Lennox Commercial

Frequently Asked Questions

Solar-Ready Systems

Does solar work if you don't live in the West?

No matter where your building is located—even if it's not in Arizona or some other sunny location—you can take advantage of the money-saving benefits of the SunSource® Commercial Energy System.

What are some of the advantages of solar power?

Solar power has a number of advantages, from economical to environmental.

  • Electricity generated from sunlight is free and limitless.
  • A SunSource® Commercial Energy System, with as few as one solar module, can save you money on your monthly bills. The U.S. federal government and some states provide tax credit for renewable-energy systems. Depending on where you live, you may also be eligible for incentives through your utility company. To find out what incentives are available in your area, contact your local utility provider.
  • Solar is a fast-developing renewable energy source because it produces no air pollution or hazardous waste. By comparison, electricity generated by power plants produces carbon dioxide emissions that are believed to contribute to climate change and pollution.
  • The SunSource system offers the flexibility to start small and add more modules at a later date for greater energy savings. To determine your building's savings in just two steps, use our SunSource solar calculator.

How does this system differ from a single inverter system?

There are several important differences. With the SunSource system:

  • DC voltages are much lower. This relaxes some important code requirements.
  • Each microinverter uses maximum power point tracking to optimize output of the solar modules on an individual basis. This gives significant performance enhancement when there are shadows cast upon the modules.
  • The energy monitoring system and diagnostic features provide information on a module by module basis. It is possible to see when a module is underperforming.

What do terms like "on-grid" and "grid-tied" mean?

On-grid solar systems, also called "grid-tied" systems, are connected to the utility electrical network in your area. The SunSource system is an on-grid system designed to help you lower your utility operating costs and take advantage of incentives from utility companies. "Off-grid" refers to typically more expensive systems that are not connected to the utility electrical grid.

Will a SunSource® Commercial Energy System work for my building?

The SunSource design allows it to be installed on rooftops of virtually any shape or size.

What Lennox® products are available with the SunSource® Commercial Energy System?

Currently, only the 3-6 ton Energence® rooftop units are available with the SunSource System. It is available as a factory-installed option.

Can I use a solar-ready Energence® rooftop unit with traditional solar systems?

No. Solar-ready Energence® rooftop units have been designed to operate only with solar modules sold by Lennox. It is not required to buy the rooftop unit and modules at once. If necessary, customers can buy the solar-ready unit first and add the solar modules at a later time.

How many modules can I install per rooftop unit?

Each 3- to 6-ton solar-ready Energence rooftop unit can take up to 16 solar modules for single-phase or 24 for three-phase applications. It is the maximum current that a single string of inverters can have. As you connect them together, the current increases and the max of 16 (1PH) or 24 (3 PH) inverters (20 A) is the upper limit of the cables. We have designed the RTUs to accept a single string.

Is there a field-installed solar option?

No. SunSource Commercial Energy System is currently available as a factory-installed option only, for 3-6 ton Energence rooftop units.

Will the Prodigy® control system recognize any part of the solar installation?

No. The Prodigy system only tracks information related to the Energence rooftop unit. The Envoy communication module will monitor the status and energy production of the solar modules.

Are there any stipulations with what type of circuit breaker can be used for the HVAC unit?

The HVAC breaker in the main panel must be suitable for back feed (not marked with LINE and LOAD) and cannot be a GFCI or arc fault type breaker. These types of breakers can be on other loads in the main panel without causing an issue.

How heavy are the solar modules? What are the dimensions?

Module weight: 46.7 lbs each.

Module Dimensions (L x W x H): 65.94" x 39.41" x 1.22”.

What happens when my panels are covered in snow?

When solar modules are covered by snow, they do not receive sunlight and will not generate solar power. Our solar modules are installed at an angle and have a silk glass surface which may allow the snow to slide down. In the event of accumulation, the snow will need to be brushed off to get solar power.

What is the total weight of the panels, mounting hardware, ballast, and concrete pavers (if needed)?

It depends on the number of panels installed. For a four panel array:

  • Weight of 4 modules= 186.8 lbs.
  • Total weight of mounting frame = 32 lbs.
  • Weight of modules + mounting frame= 218.8 lbs.
  • Total weight + paver (1 to 2 pavers per module depending on engineering plans provided) = 586.8 lbs (at 2 pavers per module).

NOTE: Pavers are installed in the Ballast Trays to meet system weight and engineering requirements.

How do you get graffiti off the panels (spray paint, shoe polish, etc.)?

You can use any cleaning product designed for a car windshield or glass door/window.

How far can the panels be from the unit? What gauge wire do I need?

The maximum distance is determined by the ability to communicate energy performance over power line carrier. There are recommendations about distance in the Enphase manual. A communications booster can be used to extend the performance of the power line carrier (PLC) system. To conduct the power, it is recommended to size the wires to keep the voltage drop below 1.5%. As an example for a 1-phase system, a 16 solar module system can use a #10 wire at 61 feet and a #6 wire at 155 feet. For a 3-phase system, a 24 solar module system can use a #10 wire at 64 feet and a #6 wire at 158 feet. A wire size table has been provided in the application and design guidelines.

How does the efficiency of the modules degrade over time?

Crystalline solar modules (like the ones available with SunSource system) are designed to exceed a 30 year life. Over time, a breakdown (by ultraviolet light) of the encapsulation materials on the cells prevent the modules from shedding any moisture that gets trapped inside. The trapped moisture leads to corrosion that increases the resistance of the cells electrical connections and causes decreased operating voltage and therefore less power output. Also, the breakdown of the encapsulation material can reduce the transparency of the material and limit the amount of sunlight the cells receive. This degradation in output is a very slow process that happens over an extended period of time. The solar module warranty guarantees a maximum performance degression of 0.7% p.a. in the course of 25 years, a significant added value compared to the two-phase warranties common in the industry.

What is the conversion efficiency of the microinverters?

The DC to AC conversion efficiency of the microinverter is 96%.

How much power can I get on a cloudy day?

Solar modules will still produce power on cloudy or overcast days, but at a reduced level. The amount of power will depend on the cloud cover, and will vary accordingly.

How does the system prevent electricity from being put back on a dead grid?

The microinverters are specially designed to safely operate the grid. Usually, inverters need to comply with IEEE standard 1547 and UL standard 1741 before they can be certified for utility interaction. The Enphase microinverters meet these two standards.

What type of maintenance is required for the solar modules?

The solar modules do not require a great deal of upkeep. Keep the glass surface of the solar module clean and free of debris. Use water and a soft sponge or cloth for cleaning the glass surface. A mild non-abrasive cleaning agent can be used if necessary. IMPORTANT: Do not use high pressure sprayers to clean modules. It can be a good idea for the installing contractor to offer this as part of their service agreement with the building owner. They can clean the modules if necessary and inspect all mechanical and electrical connections to ensure they are clean, secure, and undamaged.

How can I order the solar module mounting kit?

The solar modules and mounting hardware will be shipped together once the order is processed.

How do I mount the panels to a roof for high wind conditions?

The solar modules utilize a ballast roof mounting frame to counteract the uplift from the wind. An analysis must be conducted for each situation to determine how much ballast needs to be used for each solar array, and if additional measures need to be taken to secure the solar modules to the roof structure. This is part of the permit process. If the system's ballast cannot satisfy the wind load conditions or local code requirements, the installer can secure the system to the roof by adding stanchions and struts as shown in the SunSource Commercial Energy System Application and Design Guidelines document.

What direction should the solar modules face?

Solar modules should be installed facing south.

Are there any mounting guidelines for the solar modules with proximity to the edge of the roof?

Yes. Consult the installation manual as well as local codes governing module setbacks.

In the event that a microinverter fails, can it be replaced without removing the panel?

Yes. There is enough clearance under the panel that a microinverter can be unbolted, removed and replaced without removing the panel.

Where can I go to find out more information about rebates?

The Database of State Incentives for Renewables and Efficiency (DSIRESolar) provides a good starting point to understand what rebates are available.

How does the communication module work?

For single-phase of 208 Wye applications, simply plug the Envoy communications gateway into any outlet in the building (without any surge protector). Data from the microinverter (on the AC solar module) is communicated over the existing power line to the Envoy via a proprietary power line carrier (PLC) system. The Envoy connects to a broadband router, which uploads collected data to a server that will make it available on the online monitoring website. For 230 and 460 VAC three phase applications, the Line Communication Filter can be wired directly into the high voltage wiring from the solar modules. It contains an Envoy communications gateway that can be connected to the router as described above.

What happens if I do not have an internet connection? How do I know the panels are working?

If there is no internet access at the installation site, it is still possible to communicate directly using an Ethernet port and a personal computer with web browser. More information is provided on the instructions of the Envoy communications gateway, under Envoy Local Interface. If no communications gateway is used, indicator lights on the microinverters indicate whether the system is working. Amperage and voltage produced by the solar modules can be measured at the connection point in the outdoor HVAC unit.

Is the Envoy communications gateway a required component for the system?

The Envoy is not required for the system to function, but it is highly recommended that one is installed on every system, so building owners can monitor the benefits provided by the solar system. Also, the Envoy communications gateway offers valuable diagnostics for building owners and the installer signal any service or performance issues.

Is the Enlighten online monitoring service provided with the microinverters, or is there an additional cost?

The Enlighten online monitoring service is provided with each module purchased from Lennox. There is no ongoing monitoring cost for the service.

Can I get both energy efficiency and renewable energy federal tax credits for solar?

Yes. Many state, federal and utility incentives and grants can help significantly reduce the first cost, or even provide an ongoing rebate. Solar components and their installation costs qualify for the solar tax credit (30%, with no cap, good through 2016).

What license do I need to install the solar panels?

Generally speaking, there will need to be someone with an electrical license supervising the installation. There are no uniform certification requirements for installing solar photovoltaic systems. A good way to find out what experience/certifications are required is to speak with your local electric utility.

Do I need to team up with a solar installer or can I install them myself?

It is important to become familiar with NEC requirements for solar PV installations. A good way to get up to speed is to take a one-week course in solar PV offered by one of several nationally known solar organizations. We have developed a checklist to use in planning an installation. Review it to get a feel for the various aspects of doing an installation. You can become a qualified installer or team up with an experienced solar installer.

Do I need a special meter from the utility? What do I need to communicate to the utility company when installing the SunSource system?

This varies from utility to utility. When you make an application for interconnection with a utility, they will tell you whether the meter is suitable or not. If not, they will change it out. Some net metering programs require an additional meter to separately measure the output of the solar power system. These meters are often called Renewable Energy Credit (REC) meters. The REC meter may or may not be supplied by the utility. Note that in some states (New Jersey, for example) the Renewable Energy Credits may have considerable value. Different states have different policies on who gets to claim these RECs. In some states, the utility claims them, in others, the building owner gets them.

Is there a certification program for solar installers?

Yes. The North American Board of Certified Energy Practitioners (NABCEP- Certification as a PV installer) is the most well known, but it isn't the only one.

Will Lennox provide sales tools and training on solar?

Sales training will be available via online eLearning, webinars or live sessions.

Technical training will be available via online eLearning, webinars or live sessions.

Does a contractor require training from Lennox to purchase SunSource system components?

No. A contractor does not require training to purchase system components.

If there is a warranty claim on a solar module or microinverter? Do I contact Lennox to file this claim?

No. Any warranty claims or questions on the solar modules or microinverters should be directed to SolarWorld at:

Laurie Hair, Customer Service, SolarWorld


Phone: 1.805.388.6322

How do the panels hold up to hail?

The solar modules have a laminated tempered sheet of glass on the top that is similar to a car windshield. They are very resilient to hail stones. To ensure that our panels are stable and break-resistant, we subject them to rigorous testing. During our hail-impact test, we replicate a natural hail storm by dropping a 1.1-pound, 2-in steel ball onto the solar panel from a height of 13 feet. This is repeated up to 20 times in the same place on at least 11 different points of impact. (The IEC specifies a standard weight of ¼ ounce per steel ball.) We also simulate the mechanical load of objects by dropping a 99 pound lead-filled sack from a height of 4 feet onto the middle of a vertically positioned solar panel up to three times. (Hail damage is not covered under the terms of warranty).

© 2019 Lennox International Inc.