Residential Energy Audits can be time consuming if done correctly.
- Lets start with the exterior walls which is an air barrier. Depending on the material the exterior walls are made of, it has an R value. Wood, concrete, metal, brick all have an R value. Inside the wall there should be a vapor barrier "house wrap" to keep water out then a thermal barrier "insulation". Interior wall "drywall" is another thermal barrier / air barrier.
- The attic: how much insulation do you have on the top of your home? Remember heat rises and its important to retain heat in the winter and repel heat in the summer. All duct work in the attic should be wrapped with insulation and duct joints should be sealed with mastic.
- Sub floor: If there is a crawl space then there should be insulation under your floor. Also another vapor barrier should be installed on the ground. Keep moisture out of the crawl space.
- Duct work: All duct work joints should be sealed with mastic to reduce energy loss. All duct work should be wrapped with insulation. All duct work should be checked to see if it is the correct size.
- How much CFM does the furnace suppose to provide? Air flow tests should be conducted to measure the air flow at the supply plenum. The CFM can be found by looking up the model and serial number of that equipment. Example: A 3 ton air handler should be approx 1850 CFM. If a measurement was taken at the supply plenum and it has 1500 CFM, of course that maybe not enough. Or if the air handler is pushing 2000 CFM but we only measure 1600 CFM this relates to static pressure. This means the duct system is to small perhaps. The plenum is getting back pressure causing some air flow to reverse itself.
- What is the temperature difference between the air supply plenum and return plenum? Heating and cooling. This is important to know these temperatures.
- All windows and exterior doors should be scanned with thermal imaging equipment. You nay be surprised to see leaks around windows and doors while the home is under standard operating negative pressure. In many cases leaks are common at bottom of exterior walls near floor.
- If there is a crawl space the auditor should look for penetrations "holes" in the sub floor where any plumbing or electrical wiring is installed. If holes are present they should be air sealed.
- If there is an electric air handler, amp draws should be taken then compared to specs of the manufacture. If it is a gas air handler "furnace" the auditor should use a combustion analyzer to measure the CO at flue and if possible heat exchanger. This will provide a set of numbers of how efficient or non efficient the furnace is.
- The home should be placed under normal operating pressure by turning on all exhaust fans. The auditor should then use a manometer to measure for positive or negative pressures. While all exhaust fans on the air handler should be turned on and again measure the pressures. While all exhaust fans on and air handler each bedroom door should be opened and closed while taking the readings with a manometer. The auditor will discover how each room will affect the pressures of the home. Some rooms maybe more or less leaky than others. In many cases I have found bedrooms to be a major issue with heating or cooling the home.
- Last, go to the electrical panel. Remove cover. Be extra careful during this procedure. Turn on all electrical in the home. Using an amp probe take amp readings per breaker if possible. Make a list of which breakers and how much amps they are using. Then turn all electrical off per room at each room not at the breaker panel. Then take another test by checking amps again. You may find large amounts of electricity being used when everything is suppose to be off.
By conducting this type of audit we find to be far more efficient than just a blower door test. A professional energy audit should cover everything we have explained. You need facts and data to move forward. Such as, what part of your house / business is utilizing the most energy? And why? You could install all the insulation in the world and it may not make a difference. If the HVAC duct system is to small or over sized why would you change out all your windows? Or insulate? First determine if you have enough insulation, then if the duct system is in good condition with proper air flow.
Health & Safety: Many many times we have gone into homes to test pressures, test flue drafts and inspect electrical. Many spray foam contractors all over the USA sell spray foam to home owners to help reduce energy usage. Great stuff and works very well. However most of these contractors DO NOT test homes for pressures after the job is complete. These contractors and the product do a great job on sealing up the home. Under floor in crawl spaces, attics, etc. However with the smallest exhaust fan on it will create a back draft in a gas flue if the building envelop is to tight. Flues are suppose to have a -3 or greater pascals pressure to vent out CO. With exhaust fans running, "bathroom", "cooking stove", "hot water heater", gas cloths drier" and "furnace" they need very good ventilation. With all these fans on at the same time it could create a large negative pressure inside the home and not the flue.
Gas Fired Equipment: If the home has a large negative pressure then most of the CO will not vent to outside. It will be present in the home. In some cases if your HVAC duct work is located on the outside of the building envelope "attic or crawl space" "home" it may cause a greater negative pressure depending on which side is leaking. Example: if the duct system is located inside the building envelope "basement" and the return side is more leaky than the supply side, this creates a positive pressure. However if the return is on the outside of the building envelope "attic" then it would be reversed, negative pressure.