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Air balancing explained

Residential Air balancing

We have had quite a few calls lately in regards to air balancing. Summer or winter you will feel the consequences of a home in need of air balancing; commonly it is known per its temperature differences across the home as some rooms or parts of the house are too cold or too hot in regards to the other rooms, or ducts that produce loud noises which is also common.

What is air balance?: it is to have the proper amount of air circulating according to the size of the room and through the house as a whole.

Will it save me money?: This is always a relative question as everyone controls their temperature of their home differently, and there are the variables such as design, installation and insulation of the ducts, AC unit efficiency, type of thermostat and location, etc. Having a unit running efficiently will make sure to spend only the necessary amount. If your current duct system is inefficient then yes, you can save some money, and you will definitely be more comfortable.

Consequences of not having a balanced home: well, there are many, the first one is that you will not be comfortable in your home, depending of how severe, it affects electricity cost, may facility growth of mold, unit would break earlier than intended per negative pressure and have poor indoor air quality.

Check the case study of a home in Katy TX below:

3228sqft Home, one 5Ton unit, 2 zones

  • Each zone is serving rooms on first and second floor. You could regulate the amount of air out on each duct but not keep and even temperature on the same floor or home.
  • Whatever room has the thermostat will control the temperature for the rest of the rooms on the opposite floor. In the case on ZONE 1 the kitchen and the second floor bath will continue to cool/heat until the temperature in the room with the thermostat on the bottom floor and opposite side of the unit is satisfied. Temperature would differ greatly among rooms on the same floor level.
  • The plenums where the ducts take off show signs that the duct design is very deficient, lots of condensation, plenums opening up at the corners for the pressure generated by incorrect zoning, lots of patches showing that other companies have tried to fix the issue at the dampers but none have identify much less correct issue on the last 12 years. Some companies specialized on fixing by replacing parts making the unit run, but lack the technical knowledge on all matters of ventilation, load calculations, air flow, pressures, etc, necessary to provide real comfort.

This is an overview of the process to follow on every home: Verify if the problem is as simple as opened or loosen ducts through the runs and not chewed out by rodents, if everything seems OK, you’ll just need thorough knowledge of load calculations for your home, room per room, calculate the amount of air in CFMs needed for each room to rotate about 7 times each hour, verify/calculate if duct is sufficient size per room per duct calculation and friction rate, and make suggestions to improve air flow, verify units size, verify if system uses zones and correct per zone, have a plan for negative pressure when one zone open and other closes and will the thermostat communicate with the zone control for this? verify if ducts have dampers if not install them on each run, bring your equipment to read CFMs and adjust damper until the calculated amount is blowing out, too closed and your system will have to work longer and more likely negative pressure will increase, too much and you will have humidity issues, mold or dryer skin depending of season. Call Avanti, we enjoy doing our work.

Calculating the heat loads for the whole house 🙂

There would be other companies which will close the dampers or grills on the ones blowing too much, and open those with little flow, spend a couple of hours doing it through the home and leave. Your unit, ducts and electrical bill will be the ones absorbing the consequences and will eventually let you know in dollars. We care about your investment and comfort, creating a long lasting business relationship and earn the benefit of your referrals. We do it right.

You already made an incredible investment buying your house; it is important then to enjoy your home to the fullest, by having the proper unit size, well designed ducts, excellent filtration and indoor air quality, providing your loved ones and guests years of comfort; and with proper maintenance you will extend the working life of the unit and minimize hundreds on cost of repairs. Don’t just live in your house, enjoy it! and we care for you to do it, call us now, the professionals on comfort.

Home comfort
Enjoy your home with a well balanced AC

2 thoughts on “Air balancing explained

  1. Would closing the grills in the room works?

    1. Thank you for your question.

      Think of the grills in your room as a fine-tuning option to accommodate your preferences when your home’s air is balanced. You cannot “fine-tune” if it is not balanced; we balance each room to work within a range depending on the heat load for that room, once this is done if you close the grills a little it would still be under that range therefore doing its work. On the contrary, if you do it and the air is not balanced you could make it considerably noisy and increase the pressure for the units’ blower; to put it in perspective, if you blow air out of your mouth and then cover it gradually with your finger you will feel both the noise and pressure increasing.

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