Welcome to
The CHERP Network:

Driving Energy Efficiency
and Economic Recovery

Finding the Best Contractor

At CHERP, we believe that Home Performance Contractors are the true heroes of the energy efficiency revolution. Without great Home Performance companies – expert in whole-house energy systems and retrofit techniques – we will never reach our national energy goals and homeowners will never achieve the levels of comfort, indoor air-quality, safety from carbon monoxide poisoning, or the energy use reductions and money savings they desire. CHERP supports great contractors. But how does a homeowner know how to choose a great contractor from the many choices available? Start by reading a few stories about the lost opportunities and high cost of NOT choosing a best-of-class contractor...

True Stories - of what can go wrong

We have found that a homeowner who has a basic understanding of building science principles and the extraordinary benefits of a retrofitted home will be more excited to launch into the process and be better equipped to choose the best contractor resources to execute the work. Education is power. And in this case, a little education could save you literally tens of thousands of dollars and result in a home that is dramatically more comfortable, quieter, safer, more durable, more valuable, less expensive to operate, and more friendly to the planet. Like we said, these are extraordinary claims and they are true – backed by research from the U.S.DOE, EPA, Lawrence Berkley Labs, NREL, Rocky Mountain Institute, Architecture 2030, the California Energy Commission, the California Public Utilities Commission, and hundreds of building scientists around the world.

The fastest way for you, the homeowner, to grasp the basic concepts of building science as it relates to your home is to read case studies of real people and what they have learned – especially their mistakes. Mistakes are instructive because they clearly highlight the value of doing things right in the first place and the cost of doing things wrong or omitting important steps along the way. Read True Stories of what can go wrong here!

Who are the Best-of-Class Home Performance Contractors?

Without getting too technical, Best-of-Class Home Performance Contractors are those who are experienced and certified in diagnosing (through a comprehensive energy assessment) all the interdependent energy systems (HVAC, air-sealing, wall and attic insulation, windows, and solar PV) in your home. The also have the expertise within their company or circle of certified sub-contractors to design and execute all the work necessary to bring all those interrelated systems up to a total optimal performance level – i.e. maximum comfort levels, maximum noise reduction, maximum indoor air-quality, maximum carbon monoxide safety, maximum energy efficiency gains, and maximum dollar savings on energy bills.

In contrast, many contractors offer only single, quick measures that qualify for basic rebates: i.e. attic and wall insulation -often without proper preparation or air sealing, or HVAC equipment “change-outs” instead of redesigning the system and the ducts for proper “right-sized” equipment size reductions and air-flow. Most HVAC contractors are not approved to offer EUC rebates because they have not been properly certified in whole-house building science procedures.

Further, even the best stand-alone insulation companies or HVAC companies are NOT considered by CHERP to be comprehensive or Best-of-Class Home Performance companies because they do not offer comprehensive services. For optimal results, however, many good single-measure contractors could work in concert with a team of other qualified sub-contractors, guided by a Home Performance General Contractor experienced in addressing all the energy systems comprehensively.

At CHERP, we encourage all contractors to learn about, and become certified in, Home Performance work because we need thousands of qualified contractors to meet our national goals. By encouraging a Best-of-Class classification of contractor we hope to protect the public, encourage high-performance retrofits in our community, and demonstrate to the construction industry that there is a huge market for high-quality, comprehensive energy-retrofit services.

The 10 energy measures performed by Home Performance Contractors

Best-of-Class Home Performance Contractors are proficient (in diagnosis, design, repair and installation) in all 10 of the following areas and can guide you in designing a Master-Plan for your project that includes the appropriate “Loading Order” in which to do the work based on the cash flow you have available:

(1) Comprehensive Energy Assessment of all existing energy systems (lighting, pool pumps, appliances and phantom loads are a subset of the assessment) and Carbon Monoxide safety testing and corrections according to Building Performance Institute standards.

(2) Air sealing: (including crawl-spaces) to reduce building air leakage according to BPI standards

(3) Fresh air ventilation systems: according to BPI

(4) Attic prep and Insulation installation: according to BPI

(5) Wall Insulation installation: according to BPI

(6) Duct design and installation: according to Measured Home Performance Guide.

(7) HVAC: Heating – Heat Pumps, Gas Furnaces and Hydronic heating systems. Air Conditioning – high-efficiency AC systems according to Measured Home Performance Guide for “right-sizing” and design specifications.

(8) Window replacement

(9) Solar PV: design and installation in concert with whole-house energy-efficiency optimization

(10) Green Labels: Certified by Build it Green, to provide a Green Point Rating Label for your home to help validate the increase in value of your home due to the retrofit work you just accomplished!

The Whole-House, Total Energy-Systems Approach: The best Home Performance Contractors will be able to provide, repair or replace any or all of the above systems in order to achieve maximum energy savings, as well as optimal comfort and health levels from the total, system-wide performance, of each system relative to the others, and relative to dollars spent.

Think about it this way – If the contractor you choose to work with cannot design, contract and perform (either in-house or with expert, certified subs) all of the work described above, then they will tend to only sell you what they can do, leaving out potentially important systems that could make it impossible to achieve maximum energy performance and comfort - and those omissions could cost you thousands of dollars of unrealized savings over the life of your investment!


A scope of work Master Plan includes a retrofit package of a combination of some or all of the 10 possible measures bundled into a comprehensive package or various packages showing the costs and benefits of each potential combination of choices. This will allow you, the Homeowner, to decide how much you want to spend and whether to do the work all at once, or in phases over time.

The Loading Order refers to the order in which each individual measure is executed. Executing the different measures in the proper order will save money and increase the effectiveness of the results. Also, some of the least expensive measures (like air-sealing or insulation) can deliver very high results for a relatively low cost – if they are installed correctly and in the right loading order.

Questions for Homeowners to Ask a Potential Contractor

These questions are general in nature and designed to determine the contractor’s general level of competence in the Home Performance industry. If they cannot answer yes to these basic questions, then they are not qualified to be doing whole-systems energy retrofit work at this time.

(1) Can you provide me with a whole-house energy system retrofit Master Plan including all 10 system measures in their proper loading order so that I may execute the work over time and in the correct order if I chose not to do everything at once?

(2) Are you an approved contractor with my local county rebate programs? And if I choose to take advantage of the rebates, will you submit my job through the approval process AND do you guarantee the rebates you are projecting for my project?

(3) Will you be pulling a city permit on my job? (Not pulling permits is an ILLEGAL practice and should be reported to the Contractor’s Board.)

(4) How many people in your company are BPI certified and can you prove it? (BPI – Building Performance Institute - is the national certification agency for all Home Performance contractors.)

(5) Are you familiar with Measured Home Performance:  A Guide to Best Practices for Home Energy Retrofits in California and will you do your work in conformance with those specifications – to be proven by a HERS rater when you are finished?

(6) Can you provide me case studies of your projects showing deep energy retrofits with actual energy savings on projects over one year old?

(7) Can you provide me with the names of 15 clients that I can call as a reference on your company?

(8) Can you provide me with financing? (not required but nice to have)

(9) Are you willing to provide CHERP with the performance test results from my project along with the pre and post energy use data from my utility bills? 

In Summary

At CHERP, we are collecting dozens of stories from Homeowners who have been unhappy with their contractors. Please read some of these stories – they are very helpful in understanding what NOT to do. Here is a summary of the lessons learned:

(1) While offering many benefits, Home Performance contracting is extremely technical and multi-faceted, requiring competence and certifications in many energy systems simultaneously.

(2) The most cost effective and safe energy efficiency retrofit work must be approached as a whole-house, multi-disciplinary, inter-related system. The home and its occupants live and breathe as a total, connected and constantly interacting system.

(3) The real benefits from retrofitting buildings for energy efficiency are huge - and so are the potential opportunity costs of not executing the technical work correctly.

(4) If you are a hammer, you see everything as a nail. A single measure contractor can only provide a single measure solution – and perhaps unwittingly cause real damage and expense in other areas.

(5) Never start your energy efficiency journey with a single-measure contractor. Always begin with a professional, whole-house energy assessment and report of the current state of all the interrelated energy systems in your home, provided by a Best-of-Class Home Performance Contractor.

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