The calculator gives an indicative estimate: it helps you get oriented and prepare the conversation, it does not replace a site visit or a quote. Every parameter used is listed in the table below, with its source, date and status.
1. Your monthly usage
We use the first available figure, in this order:
- Your usage in kWh, if you enter it (it is on your bill). This is the most reliable figure.
- Your bill amount divided by an average price per kWh. If the bill is in US$, we convert it with an indicative exchange rate.
- Your appliances: a base usage by property type (lights, fans, internet, small appliances), plus a typical usage per air conditioner, fridge, pool pump, electric water heater or other heavy appliance, multiplied by 30.4 days.
2. What one kWp produces in Las Terrenas
A kWp (kilowatt peak) measures panel power; a kWh measures energy produced or used. The annual production of 1 kWp equals the specific yield of the area (before losses) multiplied by (1 − system losses).
3. The suggested package
- Hotel or very high usage: Business (on-site study).
- Goal "be as independent as possible": Villa Autonomy.
- Goal "ride out power cuts": Backup.
- Goal "lower the bill": Grid-tied, no battery if there are almost no outages, otherwise Hybrid Comfort.
4. The battery
- Backup and Hybrid: essential energy (base usage + fridges) over the outage duration, with a factor because usage is higher in the evening, divided by usable depth of discharge and efficiency; rounded up to the next battery module.
- Autonomy: one full day of usage (or more, depending on the parameter), with the same corrections.
- Grid-tied, no battery: no battery. For safety, panels shut down during an outage.
5. The panels
- Backup: enough to recharge the battery in one day.
- Hybrid, Grid, Business: a share of annual usage (the "targeted share" parameter) divided by the production of 1 kWp.
- Autonomy: annual usage plus a margin for less sunny months.
The result is rounded up to the next 0.5 kWp and capped by the roof area you enter.
6. Production, coverage and backup
Annual production = kWp × production of 1 kWp. Share covered = production ÷ annual usage (100% at most). For packages with a battery, we also estimate how many hours of essentials (lights, internet, fridge, fans) the battery covers.
7. Savings and payback
They are only shown when the kWh price is verified and dated and the suggested package price is validated and dated. Annual savings = the lower of production and usage × self-consumed share × kWh price. Payback = package price ÷ annual savings. We do not guarantee any savings, independence or yield: the quote, after the site visit, is the only reference.
What the calculator does not know
Shade from trees or buildings, the exact roof orientation, the condition of your electrical installation, when you use power, and how electricity prices will change. That is why the site visit is essential.