The assessment that does not rise
Under Section 39-3-102 C.R.S., independently owned residential solar electric generation facilities are exempt from Colorado property taxation. Three conditions apply: the facility is on residential real property, it produces electricity from solar energy primarily for residential use, and it has a production capacity of no more than 100 kW of AC electricity.
A residential rooftop array clears the 100 kW threshold by a wide margin, so for practical purposes an ordinary Westminster home installing solar is inside the exemption rather than near its edge.
The reason this gets omitted from homeowner arithmetic is structural. Adding value to a home normally raises the assessment, and the exemption is the absence of that increase. Nothing is deposited, nothing is refunded, and no document arrives to remind you it happened.
It is still real money every year for the life of the system. Ask your installer whether their savings model accounts for it, and if the model shows an assessment increase for the array, that is a modelling error rather than a conservative assumption.
The tax you are not charged
Sales of qualifying energy sources for residential use are exempt from Colorado state sales tax, and the storage, use or consumption of qualifying energy sources sold for residential use is generally exempt from use tax.
On a system costing tens of thousands of dollars, a sales tax line is not a rounding error. The exemption is worth confirming rather than assuming, because the way it surfaces is in what a quote does not contain.
Ask directly whether the quoted price includes any state sales tax, and if it does, ask why. Local taxes can be levied separately from the state exemption, so the answer may be legitimate, but it should be an explanation rather than a shrug.
Compare quotes on this basis too. Two prices that look close can differ once you establish whether both treated the exemption the same way, which is the sort of discrepancy that only shows up if you ask.
What your association can and cannot do
Colorado Revised Statutes Section 38-30-168 prohibits homeowners associations from banning solar installations. An association cannot simply refuse to allow a functional solar system on the basis that it does not want one.
What an association may do is impose reasonable aesthetic guidelines. In practice that is where the disagreements happen, because a guideline about visibility from the street can push an array to a roof plane that receives materially less sun.
The distinction that matters is between an aesthetic requirement you can live with and a relocation that quietly costs you production for twenty-five years. Those two look identical on an approval form and are not remotely the same thing.
So if a relocation is requested, ask your installer to model both placements and put the annual production difference in writing before you agree. A specific number changes the conversation with an association in a way that a general objection does not.
The parts that survive without qualification
The 30 percent federal Residential Clean Energy Credit under Section 25D expired for property placed in service after December 31, 2025, so a cash or loan purchase in Westminster receives no federal tax credit. A quote that still applies one is overstating your return by roughly a third.
Section 48E, the commercial credit, survives at 30 percent and can be claimed by a third-party owner under a lease or power purchase agreement. Ask what the provider claims and what portion reaches you in the rate offered, and confirm the treatment with a tax advisor.
What remains is full retail net metering with the Solar Bank election, Solar*Rewards for Xcel customers in exchange for your Renewable Energy Credits, the property tax exemption under Section 39-3-102 C.R.S., and the residential energy sales and use tax exemption.
Ask any installer to rebuild the projection from those alone, and to state explicitly how the two exemptions were treated. The exemptions are the easiest items to leave out precisely because nobody sends you anything when they apply.