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Bigger is not always better!

Did you know that there is a protocol to follow when determining the size of your HVAC system? Developed by engineers in the heating and air conditioning industry and adopted by Air Conditioning Contractors of America (ACCA), Manual J has become the standard for ensuring the selection of accurately sized heating and air-conditioning equipment thru heat and cooling load calculations. This process not only ensures compliance with building codes but it also creates efficiency for homeowners.

There are three main reasons why it is important to select the correct HVAC system:

Efficiency: Resources are scarce and energy consumption can be very expensive. Purchasing an HVAC unit that is larger than needed is more expensive to operate for multiple reasons. With oversized units, the space will be cooled faster causing the system to turn on and off continuously, also known as short-cycling. Short-cycling will damage the air conditioning unit causing unnecessary wear and tear. Also, these units consume the most amount of power when the compress is first turning on and to achieve efficiency it needs to be running for at least 10 minutes or more prior to shutting down again.

Comfort: When air conditioning units are larger in size than what’s needed, the system will quickly cool down the air in the home, triggering the thermostat to its desired temperature causing it to shut off the system quickly and without allowing the proper time needed for condensation (typically 10 minutes is what’s needed), which is the process of cooling down the air conditioning coils to dehumidify the air in the home.

Air Quality: With a larger air conditioning unit than needed, the humidity was not able to correctly be removed causing too much moisture within the air. This humidity in the air typically causes mold or mildew in low air flow areas and bad odor within the space.

How do you prevent from having an oversized air conditioning unit installed? Here is how:

During an ACCA approved Manual J load calculation, Rapid Duct Testing’s team of licensed professionals will not only provide the heating and cooling load for the entire space, also known as a block load, but a calculation based on each room known as a Room-by-Room calculation. In designing heating and cooling for a residential home, it is important to consider how the heating and cooling will be distributed throughout the entire home in proportion to each room and its specs.

In a complete load calculation, not only are the apparent areas such as the orientation of all walls, ceilings, floors, appliances and glass considered by our team, but also the building materials that were used during the construction of the home such as roofing and windows. These calculations are then combined with the load calculations of other components of the home like piping and ducts to determine the total load and in turn the correct size air conditioning unit needed for the space in question.



What is HERS testing?
HERS Testing, also known as a Home Energy Rating System test, originated from the HERS program which was created to measure the efficiency of whole house energy components.

Who needs HERS Testing?
The California Energy Commission mandates that newly constructed residential and non-residential buildings have HERS testing to comply with local permits. HERS testing also applies to existing buildings such as installation of a new home HVAC system. HERS can be triggered by a new furnace, new or altered duct system, new AC condenser or refrigerant containing component, new ductless or ducted mini split system.

Why HERS Testing?
The purpose of HERS Testing is to ascertain the energy performance of a building and verify that it complies with current regulations. These tests examine the energy efficiency of the heater, AC condenser, air ducts, duct insulation, HVAC damper, and more. HERS Testing also ensures optimal air quality for the comfort, health and safety of the people who occupy that space, plus indicates opportunities to help reduce energy costs.

How is a HERS Rating Determined?
An air conditioning and heating contractor, general contractor, builder or homeowner enlists a certified HERS rater, like Rapid Duct Testing, to render several diagnostic tests, known as HERS testing. Once these tests are completed the technician will be able to determine a HERS report with the data collected.

The primary tests that comprise HERS Testing, include the blower door test (whole house test) and duct leakage test (duct blaster test).

The WHOLE HOUSE test involves a high-powered fan, called a blower door, that draws air from inside the house to the outside or vice versa. This creates a pressure differential between the home and the outside which determines air leakage. Acceptable air leakage will then be determined by the size of the home or the equipment.

Performing a smoke test for duct leakage enhances this process. Should excess leakage be discovered, corrections to the air duct sealing will be required and the process of pumping smoke (theatrical fog) into the duct system will allow the contractor to identify leakage. Additional tests that may be performed include an EER/SEER verification, fan efficacy test (fan watt draw), minimum air flow measurement, refrigerant charge verification test, etc. With each test that passes, a corresponding form is issued.

Due to the different allowances for new buildings versus HVAC modifications or replacements in older buildings, it is vital to find a HERS rater that stays up-to-date on current regulations

Home Energy Rating Standards, involve measures that cover the HVAC system and insulation in construction, it measures the homes energy efficiency and how compatible it is with recent regulations. A HERS rating can be either used for new or old constructed homes, this way home owners and buyers can both rate the energy efficiency of their current or potential homes to see what measures they can take in order to cut energy costs, and be more efficient. This rating is usually done through a certified HERS rater, who has the proper training and experience in the field.  In order to get certified for HERS testing these raters must have demonstrated a passing grade in the Calcerts or Cheers rater exam.

HERS testing regulations were established for California homes in 1999, as a requirement of the California Energy commission to establish criteria for a home energy rating program that is statewide, and relates to residential homes. The purpose of HERS testing was to establish a set rating scale to be able to differ the energy efficiency levels of different California homes in order to make the investment in energy efficient measures a top priority.

These standards are created and regulated by the California Energy Commission. These standards give the procedures to testing measures, such as how proper duct testing should be done. They also define procedures for training and certifying HERS raters.

A Hers rating is a number that shows how energy efficient a home is. The HERS index is determined by comparing energy efficiency of a given house to that of one that is of the same dimensions and is built to HERS standards and has an index of a 100. An index of 0 during testing for a home makes the house to be considered a Zero Energy Home which means it is equipped with a great number of energy efficient renewable power generation sources, and has passed all the HERS testing  methods, confirming that it meets all the energy output for that home.

To perform HERS testing on a new or old home in order to establish a rating many things about the home are considered. These tests consider insulation values of walls, heating, cooling and water systems. It also considers the lighting system, appliances, and duct leakage. Careful measures must be taken on all the factors that may cause a loss of energy in order to get the proper rating in the index. It is crucial to know exactly where your home stands in order to come up with a proper energy saving plan.

The benefits achieved through proper HERS testing are endless. By preserving energy and being more efficient you will cut costs from your bills and save money. It can also set you on the right track to setting up your home to be energy efficient. It is a great start to go green, and help the planet while saving money and living in a energy efficient home.

It is no secret that the major parts of every building’s energy bills come from cooling or heating that space. This is why it makes sense to make sure that your HVAC system is running efficiently. A heating or cooling system that isn’t leaking much air and is running efficiently can save you money each month. I am going to discuss how the professionals at Rapid Duct Testing can optimize your HVAC system for energy efficiency.

Blower Door Test

A Blower door test will allow you to measure envelope leakage. It can test how airtight your space is. A blower is attached to one of the doors (usually the main door) which pressurizes or depressurizes the building. The technician can then use a smoke pencil or other tools to discover exactly where these leaks are. This will discover leaks in your windows and other areas throughout your home.

Even if your HVAC system is in tip-top shape, if your envelope is leaking then you are simply throwing money out the window. If your envelope is allowing for conditioned air to escape, your AC system will need to work excessively to reach your desired temperature.

Duct Leakage Test

About 2/3rds of the ductwork in the United States is leaky enough that justifies some repairs or sealing. There are many problems that could arise if you don’t have properly sealed ductwork. The most common problem is your heating/cooling ends up heating or cooling your attic or basement rather than your home. Another thing that commonly happens is that the negative pressure will end up bringing outside air into your home. For example, it brings in hot air in the summer and cold air in the winter. Needless to say, this greatly reduces the efficiency of your HVAC unit.

Duct Testing is a service that ends up paying for itself in energy bills. So if you think that you may have any of these issues then just give us a call at (855)NEED-HERS or (855)633-3437. The experts at Rapid Duct Testing can help you today!