What is a Heat Loss survey? A Heat Loss survey is a full physical, non-destructive technical survey of a building by an experienced energy consultant. The energy consultant surveys the house for unintended heat loss caused by building defects. These defects can be unintended infiltration of air into the house, missing / damaged insulation, thermal bridging, dampness, leaking pipes and central heating boiler configuration.
How is a Heat Loss survey carried out? The building is first visually inspected and measured. Next all intentional openings (room vents etc) are closed and/or temporarily sealed. An air infiltration test is now done in conjunction with an infra red inspection. Various techniques are employed to pinpoint infiltration and insulation weaknesses in the building. All findings are discussed with the home owner along with recommendations. Finally a fully comprehensive report is generated and supplied to the home owner.
What equipment is used for a Heat Loss survey? A Heat Loss survey uses three main devices, an infrared camera, a blower door and a smoke machine (if required).
Thermal Imaging (using high spec infrared cameras) is based on the principle that all objects emit thermal radiation and is used in the building industry to identify patterns of heat loss from your home that are invisible to the naked eye. This camera is able to identify areas or features of buildings where heat loss is excessive.
The Blower Door is used to measure how "Air tight" your home is. All buildings are designed to allow air to circulate throughout the building and outside. Due to building defects, however, the actual air change rate and that designed can vary significantly. This causes excessive heat loss.
The Smoke Machine is used to help identify the source of the air infiltration. An example is where we fill the basement or attic space with smoke, depressurise the house with the blower door and look for the smoke entering the house. This then gives a clear indication of where the building imperfections are and solutions can be presented on the spot. The smoke generated is neutral and does not leave any residues on surfaces or fabrics and is harmless.
Is a Heat Loss survey the same as an Energy Rating? No. A Building Energy Assessment or Energy Rating provided by SEI registered assessors is purely theoretical rating of how the building should perform if perfectly built. Presently, Energy Ratings are produced from the plans of a building. In contrast, a Heat Loss survey is a real world set of tests conducted on a building as it was built. It therefore highlights design problems, snags in the building work and deterioration from wear, tear and weather damage.
Will a Heat Loss survey actually fix the problem?
No. A Heat Loss survey finds the problem. It still needs to be fixed.
Are there any risks to the house during a survey? Not normally if the house is in reasonable condition. Fireplaces and flues need to be closed off before the survey. This is both to make the test accurate and to stop soot and ashes being sucked into the fireplace and room. If a house is too damaged to carry out a survey in a safe manner, we will not start the survey.
How long does a survey take? For a 2 storey 2000 sq ft house, about 5 hours. The report is normally available in 48 hours.
What is the advantage of having a survey done? Can't I just fix everything? Absolutly one can just tackle every problem a house might have. This can be a very expensive option. The main advantage of a proper Heat Loss survey is that it enables you to spend your money wisely and get the best value in terms of payback period. It is very often the case, especially in the Irish climate, that the biggest heat losses are fairly easy to fix, once you know what they are.
Does a brand new house need a Heat Loss survey? Surely not! They do. There are many snags that affect the energy performance and subsequent heating bills. A Heat Loss survey can be thought of as just as normal as a structural survey. There is no point in paying good money for problems. If a house is in the process of being built, the Heat Loss survey is best conducted after the door and windows go in so that insulation problems and draughts are easily and readily fixed.
How much ventilation is needed? A well built house could achieve two air changes per hour at 50 pascals pressure. Most houses built have over 5 times this and others have 10 times as much!
Can a house have too little ventilation? Yes. The air tightness test in the Heat Loss survey will show if the ventilation level is too low. This can lead to problems such as mildew / mould growth on clothing and furnishings, dampness, stale odours, excessive condensation buildup especially on windows etc.