What the detached home gives you
No shared roof, no HOA approval on the structure itself in most cases, no landlord, and a service panel you are free to upgrade.
It also gives you the full range of options. Rooftop, ground mount or carport are all on the table, which is not true for a townhome or a condo.
The four variables that actually decide it
In rough order of how often they change the answer.
- Annual consumption. Twelve months of kilowatt-hours from your utility account. A system is sized against this and nothing else. Households of the same size differ by a factor of three.
- Usable roof plane. Not roof area. Unbroken, unshaded, sensibly oriented rectangles, after fire setbacks.
- Your retail rate. What you avoid paying is the value of every kilowatt-hour you use on site.
- Your export rate. What the utility pays for what you send back. This is set by your utility and tariff, not by your state, and two neighbours on different tariffs can get different answers.
Where the assumptions break
Three common ones, all of which make a proposal look better than reality.
A production estimate that ignores measured shade. A savings figure that assumes every exported kilowatt-hour is worth full retail when your tariff says otherwise. And an escalating utility-rate assumption chosen to make a twenty-year total look large.
Ask which rate escalation the proposal assumes, and what the savings look like at zero. If the project only works at 4% a year forever, it does not really work.
How long you are staying
Payback is measured in years, so a move inside that window changes the calculation and adds a transfer to handle.
An owned system generally transfers cleanly and evidence on home value is reasonably favourable. A leased system or a PPA is a different matter: the agreement has to be assumed by the buyer or settled at closing, and that is a live negotiation rather than a formality.
How the work runs
- Pull twelve months of usageFrom your utility account, in kilowatt-hours. Everything downstream depends on this.
- Identify your tariffFlat, tiered or time-of-use, and what it pays for exports.
- Assess the roofUsable planes, orientation, shade measured across the year, and remaining covering life.
- Decide the goalBill reduction, outage resilience, or both. They lead to different systems.
- Get comparable proposalsSame system size, same production basis, same escalation assumption.
- Verify the companyLicence, insurance and who is physically doing the work.
What moves the price
We do not publish a national average and present it as your price. These are the variables that separate two quotes for the same job — run your own numbers with the cost guides and calculators, and check what incentives you actually qualify for.
| Factor | Why it moves the number |
|---|---|
| System size | Set by your consumption and your usable roof, not by budget. |
| Roof complexity | Multiple planes, steep pitch or tile all add labour. |
| Electrical work | A service panel upgrade is common on older homes and is a real line item. |
| Equipment choice | Module-level electronics cost more and earn it back on shaded or complex roofs. |
| Financing structure | A dealer fee inside a financed price can be a large fraction of it. |
What to ask before you commit
Take this list to the conversation. A professional who answers these directly is telling you a lot; one who deflects is telling you more.
- What twelve months of my usage did you size this against?
- What rate escalation does the savings figure assume, and what does it look like at zero?
- How did you measure shade, and over what period?
- What does my tariff actually pay for exported electricity?
- Does my service panel need upgrading, and is that in this price?
Common questions
Is my house big enough for solar?
House size matters less than usable roof plane and your electricity consumption. A large complicated roof can fit fewer panels than a small plain one, and a modest house with high consumption may justify a larger system than a big house with low consumption.
How many panels does a typical home need?
It is set by your annual kilowatt-hours, your roof’s orientation and shade, and how much of your usage you want to offset. Two households of the same size can differ by a factor of three, which is why any figure quoted without seeing your usage is a guess.
Will solar increase my home value?
Evidence is generally favourable for owned systems. Leased systems and PPAs are more complicated, because the agreement has to be assumed by the buyer or settled at closing.
What if I move in five years?
An owned system usually transfers with the house. A loan with a UCC-1 filing, a lease or a PPA each need handling before closing, and that is a negotiation rather than a formality.