Should I enter kWh or dollars into Helio?
kWh when you have it — that’s usage. Dollars mix fees, riders, and sometimes demand or time-of-use. You can start with dollars; you’ll get a cleaner size range with actual kWh.
How to read your electric bill for solar
Your electric bill is the starting number for rooftop solar — not square footage, not a neighbor’s array, not a “typical home” chart. You need the kilowatt-hours you already buy, and enough of the charge structure to know whether dollars alone tell the story.
kWh vs dollars
Kilowatt-hours (kWh) are usage. That is how much electricity the house used in the billing period. For sizing an array, kWh is the useful number.
Dollars are what you paid. Dollars mix usage with fixed fees, taxes, riders, and sometimes demand or time-of-use charges. Two homes can pay similar dollars and use very different kWh — or the reverse — depending on the rate.
If the statement shows monthly kWh clearly, use that. If you only have the dollar total, you can still start an estimate, but you will get a cleaner size range when you can enter actual kWh. A year of bills beats one weird month.
What to enter in Helio
Paste or type what you can from a recent statement:
- Monthly kWh when it is on the bill (best)
- Or the dollar amount plus whatever the calculator asks about how you are charged
- Your address so utility territory and climate context can land correctly
- A few months if your usage swings hard season to season — summer AC or winter heat will not look like a mild shoulder month
You leave with a system size ballpark and cash / loan / lease shapes. That is homework, not a contract. For how size turns into cost ranges, see how much solar costs. Florida readers: Florida solar cost frames summer AC and utility mix after you know your kWh.
Demand charges and time-of-use (if they show up)
Not every residential bill has these. When they do, they change how you read the statement.
Demand is often a peak kilowatt (kW) for a short window — how hard you pulled power at once, not how many kWh you used all month. A big AC kick-on or EV charger can spike demand even if total kWh looks normal. Demand is not the same number as energy usage. Do not treat a demand line as monthly kWh.
Time-of-use (TOU) prices electricity differently by hour or season. Your total kWh still matters for sizing. The dollar line alone can mislead if most of your use sits in expensive hours. If the bill breaks out on-peak vs off-peak kWh, those splits are useful context for a later conversation with an installer — they are not a reason to invent a national rate on this page.
If your bill is a flat energy charge with a few fixed fees, ignore demand/TOU until something on the statement says otherwise.
Common gotchas
- One month is not a year. Vacation, a broken AC, a house that sat empty, or a heat wave can distort a single cycle. Prefer 12 months when you have them.
- Estimated reads. Some utilities estimate usage between meter reads. An estimated month is weaker input than an actual read.
- Budget / equal-pay plans. The amount you write the check for may be a smoothed payment, not that month’s true usage cost. Look for the actual kWh (and true charges) on the detail pages.
- Solar already on the roof. If you already have panels, the “grid” kWh and any export credit lines are a different story than a pre-solar bill. Size conversations change; tell the installer what is already installed.
- Master meters and HOAs. Condos and some communities do not give you a clean house-level kWh on a standard residential statement. The calculator still needs your usage; a building average is not a substitute.
- Fees that never go away. Customer charges and some riders stay even if your energy line drops. Solar offsets usage; it does not erase every line item.
What the bill does not decide
The bill sizes the conversation. The roof decides how much array fits — orientation, shade, pitch, stories, deck age. Electrical upgrades and permitting are local. Two quotes on the same house can differ because scope and equipment differ.
A Helio estimate is a ballpark from usage. An installer quote is the bid after a site survey. Short answers on cost, batteries, and installers live on the solar FAQ when you need a quick skim.
Quick answers about your bill and solar
Why isn’t one month enough?
Vacation, broken AC, empty house, or a heat wave can distort a single cycle. Prefer up to 12 months when you have them. Prefer actual meter reads over estimated ones.
What is a demand charge?
Often a peak kilowatt for a short window — how hard you pulled power at once, not monthly kWh. Don’t treat a demand line as energy usage for sizing.
What does the bill not decide?
Roof fit (orientation, shade, pitch, stories, deck age), electrical upgrades, and permitting. Helio is a ballpark from usage; the installer bid is after a site survey. Next: how much solar costs · free calculator · Florida solar cost · is solar worth it? · solar FAQ.
Next steps
- Size my system from my bill — free solar calculator
- How much does solar cost? — drivers, cash / loan / lease
- Is solar worth it? · Solar FAQ
Questions? Email the team at support@heliosolarcalculator.com