Code Required Load Calculations, Equipment Selection and Duct Design

Cost of Course

Outline for class:

Heating/Cooling Load calculations, HVAC equipment selection and duct design: Learning basics of powerful & easy-to-use software that allows HVAC contractors and installers to build home comfort systems that meet code achieved with ACCA Manual J, Manual S and Manual D.

Course Outcomes: To get HVAC contractors comfortable performing load calcs, equipment selection and duct design as required by California Energy Code by using wright-soft software. In the program students will learn what is required by code, ACCA Manual J, Manual S and Manual D. Students will learn how current code directs designers to build high performance comfort system that deliver  By end of class, students will be able to create a simple house diagram with separate rooms each with required air CFM to maintain temperature range. Diagram will show house rooms with dimensions in feet, duct diagrams, duct sizes, furnace, windows, doors and return air grill.

Software Requirement:

upload free version of Wrightsoft software for student project.

Hardware Requirement:

Required computer and monitors windows 10 and large monitor, (two large monitors are better) internet access.

Instructor: George Matthews, Building Energy Compliance Testing

Module 1

What California building energy code requires and why. ACCA Manual J, Manual S and Manual D or ASHRAE equivalent are required by code before installing an HVAC comfort system.

Objectives:

·         Student will learn basic energy code requirements for California RE: HVAC.

·         Student will become familiar with ACCA Manual J, Manual S and Manual D.

·         Student will understand  where to use Manaul J, Manual S and Manual D.

Media

Activities

Module 2

Downloading Wrightsoft software, free student version, and installing on machine. Become familiar with palate of choices such as draw line, draw square, specify feet/inch grid, add windows and doors. Become familiar with or review system of “point and click” and “drag and drop” drafting If not already.

Objectives:

·         Student will download and install Wrightsoft software

·         Student will become familiar with palate of choices

·         Student will practice the review system

Media

Activities

Module 3

Perform home energy assessment to gain knowledge of energy loads, heating and cooling, to overcome. Students will need to document a house’s size by measuring every room and plotting on paper diagram such as large format grid paper. Every room gets measured in feet/inches and conveyed to sketch. Use digital measurement device like Bosch compact Laser Measure device.

Document crawlspace or slab and R value of insulation, repeat for walls and attics. Measure windows and note frame material and window pane number and type of coating such as low e. Document attic insulation and existing HVAC duct system if it matters to upcoming system design. Learn to make some assumptions of air leakinesss/tightness. For extra credit, do blower door test to assess air tightness of shell or envelope.

Make a clear diagram with all information as this will be translated into your digital energy model.

Module 4 Input data to program
Take sketch of house with interior room dimensions to computer and begin to transfer data into 2D digital model that is simple to create. Build one room at a time

Input insulation values into attic, walls and floors.

Module 5 Manual J – Load Calcs   
From newly created digital sketch model navigate to load calc center and look at the load numbers for heating and cooling. Input correct geographical climate data, heating degree days and cooling degree days. Find the number of BTUs and move on to finding equipment that fits those parameters.

Module 6 Equipment Selection,
Find a few different furnaces that you think will work to supply the correct amount of air flow, BTUs heating and cooling. Download the equipment’s performance numbers from the spec sheet on the manufacturer’s website. Compare and contrast the different performance levels of the machines. Compare motors and specs such as “air-tight box” and especially static pressure at X airflow. Static pressure is huge here. We must get it right as we will be adding the resistance of all the ducting, plenums, elbows and wyes in the forced air system.

Module 7 Design your ducts.
This is really the fun part of the class. Digitally drafting the duct starting at the AHU and terminating in each room exactly where you think they will both fit and work best. Drag registers to their location. Click, drag and drop lines for ducts and build your system. Click the command and watch each duct populate with CFM that duct will have to move to get the perfect amount of air and the diameter of the duct to the inch. No more guessing. You might get 4, 5 and 7 inch ducts depending on the needed airflow.

Module 8 Register Grills – How much resistance? What Model/Brand? Performance thereof.
Learn the difference in resistance in grills and how much of their surface area is actually open space air can course through or block. This is not in the California energy code but the quest for efficiency, comfort and quiet make it smart to control the air in optimal fashion.

Module 9 Feedback Testing
After fabrication of system, test airflow, leakage and static pressure numbers. Measure airflow from every register and compare to plan. Is it sufficient? Does system leak 5% or less? Does system move 350 CFM per ton? (Hopefully more!). Is the Watts/CFM less than 0.58 watts/CFM. If airflow is not close, adjust dampers installed at plenum on each duct run start coller.

Module 10  Beyond the code compliance: Productivity, efficiency, quality control tool, sales tool.
Using Wrightsoft as a money making tool that sets you apart from your competition in create value for each job. Reducing callbacks through quality control of commissioning system before handing it over to client. Develop relationship with client.

Create a detailed shopping list for complete systems and one trip to HVAC supplier. Get pricing from complete and detailed list in a format one can email to supplier. Saves time.

Create detailed sales report to make your clients confident In your professional, proposal.

Guarantee that this is state-of-the-art system performance design that is more comfortable, creates better air quality than any HVAC system they ever had while being highly economical to run.

If you want, you can figure out how much it will cost them per year to run their heating and cooling system.

Module 11 Continuous Fresh Air Ventilation systems for homes. HRVs. How to spec and design systems to bring in HEPA air to one's home.

To sign up, Contact Building Energy Compliance Testing

George Matthews

Dear Customer,
This is our approach to bringing more value to your energy compliance reports.

Doing load calculations and duct design is required by the energy code, Title 24, part 6 and CalGreen Title 24 part 11. Many building departments don't know this, but they do know they need a CF1R energy report. You are familiar with the energy report that you get from energy consultants before you can get a permit to add on, etc.

The same data-set is used for both so we do the work in Wrightsoft which does load calcs and duct (manual J, D and S) design and assists with equipment selection. We then export that dataset into EnergyPro and, after a few modifications, we generate the CF1R PRF-1. We feel that we can offer our clients a two-fer this way and get them more value for their energy compliance budget.

We started doing Wrightsoft after years of watching air conditioner installations fail (over 80%+!) because HVAC contractors don't do the math and don't know how to build energy models like in Wrightsoft. This was an attempt to follow the code and design systems that work properly and pass code mandated HERS tests.

We also use the kind of duct designs one can learn at PG&E's Pacific Energy Center in the class, "Optimizing Residential Duct Systems". Keeping the ducts inside the conditioned shell and optimizing airflow makes for better operating systems that provide more comfort at lower cost. We also design our systems to be able to run properly with restrictive MERV 13 filters which filter out pollen, pet dander, wood smoke and PM2.5 particles for our clients with respiratory concerns.

We think that pulling it all together for our clients creates better housing that is healthier, more comfortable, durable and less costly to operate. We hope you agree.

George Matthews

Go Electric, Step off the Gas
BECT just went electric. We got an electric vehicle. It is a joy to drive and uses no petroleum. It feels great to ride smooth with no gears and not have any green house gasses out the exhaust pipe or my dollars flowing to Saudi Arabia.
You can get off of the natural gas at your house with BECT's help.

We've done about 40 load calculations and duct design for Bay Area architects and homeowners so far. Getting to know the size of what Bay Area homes actually need in a furnace, heat pump or air conditioner has been eye opening. Turns out that most all HVAC contractors install a 60K or 80K furnace into a house without much thought. If one actually crunches the numbers, you learn that that houses might only need 24 or 30 or 36 thousand BTUs of heat to keep warm and comfortable on the coldest day of the year.

What this means is that Bay Area homes are a perfect match for heat pumps. These are all electric devices that extract heat from seemingly cold air and move it into your home so you can be comfy. In the summer they "switch gears" to become air conditioners. These systems can be ducted like most US houses or can be "mini-split" system which are popular in throughout Europe and Asia.

The beauty of heat pumps is that they can run on electricity from solar panels or wind power, biofuels, hydropower or batteries. They don't require any carbon, fossil fuel energy. They are a proven technology, used world-wide. You can make the switch and be part of the global climate change solution.

Heat pumps along with air sealing, high levels of insulation and ventilation can make your house both highlyt comfortable with great air quality while enjoying low energy bills. You can be solving the global climate change problem from the comfort of your home.

Give BECT a call, we can help you get off of carbon energy and be part of the solution.

Which air filter should I be using in my home's furnace/Air Con system?
I want to get the smoke out of the air where my children live. I want lower energy bills.

This is the question for health and measured performance. What difference does it make? Apparently, having a lower pressure drop across the air filter yields more airflow and less wattage used by the motor, (hopefully a permanent magnet, electronically cummutated motor of the right size.)



At BECT, designing duct systems, the most challenging data to find is the pressure drop across filters, "Y"s, evaporator coils, register boots, start collars, ducts, plenums and grills. Once we have all that data we input it to Wrightsoft software and we can prove/know/model the performance of the airflow. Without all those we are making educated guesses, hopefully correct.

Many of the components of a duct system are difficult to find pressure drop numbers for. Knowing that, we can eliminate variables and work with what we know to be true by specifying low pressure drop components. Oversized evaporator coils, up-sized return ducts and proven air filters matched to filter boxes with lo-resistance grills fit that bill.

Below is a note from 3M to a user about their filters and how much other manufacturers' filters rate RE: MERV and pressure drop in inches of water column. This is critical data when designing a high performance duct system.

"SUMMARY: The Ultra Allergen 1500MPR (for 1 inch depth HVAC) is the LOWEST pressure at 0.15 (vs .20 for the MPR 600). So it didn't make sense for me to go for MPR 300, MPR 600 or MPR 1000.

The complete response from 3M below:

Generally speaking, for most residential HVAC systems, the filter will become restrictive when it reaches a .5 pressure drop.
All of our filter media fibers are polypropylene and polyolefin plastic which will remove particles that measure 3 to 10 microns.
Microparticle Performance Rating (MPR), MERV Ratings, and pressure drops are as follows:

Elite Extra 2400
3-10 microns - 96%
MERV 13
pressure drop .21

Elite Allergen 2200
3-10 microns - 94%
MERV 12
pressure drop .18

Maximum/Ultimate Allergen 1900
3-10 microns - 93%
MERV 12
pressure drop .16

Allergen Deep Pleat 1550 (4").
3-10 microns 97%
MERV 12
pressure drop .12

Ultra Allergen 1500
310 microns - 90%
MERV 12
pressure drop .15

Odor Reduction 1200
3-10 microns - 85%
MERV 11
pressure drop .24

Micro Allergen 1000
3-10 microns - 80%
MERV 11
pressure drop .21

Dust & Pollen 600
3-10 microns - 65%
MERV 7
pressure drop .20

Dust Reduction 300
3-10 microns -35%
MERV 6
pressure drop .20

Flat Panel
3-10 microns -5%
MERV 1
Pressure Drop .08

Pressure drop is a measure of air flow resistance. It is measured by inches of Water Column (W.C.) at 300 feet per minute (FPM).
Clean/new filters are not restrictive to air flow. Filters will become restrictive if they are not changed when needed. A filter's life is actually determined by the user's living conditions and will vary for every user. Generally speaking, we recommend changing filters approximately every 3 mo nths.
To determine when the filter needs to be change, we suggest holding it up to the light. When you cannot see light through the filter, it is ready to be changed, even if it is before 3 months.
If you are concerned about airflow, you might want to use the filter with a lower pressure drop.
If you have a high velocity furnace with high fan speed, you may need to change the filters more frequently, every 1.5 to 2 months."

Compare the above when choosing filters. Doing so could be the difference between staying below .58 watts/CFM when doing Fan Watt Draw HERS tests. First you need the airflow to pass Total Airflow HERS test, then you need low watts from the motor to pass Fan/Watt Draw.

Register Sealing before having BECT do a duct leakage test

Subject : Register Sealing before having BECT do a duct leakage test

Hello,

Please make sure that the registers are sealed as in the photo below, before BECT comes to test the system for duct leakage.

Seal the register boxes to drywall or hardwood floor with UL 181 aluminum tape as shown below.

Aluminum Tape (must be UL 181)        

                              Register sealed to drywall with Al tape.

The photos below are examples of what the registers/returns should not look like.

Unsealed boot in drywall, on ceiling. This won't hold air.

Unsealed 1950s boot in hardwood floor, unsealed.

1920s register boot, unsealed to plaster yet painted black.

Also, please make sure that your forced air unit set on the highest speed so that you can achieve 350 cfm/ton​ for the 1. Total Airflow Test and 2. The Fan/Watt Draw Test.


Also, don't forget to drill a 1/4 inch hole in each side of the plenum (both supply plenum and return plenum) and mark the hole, HSSP, for Hole for Static Pressure Probe. Put aluminum tape over the hole but make sure marking is visible for HERS test. If those access holes are not there - you'll need to do it at the test. They are so that someone can insert a probe on each side and see the difference in temperature and humidity changes before and after the air moves through the evaporator coil.

If you have any questions on how to seal it, we also have a video on our website detailing how to properly seal your ducts. Click this link here to watch the video, http://bect.us/videos/. You can also watch our other videos on energy efficiency in the home on BECT's YouTube channel. Check it out here, https://www.youtube.com/channel/UCAd8LCb6fzHAkzqOu9loGrQ/videos?view_as=subscriber.

Stay cool and comfortable, 

BECT

Dear CEC, Please approve Wrightsoft software for alterations and additions compliance, (Title 24 performance)

Dear Commissioner McAllister,

I am writing to request that you to approve Wrightsoft software to perform title 24 energy compliance (performance) for residential alterations and additions in California.

I am told that the software is now able to perform compliance for new homes but not for alterations and additions, the far more common jobs found here in the San Francisco Bay Area.

I have been using Wrightsoft for the last year and am extremely impressed with it as a tool to perform load calculations, duct design and equipment selection. As a HERS rater I see failure to perform to code every day in the HVAC systems I test, with about 75% of them fail to move enough air in AC mode. Having HVAC systems be designed properly yields systems that perform to those design standards.

I understand that the CEC is now evaluating Wrightsoft. If that is so, I ask you to accelerate the evaluation and allow Wrightsoft to be used in title 24 compliance in alterations and additions.

It is my understanding that 1% of California residential HVAC changeouts get load calculations done. This must be why I see such wildly oversized air conditioning systems in my testing.

Here is what I’d like you to do to improve energy efficiency and efficacy in new/alterations in California,

1.       

Allow Wrightsoft to be used for T24 compliance in Alterations and additions.

2.       Compel the Contractors State License Board to teach HVAC contractors to use load calculation software and that calculations, design and equipment selection is code required.

3.       Sponsor classes to teach HVAC contractors how to use load calculation/duct design software.

4.       Encourage title 24 consultants to use load calculation software and do both compliance and design.

Doing only compliance misses the greater point of creating heating/cooling/ventilation systems tailored to a particular house and actually achieving efficiency and performance. I see “T24 compliant” houses fail HERS tests every day.

If you need any help, please do not hesitate to call me.

Thanks for your help in creating an energy efficient economy in California.

Very truly yours,

George Matthews

Building Energy Compliance Testing www.bect.us Phone 510 520 4443

Walnut Creek, CA 94597

In an affluent Bay Area suburb a custom builder turns over the newly remodeled 1950 ranch house, 3000 square feet of beauty for the young successful professional's family.

The builder is proud of the beautiful house, new again, gleaming, high ceilinged great room and chef's modern show kitchen. The contractor awaits his final payment and joy of a job well done and onto a new project. The new project photos look fantastic on the builder's website.

The HERS rater shows up and performance tests the new addition's forced air heating and cooling system. Failure on 3 of the first 4 tests. The contractor failed to read the energy report and the required Quality Insulation Installation (Translation: insulation installed to manufacturer specs) was never installed.

Here is the letter.

Dear owner and General Contractor,                                                                                                      3/1/2018

As per our conversation, this letter is detailing the results of my visit to 987 Oak Drive, Santa Suburba, CA.  

The house is failing to pass the energy code. I tested the duct leakage and airflow for the two HVAC systems on the property. Three of the four tests for duct leakage and total airflow did not pass and therefore the house did not comply with the HERS  Energy Code Standards.   The new addition HVAC system had 719 CFM total airflow (pass) and 165 CFM duct leakage (40 CFM max is passing). The new ducts in the south HVAC system had 1055 CFM airflow (1400 min. to pass) and 401 CFM of duct leakage, (70 CFM leakage is maximun leakage to pass). 

Below is a list of energy efficiency measures as they now exist in the house. These items are the most likely to be modified in order to comply with the California Energy Code.  

• Quality Insulation Installation, a required measure in the Title 24 energy report, was not done. 
• No radiant barrier in the roof sheathing plywood was installed 
• 80% efficient furnace installed instead of a 90%+ efficient furnace. 
• The water heater is 62% effiecient rather than 90%+.  
• Insulation is missing in areas in the new addition's attic. 
• The mandatory measure (in both energy code and CalGreen): Manual J, D and S, HVAC load calculations, equipment selection and duct design, were not done. 

In order to pass and receive your final, I suggest that you get in contact with your energy consultant to determine how to get the house to meet the 2016 California energy code given the above conditions. 

Please do not hesitate to call me with any questions.  

Very Truly yours,

Geo

It was most unfortunate to have to write a letter like this. The energy consultant obviously did not get the point to the GC that QII had to be done and documented by a HERS rater in order to pass. Once the insulation was covered over with  drywall the opportunity to inspects was gone.

Please read the energy report and CalGreen. Spend a few minutes reading the mandatory requirements in each. The reference above equipment can last 30 years. Energy consumers are poorly served when equipment from the 70s or 80s is thoughtlessly put into a house designed for the next generation.