Product Review of Lennox Solar Air Conditioner

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A description of a solar power assisted air conditioning unit manufactured by Lennox.

Everyday you hear green jobs, sustainability, or carbon footprint, so Lennox has developed the first ever Residential Solar Air Assisted Air Conditioner, the SunSource XPG20. Hopefully you will be better informed about the benefits and concerns with this product and information about tax incentives. This model is new on the market, but similar model that are also solar ready can be found on the Lennox website such as the XP15 or XP17.

Is it Really a Solar Air Conditioner?

The SunSource system is not 100% solar powered. The XPG20 System simply takes the concept of solar energy to a smaller scale by using the Sun's energy to generate a portion of the power for the heating and cooling system.

As stated from a Lennox promotional literature:

Patent Pending solar assist technology uses a combination of solar energy and electricity to reduce peak demand on home electric usage. The combination of the two-stage scroll compressor, combined with the 170 Watt DC Solar Assist Panel results in up-to 8% drop in electricity usage results in one of the most energy efficient home HVAC units you will find on the market today, without going to geothermal.

As compared to the same unit with no solar assist, the SunSource unit achieves a higher SEER of 20.00 as compared to 18.2 and EER of 13.7 as compared to 12.7 without solar assist.

Energy Efficiency

Two-stage scroll compressor— runs at low speed most of the time, which means it's less expensive to operate and provides more consistent comfort. The unit is designed to work with the Humiditrol whole-home dehumidification system.*

• Power from the single solar panel reduces electricity needs of the outside fan motor. (Typically a 170 or 205 watt solar panel installed)

• Efficiency ratings of up to 18.20** SEER and 9.70** HSPF—can save you hundreds of dollars a year, compared to a standard heat pump

• Tested with simulated power from the 205 watt solar module, the system is 20 SEER and 10.7 HSPF

• ENERGY STAR® qualified—meets or exceeds EPA guidelines for energy efficiency

• This product qualifies for a tax credit under the American Recovery and Reinvestment Act.***

• Each of these units will offset 376 pounds of CO2 annually, which is the equivalent of seven mature trees or carpooling to work one day per week.

Footnotes from Lennox website

*Must be accompanied by either a variable speed air handler or furnace and the ComfortSense® 7000 Series touch screen thermostat.

**SEER and HSPF are for operation without solar power input.

***Eligible heat pumps and air conditioners must meet the Federal minimum efficiency standards of 16.00 SEER and 13.00 EER for air conditioners or 15.00 SEER, 12.50 EER, and 8.50 HSPF for heat pumps, as set forth by the Internal Revenue Service (IRS). Not all system combinations apply. Verify actual system efficiency at and consult your tax expert before claiming energy efficiency tax credits.

The unit comes with a 10-Year Limited Warranty on compressor and all remaining covered components, excludes solar panel.

Benefits vs. Costs

Since Lennox states that there is only 8% savings in electricity usage, the XP unit is going to cost somewhere in the range of $7500-$12,000 for a 3-ton system, installed. Once you add in the extra costs of the solar assist panel and installation, you can spend an extra $2500-$5000 on the total job.

When your cooling needs are at their peak, the solar assist will be at its peak efficiency also. This also reduces you demand charges when utility usage is at peak load. It’s the peak demand and loading that can contribute to brownouts, higher spot fuel prices and power quality issues.

You must make sure you have adequate sunlight to optimize the efficiency of the solar panel. You must install the panel facing south either on grade or on your roof. Keep it away from overhanging trees. Each panel requires about 15 square feet of space. If you belong to a home owner’s association, check the by-laws to determine if you are permitted to install solar panels on your roof.

Tax Incentives

The solar panel, its wiring and support rack qualify for an uncapped rebate of 30%. The rest of the heat pump and installation are 30% capped at $1,500.00. Be sure you do not get scammed by your salesman stating that you can receive a rebate of 30% on the total installation. It is best to consult with an accountant or other tax professional.

Units must be installed between January 1, 2009 and December 31, 2010 to be eligible for tax credits. See Lennox’s website:


If you are planning on replacing your central air conditioning system and are concerned about saving money over the long term, this system may be for you. Keep in mind that when you are away from home during the day, the solar energy is not stored, so if you are at work, you will probably save more money by installing a programmable thermostat than from the 8% electricity savings. However the units are very efficient and they qualify for a 30% capped rebate without even installing the photovoltaic panels. So even if it cost $3000 to install the solar cell, your out of pocket cost would be $2100. You would recoup that in about 10 years depending on your rate charges, so for the next 5 to 8 years, you would be making money. Also the solar panel most likely will last for at least 25 years and the replacement cost would be substantially less since the wiring and racks would be in place.


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