Energy Valuation
& HERS Ratings
Solar, efficiency retrofits and high-performance construction carry real value that a standard appraisal routinely records as nothing. Valued properly, on the Appraisal Institute’s green addendum — and HERS ratings produced alongside it, through an associated RESNET-certified Rater.
The problem this solves
A homeowner spends thirty thousand dollars on an owned solar array. The house is appraised. The array is recorded as a feature, no adjustment is made, and the value contribution is zero — not because it is worthless, but because the appraiser had no supported method to say otherwise.
That is a defensible outcome for the appraiser and a bad one for the owner. The fix is not optimism about the number, it is having a method: production data, comparable evidence, and a reporting form built for exactly this.
Energy features we appraise
- Owned solar photovoltaic
- Leased & PPA solar — correctly, which often means no value
- Battery storage
- High-efficiency HVAC & heat pumps
- Envelope & insulation retrofits
- Windows & glazing upgrades
- Solar water heating
- High-performance new construction
Not listed? Ask. This is what comes up most, not a limit.
To value it properly
- The installation contract or invoice
- Whether the system is owned, financed, or leased — this changes the answer more than anything else
- Production or monitoring data, if you have it
- Warranty and any transferability terms
- Permits for efficiency work
The index, in one minute
A HERS rating is a modelled measure of how much energy a home actually uses, expressed as one number. It is the measurement standard behind most energy programmes in residential construction, and it is administered by RESNET.
Lower is better, and each point below 100 represents roughly one percent less energy use than the reference home. Above 100 means more.
When one is actually needed
- 45L tax credit — the new-energy-efficient-home credit requires a certified rating
- ENERGY STAR certification for a new home
- Code compliance where the jurisdiction uses the ERI path
- Lender and utility programmes that price or rebate on measured performance
HERS ratings — who signs them, plainly
HERS ratings are available now, produced through an associated RESNET-certified Rater. The rating is issued under that Rater’s certification and ID number, and it says so on its face.
My own RESNET certification is in progress and expected before the end of 2026. Until it is in hand I am not a certified Rater and this page will not say I am. That is the same disclosure made on the commercial page, for the same reason: a credential overstated once is the first question opposing counsel asks, and this practice’s whole argument is that the credentials are real.
The valuation side is mine directly — what the array, the envelope or the retrofit actually contributes to value, supported and reported on the Appraisal Institute’s green addendum. Rating and appraisal answer different questions, and most people need one or the other rather than both. Ask and you will be told which.
Common questions
Can you provide a HERS rating?
Yes — through an associated RESNET-certified Rater. The rating is issued under that Rater’s certification and ID, not under mine, and that is stated on the rating itself. My own RESNET certification is in progress and expected before the end of 2026; when it is in hand this page will say so, and not a day before. The distinction matters to anyone relying on the rating, so it is made here rather than left to be discovered.
What does the HERS Index number actually mean?
It is a scale where a home built to the 2006 International Energy Conservation Code scores 100, and a net-zero home scores 0. Lower is better, and roughly each point below 100 represents about one percent less energy use than that reference home. A score of 60 is a home using materially less energy than the reference; a score above 100 is a home using more.
When do I actually need one?
Most often for the 45L new-energy-efficient-home tax credit, for ENERGY STAR certification, for code compliance where the jurisdiction uses the ERI path, and for certain lending and utility programmes. Builders need them per plan or per home; owners usually need one only when a specific programme asks for it. If a programme is not asking, you probably do not need one, and I will tell you that.
Is a HERS rating the same as an appraisal?
No, and they answer different questions. A rating measures modelled energy performance and produces an index number. An appraisal states what that performance, and the equipment producing it, contributes to value. They are complementary and they are commissioned separately — but having both from one place is the reason this page exists.
My appraisal gave my solar system no value. Is that normal?
It is common, and it is usually wrong. An appraiser who has not been trained in energy valuation frequently records solar as a neutral feature because they have no method to support an adjustment. Whether the system is owned or leased changes the answer completely, and a leased system genuinely may contribute nothing. An owned system with documented production usually does.
What do you need to value energy improvements?
Whatever documents the system: the installation contract, the inverter or production data, the warranty, whether it is owned, financed, or leased, and any efficiency work with permits. Production history is the strongest evidence there is.
Is this a separate appraisal or part of one?
Part of one. Energy features are valued within the residential appraisal, reported on the Appraisal Institute's Residential Green and Energy Efficient Addendum so the contributory value is stated explicitly rather than buried in a lump-sum adjustment.
Does this apply outside Arizona?
Real estate appraisal is a state-licensed activity, so the residential work is Arizona only. Personal property and equipment — including energy equipment appraised as personal property rather than as part of real estate — are not state-licensed and are accepted nationwide.
Arizona for real estate, nationwide for equipment
Residential appraisal is state-licensed and performed in Arizona. Energy equipment valued as personal property is not state-licensed and is accepted nationwide and internationally.
Ready for a number you can defend?
Tell us what you have and what it's for. You get a fixed written quote — never an hourly meter, never a sales call.
What the work actually looks like
Real assignments, client details removed — what each engagement actually turned on, rather than how it felt.
A house, a workshop of machine tools, a forty-year firearms collection and a stake in the family company — four disciplines that three appraisers had only partly covered. One engagement, one effective date, one set of assumptions.
A donation the regulations would have aggregated past the appraisal threshold, which the donor had assessed item by item. One qualified appraisal covering the group, itemized, signed inside the window the regulations allow.
An opposing report whose number was not obviously wrong — which is what made it dangerous. It failed on its own certification, and was answered section by section with an independent valuation to the correct definition of value.