Tag Archives: tips

How to avoid or fix a humidity problem

One of the problems that we run into during the summer months is “Our space humidity is too high”.

Or, “We would like to design our space temperature and humidity to be “68 degrees and 45% RH,” for example.

The purpose of this post is to help you quickly determine if standard unitary equipment will do the job, or if you will need a more customized solution (both of which we can help with).

In order to learn this subject, all you need is an open mind and a psychrometric chart. If you don’t have a psychrometric chart handy, don’t worry, we will show you all the info you need below.

Discussion #1

How to design for a specific space temperature and humidity requirement:

1. Choose the design space temperature and humidity requirement

2. Plot this point on a psychrometric chart

3. Draw a line straight to the left to determine the MAXIMUM discharge air temperature

4. Add reheat if necessary

5. Vapor barrier and other considerations may come into play depending on building construction and project requirements

The major point to note here is that standard air conditioning equipment is typically designed for a discharge temperature between 55-58 degF. So if the required discharge temperature is close to this, you can probably get away with unity equipment.

If, however, the required discharge temperature falls into the 40s or lower, you will need to look at a custom solution. Either way, ask your distributor or manufacturer’s rep to run an equipment selection to verify that you can achieve the necessary discharge temperature for your application.

Discussion #2

How to correct a space humidity issue:

1. Plot the current space temperature and humidity on a psychrometric chart

2. Plot the desired space temperature and humidity on a psychrometric chart

3. If you can draw a straight line to the right to achieve your desired set point, simply raise the space temperature set point

4. Vapor barrier and other considerations may come into play depending on building construction and project requirements

This is the very first step to take when diagnosing a humidity issue. It’s a common misconception that lowering the space temperature reduces the relative humidity. As you can see from the psychrometric chart, when you lower the dry bulb temperature, you actually RAISE the RELATIVE humidity.

If this doesn’t fix the problem let us know and we can help you find a solution that will work for your project. Many times an airflow or building envelope tweak can fix the issue.

Do you have a humidity problem we can help fix?

Are rooftops a commodity? Maybe.

Are rooftops a commodity?

Maybe.

But there is a lot to think about when replacing an existing unit, or doing a design/build job.

Is quick and easy access important? Maybe we should look at a unit with hinged and toolless access and a slide out blower.

Is comfort critical? Maybe we should look at more cooling stages and adding a VFD.

Is this a mission critical job where no downtime is important? Maybe we should add Fault Detection & diagnostics to give us early failure warning sign alerts.

Do we need to keep utilities on budget? We might want to look at a high efficiency unit, or adding a VFD.

Is ease of scheduling important? Then we might want to look at a control solution, which could require a special MODBUS, Bacnet or N2 board.

What are the existing controls? Maybe there is a proprietary control system that won’t communicate with a standard rooftop board.

Do we need cooling year round? There are lots of ways to do this- economizer, condenser fan cycle control, condenser fan speed control based on liquid pressure, condenser fan speed control based on liquid temperature. Which method is the best for the application? Maybe it’s a combination?

What city is the job in and what are the local energy and mechanical codes? Does code require an economizer? Should that economizer be dry bulb, enthalpy, or dual enthalpy?

How many stages of cooling does code require?

Does code require CO2 sensors or a smoke detector? Maybe two smoke detectors depending on the unit size?

If we have to meet ASHRAE 90.1-2010 we will need to add a VFD if the unit is 10 tons or larger.

Is there a humidity requirement? Might need to consider hot gas reheat. Or we might need to design to a 45 or 50 degF discharge temperature (grab your psychrometric chart first!).

Is it important to have replacement parts available quickly? Might need to make sure we select a unit supported by a distributor with a local stock of parts.

Is building pressure control important? Should we look at on/off power exhaust? Or modulating exhaust with a VFD and building static controller?

And…the list goes on.

Either way, this LONG list is the reason we ask so many questions when we get asked to price a rooftop unit.

We want to make sure we get the right unit on the job the first time.

What questions did we forget to address?

HOW-TO Access Your UPGnet Profile and Change A Password

 

“Can you reset my UPGnet.com password?” is one of the most frequently asked questions I get from our dealers. With technology hacking these days, a strong password is vital to keeping information secure. But it can also be annoying when every website you use has different password requirements and different expirations. Most people take advantage of the browser password storage option. The big downside to that is you get used to using the storage option then when you need to remember your password, you can’t see what the password is, and you can’t remember it on your own.

Such is the case with many of our dealers and UPGnet.com. UPGnet has a set amount of time before they expire a user’s password and require a password change. That’s where I come in. As one of your UPGnet Administrators at cfm, I have easy access to go in and reset your password. However, this isn’t always the easiest or quickest option if for some reason I am unavailable. So here are a couple of easy steps to get you into your UPGnet.com user profile so you can update your password and settings to get an email from UPGnet when your password is about to expire.

Step 1.

First log in by going to www.upgnet.com. Once there, you will be asked to enter your username and password. Your username is all lower case and all one word (johnsmith). Enter your password and hit LOGIN.

Step 2.

Once logged in, you will see the screen below. Feel free to click the DO NOT SHOW THIS PAGE AGAIN link if you want it to take you straight to the homepage.

Click on the GO TO CENTERS button to head to the UPGnet.com home screen.

Step 3.

Click on the ADMIN AND HELP CENTER link to the left.

Step 4.

Click the PROFILE button

Step 5.

You should now see a screen like the image below that gives you access to your UPGnet.com profile. You will see all of your information such as phone, address, email etc.

About halfway down on the screen you will see a check box called * !PasswordExpEmail!. Check this box and click UPDATE PROFILE to ensure that a “Password Expiration” email goes to the email address in the user profile. UPGnet.com usually sends an email reminder 2 weeks before your password is set to expire.

And lastly,

Step 6.

At the bottom of your profile screen you will see a spot where you can update your password. Please make note that you must know your old password to update a new password on UPGnet.com.

All passwords must include the following:

  • one uppercase letter
  • one lowercase letter
  • one number
  • one special character such as: !@#$%^&*

NOW YOU’RE ALL SET with step-by-step instructions on how to access your UPGnet.com user profile and password. Please remember that if you ever need any assistance with UPGnet.com, contact your cfm Marketing Team and we will always assist you.

Get In The Millennial State of Mind

Millennials are the digital generation, they’re smart, savvy and socially conscious and they make up the largest generation today, with estimated 79-80 million members. Why is this important to your business? The larger the population, the bigger the impact on culture, opportunities, behavior, trends and so much more. If they don’t fall within your businesses target audience they should because this generation will be valuable down the road.

These young adults are also some of the most educated individuals in US History with over a third earning a four-year degree or higher. This tech-savvy generation researches brands and services and do their homework when it comes to finding a brand, product or service. They look for companies who are authentic, honest and are upfront with pricing.

More and more millennials are purchasing homes and the rise of this generations home buying has been growing year over year. Last year was the largest increase of any age group over a previous year.

So how do you advertise to this progressive, fearless and tech savvy generation? It’s certain that they find most of their information about products and services through social media, online research and referrals from friends. This group has the highest use of the internet as the main source of gathering information so you need to be at the right place at the right time to capture their attention. Below are several key factors to consider when marketing to millennials.

  • Emphasize Digital Marketing

Make sure your website is up-to-date and mobile friendly, if not, they will pass you by. Have a social media presence on Facebook, Instagram and Twitter. Digital display and video ads that run across multiple devices (especially a mobile device). You can retarget them with your ads as they move along the internet. Millennials would rather watch a video or see a graphic ad than read text. Remember, this group has grown up with technology and this is the norm for them.

  • Appearance and Style

Show the difference between your product and service and your competitors; that way the “all of these look the same” mindset is gone. Talk to them about digital thermostats and how HVAC units are more digital than ever before. This will intrigue them and they will respect that you took the time to give them additional information even though they’ve done their research online prior to calling you. After all, this is the most tech savvy generation.

  • Referrals

Word of mouth is still the best type of lead and it holds true with this group since they are social media gurus. Reviews and recommendations on your social sites and other review sites is imperative if you want to be considered by a millennial. Ask for a reference from another millennial that you’ve done work for and use that to gain additional millennial customers.

If you want to take advantage of this generation and their buying power you’ll need to stay up-to-date on their trends and incorporate your marketing strategies and advertising tactics to attract and retain them.

Do you need help marketing to millennials? Give me a call today and I can help you construct a plan.

EER, IEER, SEER, IPLV, HSPF… What do all of these efficiency terms REALLY mean

EER, IEER, SEER, IPLV, HSPF… You have probably seen all of these terms before and never even thought of what the heck they stand for, or why you would care to look at one over the other. In order to look out for the best interest of the building owner, however, it is important that all of us in the industry can articulate the differences to our customers to ensure the proper equipment is selected.

With the Department of Energy changes on the horizon, I thought I would take the opportunity to dive into what all of these efficiency terms REALLY mean, and what impact they have on end-users and the environment.

EER – (Energy Efficiency Ratio)

This value shows efficiency when operating at peak load capacity (when you could fry an egg on the sidewalk). Although it is a good reference, it can be a misleading representation if you live in a part of the country with seasons.

Defined as “the ratio of the cooling capacity of the unit (in Btu per hour) to the power input (in Watts)” – Energy.gov. This is calculated at 95/75 degrees DB/WB (AHRI Standard Rating Conditions).

IEER – (Integrated Energy Efficiency Ratio)

This value is more representative of the actual efficiency you will get out of your HVAC equipment. To calculate this value, efficiencies are reported at different loads (outdoor temperatures ranging from 65 to 95 degrees F) and then given weights to obtain an overall efficiency value. Surprisingly, the peak load efficiency only counts for 2 percent of the overall value! IEER is calculated as follows:

IEER = (0.02 * A) + (0.617 * B) + (0.238 * C) + (0.125 * D)

Where as:

A = EER at 100% net capacity at AHRI standard condition (95 deg F)

B = EER at 75% net capacity and reduced ambient (81.5 deg F)

C = EER at 50% net capacity and reduced ambient (68 deg F)

D = EER at 25% net capacity and reduced ambient (65 deg F)

SEER – (Seasonal Energy Efficiency Ratio)

Calculated very similar to IEER above, however, this is more common for residential equipment.

IPLV – (Integrated Part Load Value)

More geared towards Chillers, but still calculated the same way, and gives a standard for real-world efficiency comparison. The formula from AHRI is below:

IPLV = (0.01A) + (0.42B) + (0.45C) + (0.12D)

Where:

A = COP or EER @ 100% Load

B = COP or EER @ 75% Load

C = COP or EER @ 50% Load

D = COP or EER @ 25% Load

So, if you are designing for a space with somewhat constant internal loads that are independent of outdoor air temperature, EER is a good indicator. These types of applications come about from time to time in commercial and industrial spaces so it is important to make sure to use the correct basis for comparison.

However, in the much more likely scenario that you live in a place with varying outdoor air temperatures and internal loads, IEER and SEER will be your best bet!

Thoughts?

Are you different than your competitor?

This is what we all strive for in HVAC retail sales.

Why would Mr. & Mrs. Homeowner choose me when most likely they have at least 3 bids and they are most likely confused? I gave them a Good, Better, Best offer so they can choose which system fits best into their budget. But wait a minute, didn’t your competitor give them three options also? And the next company gave them 4 options. And on. Now they have 9 – 12 new system options. Whew!

With potentially 12 options sitting on the consumers dinner table, how do they choose the right one for them?

Let’s start with the System Solutions questionnaire. This means you must dig into the homeowners needs, wants and expectations. Hot spots, cold spots, allergies, the wood accents in the house drying and cracking, finishing the basement, want a quieter system, overall comfort level in the house, efficiency or carbon footprint desired, budget, etc. These are all important topics for the questions you must ask. But wait, asking is not the only vital part. The key to success is LISTENING! Then the key is successfully communicating your System Solutions for their needs, wants and expectations.

“I wake up in the morning with a bloody nose sometimes on a really cold winter morning.” “Wow, Mr. or Mrs. Homeowner that sounds serious and like something we need to address. Would you like me to include an option to take care of that in my System Solutions?” “Yes, absolutely.”

Now, almost every one of your competitors will put a humidifier on this system but do they quantify why they choose the humidifier they offer? Doubtful? Do they size it according to the structure needs? Doubtful. Do they explain why they have chosen a 2-stage furnace or a modulating furnace to get more run time to keep the humidity level more consistent? Doubtful.

The key is being a counselor, teacher, informant, etc. The key is digging the emotion out of each of the needs, wants and expectation. Your homeowner has most likely done some sort of research on a new heating and air conditioning system on their phone. The information they perceive to be accurate may or may not be. You must be patient in your questioning, listening and your delivery of the proposal of your System Solutions. Make sure to show them how you considered their budget with your System Solutions. You can get 14 SEER out of the 13 SEER Air Conditioner with the appropriate matched standard ECM motor in the 2-stage furnace, as one of the options. Now you not only provide them with the solution for a great furnace to help with a more consistent humidity level in the house but you also differentiate your company because you gave them a 14 SEER system using a 13 SEER A/C which costs them less money to install than the competitor who gave them a 14 SEER A/C and a standard PSC motor in a single stage furnace. Give them the relief of knowing you are the right person and company before you leave their house.

These are just a few ways to create differentiation from your competitor and win the trust of the homeowner. You earned their trust, took care of their needs, wants and expectations, as well as listened and communicated effectively.

Good Selling!

cfm Tech Tips – SSE (Simplicity Smart Equipment) Control Boards

York Commercial Equipment is currently manufactured with Simplicity SE controls. These controls are dynamic and versatile. An SSE Control Board can be programmed (in the Factory or the Field) for use in a Constant Volume unit, Variable Volume unit, Single Zone VAV unit, Fixed Variable (also known as Intelli-Speed), Reheat Unit, Split System Condensing Unit or Heat Pump. The control board comes with a Joystick, Enter Button, Cancel Button and Display Screen to facilitate programming in the field without a computer. This Tech Tip will help familiarize you with the programming steps for SSE Control Boards.

Factory Programming & Default Settings

New units are pre-programmed at the factory with default settings to accommodate unit operation as built. Every RTU is built with 3 sensors – Supply Air, Return Air and Outdoor Air. As shipped – any RTU can operate stand alone with the on-board sensors, or can operate from thermostat inputs. This results in flexibility when changing out a unit. Say you need to operate the unit immediately after the changeout and intend to operate from a thermostat, but the thermostat cable needs replacing and you need the unit to operate while pulling new thermostat wire. Simply set the unit to run on sensor operation. It will operate from its Return Air sensor until you connect the thermostat. Communication (BacNet, N2, Modbus, etc) is also available for BAS operation.

The Unit Control Board

The Unit Control Board communicates with the Economizer via the SA Bus, thus all programming is done through the Unit Control Board, making economizer setup very simple.

To program from the front of the board, use the joystick to scroll down to the desired menu option. With the cursor (>) in front of the desired option, press the enter button. Use the joystick to scroll to the next required option and again hit enter. Once you get to the desired setting, move the joystick sideways to change information while the display is flashing. Hit enter to save the information. The attached points lists are divided into sections for ease of finding information and navigating the control to make changes.

Example: Details > Control > Econ > Setup > Econ-MinPos

This shows the pathway in to change the economizer minimum position setting.

programming options

Use the example scenario & programming guide below as a reference while replacing a Unit Control Board.

A control board needs to be replaced in an existing unit.

Option:
  1. Available if the board is powered and displaying information on the screen.(Best Option)
    1. Plug a flash drive into the USB Port on the front of the control board in the unit.
    2. Using the attached points list, navigate to Update > Backup, and hit Enter.
    3. The current setpoints will be saved to the Flash Drive.
    4. Install the new Control Board and power it up.
    5. After countdown is complete, insert the Flash Drive into the new Control Board.
    6. Navigate to Update > Restore, and hit Enter.
    7. The original settings will be uploaded to the new control including Model and Serial numbers.
  2. If a flash drive isn’t available when the control board is replaced.
    • Use the ‘Quick Points List’ making sure all points marked with an asterisk are set correctly for the unit.

Not every scenario can be listed in this article, but the method is the same for any programming requirement. Use these Additional Materials for ease of navigation.

Additional Materials:

Quick Points List – Partial list of program points, for use when replacing a board or commissioning a unit.

SSE Master Points List – Full list of program points, for use as needed.

Sensor and Fault information

SSECombo1HR.jpg

Replace a PSC direct drive blower motor

If you’re in need of a PSC direct drive blower motor or just looking for a simple guide on how to replace one, cfm has you covered! We’ll be using the Evergreen motor in this example, so the same process won’t apply for a belt drive blower. We broke the process down into three segments, with a handful of sub segments to keep it simple

Pre-Installation

Suitable Applications:

The Evergreen motor is designed as a replacement motor for use on the following types of HVAC systems.

  • PSC Direct Drive Blower Motors only (Not for use on Belt Drive Blowers)
    • 115 or 230 VAC
    • 1/5 HP thru 1 HP
    • Residential and Light Commercial
      • Split Systems and Packaged Units
    • Clock-wise (CW) or Counter Clock-wise (CCW) rotation

Before Installation:

  1. Make note of the current motor speed selections.
  2. If the Existing blower motor is operational –
    1. Record the Total External Static Pressure (TESP)
    2. Record the Temperature Difference across the unit in Heat Mode and/or Cool Mode

Installation of the Motor:

Motor Bracket and Mounting:

  • The Evergreen motor requires a belly band style mounting bracket.
  • The Evergreen motor is a NEMA 48 frame.
    • This is the most common frame size for indoor blower motors.
  • If the original motor has the same frame size, the original mounting bracket should work.
  • If not, a new motor mount may be required.
    • The belly band must fit the motor properly.
    • It should be tight enough to prevent the motor from shifting on start-up

  1. Remove the blower assembly from the unit.
  2. Loosen the blower set screw.
  3. Remove the motor mount from the blower housing.
  4. Remove the motor from the motor mounting bracket.
  5. Position the new motor into the mounting bracket.
    1. Do not cover any motor vents with the bracket.
  6. Reassemble the motor mount to the blower housing with the new motor in place and the electrical connections facing down.
    1. Position the electrical connections between 4 and 8 o’clock.
  7. Center the blower in the blower housing.
  8. Position the blower set screw on the flat portion of the shaft, tighten securely.
  9. Replace the blower into the equipment.

Electrical Connections:

  • Evergreen electrical connections consist of three sets of motor leads –
    High Voltage Power Leads
    • Connected directly to Line Power
    • Powered at all times the unit is powered.
    High Voltage Communication Signal Leads
    • Connected to the control terminals that previously operated the PSC Motor
    Low Voltage Communication Signal Leads
    • Connected to the thermostat terminals of the control
  • The motor comes with a yellow jumper installed in the electrical plug and a white jumper shipped with the motor.
  • These jumpers are used to select the voltage in which the motor will be used.
    • If the motor is being installed in a 230V application, leave the yellow jumper installed in the motor plug.
    • If the motor is being used in a 115V application, remove the yellow jumper and replace it with the white jumper.
High Voltage Power Wires:
  • A Black Lead and a White Lead.
  • Provide operating power to the motor.
  1. Connect the Black L1 wire of the Motor to Line Voltage
    1. L1 on 115VAC systems.
    2. L1 on 230VAC systems.
  2. Connect the White L2/N wire to L2 or N
    1. L2 on 230 VAC systems
    2. N on 115VAC systems
  3. Connect the Green w/Yellow stripe ground wire to any cabinet ground within reach.
High Voltage Signal Wires:
  • A Black Lead and a Red Lead.
  • These leads determine the Horse Power selection and give the motor a run command.
    • When high voltage appears on these signal leads, the motor will operate at its lowest speed at the predetermined Horse Power rating.
  • Connected as follows:
    Red only with Black taped off
    Lowest Horse Power rating
    Black only with Red taped off
    Mid Horse Power rating
    Black and Red together
    Highest Horse Power rating
  1. Connect the lead(s) in parallel to all of the motor outputs from the control.
    • IE, if the control wants the motor to operate for any reason – High Heat, Low Heat, High Cool, Low Cool, Fan Only, the signal lead(s) receive high voltage power.
  2. Identify the horse power rating of the original PSC motor.
  3. Use the chart in the installation instructions to determine which High Voltage communication connection(s) to use for the desired horsepower rating.
Low Voltage Communication Signal Wires:
These wires communicate to the motor that there is a call for Heat or Cool and the motor speed must be modified.
Yellow
High Speed
Orange
Medium High Speed – (Available for ‘Y’ connection – See Diagram Below)
Brown
Medium Low Speed
White
Low Speed – (Available for ‘Y’ connection – See Diagram Below)
Blue
Common (Low Voltage)
  • Evergreen motor speed is selected by the low voltage inputs powered directly from the system thermostat terminals.
  • The Low Voltage Communication Signal Wires are connected to the thermostat terminals on the control board.
  • Unused Motor Communication Signal Wires are taped off and not used.
  1. Connect the Low Voltage Signal COMMON wire to the common thermostat terminal.
  2. Connect the desired speed(s) – Low Voltage signal wire(s) – to the appropriate HVAC System thermostat connection(s).
  3. Select Low Voltage Communication wires for speeds that best suit operation of the equipment.
    • Select a heating speed that operates the equipment within the correct temperature rise for heating.
    • Select a cooling speed that gives approximately 400 cfm per ton of cooling.
  4. If the same motor speed is required for both Heating and Cooling operation, you must use the ‘Y’ connection provided with the motor.
    • Follow the installation instructions with the motor to apply it.
Important Note:
The ‘Y’ connection can only be used with the Orange or White Motor Leads

Labeling & Data Entry:

  1. Install the System ID Label on the HVAC system near the existing wiring diagram.
  2. Enter the Evergreen data.
  3. Record the Horse Power of the motor and the Date of Installation for future reference if needed.

Post-Installation of the Motor:

  1. Confirm airflow is matched to the systems performance requirements.
  2. Measure airflow with industry accepted instruments.
  3. Confirm the temperature rise on all fossil fuel heating systems to meet the OEM data plate specifications.
  4. Adjust the speed selections to achieve the design CFM per ton of cooling.

If you’d like to see an install guide for replacing a belt drive blower motor, leave us a comment below with some details of your project. You can also find Evergreen replacement motors & additional details via the cfm eStorefront.

Download the original service letter:
Evergreen-motor_Tech-Tips-TT-01-17_April-2017.pdf (155 downloads)

Energy Analysis Case Study – Unit Heaters vs Tube Heaters – Part II

Earlier this spring we wrote a blog post discussing why you might choose unit heaters or tube heaters for your heating only project. The article detailed how each type of system worked, which applications were ideal for each style, and which applications were not ideal. But it was missing something. Where was the real world example? How do we actually determine which heater style is best not just in theory, but with numbers to back it up? Great questions! Let’s look at a real world example now.

A couple weeks ago we received a call from one of our really good customers who asked for some product selection assistance on a project he was working on; a 96′ by 78′ workshop with a multi-tiered roof line. We were asked to do a load calculation and help the contractor select the best type of system to heat the space based on the customer needs. Here’s how it all went down.

We met with the customer on the first cold morning of the year. It was about 40 degrees outside with a 20 MPH north wind, and the day before was 77. The regret for not meeting 24 hours earlier was sky high, but since you really don’t care we will keep moving on.

This is a large, 3 section barn under construction with most of the steel frame still exposed.

This barn will be the project site for our energy analysis.

The owner was not on site when we arrived, so we started to assess the half constructed building so we could get an idea on heat load. The structure was a butler style building with a metal shell, and the walls and ceiling had R-13 plastic wrapped insulation. The long side walls were 10′ tall, and as you moved to the center there was a pair of 18′ peaks, and then a 26′ peak in the center. The long north wall had six 10′ x 10′ overhead doors, and the east and west side each had one 15′ x 12′ and two 12′ x 10′ overhead doors.

The owner finally arrived as we started to put on our thinking caps. After doing hundreds of load calcs similar to this building, we estimated 45 btuh per square foot which came out to about 335,000 btuh of heat load. But before coming up with a solution, we better ask the owner what he wants. After all, it’s his building. Who cares what I think he should do.

cfm: “So what are you looking to do with your space?”
Owner: “Just want to keep it from freezing. We might have a gathering in here every once in a while, but we aren’t that particular on keeping it really warm”
cfm: “What temperature do you want to maintain on the coldest day of the year?”
Owner: (after a long drawn out story about all the examples he might run into) “There might be times we would like it to be 60 degrees”
cfm: What type of power do you have?
Owner: “We don’t have natural gas. We are bringing electricity over here next week”
cfm: “Would you be interested in using propane? It will save you a ton of money on utilities”
Owner: “Yes”

The conversation continued, and we got into what type of equipment he wanted. The owner had done some research and he was interested in tube heaters, although he wasn’t totally convinced yet. We all agreed with tube heaters (for now) and came up with a good product selection based on the 335,000 btuh load, and then mentioned it was subject to running the numbers. We of course checked our clearances based on the tables in the installation manual to make sure we weren’t going to be too close to any combustibles. We also discussed how the heat distribution patterns would work, with most of the heat coming from the burner boxes and then a decreasing intensity the further away you went. So far the owner liked what he was hearing.

Load Calculation & Energy Analysis Results

So here is the really fun part- now that we have all the information, what is the best solution for this customer? Infrared like he asked for? Or are unit heaters a better option? We certainly don’t want to try to “sell him” unit heaters when he asked for tube heaters, but one or two of you (being a little facetious here) may have an experience in the past with an owner “wanting” something, but then changing their mind once they see the price. So how do we quantify the right solution? We run a cost analysis showing payback and return on investment (ROI).

Here are screen shots from the load calculation and the energy analysis we ran. You might notice that the load ended up being about 315,000 btuh, close enough to the estimated 335,000 load from earlier that we did not make any selection changes.

Load calculation assumptions and building sensible loads:

Image showing the results of a load calculation for determining heat load.

Load calculation assumptions and building sensible loads.

Load calculation net loads:

This is a chart showing the load calculation net loads for the case study site.

Load Calculation Net Loads

Energy payback analysis:

This is a visual comparison between the two heating options and their cost of ownership.

*The price of propane we used was $1.75 per gallon
**Owner equipment cost is estimated and does NOT include installation labor, gas or flue piping, electrical, thermostat wire or hanging hardware for the unit heaters.

Analysis Results:

The tricky part about running an energy analysis on infrared is there are no published efficiencies. So what do we use? Well, we know the flue gases don’t condense, so our combustion efficiency can be no more than about 82 or 83%. But one thing we do know is infrared keeps the heat down low to the floor, which will reduce the heat load on the roof (our delta T between the ceiling and ambient air will be far less with tube heaters which will reduce overall load). And our air changes will also be reduced, especially since the ceiling is 26’ tall in the center. With forced air, the ceiling air will be warmer and it will want to leave the building much faster than the radiant solution. So to account for both of these factors, we reduced the roof load and the air changes per hour to come up with an effective “radiant heat” heat load of 270,000 btuhs.

Chart showing the energy analysis results for payback and ROI.

In this particular case, based on our results we can see that installing tube heaters would be the best option.

The moral of the story will be different for every job. But for this project, it probably makes sense for the owner to proceed with tube heaters. A 3.7 year payback is pretty good, and it’s hard to argue with a 26.7% ROI. You won’t find that kind of return in the stock market, unless your name is Warren Buffett. And in that case you’re probably not reading this article.

What has been your experience with tube heaters and their energy efficiency compared to 80% unit heaters? Do you have any jobs that we can help you look at? Just ask us in the comments below, or give us a call toll-free @ 1-800-322-9675