warm to cool. Conduction is transfer through contact, convection through air currents induced by density differences, and radiation through the emission of waves. A home might have any combination of these. Air conditioners and high-efficiency furnaces work by taking advantage of latent heat, or significant energy transfer accompanying change of state.

The house inspection focuses mainly on whether every livable space has sufficient heat and how well the furnace(s) and stoves are performing. Should there be a high-efficiency furnace, air conditioner, or heat pump, the home inspector examines how well its capacity for using the latent heat of vaporization to transfer energy is functioning. He verifies that the thermostat works as designed and that room radiators or registers provide sufficient heat. He may provide an add-on service of using infrared devices to create thermal images of the house.

The main concern with home airflow is the rate at which indoor air is exchanged for outdoor air through ventilation or infiltration. Filtration, or house "breathing," takes place naturally through cracks and door or window openings. Too high an exchange rate makes the building feel drafty, causes inordinate heat loss, and induces moisture problems. Too low an exchange rate makes for stale, stuffy, or even toxic, air quality.

The house inspection includes tests for operability of doors and windows so that sufficient capacity in the building for ventilating naturally is assured. The inspector examines crawl space and attic ventilation as well. Proper ventilation in these parts of the house is vital to ward off condensation, moisture buildup, and ice dams. During the inspection there is also a test of exhaust fan performance in bathrooms and kitchen. When the focus is on energy conservation, house construction can be rather tight, over-limiting airflow. In this case, the inspector might recommend installing mechanical air exchangers or ventilators at key locations in the house to increase airflow.

Moisture flow occurs in bulk, from capillary action, from diffusion of vapor, and from being carried by airflow. Leaks in the house are examples of bulk flow. Capillary action, also called rising damp or wicking, is moisture seeping into wood and like substances. Vapor diffusion is simply the natural dispersion of moisture in a gaseous state. Air-transported moisture is the movement of humid air, which condenses when the striking of cool surfaces causes its temperature to go below the dew point.

Much focus of the house inspection is on moisture. The inspector searches for leaks because they lead to damaged property and insects. He investigates indications of capillary action for similar reasons. Vapor diffusion tends not to be an inspection concern, but condensed moisture is.

Energy conservation is to be encouraged because it is beneficial to the environment and to the user's budget. The home inspection report will point out ways to improve conservation (e.g., insulation, vapor barriers) and also some of its undesirable ramifications, such as stale or polluted air.