Opportunities › Solar potential estimation for residential properties › Proposed app
Sunsill
Check the sun and savings at your spot before you buy plug-in solar
- Score
- 50
- confidence 43
- Evidence
- 4
- items on the page
- Rivals
- 0
- named in sources
- First version
- 30 d
- estimate
- Type
- Mobile app
- PWA: installs on iPhone and Android
- Market since
- 2007
- Mature market · AI estimate
ScreensConcept
Mobile app: Homeowners visit their property to assess panel placement and need quick estimates outdoors before making a purchase decision. Sample screens on a phone, in the proposed brand. Their numbers are sample data.
Where will it go?
- PostcodeM14 5XX
- PlacementGarden wall
- FacingSouth-west
- Tilt60°
- Panel size800 W
About this appAI proposal
Sunsill estimates how much electricity a plug-in solar panel could make at your UK address, and what that is worth on your tariff. Enter a postcode, pick the wall, balcony, garden or roof where the panel would go, and get a yearly range in kWh and pounds.
Shading is the weak point of most estimates, so Sunsill shows it instead of hiding it. You see the obstructions it assumed and can mark a tree or new extension it missed. The result updates at once and shows a low, likely and high case.
It is for homeowners with outdoor space who want to know whether the payback makes sense before they spend. No site visit or sales call is needed for a first answer.
- Tagline
- Know what your spot is worth in sun.
- Voice
- PlainHonestPractical
- Why this name
- Sun plus windowsill: a small, homely place where a little panel might sit. Two plain syllables, easy to say. Trademark check still needed.
In the first version
Members say which features they would use. It tells PWAS what people want; it changes no score.
Address-level generation estimate
Yearly and monthly kWh for your spot, based on location, tilt, direction and nearby obstructions.
No member yet
Editable shading map
See assumed buildings and trees. Add or remove obstacles the data missed, like a new extension or a tall hedge.
No member yet
Low, likely and high range
Results come as a range, so you see how far shading and weather uncertainty could move your savings.
No member yet
Tariff-based savings
Enter your unit rate and daytime use. Sunsill values the power you use and flags what would go unused.
No member yet
Brand identityAI proposal
Check the name against trademark registers before using it.
Palette
#1F2A33Deep Slate · text#FBF6EAWarm Paper · surface#F2A516Sun Amber · primary#3E7D5AMoss · savings, positive#5C7C99Shade Blue · shading data#C2562FClay · warning
Typography
Aa
Sunsill
PricingAI proposal
The material gives no competitor prices. These tiers are a starting point to test; installer referral fees named in the opportunity could later fund a bigger free tier.
Free
Free
- One address
- Basic yearly estimate
- Payback with your tariff
Full report
$9 once
- Editable shading map
- Low, likely and high range
- Compare placements
- PDF and share link
Tracker
$3 a month
- Everything in Full report
- Log output and meter readings
- Actual vs estimate
Would you pay Tracker · $3 a month?
Your answer tells PWAS which prices people accept. It changes no score.
No answers yet.
What it could be worthEstimate
What a software business making this much sells for today, from real deals. Pick a monthly revenue.
If it makes
Worth about
$194,000
Sale range $132,000 to $263,000
$120,000 a year in revenue
From 87 software businesses listed and sold on Empire Flippers in the last year, revenue vetted by the broker: they sell for about 19× their monthly revenue, most between 13× and 26×.
Measured on profit, the middle deal is 32× monthly net profit: about 2.7 years of profit.
An estimate, not an offer or financial advice. A real price depends on profit, growth, churn, how much of the work is the owner's, and the buyer.
How it would growAI proposal
How the product would reach new customers through its own use, and how the first ones would be found. A plan to test, not a result.
- Built-in loop
- Shared outputs. Users share a report link or PDF with a partner, landlord or electrician. The report carries the Sunsill name and a link to run the same check on another address.
- Do they become customers?
- Recipients are often fellow householders or neighbours who could run their own estimate, but many will only view it. Test how many shared reports lead to a new address check.
- First customers
- UK homeowners with a south-facing garden, wall or balcony who are weighing a first plug-in solar panel and ask about payback in online forums.
- Where to reach them
- Hacker News and Reddit UK: Post the free estimator in UK solar, energy and money threads, and ask for feedback on shading accuracy.
- Energy-saving communities: Offer free estimates to local energy groups and money-saving forums, and answer shading questions in the open.
- Search content: Publish guides on plug-in solar payback by region that link to the estimator.
- First milestone
- 500 completed estimates and 25 paid full reports from UK homeowners within eight weeks of launch.
Why people already pay for this
- VerifiedHacker News post received 126 points and 44 comments
- Public claimPlug-in solar panels have just become legal in the UK and will go on sale soon, creating a new market for consumer assessment tools.
- Public claimThe product estimates both electricity generation and financial value, addressing a key decision point for potential buyers.
- Public claimAccuracy of shading models is a critical gap, as trees and recent building changes may not be reflected in available data.
Tech stack
Every proposal builds on the same PWA base, installable from the browser on any phone or computer. Dashed boxes are what this app adds.
- AppNext.js and TypeScript
- PWAManifest and service worker
- UITailwind CSS
- Data and authSupabase Postgres
- PaymentsStripe
- EmailResend
- HostingVercel
- This app · Solar yield dataOpen irradiance and weather datasetGives yearly sun for any UK location to compute generation.
- This app · Building and height dataUK building footprint and terrain dataNeeded to model nearby obstructions and shading from buildings.
RisksAI inference
- DataShading data may miss trees and recent building changes, as the evidence notes. Wrong estimates would erode trust, so user edits and ranges are central.
- CommercialUsers may take the free estimate and never pay. Willingness to pay for a report or tracker is untested.
- DataLicensing terms and cost of building and terrain data could limit coverage or squeeze margins.
- RegulatoryPlug-in rules and product availability in the UK may change, and savings figures could be seen as financial advice.
- CommercialInstallers or retailers may add their own free calculators once plug-in panels go on sale.
Everything marked AI proposal or AI inference was written by a model from the evidence on the opportunity page. The proposed name must be checked against trademark registers before it is used.