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Rough estimate in 1 minute

Which solar system fits your home

Answer a few short questions about your bill and when you use power, and see whether on-grid or hybrid fits, how many kW of panels, how big a battery, and which inverters we sell in that size.

  • No sign-up, nothing stored
  • Worked out on your device
  • Our team confirms after seeing your bill and site
Start

Estimate

Answer 5 questions

Questions marked * are needed; skip the others and we take them as "not sure".

  1. Electricity provider
    Where
    Supply phase

    Look at the meter: 2 wires in = 1-phase, 4 wires = 3-phase

  2. Monthly use

    From your bill; units (kWh) are more accurate than baht

    kWh
  3. When do you use most power
  4. Do you want backup power in a power cut
    Battery until when, evening use, EV (optional)
    Until when should the battery run the home

    With a TOU meter power is cheap after 22:00, so a battery for 17:00–22:00 is enough and smaller

    Do you charge an EV at home
    What runs 17:00–22:00

    Used for the battery size. Watts are on the label or in the manual, e.g. a 1,200 W air conditioner for 5 hours. Leave blank if unsure.

    Appliance 1
    W
    h

    About 0 units a day 17:00–22:00

  5. m

    The further, the more cable and installation cost. Leave blank if you don't know.

    Power cuts, voltage dips and roof (optional)
    How often is the power cut
    How long
    Usually when
    How often do lights dim or appliances reset
    What should keep running in a power cut
    m²

    Leave blank if you don't know

How it works

How the estimate works

  1. 1

    Units per month

    Baht are divided by an average price per unit; units from the bill are used as they are.

  2. 2

    Day and night

    Split by when you use most power. Panels only make power while the sun is up; night power comes from a battery or the grid.

  3. 3

    On-grid, hybrid or off-grid

    Lots of night use, wanting backup, power cuts every week, or a battery until the morning or 22:00: hybrid with a battery. No grid at all: off-grid. Otherwise on-grid.

  4. 4

    Battery and panel size

    The battery from what it hands out without sun (all night, or only 17:00–22:00 with a TOU meter), in whole batteries; panels enough for the daytime use and the battery's charge, in whole panels; the inverter a little smaller than the panels, as is usual.

  5. 5

    Models we sell

    Inverters from our Solis, Deye and Luxpower pages of the same type (on-grid, hybrid, off-grid) and phase, the smallest that is big enough, one per brand.

FAQ

Choosing a solar size

What size solar system do I need

It depends on how much power you use while the sun is up. Panels only work by day; much more than your daytime use flows to the grid or has to go into a battery. This page sizes from your monthly units and when you use them, rounded to whole panels.

On-grid or hybrid

On-grid has no battery: it uses solar by day to cut the bill and stops in a power cut. Hybrid has a battery for the night and backup in a power cut, and costs more.

Do I need a battery

Not every home. With mostly daytime use and few power cuts, on-grid is enough. With lots of night use, a wish for backup, or frequent cuts, a battery helps.

Is a TOU meter worth it with an EV

A TOU meter charges more Monday–Friday 09:00–22:00 and less 22:00–09:00 and all day at weekends and on public holidays. Charging the car after 22:00, with panels by day and a battery for 17:00–22:00, means almost no on-peak use, so TOU usually suits. With a lot of weekday on-peak use and no battery it may not. Whether it pays depends on your real bill; send it on LINE and our team will work it out.

How big a battery to run the air conditioner until 22:00

From the power used 17:00–22:00: a 1,200 W air conditioner for 5 hours = 1.2 kW × 5 = 6 units a day. Not all of a battery is usable, so it must be bigger than 6 kWh, and the panels must fill it every day. Choose "Until 22:00" and add your appliances in question 4: this page works out the number of batteries and panels and compares them with an all-night battery.

Can I have solar with no grid at all

Yes, an off-grid system: solar by day and the battery without sun, with no grid to fall back on, so the battery has to last the night plus days with little sun and the panels have to fill it. Choose "No grid power" in question 1 and list your appliances; this page works out the size.

How accurate is this

A first rough guide to the right size, not a quotation. The real size depends on several months of bills, the roof's direction and shade, and the supply. Our team confirms after seeing your bill and site.

Why no savings or payback figures

Those need your real tariff (TOU, Ft) and the real installed price. We'll show them once our engineer has checked the formulas; until then, send your bill on LINE and our team will work it out.

Is what I type stored

No. It's worked out in your browser and sent nowhere. To ask our team, copy the summary and paste it in LINE yourself.

Want a closer size

Send photos of your last 1–3 bills on LINE and the TAMNIYOM team will help with the size and models.

Send your bill on LINE
Send your bill on LINE