"Like Italy in the 1960s", HVAC contractors have no idea how to build to California's Energy Code.

A lovely guest house in the country. Brand new, white, gleaming and beautiful. The owner is British. I tested the performance of her new HVAC system. It failed three HERS tests.

I explained to her each of the tests and why the system failed. The ducts leaked too much air. The system did not move enough air for the size of the air conditioner. Why? The return ducts are either too few or too small. The MERV 8 filter installed is restricting air flow so it should be bigger or perhaps there should be two of them. The 2017, airtight, well insulated 1500 square foot house with low e, argon dual pane windows doesn't take much to heat or cool. How did it end up with a 3 ton AC and restricted, leaky ducts?

The homeowner told me that it was "like Italy in the 1960s." A top-heavy bureaucracy well insulated from those doing the actual work or needing to get things done. The individual people are often brilliant, but people are not working together. Some were also incompetent.

We have a real problem in the SF Bay area with HVAC contractors installing air conditioning systems without following the CA energy code's "Mandatory Measures", nor CalGreen. Every day I test new systems that have not been sized and designed as per code requirements. This yields systems that use more energy and provide less comfort. This has a real effect on energy use in the SF Bay Area. These improperly designed system can last 30 years or more and will waste energy daily 'til near 2050 when they will fail.

California Title 24 Energy experts say that 1% of residential HVAC systems are properly calculated for sizing and have their ducts designed per the specs in Title 24. Only 10% get permitted and tested.

Of course, the Energy Commission did not make up these design specs. They use the Air Conditioner Contractor's of America Manual J, Manual D and Manual S sizing, duct and register grill design specifications.

Sadly, there is no continuing education from the Contractors State License Board for HVAC contractors. Hence, they have no idea of what is in the California Energy Code or how to build comfort system that conform to it.

We are now in the 2016 energy code. Builders and HVAC contractors are nowhere near understanding what is in the current code or how to meet it. At the same time we are nearly 2 years away from the 2020 energy code when new buildings will be "Zero Net Energy", meaning that houses will generate as much energy in a year as they use in a year. We have a lot of work to do to educate the building industry workforce in order to get up to speed with upcoming code changes.

Let's fix this problem.  Just like engineers design our building so they stand up to earthquakes via code required structural design, let's have our HVAC systems engineered per our energy code. We need to require building department design review first, before permitting these long lasting, energy using systems to get built.

CSLB and California local Building Departments, please get up to speed educating the building industry workforce and enforcing the energy code.

George Matthews, owner
Building Energy Compliance Testing
Serving the San Francisco Bay Area

Filter Grill Requirements Update from the CEC

While testing at BECT.us I have come across a number of air conditioning systems that do not meet the total airflow and fan/watt draw levels of performance that the code calls for. When this happen the HVAC contractor has to redo the return duct design and then install it at significant cost of time and reputation. It shows that the system was never actually designed but pieced together using a best guess. There has got to be a better way.

The CEC has just sent out an update of their filter grill requirements which are a critical part of the return duct system. Here is there update.

"Filter Grille Area Requirements

When complying with the Alternative to Section 150.0(m)13B, the nominal size of the air filter media should be used to calculate the minimum total return filter grille gross area. If the air filter is not located at the filter grille, use the nominal size of the filter grille to determine the area. The calculated area must be equal to or greater than the values in TABLES 150.0-C or D.

Additionally, TABLES 150.0-C and D also require that:

 1. Each return duct must be no longer than 30 feet.

2. Each return duct must not have more than 180 degrees of total bend.

3. If the total bending of a return duct is more than 90 degrees, one bend must be a metal elbow.

4. Return grille devices, which include the air filter and return grille locations, must be labeled in accordance with the requirements of Section 150.0(m)12A.

 5. The label must state the grille’s design airflow rate and a maximum allowable clean-filter pressure drop of 12.5 Pa (0.05 inches water) for the air filter, as rated in accordance with AHRI Standard 680 for the design airflow rate for the return grille. Please note that additional air filtration requirements of Section 150.0(m)12 may apply."

I've seen some contractors who were shocked at how much filter area the code was calling for. Of course, the best way to make sure that the filter grill requirements are met is to use a proper duct design system such as Right Soft. The vast majority of installations that I see are not designed at all.

I hope that bringing this to light could alleviate some of the pain I've seen in the eyes of someone who has to redo their hard work often in a sweltering attic.

New, Free Load Calculation Software

Load calculations are the way to dial in the capacity of your heating and cooling systems so that they work at peak efficiency while delivering comfort. They are also required by California’s 2013 Energy Code, Title 24, Part 6.

While software like Right-J from Wrightsoft cost $499, there is a new free option to do load calcs, Cool Calc. The software is web based and uses google maps and other on-line data to capture information about the house. The software won the Gold Award in the 2015 Dealer Design Awards.

Many contractors still use crude and inaccurate rules of thumb to size their systems while putting themselves into potential legal liability. One of our clients was threatened with legal action after he used an old rule of thumb for sizing. The system he designed and installed did not perform to manufacturer specifications. The building owner had some testing done and threatened a lawsuit unless the system was done to specs. That contractor now uses Wrightsoft software and creates state-of-the-art installations.

Opting for free and proven software can be a smart way to go. It is infinitely better than guessing like so many do. The Air Conditioner Contractors of America have been around for over 40 years. You can trust them when it comes to the methodology of sizing air conditioning systems. Now, with the 2013 California Energy code enforced around the state, this is a good time to switch from guessing to calculating air conditioner system sizing. Check out Cool Calc at Next Generation HVAC Sizing and Selection tools | Cool Calc

George Matthews

Building Energy Compliance Testing

San Francisco to Silicon Valley

www.bect.us